MXPA99007327A - Process for the preparation of substituted piperidine-epoxides - Google Patents

Abstract

The present invention concerns a process for the preparation of a compound of formula 1 or a salt thereof characterised in that the process comprises a) epoxidation of a compound of formula 2 or a salt thereof in which formulae A is arylene;R1 is -C*R3R4R5;R2 is -O-alkyl, -O-cycloalkyl, -O-alkenyl, -O-aryl, -O-aralkyl, -O-aralkoxyalkyl, -O-alkylsulfonyl, -O-arylsulfonyl, chlorine, bromine or iodine;R3 is hydrogen;R4 is aryl;R5 is alkyl, cycloalkyl, aryl, alkoxyalkyl or hydroxyalkyl;and, wherein C* is an asymmetric carbon atom;b) optionally followed by isolation of the desired stereoisomer.

Description

PROCESS FOR THE PREPARATION OF PIPERIDINE-SUBSTITUTE EPOXIDES The invention describes a novel process for the preparation of substituted epoxide piperidines. More particularly, the invention describes the preparation of compounds of formula 1 R1 1 10 And you come out of the same, where A is arylene; RJ is -C * R3R4R5; fifteen REF .: 30805 _i_l_W_l_ÉH_ÉIÉ _? _ Iai_M_ > *_"_4_.

R2 is -O-alkyl, -O-cycloalkyl; -O-alkenyl, -O-aryl, -O-aralkyl, -O-aralkoxyalkyl, -O-alkylsulfonyl, -O-arylsulfonyl, chlorine, bromine or iodine. R ~ hydrogen; R4 is aryl; R5 is an alkyl, cycloalkyl, aryl, alkoxyalkyl or hydroxyalkyl; and C * is an asymmetric carbon atom.

The compounds of formula 1 are novel and can be used as chiral component blocks in the preparation of renin inhibitors, especially trisubstituted renin inhibitors as described in WO 97/09311 for example (3R, 4S, 5S) 4- [4 (3 -benzyloxy-propoxy) -phenyl] -5-ethoxy-3- (naphthalene-2-ylmethoxy) -piperidine. The synthesis of optically active renin inhibitors via conventional resolution of racemates is described in WO 97/09311 resulting in a considerable loss of product. The present invention provides a process that avoids the disadvantages of the previous process.

According to the present invention, the above compounds of formula 1 or salts thereof can be prepared by a process characterized in that it comprises: a) the epoxidation of a compound of formula 2 or a salt of the same in whose formula R1, R2 and A are as defined above; and b) optionally followed by isolation of the desired stereoisomer.

The term "alkyl" means alone or in combination with a branched or unbranched alkyl group containing from 1 to 8 carbon atoms, preferably from 1 to 6 carbon atoms. Examples of branched or unbranched C_-C8 alkyl groups are methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, isomeric pentyls, isomeric hexyl, isomeric heptyls, isomeric octyls and ethyl is preferred, n-propyl, and isopropyl and particularly preferred methyl.

The term "cycloalkyl" means alone or in combination with a cycloalkyl ring containing from 3 to 8 carbon atoms and preferably a cycloalkyl ring containing from 3 to 6 carbon atoms. Some examples of C3-Cs cycloalkyl are cyclopropyl, methyl-cyclopropyl, dimethyl-cyclopropyl, cyclobutyl, methyl-cyclobutyl, cyclopentyl, methyl-cyclopentyl, cyclohexyl, methyl-cyclohexyl, dimethyl-cyclohexyl and cycloheptyl.

The term "alkenyl" means alkenyl groups containing from 2 to 8 carbon atoms. Examples of alkenyl groups include vinyl, allyl, isopropenyl, pentenyl, hexenyl, heptenyl, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, 1-propenyl, 2-butenyl, 2-ethyl-2-butenyl, and the like, preferably an allyl.

The term "aryl" means alone or in combination with a phenyl or naphthyl group which can be substituted by one or more substituents selected from alkyl, cycloalkyl, alkoxy, halogen, carboxy, alkoxycarbonyl, hydroxy, amino, nitro, trifluoromethyl, and the similar ones. Examples of aryl are phenyl, tolyl, methoxyphenyl, fluorophenyl, chlorophenyl, hydroxyphenyl, trifluoromethylphenyl, 1-naphthyl, and 2-naphthyl.

The term "arylene" means alone or in combination with a phenylene or naphthylene group which may be further substituted by one or more substituents selected from alkyl, cycloalkyl, halogen, nitro, alkoxy, hydroxy, amino, preferably halogen alkyl and nitro. Examples of arylene are ortho-phenylene, meta-phenylene, para-phenylene, toluenes, methoxyphenylenes, fluorophenylenes, chlorophenylenes, and naphthylenes. Phenylenes are preferred, wherein the phenylene substituents which are defined by formula 1 are placed in the ortho, meta, or preferential position for each other and wherein one or more additional substituents selected from alkyl, halogen, and Nitro can occur in the arylene cycle. Especially the preferred substituents are methyl, chlorine, and nitro. Particularly preferred is unsubstituted phenylene and especially unsubstituted para-phenylene.

The term "alkoxy" means alone or in combination with the -O-alkyl group, wherein the alkyl is as defined above. Examples are ethoxy, n-propyloxy, and iso-propyloxy. Preferred is methoxy.

The term "alkoxyalkyl" means alone or in combination with an alkyl group, wherein a hydrogen is substituted by an alkoxy group. Some examples are methoxymethyl, ethoxymethyl and 2-methoxyethyl. Particularly preferred is methoxymethyl.

The term "hydroxyalkyl" means alone or in combination with an alkyl group, wherein a hydrogen is substituted by a hydroxy group. Some examples are hydroxymethyl, 1-hydroxyethyl and 2-hydroxyethyl.

Preferred is hydroxymethyl.

The term "aralkyl" means alone or in combination with an alkyl group wherein a hydrogen is substituted by an aryl group. A preferred example is benzyl.

The term "aralkoxyalkyl" means only or in combination with an alkyl group, wherein a hydrogen is substituted by an alkoxy group in which a hydrogen is substituted by an aryl group. A preferred example for aralkoxyalkyl is 3- (2-methoxy-benzyloxy) -propyl.

The term "alkylsulfonyl" means alone or in combination with a sulfonyl group which is substituted by an alkyl group. The alkyl group can be replaced by a halogen. Preferred examples are methylsulfonyl and trifluoromethylsulfonyl. The term "arylsulfonyl" means alone or in combination with a sulfonyl group which is substituted by an aryl group. Preferred is the tosyl group. The term "salts" means compounds which are formed by the reaction of compounds of formula 1 with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, acid "" - '"• - * -» - * - nitric, phosphoric acid, and the like, and organic acids such as acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, malic acid, malonic acid succinic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, and the like The term salts includes solvates and particularly hydrates 10 such salts.

The term "halogen" means fluoro, chloro, bromo, iodo, and preferably chloro and bromo. More preferably it is chlorine. 15 The term "anion" means an atom, a group of atoms or a molecule with a negative charge. This load can be a multiple or individual load. Examples of anions are halogen anions, SO? 2 ~, P043 ~.

Particularly preferred is the C1- anion.

The term "asymmetric carbon atom (C *)" means a carbon atom with four different substituents. According to the Cahn-Ingold Convention ^ ___________________________? _.

Prelog, the asymmetric carbon atom can be of the "R" or "S" configuration. A preferred example of an asymmetric carbon atom C * is shown in the following formula Wherein the asymmetric carbon atom C * is of the R configuration The term "-0-" in groups such as -O-alkyl, -O-cycloalkyl, -O-alkenyl, -O-aryl, -O-benzyl, -O-aralkoxyalkyl, -O-alkylsulfonyl, -O- arylsulfonyl, they mean an oxygen with a free valence. For example -O-alkyl means an alkoxy and -O-cycloalkyl means a cycloalkoxy.

In a preferred aspect, the above invention relates to the preparation of compounds of formula 1, wherein R5 is an alkyl or cycloalkyl and R1, R2 and A are as defined above.

The above process is also preferred, wherein R 4 is an unsubstituted phenyl or substituted phenyl, and wherein the substituents of the phenyl are one or more selected from the alkyl, halogen or nitro, preferably the methyl or chlorine. In a particularly preferred aspect of the above process R "" is an unsubstituted phenyl and R1, R2 and A are as defined above.

Particularly preferred is the above process, wherein R 4 is a phenyl, particularly preferred is unsubstituted phenyl and R 5 is a methyl and R 1, R 2 and A are as defined above.

Also preferred is the above process, wherein A is a substituted or unsubstituted phenylene ortho, meta, or para wherein the phenylene substituents which are defined by formula 1 are placed in the ortho, meta or for each other position . The position for is the preferred one. The substituted phenylene has one to four additional substituents selected from alkyl, halogen and nitro. Particularly preferred is the above process, wherein A is an unsubstituted phenylene and especially unsubstituted para-phenylene.

Also preferred is the process of the present invention wherein R is -O-alkyl, -O-cycloalkyl, -O-aryl, or -O-aralkyl, preferably -O-benzyl and -O-methyl. Particularly preferred is -O-benzyl.

In a preferred aspect of the present invention a compound of formula 2 is reacted with a halogen or a halogen releasing agent such as the N-bromo compounds. Preferred examples are bromine, N-bromosuccinimide, dibromoisocyanurate and 1, 3-dibromo-5,5-dimethylhydantoin. Particularly preferred is bromine.

The preparation of compounds of formula 2 by means of a process comprises the reaction of compounds of formula 3 or. _. , _ .* _ 4. . »-. » . . -..._?_...- -,"_,_ Y "_. . .

- - TO OH A l2 R2 4 With the compounds of the formula RX-NH2 or a salt thereof, preferably in the presence of formaldehyde or a chemical equivalent thereof, wherein R1, R2 and A are as described above.

Another preferred aspect of the present invention is the isolation of the desired stereoisomer of a compound of formula 1 or a salt thereof, preferably by crystallization. Particularly preferred is the crystallization of the free compound of the formula 1 and preferably in the presence of ethyl acetate.

Also preferred is the above process followed by a reaction with a metal alcoholate such as potassium t-butoxide, aluminum isopropoxide, titanium (IV) t-butoxide, with a lithium amide such as lithium diisopropylamide or with a organolithium compound such as phenyl lithium, sec-butyl lithium or methyl lithium to form a compound of the general formula i you or a salt of the same. In addition, a preferred aspect of the above process is the reaction of a compound of formula 1 or a salt thereof with phenylthio. Particularly preferred is the above process, wherein the desired stereoisomer of a compound of formula 1 reacts with phenylthio.

Another preferred aspect of the present invention is the transformation of the compound of formula 1 to renin inhibitors, especially trisubstituted renin inhibitors and particularly preferred to (3R, S, 5S) -4- [- (4- (3-benzyloxy) propoxy) -phenyl] -5-ethoxy-3- (naphthalen-2-ylmethoxy) -piperidine, wherein this transformation is effected by reaction with phenylthio, the alkylation of the 3-hydroxy function, the hydroboration of the ether compound formed and subsequently the basic oxidative treatment, for the transformation of the intermediate carboboranes into the secondary alcohols, the reorganization of protective groups, the separation of the N-phenylethyl and the O-benzyl function and the reintroduction of a N-Boc protective group, the functionality selective of the phenolic function, the alkylation of the secondary hydroxy function of the piperidine ring and the separation of the Boc-protective group. The above process is particularly preferred, wherein a post of formula 1 or a salt of the same is converted to (3R, 4S, 5S) -4- (4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3- (naphthalene-2-ylmethoxy) -piperidine characterized in that a) the (IR, 6R) -6- (4-benzyloxy-phenyl) -3- [(R) -1-phenylethyl] -7-oxa-3-aza-bicyclo [.1.0] heptane is transformed into (3S ) -4- (4-benzyloxy-phenyl) -l- [(IR) -phenyl-ethyl] -1,2,3,6-tetrahydro-pyridin-3-ol by means of the reaction with phenylthio; b) the rean with sodium hydride and ethyl iodide yields (3S) -4- (4-benzyloxy-phenyl) -3-ethoxy-1 - [(IR) -phenyl-ethyl] -1, 2, 3, 6 -R) -tetraropyridine; c) the hydroboration with sodium borohydride and boron trifluoride etherate followed by the rean with potassium hydroxide and hydrogen peroxide produces (3R, 4R, 5S) - (4-benzyloxy-phenyl) -5-ethoxy-1 - [( IR) -phenyl-ethyl] -piperidin-3-ol); d) hydrogenolysis yields (3R, 4R, 5S) -5-ethoxy-4- (4-hydroxy-phenyl) -piperidin-3-ol; e) the rean with di-tert-butyldicarbonate and sodium hydrogen carbonate followed by the addition of NaOH produces (3R, 4R, 5S) -5-ethoxy-3-hydroxy-4- (4-hydroxy) tert-butyl ester phenyl) -piperidine-1-carboxylic acid; f) treatment with 3-bromo-propoxymethyl-benzene and potassium carbonate produces tert-butyl acid ester (3R, 4R, 5S) -4- [4- [3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3-hydroxy-piperidine-1-carboxylic acid; g) a rean with 2-bromomethyl-naphthalene and sodium hydride produces (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3-tert-butyl ester - (neftalen-2-ylmethoxy) -piperidine-1-carboxylic acid; 5 h) the rean with hydrochloric acid yields (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3- (naphthalen-2-ylmethoxy) -piperidine.

The compounds of formula 1 and their salts are new and also form part of the present invention, wherein R1, R2 and A are as defined above. A preferred compound is (IR, 6R) -6- (4-benzyloxy-phenyl) -3- [(R) -1-phenyl-ethyl) -7-oxa-3-aza-bicyclo [4.1.0] heptane . The compounds of formula 2 and their salts are new and also form part of the present invention wherein R 1, R "and A are as defined above Particularly preferred is (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-20 ethyl) -1, 2, 3, 6-tetrahydro-pyridine and salts thereof.

In addition, the compounds of formula 6 and their salts are new and also a part of the present invention: i ??? i tul i u nü miin-ii n -? i r m - - "- -" "" - "- ..- _ -. _-. __ .., -, -.. _, __- i. wherein R1 and A are as defined above and R6 is alkyl, cycloalkyl, alkenyl, aryl, aralkyl, aralkoxyalkyl, alkylsulfonyl or arylsulfonyl. Particularly preferred is (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -piperidin-4-ol and salts thereof.

In addition, the compounds of formula 5 and their salts are novel and form part of the present invention, preferably (3S) -4- (4-benzyloxy-phenyl) -1- [(IR) -pheny1-ethyl] -1 2,3,6-tetrahydro-pyridin-3-ol.

The invention also discloses the use of a compound of formula 1 in the preparation of renin inhibitors, preferably (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3 - (naphthalene-2-ylmethoxy) -piperidine, wherein R1, R2 and A are as defined and described above. The transformation of -? - ai-b - ^ - to compounds of formula 1 in renin inhibitors, especially at (3R, 4S, 5S) -4- [4 (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3 - (naphthalen-2-ylmethoxy) -piperidine, can be carried out as described above.

In addition, the invention also describes compounds obtained by the above process.

In more detail, the process of the invention can be described as follows: The epoxidation of a compound of formula 2 or a salt thereof and optionally the isolation of the desired stereoisomer: R1 wherein R1, R2 and A are as defined above.

A compound of formula 2 can react with compounds which are known to be used in epoxidation reans. Examples for such reagents are halogens and organic bromine compounds such as N-bromosuccinimide, dibromoisocyanurate and 1,3-dibromo-5,5-dimethylhydantoin a. "Bromine is preferred, especially in the presence of an acid. , Preferably HBr and chemical equivalents thereof.

Inert solvents can be used alone or in combination, particularly, solvents known for their use in epoxidation reactions. Examples of such solvents cyclic ethers or branched dimethyl ether, diethyl ether, tetrahydrofuran and monoglyme or diglyme alone or in a combination such as having sufficient miscibility with water are produced. A preferred solvent is dioxane. The above reaction is preferred to be carried out in the presence of an acid. Examples of such acids are optically active or inactive acids such as - .. ~ .- »'^ hydrohalic acids, sulphonic acids and H2S04. Particularly preferred is HBr.

In general, the above reaction can be carried out over a wide range of pH. A preferred pH is in the range of about 1 to 4 and particularly preferred is a pH in the range of about 1.5 to 3.

A temperature range of about -20 ° C at The boiling point of the solvent is suitable for the reaction of the present invention. The preferred temperature range is between about -20 ° C to about 20 ° C, preferably about 0 ° C to about 5 ° C.

In a preferred aspect, the above reaction is followed by the addition of a base such as NaOH, KOH, or a nitrogen base such as triethylamine. Preferred is the use of NaOH or KOH. The temperature range of the addition of the base in between -20 ° C and the point of boiling of the solvent. The preferred temperature range is between -20 ° C and 20 ° C. Particularly preferred is the addition of the base between 0 ° C and 5 ° C. In the event that the epoxidation agent reacts with a - »- •" - "* - * - compound of formula 2 without the addition of an acid, the epoxide can be obtained without the use of a base.

In accordance with the above process the compounds of formula 1 are formed as a mixture of stereoisomers and particularly as a mixture of diastereomers, or only one of the diastereomers is formed. In a preferred aspect one of the diastereomers is preferably formed. In a preferred aspect of the invention (R) -4- (4-benzyloxy-phenyl) -1- (1-pheny1-ethyl) -1,2,3,6-tetrahydropyridine produces a mixture of (IR) , 6R) -6- (4-benzyloxy-phenyl) -3- [(R) -1-phenyl-ethyl] -7-oxa-3-aza-15-bicyclo [.1.0] heptane and de (IS, 6S) -6- (4-benzyloxy-phenyl) -3- [(R) -1-phenyl-ethyl] -7-oxa-3-aza-bicyclo [4.1.0} heptane by means of an epoxidation reaction.

Optionally the desired stereoisomer especially the diastereomer can be isolated by methods known in the art such as crystallization, chromatography or distillation, preferably crystallization or chromatography. These methods further include the formation of salts or derivatives of compounds of formula 1 and in a ??????????????? V-next step the separation of these salts or derivatives by the previous methods. These methods, especially methods for the separation of diastereoisomers are well known in the art and are for example described in the Houben-Weyl document, Methods of Organic Chemistry (pp. Vol. E21, p.81.91).

Preferred solvents taken alone or in combination which can be used for the crystallization of compounds of formula 1 are protic or aprotic solvents which do not react with the compounds of formula 1. Examples of such solvents are alcohols such as ethanol, isopropanol or methanol, esters such as ethyl acetate, ethers such as diethyl ether or diisopropyl ether, alone or in an appropriate combination as well as in a combination with an appropriate amount of hydrocarbon such as pentane or Hexane Particularly preferred is ethyl acetate and especially, where diethyl ether is added.

A preferred method of isolating a diastereomer as above is the crystallization of a free compound of formula 1. Particularly the crystallization of a free compound of formula 1 in ethyl acetate, by means of the addition of diethyl ether.

After the formation of the compounds of formula 1 the epoxide is opened by the reaction of a metal alcoholate such as potassium t-butoxide, aluminum isopropoxide, titanium (IV) t-butoxide, with a lithium amide such such as lithium diisopropylamide or with an organolithium compound such as phenyl lithium, sec-butylithium or methyl lithium to give a compound of the general formula 5.

In addition, a preferred aspect of the above process is the reaction of a compound of formula 1 or a salt thereof, with phenyl lithium. Particularly preferred is the above process, wherein the desired stereoisomer of a compound of formula 1 reacts with phenylthio. The solvents for this reaction are taken alone or in combination are for example ethers such as tetrahydrofuran, diethyl ether, or methyl tert-butyl ether, aromatic hydrocarbons such as toluene or chlorobenzene or pyridine. The solvent, which is preferred, depends on the reagent. In the case of phenyl lithium as the reactant, methyl tert-butyl ether is a particularly preferred solvent.

The epoxide opening can be carried out in a temperature range from about -40 ° C above the boiling point of the solvent. The preferred temperature is from about -25 ° C to over 0 ° C. Particularly preferred is a temperature of about -15 ° C.

The obtained compounds can be used for the preparation of renin inhibitors as described in WO 97/09311. In general, this preparation can be carried out as follows: The alkylation of the 3-hydroxy function of for example (3S) -4- (4-benzyloxy-phenyl) -1- [(IR) -phenyl-ethyl] -1, 2, 3, 6-tetrahydro-pyridin-3-ol can be carried out in solvents such as ethers similar to tetrahydrofuran and 1,2-dimethoxyethane, dimethylformamide or dimethyl sulfoxide with aliphatic chlorides, bromides, iodides, tosylates or mesylates in the presence of a base such as sodium hydride or potassium tert-butoxide. The alkylating agents can be used either containing the desired complete substituents or optionally appropriate protected functional groups which allows for additional structural modifications in a last phase of the synthesis. This substituent is represented by means of R 'in formulas 7 and 8.

The hydroboration of the ether compounds followed by a subsequent basic oxidative treatment produces compounds of the general formula 7 with a high diastereoselectivity. The hydroboration can be carried out according to the methods known per se, for example in a solvent which is inert under the reaction conditions, such as an ether, for example, 1,2-dimethoxyethane, at a temperature between about 0 ° C and 70 ° C, and with a release reagent of diborane or containing diborane such as for example borane in tetrahydrofuran or a mixture of sodium borohydride and diethyl ether boron trifluoride. The carboboranes which are formed as intermediates can be converted, for example, to secondary alcohols of the general formula 7 by means of the reaction with bases, for example, potassium hydroxide, and an oxidizing agent, for example, hydrogen peroxide, at a temperature between about room temperature and 120 ° C. The reorganization of the protective groups, the elimination of the R1 and R2 functions and the re-introduction • - *** - "'- * • of an N-protected group by means of well-established procedures such as: Hydrogenolysis with hydrogen in the presence of a palladium catalyst followed by the introduction of the Boc group with di- tert-butyldicarbonate in dioxane / water converts the compounds of the general formula 7 into compounds of the following formula 8 which carry a phenolic and an aliphatic OH function which can be selectively activated.

R) OC The selective functionalization of the phenolic function in compounds of the general formula 8 can be carried out with alkylation reactions using benzylic or aliphatic chlorides, bromides, iodides, tosylates or mesylates in the presence of a base similar to potassium carbonate in solvents such as a ether similar to tetrahydrofuran, or a dimethylformamide, dimethylsulfoxide, acetone, methyl ethyl ketone or pyridine at temperatures between 0 ° C and 140 ° C. The alkylating agents used may either contain the desired complete chain or optionally protected functional groups optionally which allow additional modifications to the structure in a last phase of the synthesis. The functionalization of the secondary hydroxy function of the piperidine ring can then be carried out in solvents such as ethers similar to tetrahydrofuran or 1,2-dimethoxyethane, or in dimethylformamide or dimethylsulfoxide in the presence of a base similar to sodium hydride or to potassium tert-butoxide and an appropriate alkylating agent, preferably a methyl aryl chloride, bromide, mesylate or tosylate at temperatures between 0 ° C and 40 ° C. The alkylating agents used may contain either the entire desired substituent or optionally appropriately protected functional groups which allow for additional structural modifications in a last phase of the synthesis. Additional structural variations may include the elimination of protective functions followed by functionalizations of the released functional groups, for example, etherification of a phenolic radical. The final removal of the protective Boc group can be carried out in the presence of acids such as hydrochloric, hydrobromic, sulfuric, phosphoric, trifluoroacetic acid in a variety of solvents such as alcohols and alcohol / water mixtures, ethers and chlorinated hydrocarbons. The protective Boc group can also be substituted with anhydrous zinc bromide in inert solvents such as dichloromethane.

The preparation of the starting compounds of formula 2 can be represented by means of the following scheme: Hal Hal R-Hal I A A I I or OH R I.6 10 R1 In detail, a compound of formula 2 can be obtained by means of the reaction of compound 6 with an acid, for example, oxalic acid dihydrate in an inert solvent, wherein compounds 6 are formed by means of the reaction of a compound of formula 10 in _____ * ______ * _____! _________. an inert solvent with n-butyllithium or a Gringnard reagent to form an organometallic intermediate which is reacted with a compound of the formula 11. The preparation of the compound 10 can be carried out by the reaction of a compound of the formula 9 with a compound of the formula RD-Hal in the presence of a base and preferably a catalyst such as Nal in an inert solvent. R6 is alkyl, cycloalkyl, alkenyl, aryl, aralkyl, aralkoxyalkyl, alkylsulfonyl, or arylsulfonyl. Compound 11 can be obtained by means of the reaction of R1-NH2 with l-ethyl-l-methyl-4-oxo-piperidinium iodide in the presence of a base. The compound l-ethyl-l-methyl-4-oxo-piperidinium iodide is obtained by the reaction of l-ethyl-4-piperidone with methyl iodide in an inert solvent.

OR Alternatively, a compound of the formula 2 can be obtained by means of the reaction of an ammonium salt R1-NH3 + X "with formaldehyde and the compound 3 which can be obtained by means of the reaction of methyltriphenylphosphonium bromide, tert- potassium butoxide and compound 12 in an inert solvent. 12 Alternatively, a compound 2 can be prepared by the reaction of an ammonium salt of formula R1-NH3 + X- with formaldehyde and with a compound of formula 4. Compound 4 is formed by the reaction of an organometallic compound containing an methyl group bound to the metal as in methylmagnesium bromide or methylithium with compound 9, while compound 4, wherein R2 means chlorine, bromine or iodine can be prepared via oxidation of a halochrome (for example described in US 3954876 or in DE 2302751). or 13 14 Alternatively, the compounds of formula 2 can be obtained by the reaction of a salt of formula R1-NH3X with formaldehyde and the one compound 4. Preferably, R1-NH3X is generated in the reaction mixture of a compound R1-NH2 using the appropriate amount of a suitable HX acid. In addition, compound 4 can be obtained by means of the reaction of compound 14 with a suitable organometallic compound. In addition, compound 14 is formed by the reaction of compound 13 with R6-X in the presence of a base and an inert solvent. R5 is as defined above.

In addition, a compound of formula 1, wherein R ~ means chlorine, bromine or iodine is converted to the corresponding allyl alcohol of formula 5 by the use of a reagent such as aluminum isopropoxide. In addition, the substituted halogen can be replaced by, for example, a substituted oxygen, a substituted carbon or a substituted nitrogen through the use of an appropriate oxidant, by the use of catalyzed cross-coupling or Heck reaction conditions of a transition or through the use of for example amination conditions with the catalysis of a transition metal (SL Buchwald et al., J. Org. Chem. 1997, 62, 1568) respectively.

The following preparations and examples illustrate the preferred embodiments of the present invention but do not attempt to limit the scope of the invention.

EXAMPLES Example 1 (Preparation of the product) a) Preparation of (IR, 6R) -6- (4-benzyloxy-phenyl) -3- [(R) -1-phenyl-ethyl] -7-oxa-3-aza-bicyclo [4.1.0] heptane At room temperature 44.3 g of (R) -4- (4-benzyloxy-phenyl) -l- (1-phenyl-ethyl) -1,3,3,6-tetrahydropyridine (120 mmol) are suspended in 440 mL of dioxane. Under stirring 40.4 g of 48% aqueous hydrobromic acid (240 mmol) are added at 15-20 ° C for 5 minutes, followed by 24 ml of water. At the same temperature, the pH of the mixture is adjusted to pH 2 using 65 ml of 2 N NaOH. The slightly cloudy solution is cooled to 2-3 ° C, and 21.2 g of bromine (133 mmol) are continuously added over 1.5. hours from a syringe pump via a Teflon cannula. After addition of the bromine, stirring at 2-3 ° C is continued for another 1.5 hours. At this point, all the starting materials have reacted. At 0 ° C, 160 ml of 4N NaOH (640 mmol) are added for more than 30 minutes and stirring is continued. After 2 hours the intermediate has reacted completely with the final product. The reaction mixture is extracted using a mixture of 500 ml of ethyl acetate and 200 ml of 20% sodium chloride aq. The aqueous phase is separated and extracted with a 300 ml portion of ethyl acetate. The organic phases are washed with 300 ml of 20% aq sodium chloride, combined, dried (MgSO) and evaporated under reduced pressure to give 51.3 g of crude product as a brown oil.The crude product is taken up in 50 ml of acetate After the solution, the crystals begin to separate, 50 ml of diethyl ether are added and the suspension is cooled to 0 ° C. A second portion of 25 ml of diethyl ether is added and the suspension is stirred by another At 0 ° C the crystals are collected in a filter funnel and washed with a portion of cold diethyl ether.The product is then dried for 2 hours at 26 mbar / 45 ° C. 23.5 are obtained - ^ - ^ a - * g of (IR, 6R) -6- (4-benzyloxy-phenyl) -3- [(R) -1-phenyl-ethyl] -7-oxa-3-aza-bicyclo [ 4.1.0] heptane.

Example 2 (Preparation of the starting material) a) Preparation of 4-benzyloxybromobenzene. 200 g (1.16 mol) of 4-bromophenol are dissolved in 2.1 L of acetone under an argon atmosphere. Then 320 g (2.31 mol) of K2C03 and 3.465 g (23.1 mmol) of Nal are added. The mixture is stirred at room temperature and 292.7 g (2.31 mol) of benzyl chloride are added for 1 hour. The mixture is then boiled for 48 hours. The acetone (ca 500 ml) is partially removed in the rotary evaporator. 1.2 L of Na2C03 at 10% aq are added to the residue. After extraction with ethyl acetate (lxl L + 2x500 mL) the organic phase is washed with 1 L of a mildly saturated NaCl solution. After drying over Na 2 SO 4 and concentration, the main part of the benzyl chloride is removed. 400 mL of pentane are added to the residue. Crystallization begins during stirring at 0 ° C. The crystals are separated and washed with 2x150 mL of pentane and dried for 2 hours at 15 mbar (40 ° C bath temperature) and 2 hours under a high vacuum at room temperature. 230 g (75%) of 4-benzyloxybromobenzene are obtained. b) Preparation of l-ethyl-l-methyl-4-oxo-piperidinium iodide.

To a solution of 93 g (730 mmol) of l-ethyl-4-piperidone (Aldrich 27950-1) in 730 mL of acetone 124 g (876 mmol) methyl iodide (Acros 12237) are added over 30 minutes. The temperature is maintained at 25-30 ° C. The product begins to precipitate after the addition of 1/5 of methyl iodide. The mixture is stirred for 5 hours at 22 ° C and 30 minutes at 0 ° C. The cold suspension is filtered and the product is washed with acetone. 188 g (95%) of l-ethyl-l-methyl-4-oxo-piperidinium iodide are obtained. c) Preparation of (R) -1- (1-phenyl-ethyl) -piperidin-4-one, a) Under an argon atmosphere, 84.6 g (698 mmol) of (R) - (+) - 1-phenylethylamine (Merck No. 807031) and 1.4 L of ethanol are mixed. A solution of 203 g (1.47 mol) of K2C03 in water is added. The mixture is heated to 80 ° C and under stirring and a solution of 188 g (698 mmol) of l-ethyl-1-methyl-4-oxo-piperidinium iodide in 700 ml of water is added. The mixture is heated again for 105 minutes under stirring and then the ethanol is removed in the rotary evaporator.

The residue is extracted with dichloromethane (1X1.5 L + 1X1 L). The organic phases are washed with a solution of moderately saturated NaCl (2 × 800 mL) and dried over Na 2 SO 4. After evaporation of the solvent, 144 g of (R) -1- (1-phenyl-ethyl) -piperidine are obtained. 4-one raw. 70 ml of 37% hydrochloric acid are added at 5 ° C to 300 ml of isopropanol for 30 min. The mixture is added for 2 hours under stirring at 15-20 ° C to a solution of 144 g of crude (R) -1- (1-phenyl-ethyl) -piperidin-4-one in 100 mL of ethyl acetate. Crystallization begins after the addition of 1/3 of the above mixture. The suspension is stirred overnight at room temperature and then for 3 hours at 0 ° C. After adding 80 mL of pentane the mixture is again stirred for 3 hours at 0 ° C. The product is separated and washed with isopropanol (3x70 mL). After drying, the hydrochloride (188 g) is suspended in 1 L of dichloromethane and 700 mL of 10% Na 2 CO 3 are added. The organic phase was separated and washed with saturated, NaCl (lxlL) medium. After drying over MgSO4, the organic phase is concentrated. The residue is dried for 2 hours at high vacuum. 113 g of (R) -1- (1-phenyl-ethyl) -piperidin-4-one are obtained. d) Preparation of (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -piperidin-4-ol Under an argon atmosphere 175.2 g (666 mmol) of 4-benzyloxybromobenzene are dissolved in 1.4 L of dry THF.

(MS 4A). The solution is cooled to -75 ° C and a solution of 416 mL of 1.6 M butyl lithium (666 mmol) in hexane is added over 40 minutes. After stirring for 1 hour a solution of 113 g (555 mmol) of (R) -1- (1-phenyl-ethyl) -piperidin-4-one in 400 mL of THF is added for 1 hour at -75 ° C. The mixture is stirred for an additional 1 hour and, after warming to room temperature, it is drained in 1.5 L of water, ice. The mixture is extracted with 1 L of ethyl acetate, the organic phase is washed with 1 L of a solution of moderately saturated NaCl, dried over Na 2 SO 4 and concentrated. 262 g of (R) -4- (4-benzyloxy-phenyl) -1- (1-pheny1-ethyl) -piperidin-4-ol are obtained. e) Preparation of (R) -4- (4-benzyloxy-phenyl) -1- (1- (1-phenyl-ethyl) -1,2,3,6-tetrahydropyridine. 121.7 g of crude (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -piperidin-4-ol are dissolved at 40 ° C in 1.21 L of dichloroethane. 59.4 g (471 mmol) of oxalic acid dihydrate are added (Merck 492). The mixture is boiled for 3 hours, while 20 mL of water are separated. The reaction mixture is washed at room temperature with 1.2 L of 10% Na 2 CO 3. The precipitate (52 g) is separated from filtrate A and added to a mixture of 250 L of 2 N NaOH and 300 mL of dichloromethane, where it dissolves after stirring for 30 minutes at 30-35 ° C. The organic phase is separated and washed with a mildly saturated NaCl solution. The precipitate obtained is separated and dissolved in 200 ml of dichloromethane and 60 ml of methanol. The combined organic phases are concentrated and then dried over Na2SO4. Add 80 mL of ethyl acetate to the residue and stir for 2 hours. The crystals are separated, washed with pentane, and dried. 36.5 g of (R) -4- (4-benzyloxy-phenyl) -1- (1-pheny1-ethyl) -1,2,3,6-tetrahydropyridine are obtained.

The organic phase of the aforementioned filtrate A is washed with 1.5 L of a mildly saturated NaCl solution. After drying, the organic phase is concentrated. 80 mL of ethyl acetate and 30 mL of ether are added to the residue. After stirring for 3 hours at 0 ° C the crystals are separated and washed with ethyl acetate (2x20 mL) and pentane (50 mL) and dried. 33.0 g of (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -1,2,3,6-tetrahydropyridine are obtained. 10 In total: 33.0 g + 36.5 g = 69.5 g of (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -1, 2, 3, 6 tetrahydropyridine (73%) are obtained based on (R) -1- (1-phenyl-ethyl) -piperidin-4-on)). 15 Example 3 (Preparation of the starting material) a) Preparation of l-isopropenyl-4-benzyloxy-20-benzene At room temperature, 29.6 g of methyltriphenylphosphonium bromide (83 mmol) are suspended in 75 L of tetrahydrofuran. A solution of 9.2 g of Potassium tert-butoxide (82 mmol) in 35 mL of tetrahydrofuran for more than 30 minutes, and the mixture is stirred for 10 minutes at room temperature and then cooled to 0 ° C. At this temperature, a solution of 17.0 g of 4-benzyloxyacetophenone (75 mmol) in 100 mL of tetrahydrofuran for 1.5 hours is added to the solution of the ilide, stirring at 0 ° C is continued for 1 hour, then 1 is added. mL of acetic acid to the reaction mixture The reaction mixture is poured into a mixture of 300 mL of saturated aq sodium bicarbonate, 200 g of ice and 250 mL of ethyl acetate, then the aqueous phase is extracted with acetate. The organic phases are washed with 200 mL of 20% aq sodium chloride, combined, dried (Na2SO) and evaporated under reduced pressure to give 40.5 g of a white solid residue. suspend in 250 mL of hexane, and the mixture is stirred overnight at room temperature. Sfinoxide is filtered and washed with hexane. The filtrate is evaporated to give 15.8 g of a white solid. In order to remove the 20 traces of triphenylphosphinoxide, the product is passed through a pad of silica gel using hexane-ethyl acetate in a 95: 5 ratio (750 L) as the eluent. The combination of the fractions containing the desired compound are evaporated. The residue is suspended - > _ ».._._, -__.-_, _ .., _ _ _, __« _ _. _ - _ _. _, _, ..... m _ ^ ___ ^ ____ l_w______ in 80 mL of pentane, then the product is collected by filtration, washed with pentane and dried at a constant weight. 14.1 g of l-isopropenyl-4-benzyloxy-benzene are obtained. b) Preparation of (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -1,2,3,6-tetrahydro-pyridine. .7 g of (R) -1-phenylethylamine hydrochloride (131 mmol) in 60 mL of water are dissolved at room temperature. 22 mL of aqueous formaldehyde is added to 36.5% and the mixture is stirred for 10 minutes at room temperature and then heated to above 40 ° C. At this temperature, a solution of 26.75 g of l-isopropenyl-4-benzyloxy-benzene (119 mmol) in a mixture of 30 L of dioxane and 74 L of dichloromethane for 1.25 hours is continuously added. During and after the addition of the olefin solution, the dichloromethane is distilled. After removal of dichloromethane, the reaction mixture is stirred at 70 ° C overnight. A solution of 9.96 g of concentrated sulfuric acid (99 mmol) in 30 mL of water is added over 5 minutes to the reaction mixture which is then heated to 95-100 ° C and stirred at this temperature for 5.5 hours. The reaction mixture is slowly poured into a mixture of 250 L of 10% aq sodium carbonate and ice, and then extracted with 600 L of dichloromethane. The organic phases are extracted with a 600 mL portion of 20% sodium chloride, combined, dried (Na 2 SO 4) and evaporated under reduced pressure to give 64 g of crude product as an oil. coffee-red which is partially crystallized. The crude product is dissolved in 250 mL of dichloromethane. 120 mL of isopropanol and dichloromethane are added as well as a small part of the isopropanol is distilled under reduced pressure (in the rotary evaporator, bath 45 ° C). The white crystals begin to precipitate, and the suspension is stirred at 0 ° C for 2 hours. The crystals are collected in a filter funnel and washed with three 50 mL portions of cold isopropanol and 60 mL of hexane. 29.2 g of (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -1,2,3,6-tetrahydro-pyridine are obtained after drying for 2 hours at 16 mbar / 50 ° C and for 2 hours at 0.2 mbar / 220C.

Example 4 (Preparation of the starting material) a) Preparation of 2- (4-benzyloxy-phenyl) -propan-2-ol The reaction flask is charged under an argon atmosphere with 3.45 g of magnesium (142 mmol). A solution of 21.16 g of methyl iodide (147 mmol) in 120 mL of tert-butyl methyl ether is added over 45 minutes at 45 ° C under stirring. The stirring is then continued for 1 hour at 45 ° C and then a solution of 27.12 g of 4-benzyloxyacetophenone (120 mmol) in 100 mL of tetrahydrofuran is added over 45 minutes, while a temperature of 45 ° C is maintained again.

Stirring at 45 ° C is continued for 1.5 hours. After cooling to room temperature, the white suspension is poured into a mixture of 100 mL of 10% aqueous ammonium chloride and ice and extracted with 150 mL of ethyl acetate. The aqueous phase is separated and extracted with 100 ml of ethyl acetate. The organic phase is washed with 120 mL of 20% aq sodium chloride, combined, and dried (MgSO4) and evaporated under reduced pressure to give 29.9 g of crude product as an oil which is partially crystallized. The crude product is taken up in 30 mL of dichloromethane. The solution is concentrated in the rotary evaporator almost to dryness. Then 6 mL of ethyl acetate are added followed by a gradual addition of a total of 180 mL of hexane. The suspension is then maintained at 0 ° C for 30 minutes. The crystals are collected and washed with cold hexane. After drying for 2 hours at 16 mbar / 45 ° C, 26.7 g (92%) of 2- (4-benzyloxy-phenyl) -propan-2-ol are obtained. b) Preparation of (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -1,2,3,6-tetrahydro-pyridine At room temperature 6.94 g of (R) -phenylethylamine hydrochloride (44 mmol) are dissolved in 24 mL of water. 8.0 g of formaldehyde are added to 36.5% aqueous (2.92 g HCHO, 97 mmol), and the mixture is stirred for 10 minutes. Then, a solution of 9.68 g of 2- (4-benzyloxy-phenol) -propan-2-ol (40 mmol) in 10 mL of dioxane is added. The reaction mixture is heated to 70 ° C and stirred overnight at that temperature. A solution of 1.72 g of concentrated sulfuric acid (17.6 mmol) in 8 mL of water is added to the reaction mixture for 5 minutes. The reaction mixture is then heated to 100 ° C and stirred at this temperature for 7 hours. The reaction mixture is slowly emptied into a mixture of 150 mL of 10% aq sodium carbonate and 50 g of ._. _ ... _ ..-, _ _ ice and extracted with 450 mL of dichloromethane. The organic phases are extracted with 150 L of water, combined, dried (Na 2 SO 4) and evaporated under reduced pressure to give 18.1 g of crude product as an orange-red oil which is partially crystallized.

The crude product is dissolved in 60 mL of dichloromethane. 80 mL of isopropanol are added and the dichloromethane and a small portion of isopropanol are distilled at 400 mbar (in a rotary evaporator, bath at 55 ° C). The precipitated white crystals, and the suspension is stirred 1 hour at room temperature and additionally 1 hour at 5 ° C. The crystals are collected and washed with two portions of 25 mL of isopropanol and with 2 portions of 25 mL of hexane. The product is then dried for 2 hours at 16 mbar / 40 ° C and for 3 hours at 0.2 mbar / 22 ° C. 9.1 g (61%) of (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -1,2,3,6-tetrahydro-pyridine are obtained. c] Preparation of (R) -1-phenylethylamine hydrochloride. ,. _. _, _ ,. »» _ - .., .- _ _-. ».., ._ __-. _, - «_-, _. ,. -, "-, -" -, ^ ~? .-- - At room temperature, 122 g of (R) -l-phenylethylamine (1.0 mol) are dissolved in 30 mL of isopropanol. The solution is stirred and cooled to 0 ° C. Then, a previously prepared solution of 100 mL of 37% hydrochloric acid (118 g, 1.2 mol) in 320 mL of isopropanol is added for 1 hour. The solution is stirred at 0 ° C for an additional 40 minutes, and then concentrated in a rotary evaporator (16 mbar, 45 ° C bath) for a volume of 30 mL. The translucent gel which has been formed is transferred to a flask, and then, under agitation, 250 mL of tert-butyl methyl ether are slowly added. The crystals begin to form and the suspension is stirred at 0 ° C for 3 hours. The product is collected by filtration, washed with 100 mL of tert-butyl methyl ether. And it is dried at 30 ° C / 16 mbar for 4 hours. 133 g (84%) of 1-phenylethylamine hydrochloride are obtained.

Example 5 (Preparation of the starting material) a) Preparation of methyl 4-benzyloxybenzoate To a solution of 15.2 g of methyl 4-hydroxybenzoate (100 mL) in 125 mL of N, N-dimethylformamide was added with stirring 33.13 g of potassium carbonate (240 mmol). Then 17.45 g of benzyl bromide (102 mmol) are added over 5 minutes. The mixture is stirred at 25 ° C using a water bath. The reaction is complete after 3 hours. The reaction mixture is poured into a mixture of 180 g of ice and 200 mL of ethyl acetate. After extraction, the aqueous phase is separated and extracted with three 80 L portions of ethyl acetate. The organic phase is washed with two 150 ml portions of water, combined, and dried (MgSO.) and partially concentrated to give a slurry. 60 mL of pentane are added and the suspension is stirred for 2 hours at room temperature. The crystalline methyl 4-benzyloxybenzoate is collected on a filter, washed with pentane and dried. b) Preparation of 2- (4-benzyloxy-phenyl) -propan-2-ol).

Under an argon atmosphere, 6.63 g of magnesium (272 mmol) are suspended in 15 mL of tert-butyl-methyl-ester. A solution of 38.68 g of methyl iodide (273 mmol) in 145 L of tert-butyl-methyl-ether is added during 45 minutes under stirring for a while maintaining the temperature at 40 ° C. Then the agitation is continued *? __ 40 ° C for 1.5 hours and then the mixture is cooled to room temperature.A solution of 30.0 g of methyl 4-benzyloxybenzoate (124 mmol) in 120 L of tetrahydrofuran is added over 1 hour. 20 ° C. After completion of the addition, the reaction mixture is heated to 42 ° C. and stirred for 3 hours at this temperature.After cooling to room temperature, the reaction mixture is poured into a mixture of 300 ml. 10% aqueous ammonium chloride and 100 g of ice are extracted with ethyl acetate.The organic phases are washed with water and saturated sodium bicarbonate, combined, dried and evaporated to give a crude product as an oil. which is partially crystallized.The product dissolves at 25 ° C in diethyl ether.When the crystals begin to separate the solution is cooled to 18 ° C. After 30 min, hexane is added, then the solution is stirred for 1 hour at 5 ° C. 2- (4-benzyloxy-phenyl) -propan-2- The crystalline ol is collected on a filter and washed with hexane. c) Preparation of (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -1,2,3,6-tetrahydro-pyridine The reaction flask is charged with 10.66 g of ( R) -1-phenylethylamine (88 mmol) at room temperature, and 40 mL of water. Under stirring, the pH of the mixture is adjusted to a value of 4.1 by means of the slow addition of aqueous hydrochloric acid. Then 16.0 g of formaldehyde (5.84 g HCHO, 194 mmol) are added to the water at 36.5% and the mixture is stirred for 10 minutes. A solution of 19.38 g of 2- (4-benzoloxy-phenyl) -pxopan-2-ol (80 mmol in 20 mL of dioxane) is added. The reaction mixture is heated to 70 ° C and stirred overnight at this temperature. A solution of 3.44 g of concentrated sulfuric acid (35 mmol) in 16 mL of water is added over 5 minutes to the reaction mixture which is then heated to 100 ° C and stirred at this temperature for 7 hours. The reaction mixture is slowly poured into a mixture of 300 mL of 10% aqueous sodium carbonate and 100 g of ice and extracted with dichloromethane. The organic phases are extracted with water, combined, dried, and evaporated with a red-orange oil which is partially crystallized. The crude product is dissolved in 120 mL of dichloromethane. 160 mL of isopropanol and dichloromethane are added as well as a portion of the isopropanol is distilled at 400 mbar (bath at 55 ° C, rotary evaporator). White crystals precipitated. The crystals were collected on a filter funnel and washed with isopropanol and then with hexane. The compound obtained (R) -4- (benzyloxy-phenyl) -1, 2, 3, 6-tetrahydro-pyridine is then dried for 2 hours at 16 mbar / 40 ° C and for 3 hours at 0.2 mbar / 22 ° C .

Example 6 Preparation of a precursor for renin inhibitors Preparation of (3S) -4- (4-benzyloxy-phenyl) -1- [(IR) -phenyl-ethyl] -1,2,3,6-tetrahydro-pyridin-3-ol Under an argon atmosphere of 5.77 g of (IR, 6R) -6- (4-benzyloxy-phenyl) -3- [(R) -1-phenyl-ethyl] -7-oxa-3-aza-bicyclo [4.1 .0] heptane (15 mmol) and 225 mL of tert-butyl methyl ether are charged to the reaction vessel. The mixture is cooled with stirring at -15 ° C and, at this temperature, 18.75 mL of 1.6 M phenylthio (30 mmol) are added continuously for more than 45 minutes from a syringe pump via a Teflon cannula. Stirring is continued for about 3.5 hours. At this point the reaction is completed. The light brown reaction mixture is poured into a mixture of 100 L of 7% aqueous sodium bicarbonate and ice and extracted with 250 mL of ethyl acetate. The aqueous phase is separated and extracted with a fresh portion of 250 mL of ethyl acetate. The organic phases were washed with two 100 mL portions, that is, 200 mL of 20% aqueous sodium chloride, combined, dried (MgSO4) and evaporated under reduced pressure to give 6.8 g of crude product as a solid coffee. The crude product is taken up in 30 mL of dichloromethane. The solution is concentrated in a rotary evaporator in an oil of approximately 9 g in weight. 10 mL of ethyl acetate are added and the crystals begin to separate. A second portion of 5 mL of ethyl acetate followed by approximately 25 mL of hexane is added. The suspension is then stirred at 0 ° C for 2 hours. The crystals are collected and washed with a portion of cold hexane. The product is dried for 2 hours at 16 mbar / 45 ° C. 5.0 g (86%) of (3S) -4- (4-benzyloxy-phenyl) -l- [(IR) -phenyl-ethyl] -1,2,3,6-tetrahydro-pyridin-3-ol are obtained. as light brown crystals, mp 112-114 ° C.

Example 7 (Preparation of a renin inhibitor) Preparation of (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3- (naphthalene-2-ylmethoxy) -piperidine. a) 49.3 g (128 mmol) of (3S) -4- (4-5-benzyloxy-phenyl) - [(IR) -phenyl-ethyl] -1,2,3,6-tetrahydropyridin-3 are dissolved. 250 ml of N, N-dimethylformamide, from the portion in portion treated with 25 g (about 600 mmol) of a dispersion of sodium hydride in refined oil (55-65%) and the reaction mixture is heated to 50 ml. ° C under one atmosphere of argon per i hour. After cooling to 5 ° C the mixture is treated slowly with 23 ml (285 mmol) of ethyl iodide and stirred without cooling for 1 hour. Consequently, the reaction mixture is drained in 2 liters of water, ice and extracted three times with 1 liter. ethyl acetate. The combined ethyl acetate phases are subsequently washed with water, dried over magnesium sulfate and evaporated in a rotary evaporator at a maximum temperature of 40 ° C. The residue that is therefore obtained is the gel chromatography silica with ethyl acetate / hexane. Then in this way (3S) -4- (4-benzyloxy-phenyl) -3-ethoxy-1 - [(IR) -phenyl-ethyl] -1,2,3,6-tetrahydro-pyridine is obtained as an oil colorless. -a -? - a-a-s ______________ i_____. b) 35 g (84.6 mmol) of (3S) -4- (4-benzyloxy-phenyl) -3-ethoxy-1 - [(IR) -phenyl-ethyl] -1,2,3,6-tetrahydro are dissolved. -pyridine in 500 ml of 1,2-dimethoxyethane, treated with 9.91 g (262 mmol) of sodium borohydride and then treated while cooling to a maximum temperature of 28 ° C with a solution of 44.3 ml (353 mmol) of boron trifluoride etherate in 44.3 ml of 1,2-dimethoxyethane and the reaction mixture is stirred at room temperature for 2 hours. Subsequently, while cooling to a maximum temperature of 35 ° C, 169 ml of a 4.1 N solution of potassium hydroxide followed by a solution of 33.9 ml of 30% hydrogen peroxide is added dropwise and the reaction mixture is heated under reflux for 3 hours. After the After cooling to room temperature the reaction solution is emptied into 2 liters of water and extracted twice with 1 liter of dichloromethane each time. The combined dichloromethane phases are washed with water, dried over magnesium sulfate and evaporated in an evaporator. rotary at a maximum temperature of 40 ° C. The residue that is obtained is therefore chromatographed on silica gel with ethyl acetate / hexane. In this way (3R, 4R, 5S) - (4-benzyloxy-phenyl) -5-ethoxy-1 - [(IR) -phenyl-ethyl] -piperidin-3-ol) is obtained as a colorless oil. - «- il-ii-ti-g-t-S-li. c) 20 g (46.3 mmol) (3R, 4R, 5S) - (4-benzyloxy-phenyl) -5-ethoxy-1- [(IR) -phenyl-ethyl] -piperidin-3-ol) dissolved in 500 ml of methanol are hydrogenated in the presence of 3.5 g of palladium catalyst (10% on charcoal) for 7 hours. The reaction mixture is then filtered and evaporated, yielding crude (3R, 4R, 5S) -5-ethoxy-4- (4-hydroxy-phenyl) -piperidin-3-ol MS: 237 (M +). d) 11 g (46.3 mmol) of crude (3R, 4R, 5S) -5-ethoxy-4- (4-hydroxy-phenyl) -piperidin-3-ol are dissolved in 100 ml of dioxane / 50 ml of water, and treated with 11 g (50 mmol) of di-tert-butyldicarbonate and 8.4 g (100 mmol) of sodium hydrogen carbonate. The reaction mixture is then stirred for 2 hours. 100 ml of 2 N NaOH are added and the mixture is again stirred for an additional 1 hour. Then it is acidified with solid citric acid. Then, the product is extracted 3 times with dichloromethane, the organic phases are washed twice with distilled water, and then dried over magnesium sulfate, filtered and concentrated in a water jet vacuum. The thus obtained crude product is chromatographed on silica gel with ethyl acetate / dichloromethane. In this way tert-butyl acid ester is obtained (3R, 4R, 5S) -5-ethoxy-3-hydroxy-4- (4-hydroxy-phenyl) -piperidine-1-carboxylic acid as a colorless oil; MS: 338 (M + Ht). e) a solution of 11.8 g (35.0 mmol) of (3R, 4R, 5S) -5-ethoxy-3-hydroxy-4- (4-hydroxy-phenyl) -piperidine-1-carboxylic acid tert-5-butyl ester. in 40 ml of dimethylformamide are treated in succession with 10.3 g (45.0 mmol) of 3-bromo-propoxymethyl-benzene and 8.29 g (60.0 mmol) of potassium carbonate. This mixture is stirred at 120 ° C for 26 hours. Subsequently, it is filtered and concentrated in a few milliliters, it is drained in 300 ml of an ice / water mixture and extracted 3 times with 100 ml of dichloromethane each time. The combined organic phases are washed once with a small amount of water, and dry over magnesium sulphate, evaporate under reduced pressure and dry at high vacuum. The obtained crude product is separated in this way on silica gel using a mixture of dichloromethane and methanol as an eluent and acid tert-butyl ester is produced (3R, 4R, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3-hydroxy-piperidine-1-carboxylic acid as a colorless oil; MS: 486 (M + H +); 508 (M + H +). - > - **** ^ ~ * - f) 14.6 g (30.0 mmol) of tert-butyl ester of (3R, 4R, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5- ethoxy-3-hydroxy-piperidine-l-carboxylic acid and 7.74 g (35.0 mmol) of 2-bromomethyl-naphthalene are dissolved in 110 ml of dimethylformamide under an argon atmosphere and then 1.77 g (40.0 mmol) of a dispersion of Sodium hydride (55% in mineral oil). Subsequently, the mixture is stirred at room temperature for 5 hours. The reaction mixture is drained on ice-water, the product is extracted three times with dichloromethane, the organic phases are washed twice with distilled water, and then dried over magnesium sulfate, filtered and concentrated in a jet vacuum. of water. Chromatography is performed on the crude product thus obtained on silica gel with dichloromethane and methanol. The tert-butyl ester of (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3-naphthalen-2-ylmethoxy) -piperidine-1- is obtained carboxylic as a colorless oil; MS: 626.5 (M + H +). g) 14.4 g (23.0 mmol) of (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3-naphthalen-2-ylmethoxy tert-butyl ester ) -piperidine-1-carboxylic acid are placed in 350 ml of pure methanol at 0 ° C, and then added _, _, dropwise 24 ml (48 mmol) of hydrochloric acid in methanol (2.0 molar) at 5 ° C as the maximum temperature, and subsequently the mixture is heated to room temperature. After 120 minutes the reaction mixture is poured into an ice-cold sodium hydrogen carbonate solution and the product is extracted three times with dichloromethane, the combined organic phases are washed once with distilled water, dried over magnesium sulfate , they are filtered and concentrated in a water jet vacuum. The crude product obtained in this way is chromatographed on silica gel with dichloromethane and methanol. This way you get (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3-naphthalen-2-ylmethoxy) -piperidine as a colorless oil; MS-.526 (M + H +).

It is noted that in relation to this date, the best method known by the applicant, to carry out the aforementioned invention is that it is clear from the manufacture of the objects to which it refers.

Having described the invention as above, property is claimed as contained in the following:

Claims (19)

1. A process for the preparation of a compound of formula 1 or a salt thereof 1 characterized in that the process comprises a) the epoxidation of a compound of formula 2 or a salt thereof 2 in whose formula A is arylene; R1 is -C * R3R4R; R ^ is -O-alkyl, -O-cycloalkyl; -O-alkenyl, -O-aryl, -O-aralkyl, -O-aralkoxyalkyl, -O-alkylsulfonyl, -O-arylsulfonyl, chlorine, bromine or iodine. R3 hydrogen; R is aryl; R5 is an alkyl, cycloalkyl, aryl, alkoxyalkyl or hydroxyalkyl; and, where C * is an asymmetric carbon atom. b) optionally followed by the isolation of the stereoisomer.

2. The process according to claim 1, characterized in that R5 is alkyl or cycloalkyl.

3. The process according to claim 1 or 2, characterized in that R4 phenyl which is optionally substituted by one or more groups independently selected from alkyl, halogen or nitro.

4. The process according to any of claims 1 to 3, characterized in that R 4 is phenyl and R 5 is methyl.

5. The process according to any of claims 1 to 4, characterized in that A is phenylene and, wherein the phenylene is optionally substituted by one to four additional substituents independently selected from alkyl, halogen or nitro.

6. The process according to any of claims 1 to 5, characterized in that R2 is -0- benzyl or -O-methyl.

7. The process according to any of claims 1 to 6, characterized in that a compound of formula 2 is reacted with a halogen or a halogen-releasing agent.

8. The process of claim 7, characterized in that bromine is used.

9. The process according to any of claims 1 to 8, characterized in that a compound - - "----- ^ - ^ - ^ -" = - of formula 2 is prepared by means of a process comprising reacting a compound of formula 3 or formula 4 A R2 OH A R2 4 with a compound of formula R1-NH2 or a salt of the same and, wherein R1, R2 and A are defined as in claim 1.

10. The process according to any of claims 1 to 9, characterized in that the desired stereoisomer of a compound of formula 1 or a salt thereof is isolated by means of crystallization.

11. The process according to any of claims 1 to 10, characterized in that a reaction with a metal alcoholate is preferably followed, ^^^^^^? ^ ¿^ ^ ^ ^^^^ mt? ? ^? * ?? ^^^ M ^ * ^ t ~ ^ --- ^ - * UÉ? ^ - l-- l ^ * mÉaml a lithium amide or an organolithium compound to give a compound of formula 5 R 'I 5 or a salt of the same,

12. The process according to any of claims 1 to 11, wherein a compound of formula 1 or a salt thereof is converted to (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3- (naphthalen-2-ylmethoxy) -piperidine characterized because: a) the (IR, 6R) -6- (4-benzyloxy-phenyl) -3- [(R) -l-phenyl-ethyl] -7-oxa-3-aza-bicyclo [4.1.0] heptane is transformed in (3S) -4- (4-benzyloxy-phenyl) -1- [(IR) -phenyl-ethyl] -1, 2, 3,6, -tetrahydro-pyridin-3-ol by means of the reaction with phenylthio; b) the reaction with sodium hydride and ethyl iodide yield (3S) -4- (4-benzyloxy-phenyl) -3-ethoxy-1 - [(IR) -phenylethyl] -1,2,3,6 -R) -tetrahydropyridine; 5 c) the hydroboration with sodium borohydride and boron trifluoride etherate followed by the reaction with potassium hydroxide and hydrogen peroxide produces (3R, 4R, 5S) - (4-benzyloxy-phenyl) -5-ethoxy-1- [ (IR) -phenyl-ethyl] -piperidin-3-ol); D) hydrogenolysis yields (3R, 4R, 5S) -5-ethoxy-4- (4-hydroxy-phenyl) -piperidin-3-ol; e) the reaction with di-tert-butyldicarbonate and sodium hydrogen carbonate followed by the addition of NaOH produces tert-butyl ester of (3R, 4R, 5S) -5-ethoxy-3-hydroxy-4- (4- hydroxy-phenyl) -piperidine-1-carboxylic acid; f) treatment with 3-bromo-propoxymethyl-benzene and potassium carbonate produces tert-butyl acid ester (3R, 4R, 5S) -4- [4- [3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3-hydroxy-piperidine-1-carboxylic acid; _ ***. «^ ~ - ^ g) a reaction with 2-bromomethyl-naphthalene and sodium hydride produces tert-butyl ester of (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] - 5-ethoxy-3- (nephthalen-2-ylmethoxy) -piperidine-1-carboxylic acid; 5 h) the reaction with hydrochloric acid yields (3R, 4S, 5S) -4- [4- (3-benzyloxy-propoxy) -phenyl] -5-ethoxy-3- (naphthalen-2-ylmethoxy) -piperidine.

13. A compound according to formula 1 or a salt thereof, characterized in that R1, R2, R ', R4 and A are as defined in any of claims 1 to 6.

14. A compound according to formula 2 or a salt thereof, characterized in that R1, R2, R3, R4 and A are as defined in any of claims 1 to 6.

15. A compound according to formula 6 or a salt thereof. characterized in that R1 and A are as defined in any of claims 1 to 6 and R6 is alkyl, cycloalkyl, alkenyl, aryl, aralkoxyalkyl, alkylsulfonyl or aryl sulfonyl.

16. A compound according to formula 5 or a salt thereof, characterized in that R1, R2, R3, R4, R5 and A are as defined in any of claims 1 to 6.

17. A compound according to any of claims 13, 14, 15 and 16 selected from: (IR, 6R) -6- (4-benzyloxy-phenyl) -3- [(R) -1-phenyl-ethyl] -7-oxa-3-aza-bicyclo [4.1.0] heptane; (R) -4- (4-benzyloxy-phenyl) -l- (1-phenyl-ethyl) -1,2,3-6-tetrahydro-pyridine; ?? É i ?? go? 1 1? I ??? - - - - - - '•' * .. ^? ___, - - - - -. - .- .-- (R) -4- (4-benzyloxy-phenyl) -1- (1-phenyl-ethyl) -pyridin-4-ol; (3S) -4- [4-benzyloxy-phenyl) -l- [(IR) -phenyl-ethyl] -1,2,3,6-tetrahydro-pyridin-3-sl.

18. The use of the compound according to claim 13 in the preparation of renin inhibitors.

19. A compound obtained by the process according to any of claims 1 to 11. SUMMARY OF THE INVENTION The present invention relates to a process for the preparation of a compound of formula 1 or a salt thereof 1 characterized in that the process comprises a) the epoxidation of a compound of formula 2 or a salt of the same whose formula A is arylene; R1 is -C * R3R4R5; R2 is -O-alkyl, -O-cycloalkyl; -O-alkenyl, -O-aryl, -O-aralkyl, -O-aralkoxyalkyl, -O-alkylsulfonyl, -O-arylsulfonyl, chlorine, bromine or iodine, RJ hydrogen; R is aryl; R5 is an alkyl, cycloalkyl, aryl, alkoxyalkyl or hydroxyalkyl; and, where C * is an asymmetric carbon atom. b) optionally followed by the isolation of the stereoisomer. a_M_fíÍ_tf_íl_M_a_l_Í _? _?