US3855236A - Multi-step process for preparing 1-(substituted-hydrocarbyl)-3,4,5-tribromopyrazoles - Google Patents

Abstract

This chemical process invention provides 3,4,5-tribromopyrazole by direct tribromination of pyrazole in an aqueous reaction medium with alkali metal hydroxide. It further provides Nalkylation in the same aqueous alkaline medium to obtain 1(substituted-hydrocarbyl)-3,4,5-tribromopyrazoles useful as herbicides.

Description

United States Patent 1 Kornis et al.

[ Dec. 17, 1974 Wiley:

MULTI-STEP PROCESS FOR PREPARING l-(SUBSTITUTED-HYDROCARBYL)-3,4,5- TRIBROMOPYRAZOLES Inventors: Gabriel Kornis; Eldon G. Nidy, both of Kalamazoo, Mich.

Assignee: The Upjohn Company, Kalamazoo,

Mich.

Filed: Feb. 23, 1972 Appl. No.: 228,770

US. CL... 260/310 R, 260/243 B, 260/247.5 E, 260/268 H, 260/293.7, 260/539 R, 260/539 A, 260/561 HL, 71/92 Int. Cl C07d 49/18 Field of Search 260/310 R, 293.7, 268 H, 260/247.5 E

References Cited OTHER PU BLlCATlONS Pyrazoles, Pyrazolines, Pyrazolidines, ln-

dazoles, & Condensed Rings, (1967), pages 84-85.

Primary Examinen-Henry R. .liles Assistant Examiner-S. D. Winters Attorney, Agent, or FirmCarl A. Randles, .Ir.;

Roman Saliwanchik 17 Claims, No Drawings MULTl-STEP PROCESS FOR PREPARING 1-(SUBSTITUTED-HYDROCARBYL) 3,4,5-

TRIBROMOPYRAZOLES SUMMARY OF THE INVENTION This invention pertains to a new chemical process and some of the specific new practices thereof. The invention is more particularly directed to a new chemical process for preparing certain l-(substituted-hydrocarbyl)-3,4,5-tribromopyrazoles having the following structural formula:

I:.. .1 V wherein n is an integer O, l, 2, or 3; R is hydrogen, alkyl of from 1 to 5 carbon atoms, inclusive, the total number of carbon atoms in the group being not more than 9; and A is the carboxyl group or a carboxylic amide group of the formula group is a saturated heterocyclic amino group of from 3 to 7 ring atoms, inclusive, having a total of not more than carbon atoms.

The new process of the invention comprises a combination of reaction practices for preparing the l- (substituted-hydrocarbyl)-3,4,5-tribromopyrazoles of Formula I. The first practice of the integral process which pertains to preparation of pyrazole is known, and it is not critical in the process because pyrazole prepared in various ways can be used as the starting compound. This first practice is broadly described by Copenhaver in US. Pat. No. 2,515,160 issued July 1 l, 1950, for preparing pyrazole by reaction of a l,1,3,3-tetraalkoxypropane with a mineral acid addition salt of hydrazine hydrate. The Copenhaver practice is advantageous in the combination process of this invention however, because it has been found that there is no necessity for separation and recovery of the pyrazole produced. The process of the invention is continued utilizing the aqueous reaction medium started with. Thus, the known Copenhaver practice is functionally combined with the second and a third specific reaction practices which are new according to this invention to give a new and better synthesis of the desired compounds.

The new second reaction practice is directed to the bromination of pyrazole, and in contrast to published methods, furnishes tribromopyrazole in one step under exceedingly mild conditions. The yields of the desired product are excellent substantially quantitative in some cases. The third and final reaction practice of the combination process involves in situ N-alkylation of the 3,4,5-tribromopyrazole to give the desired compounds.

DETAILED DESCRIPTION OF THE INVENTION The new process of this invention is characterized by utilization of the relatively inexpensive and ubiquitous reaction medium, water; the use of economical alkali metal hydroxide bases, preferably sodium hydroxide; and facile recovery of the desired product. These characteristics coupled with in situ preparation of pyrazole by the Copenhaver method and further in situ preparation of 3,4,5-tribromopyrazole by applicants new method provide a truly significant advance in the art of preparing the useful compounds of Formula I. The compounds are herbicides, especially the l-(alkanoamide)-3,4,5-tribromopyrazoles.

In effectuating the new integral process, a Copenhaver-type substantially aqueous reaction medium having the pyrazole in solution is first made alkaline to liberate the pyrazole from its hydrochloride salt. It is then treated with bromine and aqueous alkali metal hydroxide in order to imparta negative charge on the lnitrogen atom, which accelerates the bromination process. Furthermore the aqueous alkalimetal hydroxide also serves to neutralize the hydrogen bromide formed during the reaction. Bromine is added while the temperature of the aqueous mixture is maintained at about 35 C. Lower or higher temperatures can beused, but the guiding principle is to add the halogen slowly so that a runaway exothermic reaction will not occur. Analytically pure tribromopyrazole can be prepared in yields of greater than percent. This bromination procedure is definitely superior to published methods for the preparation of tribromopyrazole. For example Reimlingeret al., in Chem. Ber. 103, 1942-48 (1970) heated under reflux a mixture of the silver salt of 4- bromopyrazole and bromine for 5 hours, and after lengthy purification, isolated a 60 percent yield of tribromopyrazole.

Similarly, I-Iuttel et al., Ann. 593, 179 (1955) had to revert to a stepwise bromination, lengthy heating and separation of the mixture produced to obtain finally the desired product in a 54 percent yield.

After the halogenation reaction is completed and 3,4,5-tribromopyrazole is obtained, more alkali metal hydroxide is added to the substantially aqueous reaction mixture in order to promote the prospective alkylation at the nitrogen atom of the pyrazole ring with an a, B, 'y, or A-monohalogenated alkanoamide or alkanoic acid.

The N-alkylation reaction is promoted by heating the substantially aqueous reaction medium containing 3,4,5-tribromopyrazole, alkali metal hydroxide, and haloalkanoamide or haloalkanoic acid. The reaction is completed within an hour and upon cooling, followed advantageously by chilling, the desired l-(substitutedhydrocarbyl)-3,4,5-tribromopyrazole is recovered by conventional methods.

I 3.4 NaOII 3 Br: Br-

1.1 CIIaCIICON(CII3)1 N .1 N J I 131' Br f N 1 .1 NaOH (IZII COQII Br Among the a,/3, y, or A-monohalogenated alkanoamides or -alkanoic acids suitable for the alkylation step of this new process may be named 2-chloro-N,N- dimethyl acetamide, 2-chloro-N,N-dimethyl propionamide, 2-bromo-N,N-dimethyl butyramide, 2-chloro-N- methyl valeramide, 2-bromo-N-propyl hexanamide, 3- chloro-N,N-dimethyl propionamide, chloroacetic acid, 2-bromopropionic acid, 3-chlorobutanoic acid, and the like.

For the alkali metal hydroxide component of the reaction mixtures, sodium hydroxide is preferred. Potassium hydroxide can be used in the same way. Other alkali'metal hydroxides are suitable but relatively expensive.

As indicated above, the Copenhaver pyrazole synthesis and use in situ is an optional, though advantageous, step even though the remainder of the process of the invention can be utilized separately. One can therefore take pyrazole otherwise produced and in various degrees of purity and dissolve it in aqueous alkali metal hydroxide for reaction with bromine. The halogenation procedure and subsequent N-alkylation are effected in the same advantageous way no matter what the source of the pyrazole.

The foregoing general structural formula and definition of variables provide a broad outline of the scope of this invention. This scope can be more readily recognized by consideration of some specific variations. Accordingly, some specific loweralkyl groups of from 1 to 8 carbon atoms, inclusive," are for example: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and isomeric forms thereof.

Some specific alkenyl groups of from 3 to 8 carbon atoms, inclusive," are for example: allyl, l-methylallyl, 2-methylallyl (methallyl), 2butenyl (crotyl), 3- butenyl, 1,2-dimethylallyl, 3-methyl-2-butenyl, 3- pentenyl, 2,3-dimethyl-2-butenyl, 1,l,2,-trimethylallyl, l,3-dimethyl-2-butenyl, l-ethyl-2-butenyl, 4-methyl-2- pentenyl, 2-ethyl-2-pentenyl, 4,4-dimethyl-2-pentenyl, Z-heptenyl, Zoctenyl, 5-octenyl, l,4-dimethyl-4- hexenyl, and the like.

Some specific alkynyl groups of from 3 to 8 carbon atoms, inclusive, are 2-propynyl, 3-butynyl, 2- pentynyl, 1,1-dimethyl-2-propynyl, 2-hexynyl, 2- heptynyl, 2-octynyl, 1,1,3-trimethyl-4-pentynyl, and the like.

Some specific aralkyl groups of from 7 to 13 carbon atoms, inclusive, are for example: benzyl, phenethyl, l-phenylethyl, Z-phenylpropyl, 4-phenylbutyl, 6- phenylhexyl, 5phenyl-2-methylpentyl, benzhydryl, 1- naphthylmethyl, 2-( 1-naphthyl)ethyl, 2-( 2- napthyl)ethyl, and the like.

The phrase aryl of from 6 to 10 carbon atoms, inclusive," includes for example, phenyl, the tolyls, the xylyls, mesityl, 4-tert-butylphenyl, 2,5-dichlorophenyl, 3-anisyl, 4-ethylphenyl, 3,4,5-trimethoxyphenyl 4-bromo-2-methoxyphenyl, 2-chloro-4-tolyl, and the like.

The phrase cycloalkyl of from 3 to 8 carbon atoms, inclusive," includes for example, cyclopropyl, Z-methylcyclopropyl, 2,2-dimethylcyclopropyl, 2,3-diethylcyclopropyl, 2-butylcyclopropyl, cyclobutyl, 2-methylcyclobutyl, 3-propylcyclobutyl, 2,3,4-trimethylcyclobutyl, cyclopentyl, 2,2-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 2,2-dimethylcyclohexyl, cycloheptyl, cyclooctyl, and the like.

Cycloalkenyl groups of from 4 to 8 carbon atoms, inclusive, are for example, 2-cyclobutenyl, 3- cyclopentenyl, 3-cyclohexenyl, 2-ethyl-3-cyclohexenyl, and the like.

The phrase saturated heterocyclic amino group of from 3 to 7 ring atoms, inclusive, having a total of not more than 15 carbon atoms, includes for example, aziridinyl, lower-alkylaziridinyl, for example, 2- methylaziridinyl, 2-ethylaziridinyl, and 2- butylaziridinyl, polylower-alkyl aziridinyl, for example, 2,3-dimethylaziridinyl and 2,2-dimethylaziridinyl, azetidinyl, lower-alkylazetidinyl, for example, 2- methylazetidinyl, 3-methylzetidienyl, and octylazetidinyl, polyloweralkylazetidinyl, for example, 2,2-dimethylazetidinyl, 3,3-diethylazetidinyl, 2,4,4- trimethylazetidinyl, and 2,3,4-trimethylazetidinyl, pyrrolidinyl, lower-alkylpyrrolidinyl, for example 2- methylpyrrolidinyl, 3-butylpyrrolidinyl, and Z-isohexylpyrrolidinyl, polylower-alkylpyrrolidinyl, for example,

2,3-dimethylpyrrolidinyl, 2,2-dimethylpyrrolidinyl, 2,5-diethylpyrrolidinyl, and 2,3,S-trimethylpyrrolidinyl, piperidino, loweralkylpiperidino, for example, 2-

methylpiperidino, 3-methyl-piperidino, .4- methylpiperidino, 3-isopropylpiperidino, and 4-tertbutylpiperidino, polylower-alkylpiperidino, for example, 3,4-diethylpiperidino, 2-methyl-S-ethylpiperidino,

3,5-dipentylpiperidino, 2,4,-trimethylpiperidino, and.

2,3,5-triethylpiperidino, hexamethyleneimino, loweralkylhexamethyleneimino, for example, 2- ethylhexamethyleneimino, 4-tertbutylhexamethyleneimino, and v 3-heptylhexamemethylmorpholino, 3,3-dimethylmorpholino, and 2,6-di-tert-butylmorpholino, thiamorpholino, loweralkylthiamorpholino, for example, 3- methylthiamorpholino, and polyloweralkylthiamorpholino, for example, 2,3,6- trimethylthiamorpholino and 2,3,5,6-tetramethylthiamorpholino.

The foregoing specified and many other like saturated heterocyclic amino groups are contemplated as being within the scope of this invention. It will be noted that the saturated amino heterocycle can be other than alkyleneamino and there can be a second hetero atom in the ring, i.e., an oxygen atom, a sulfur atom, or a second nitrogen atom as a ring member. In general, the second hetero atom is preferably in the 4-position of a six-membered ring, but it can be in the 3-position. Accordingly, referring to the phrase Collectively the group is saturated heterocyclic amino group of from 3 to 7 ring atoms, inclusive, it will be recognized that the R and R chain can be alkylene, oxadialkylene,50

Accordingly, a further definition of the phrase is: collectively, R and R taken as a unit with the atom, are saturated heterocyclic amino groups of from 3 to 7 ring atoms, inclusive, such group having a total of not more than carbon atoms, one

2-ethyl-S- of the ring atoms being selected from carbon, oxygen, sulfur, or a second nitrogen atom, the other ring atoms being carbon, so that R,-R as a unit, is alkylene, oxadialkylene, thiadialkylene, or N- alkylazadialkylene, respectively. The following examples are illustrative of the process and products of the present invention but are not to be construed as limiting.

EXAMPLE 1 Preparation of 3,4,5-Tribromopyrazole An aqueous solution prepared by dissolving 6.8 g. (0.1 mole) pyrazole and 13.6 g. (0.34 mole) sodium hydroxide in ml. water was stirred vigorously while 48.0 g.; 15.4 ml. (0.3 mole) bromine was added dropwise during an internal of 45 minutes. The temperature of the reaction mixture was maintained at 35 C. during the addition. The reaction suspension thus produced was stirred for a further 1 hr., when it was poured into aqueous sodium bisulfite (prepared by dissolving 3.0 g. sodium bisulfite in 500 ml. water). The slightly colored suspension became clear and the white precipitate thus obtained was collected on a filter. The filter cake was washed with water and dried to give 29.3 g. (96 percent) of 3,4,5-tribromopyrazole crystals having a melting point at to C. After dissolving the crystals in warm ethanol, heating on a steam bath, adding hot water to cloudiness, and chilling, the crystals thus obtained had a melting point at 185 to 186 C.

' EXAMPLE 2 Alternative Preparation of 3,4,5-Tribromopyrazole The hydrochloride of hydrazine hydrate was first prepared by adding 30 ml. of 36.5 percent (0.3 mole) hydrochloric acid, dropwise at 0 C. and with stirring, to 15 g. (0.3 mole) hydrazine hydrate. To this hydrate was then added a solution consisting of 15 ml. water, 30 ml. 3A ethanol, and 49.5 -g. (0.3 mole) l,l,3,3-tetramethoxypropane, and this reaction mixture was heated at the reflux temperature for 2 hrs. After cooling, the mixture was made alakline with 10 N aqueous sodium hydroxide and an additional 300 ml. water containing 41.0 g. sodium hydroxide was added. To this aqueous alkaline solution was added, dropwise with vigorous stirring, 143.5 g.; 46 ml. (0.9 mole) bromine. The temperature of the reaction mixture was maintained at 35 C. When the addition of bromine was complete, stirring of the reaction suspension was continued for 1 hr. The suspension was then poured into 1500 ml. water containing 9.0 g. sodium bisulfite. The pprecipitate was collected on a filter and washed with water. There was thus obtained 82.0 g. (90 percent yield) of 3,4,5 tribromopyrazole having a melting point at 180 to 184 C.

Analysis:

Calcd. for C HBr N (304.81):

C, 11.82; H, 0.33; N, 9.19.

Found: C, 12.03; H, 0.43; N, 9.13.

EXAMPLE 3 Preparation of 3,4,5-Tribromo-N,N-a-trimethylpyrazolel -acetamide The hydrochloride of hydrazine hydrate was prepared by adding 10 ml. of 36.5 percent (0.1 mole) hydrochloric acid, dropwise at 0 C. and with stirring, to 5 g. (0.1 mole) hydrazine hydrate. To this mixture was then added a solution consisting of 5 ml. water, 10 ml.

3A ethanol, and 16.42 g. (0.1 mole) 1,1,3,3-tetramethoxypropane, and this reaction mixture was, after a 10 min. delay, heated at the reflux temperature for 30 min. The reaction mixture was cooled, and then made alkaline with.13 ml. of 10 N sodium hydroxide. A further 100 ml. water containing 13.6 g. (0.34 mole) sodium hydroxide was added, and to this predominantly aqueous alkaline solution was added, dropwise during 1 hour with vigorous stirring, 48 g. (0.3 mole) bromine. During this step the temperature of the reaction mixture was maintained at 35 C. When the addition of the bromine was completed, and the temperature had cooled to 25 C. stirring was continued for a further 20 min. when 50 ml. water containing 4.4 g. (0.11 mole) sodium hydroxide was added. The resulting mixture was again heated to the reflux temperature. The resulting solution was filtered while hot, and 14.85 g. (0.11

' mole) N,N-dimethy1-2-chloropropionamide was added to the filtrate dropwise during 5 min. This reaction mixture was heated at the reflux temperature for 45 min. with vigorous stirring and then 75 ml. water was added.

Upon cooling, followed by chilling, a pale yellow pre- C, 23.79; H, 2.50; N, 10.40; Br, 59.35. Found: C, 23.64; H, 2.42, N, 10.52; Br, 59.46.

EXAMPLE ,4

Preparation of 3,4,5-Tribromopyrazole-l-acetic Acid Following the same procedure, but adding 30 ml. water instead of 50 ml. water containing 4.4 g. (0.11 mole) sodium hydroxide and adding 14.2 g. aqueous chloroacetic acid at C. (that had been made neutral to phenolphthalein indicator with a saturated aqueous solution of sodium carbonate at 0 C.) instead of N,N- dimethyl-2-chloropropionamide, and after refluxing cooling and acidifying to pH 2 with 6 N hydrochloric acid there was obtained 31.8 g. (88 percent yield) of 3,4,5-tribromopyrazole-l-acetic acid having a melting point at 207 to 212 C.

Analysis:

Calcd. for C H Br N O (362.85):

C, 16.73; H, 0.85; N, 7.62.

Found: C, 16.55; H, 0.83; -N, 7.72.

EXAMPLE 5 Following the procedure of Examle 3, but substitut ing N,N-dimethyl chloroacetamide, N,N-dimethyl-2- chlorobutyramide, N,N-dimethyl-Z-chlorovaleramide, N,N-dimethyl-2-chlorohexanamide, N,N-dimethyl-2- chloroheptanamide, N,N-dimethyl-Z- bromopropionamide, N,N-diethyl-Z- chloropropionamide, and N-ethyl-N-methyl-2- chloropropionamide for N,N-dimethyl-2- N ,N-dimethyl-a-pentylpyrazolel -acetamide, 3 ,4,5- tribromo-N,N-a-trimethylpyrazole-l-acetamide, 3,4,5- tribromo-N,N-diethyl-a-methylpyrazole-1-acetamide,

3 ,4,5-tribromo-N-ethyl-N,a-dimethylpyrazolel acetamide, respectively.

EXAMPLE 6 3 ,4,5-tribromo-5-pentylpyrazolel 5- EXAMPLE 7 Following the procedure of Example 4, but substituting N-( 1 ,1-dimethyl-2-propynyl)-2- chloropropionamide, N-isopropyl-Z- chloropropionamide, N,N-diisopropyl-Z- chlorpropionamide, N,N-dibutyl-2- chloropropionamide, N,N-dipentyl-Z- chloropropionamide, N,N-dihexyl-Z- chloropropionamide, N-benzyl-2-chloropropionamide,

N,N-dicyclohexyl-2-chloropropionamide, N-( 3- cyclopentenyl)-2-chloropropionamide, N,N- (tetramethylene )-2-ch1oropropionamide, N,N- (pentamethylene)-2-chloropropionamide, N,N-

(hexamethylene)-2-chloropropionamide, and N,N-(3- thiapentamethylene)-2-chloropropionamide for N,N- dimethyl-2-chloropropionamide, there was prepared the corresponding:

3 ,4,5-tribromo-N-( 1 l -dimethyl-2-propynyl )-amethylpyrazole- 1 -acetamide,

3 ,4,5-tribromo-N-isopropyl-a-methylpyrazole-1- acetamide,

3,4,5-triibromo-N,N-diisopropyl-a-methylpyrazolel-acetamide,

3 ,4,5-tribromo-N,N-dibutyl-a-methylpyrazo1e-1- acetamide,

3 ,4,5-tribromo-N,N-dipentyl-a-methylpyrazo1el acetamide,

3 ,4,5-tribromo-N,N-dihexyl-a-methyllpyrazole-1- acetamide,

3 ,4,5-tribromo-N-benzyl-u-methylpyrazole-1- acetamide,

3,4,5-tribromo-N,N-dicyclohexyl-a-methylpyrazolel-acetamide,

3,4,5-tribromo-N-(3-cyclopentenyl)-o:-methylpyrazole- 1 -acetamide,

3,4,5-tribromo-N,N-(tetramethylene)-a-methylpyrazole 1 -acetamide,

3,4,5-tribromo-N,N-(pentamethylene)-oz-methylpyrazo1e- 1 -acetamide,

3,4,5-tribromo-N,N-(hexamethylene)-a-methylpyrazole-l-acetamide, and

3,4,5-tribromo-N,N-( 3-thiapentamethylene )-amethylpyrazole-l-acetamide, respectively.

The new l-(substituted-hydrocarbyl)- tribromopyrazoles of this invention (compounds of Formula I) have been found to be active as herbicides and plant growth regulators. The new compounds can be used to prevent damage to field crops due to weed competition, and they can be used to prevent unsightly and deleterious growths of weeds on home lawns, golf courses, cemeteries, railroad rights-of-way, and parks.

Compounds of this invention have been found to be highly active against both broadleaf and grassy weeds, with some variations between one compound and another within the series. lllustratively, 3,4,5-tribrom- N,N-a-trimethylpyrazolel -acetamide and 3 ,4,5-tribromopyrazole-l-acetic acid are especially active against various weeds, e.g., crabgrass (Digitaria sanguinalis L.), yellow foxtail (Setaria glauca L.), wild oats (Avena fazua L.), bindweed (Convolvulus arvens is L.), Johnson grass (Sorghum halepense L.), buckhorn plantain (Plantago lanceolata L.), curly dock (Rumex crispus L.), wild mustard (Brassica kaber DG.), purslane (Portulaca oleracea L.), and barnyard grass (Enchinochloa crusgalli L.).

Illustratively, control and significiant growth retardation of the foregoing weed species has been achieved using the named compounds and other specific compounds of this invention at rates of from 1 to 12.5 lbs. per acre. Depending upon the kinds of weeds to be controlled, the stage of weed development, the degree of infestation, and the presence or absence of aesthetic or crop plants, the compounds of this invention can be applied to soil, germinating weed seeds, weed seedlings, plant growth media, growing plants, or any other selected situs for control of weeds at rates ranging from about A to k lb. per acre up to about 50 lbs. per acre.

Ordinarily, the situs will be soil, but this term is used in the broad sense anywhere where weed growth might be a problem, e.g., gravel driveways, railroad beds, fiat built-up roofs, ponds, lakes, streams, and canals. Aquatic applications effectively use about 2 to about 10,000 or more, parts per million (ppm), by weight.

A suitable dispersible powder formulation is obtained by blending and milling 327 lbs. of Georgia Clay, 4.5 lbs. of isooctylphenoxy polyethoxy ethanol (Triton X- 100) as a wetting agent, 9 lbs. of a polymerized sodium salt of substituted benzoid long-chain sulfonic acid (Daxad 27) as a dispersing agent, and 113 lbs. of the active ingredient. The resulting formulation has the following percentage composition (parts herein are by weight unless otherwise specified):

Active in edient 25% lsooctylp enoxy polyethoxy ethanol 1% Polymerized sodium salt of substituted benzoid longchain sulfonic acid 2% Georgia Clay 72% This formulation, when dispersed in water at the rate of 10 lbs. per 100 gals., gives a spray formulation containing about 0.3 percent (3000 ppm) active ingredient which can be applied to weeds at the rate of 40 gals. per acre to give a total application of active ingredient of 1 lb. per acre.

We claim:

1. The process which comprises reacting a mineral acid addition salt of hydrazine hydrate with l,l,3,3-tetraalkoxypropane in a substantially aqueous MI I Br Br wherein n is an integer O, l, 2, or 3; R is hydrogen,

alkyl of from 1 to 5 carbon atoms, inclusive, the sum of carbon atoms in the group being not more than 9; and A is the carboxyl group or a carboxylic amide group of the formula wherein R and R are hydrogen atoms or substituent groups more fully described as follows:

Individually, R and R are lower-alkyl of from 1 to 8 carbon atoms, inclusive; alkenyl of from 3 to 8 carbon atoms, inclusive; alkynyl of from 3 to 8 carbon atoms, inclusive; aralkyl of from 7 to 13 carbon atoms, inclusive; aryl of from 6 to 10 carbon atoms, inclusive (provided both R and R are not aryl at the same time); cycloalkyl of from 3 to 8 carbon atoms, inclusive, cycloalkenyl of from 4 to 8 carbon atoms, inclusive; cycloalkenyl of from 4 to 8 carbon atoms, inclusive; and Collectively, the

group is a saturated heterocyclic amino group of from 3 to 7 ring atoms, inclusive, having a total of not more'than 15 carbon atoms.

2. The process according to claim '1 wherein the alkali metal hydroxide is sodium hydroxide.

3. The process according to claim 2 wherein an a-halopropionamide or a-halopropionic acid is employed as the reactant, and a 3,4,5-tribromo-a-methylpyrazole-l-acetamide or -acetic acid is made.

4. The .process according to claim 3 wherein N,N- dimethyl-a-ehloropropionamide is the reactant and 3,- 4,5-tribromo-N,N,a-trimethylpyrazolel -acetamide is made.

5. The process according to claim 2 wherein chloroac'etic acid is the reactant and 3,4,5-tribromopyrazolel-acetic acid is made.

6. The process according to claim 1 wherein the reaction of hydrazine hydrate with l,l,3,3tetraalkoxypropane is omitted and the pyrazole is added to aqueous alkali metal hydroxide prior to tribromination.

7. The process according to claim 6 wherein the alkali metal hydroxide is sodium hydroxide.

8. The process according to claim 7 wherein an a-halopropionamide or a-haiopropionic acid is employed as the reactant and 3,4,5-tribromo-oz-methylpyrazole-l-acetamide r -acetic acid is made.

9. The process according to claim 8 wherein N,N- dimethyl-a-chloropropionamide is the reactant and 3,- 4,5-tribromo-NgN-a-trimethylpyrazolel -acetamide is recovered.

10. The process according to claim 7 wherein chloroacetic acid is the reactant and 3,4,5-tribromopyrazolel-acetic acid is recovered.

1 1. The process for preparing 3 ,4,5- tribromopyrazole which comprises reacting bromine with pyrazole in aqueous sodium hydroxide.

12. The process according to claim 1 1 wherein 3,4,5- tribromopyrazole is prepared.

13. The process according to claim 12 wherein one equivalent of pyrazole is reacted with 3 equivalents of molecular bromine and slightly more than 3 equivalents of sodium hydroxide in a substantially aqueous reaction medium at about 35 C.

14. The process according to claim 12 wherein the 3,4,5-tribromopyrazole prepared is reacted in situ with any, ,8, y, or A-monohalogenated alkanoamide or alkano c acid in the presence of an alkali metal hydroxide.

15. The process according to claim 14 wherein 3,4,5- tribromopyrazole is reacted with an a, ,B, 'y, or A-monohalogenated alkanoamide.

16. The process according to claim 15 wherein N,N- diallryl-2-chloropropionamide is reacted.

17. The process according to claim 16 wherein N,N- dimethyl-2-chloropropionamide is reacted.

Claims (17)

1. THE PROCESS WHICH COMPRISES REACTING A MINERAL ACID ADDITION SALT OF HYDRAZINE HYDRATE WITH 1,1,3,3TETRAALKOXYPROPANE IN A SUBSTANTIALLY AQUEOUS MEDIUM TO OBTAIN A CORRESPONDING AQUEOUS REACTION MIXTURE COMPRISING PYRAZOLE, REACTING THE PYRAZOLE THUS PRODUCED IN SITU WITH BROMINE IN THE PRESENCE OF AQUEOUS ALKALI METAL HYDROXIDE UNTIL BROMINATION IS COMPLETE AND 3,4,5-TRIBROMOPYRAZOLE IS OBTAINED; REACTING THE SAID TRIBROMO PRODUCT, IN SITU, WITH AN A. B. Y. OR &-MONOHALOGENATED ALKANOAMIDE OR -ALKANOIC ACID IN THE PRESENCE OF SUBSTANTIALLY EQUIVALENT AMOUNTS OF AN ALKALU METAL HYDROXIDE, AND THENCE RECOVERING THE DESIRED 1(SUBSTITUTED-HYDROCARBYL)-3,4,5-TRIBROMOPYRAZOLE OF THE FORMULA:

2. The process according to claim 1 wherein the alkali metal hydroxide is sodium hydroxide.

3. The process according to claim 2 wherein an Alpha -halopropionamide or Alpha -halopropionic acid is employed as the reactant, and a 3,4,5-tribromo- Alpha -methylpyrazole-1-acetamide or -acetic acid is made.

4. The process according to claim 3 wherein N,N-dimethyl- Alpha -chloropropionamide is the reactant and 3,4,5-tribromo-N,N, Alpha -trimethylpyrazole-1-acetamide is made.

5. The process according to claim 2 wherein chloroacetic acid is the reactant and 3,4,5-tribromopyrazole-1-acetic acid is made.

6. The process according to claim 1 wherein the reaction of hydrazine hydrate with 1,1,3,3-tetraalkoxypropane is omitted and the pyrazole is added to aqueous alkali metal hydroxide prior to tribromination.

7. The process according to claim 6 wherein the alkali metal hydroxide is sodium hydroxide.

8. The process according to claim 7 wherein an Alpha -halopropionamide or Alpha -halopropionic acid is employed as the reactant and 3,4,5-tribromo- Alpha -methylpyrazole-1-acetamide or -acetic acid is made.

9. The process according to claim 8 wherein N,N-dimethyl- Alpha -chloropropionamide is the reactant and 3,4,5-tribromo-N,N- Alpha -trimethylpyrAzole-1-acetamide is recovered.

10. The process according to claim 7 wherein chloroacetic acid is the reactant and 3,4,5-tribromopyrazole-1-acetic acid is recovered.

11. The process for preparing 3,4,5-tribromopyrazole which comprises reacting bromine with pyrazole in aqueous sodium hydroxide.

12. The process according to claim 11 wherein 3,4,5-tribromopyrazole is prepared.

13. The process according to claim 12 wherein one equivalent of pyrazole is reacted with 3 equivalents of molecular bromine and slightly more than 3 equivalents of sodium hydroxide in a substantially aqueous reaction medium at about 35* C.

14. The process according to claim 12 wherein the 3,4,5-tribromopyrazole prepared is reacted in situ with an Alpha , Beta , gamma , or Delta -monohalogenated alkanoamide or alkanoic acid in the presence of an alkali metal hydroxide.

15. The process according to claim 14 wherein 3,4,5-tribromopyrazole is reacted with an Alpha , Beta , gamma , or Delta -monohalogenated alkanoamide.

16. The process according to claim 15 wherein N,N-dialkyl-2-chloropropionamide is reacted.

17. The process according to claim 16 wherein N,N-dimethyl-2-chloropropionamide is reacted.