GB2225781A - 10-Noranthracyclines - Google Patents

Description

1 1 - PP 4369 (FC 391) 10-NORANTHRACYCLINES The present invention relates

to a new class Of synthetic anthracycline glycosides having antitumor activity, processes for their preparation, pharmaceutical compositions containing them and the use thereof in treatingcertain mammalian tumors. The invention also relates to the aglycones of the novel glcosides and certain novel intermediates.

The invention provides the anthracycline glycosides la,b and IIa,b:

X 0 HO 0.,_) \,0H 9 All 4 0 HO 7 " z CH 1 2 0 X 0 HO Qd-H 1 1 0 HO H. 1 2 0 CH 0 OH NH 2 Ia,b a: X=H NH 2 IIa,b b: X=OH wherein X represents a hydrogen atom or a hydroxy group, and their pharmaceutically acceptable acid addition salts. Preferred salts are the hydrochlorides.

For some relevant structural features, the new compounds of the invention are related to the known CH 3 j - 0 3 antitumor glycosides daunorubicin and doxorubicin, both of which are amply described in the litterature and both of which are at present being clinically used in treating certain tumors. However, the new anthracyclines differ from natural glycosides in the presence of a five member alicyclic ring on the aglycone moiety.

The new glycosides are obtained by coupling of aglycone (3) with the 1chloro derivative of N,O-trifluoroacetyl-daunosamine (4).

0 HO 0-1 OH IP, 0 HO CH 2 OH CF 3 coo 3 cl CH 3 NHCOCIF, 3 4 Accordingly, the invention also provides a process for the preparation of an anthracycline glycoside of formula I or II or a pharmaceutically acceptable acid addition salt thereof, which process comprises:

(i) reacting 7(R,S), 9(R, S)-4-demethoxy-7-deoxy-7hydroxymethyl-10-nordaunomycinone of formula (3):

0 HO 0 On !P' I I N; (3 14 0- HO CH 2 OH 3 1 with 2,3,6-trideoxy-3-trifluoroacetamido-4-0-trifluoroacetamido-a-Llvxopyranosyl chloride of formula (4) cl CH 3 000P W 3 COO NHCOCF 3 4 in the presence of silver trifluoromethanesulfonate to obtain a diastereomeric mixture of N,O-protected glycosides; (ii) removing the Nand 0-trifluoroacetyl groups to obtain the diastereomeric free bases of formula Ia and Ila; (iii) if desired, converting the said free bases into pharmaceutically acceptable acid addition salts therof; (iv) separating the diastereomeric free bases of formula la and IIa or pharmaceutically acceptable acid addition salts thereof; (v) if desired, brominating a said free base or pharmaceutically acceptable acid addition salt thereof and hydrolysing the 14-bromo derivative thus obtained to form thereby a free base of formula Ib or lIb; and (vi) if desired, converting a said free base of formula Ib or IIb into a pharmaceutically acceptable acid addition salts thereof.

In another aspect of the invention, there is-provided the racemic intermediate 7(R,S), 9(R,S)-4-demethoxy-7-deoxy7-hydroxymethyl-10-nordaunomycinone of formula (3). This 4 racemic compound is prepared by a process comprising reacting a diasterecisomeric mixture of 7(R,S), 9(R,S)-4demethoxy-6,10-dimethoxy-7,9dideoxy-7-hydroxymethyl-10nor-daunomycinone with potassium t-butoxide and oxygen followed by treatment with aluminium trichloride.

The racemic intermediate of formula (3) can in turn be obtained by a process starting with p-benzoquinone and methylcyclopentadiene. The overall reaction scheme is shown below.

1 R e a c t i c:-, E ch e.-r e 0 OCH C H 3 55 C H 3 3 H 3 0 OCE 3 OCH 3 CH 3 ""OH 1 0 H CH- 9 3 W H 3 > c--, -1,' T OCH OCH 3 CH 3 z OCH 3 10 B-C H -0 / 6 5 lla: T = COOCH 3 W = 0 llb: T = COOH W = H 1 L aCOOCE 3 COOH 0 CH CH OCH 3 CH 3 3 3 + z OCH 12 11 1 0 OCH 0 CH 3 CH 3 CH 3 CH 3 H z 00 CH H OCH 3 3 13 14 1 - 1 j - Sa - 0 CH 3 0 OCH G 15a: G = CHO 15b: G = CH 2 OH 3 +CH 0 -+ j::

F:NHC 0 C F - W 3 coo 3 4 1 0 0 HO OH H CH H 2 U CH 3 0 - OH NH 2.

Ia Ib HO OH H CH-OH 2 3 0 0 0 OH 0 HO 2 0 CH -M -Vl- -r, 2on -r--V7 OH NHCOW 3 17 0 HO OH H H0 qH 0 2 CH --, - 0 3 (7NH_ _; OH 2 IIb k The actual starting material for the reaction sequences is 2-methyl-1,4, 4a,8a-tetrahydro-endo-1,4-methanonaphthalene-5, 8-dione (7) prepared via the Diels-Alder reaction of p-benzoquinone (5) and the isomeric mixture of methylcyclopentadiene (6), as described by A.P. Marchand et al. (j. Org. Chem., 49, 670 (1984)1. Compound (7) is promptly transformed into the corresponding dimethoxy-tetrahydronaphthalene derivative (8) by treatment with sodium hydroxyde and methyl iodide.

Cis-hydroxylation of the double bond of (8), performed with potassium permanganate in aprotic solvents such as methylene dichloride and in the presence of an organic salts such as triethylbenzylammonium chloride, gives (9) which is protected as phenylboronate by treatment with phenylboric acid in trifluoroacetic acid. The phenylboronate (10) is converted to (11a) (mixture of two isomers) by acylation with phthalic acid monomethylester in the presence of trifluoroacetic acid and trifluoroacetic anhydride at reflux.

Alkaline hydrolysis of the methyl ester followed by redu ction of the aroyl carbonyl function affords derivative (11b) which is promptly transformed to the anthrone mixture (12) by treatment with trifluoroacetic acid and trifluoroacetic anhydride at room temperature. oxidation to the anthraquinone system (13), performed by alkaline oxygen treatment of (12), and removal of the phenylboric protecting i group, gives the new tetracyclic system (14). Treatment of (14) with sodium periodate allows the formation of the 10-noranthracyclic system (15a) bearing the acyl and the formyl functions. The selective reduction of the formyl group, without affecting the ketone group, performed using tetra-n-butylammonium-triacetoxyborohydride gives the mixture of alcohols (15b).

The introduction of a tertiary hydroxyl group is carried out by known methods using potassium t-butyloxide and oxygen, see J.N. Gardner et al, J. Org. Chem., 33, 3294 (1968). Finally the treatment with aluminium trichloride allows the target anthracyclinone (3) to be obtained. The racemic anthracyclinone (3) is condensed with the protected 1-chloro-N,Oditrifluoroacetyldaunosamine (4) in the presence of silver trifluoromethanesulphonate to give a mixture of diasteroisomeric aglycosides (17). This is typically perfomed in an inert organic solvent such as methylene dichloride.

Chromatographic separation after alkaline removal of the Ntrifluoroacetyl group, gives (Ia) and (IIa). These daunorubicin derivatives can be converted to the corresponding doxorubicin derivatives (Ib) and (IIb) by bromination of the acyl side chain and treatment with sodium formate in accordance with the method described in US-A-3803124.

In one embodiment, a methanolic solution of t A? q p-benzoquinone (5) 0 1 1 0 0 cooled at -SCC, is treated with an isomeric mixture of methyl cyclopentadiene (6):

1:2 CH 3 6 allowing the solution to warm slowly at room temperature and after 3 hours, isolating the so formed 2-methyl-1,4,4a,8a tetrahydro-endo-1,4-methanaphthalene-5,8-dione (7):

0 CH 3 0 7 which, after crystallization from methanol, is reacted in methanolic solution at CC and under nitrogen atmosphere with an aqueous solution of 10% sodium hydroxyde and with methyl iodide to give 5,8-dimethoxy-2- methyl-1,4-dihydro-1 (R,S), 4 (R,S) methanonaphthalene (8):

1 1 OCH 3 CH 3 1 1 OCH 3 8 from which, after treatment in methylene dichloride solution, with potassium permanganate and triethylbenzylammonium chloride at OOC, and after purification of the crude reaction product by chromatography on silica gel using as eluent system methylene dichloride-acetone (95:5 v/v), the pure 1,2,3,4-tetrahydro-2(R,S), 3(R,S)-cis-hydroxy-5,8dimethoxy-2methyl-l(R,S), CR,S)-methanonaphthalene (9) OCH 3 CH 3 OH -OH OCH 3 9 is obtained, and subsequently reacted, at CC and in trifluoroacetic acid solution, with phenylboronic acid, isolating from the reaction mixture, after stirring at room temperature for 4 hours, the wanted 1,2,3,4tetrahydro2(R,S), 3(R,S)-c-is-phenylboronate-5,8-dimethoxy-2-methyll(M), CM) methanonaphthalene (10):

- 10 OCH 3 H 3 1 00 Z CH 3 10 0 B - C H Z M 0. 0.0OF 6 5 001 which, dissolved in a mixture of trifluoroacetic acid and trifluoroacetic anhydride, is treated at reflux temperature for 12 hours, with phthalic acid monomethyl ester:

CCOOCH 3 COOH to give an isomeric mixture of the compound (11a):

OCH 3 CH 3 1 Z T CH- 3 lla: T = COOCH 3 W=0 hydrolyzing the monomethyl ester, at 00 and for 30 minutes with a hydroalcoholic mixture of potassium hydroxide, reducing the hydrolyzed product in trifluoroacetic acid solution, with triethylsilane, at 50'C and for 24 hours, to obtain an isomeric mixture of l,2,3,4-tetrahydro- 2(_R,S), 3(R,S)-cis-phenylboronate-5,8-dimethoxy-2-methyl-6-(21- i 1 carboxybenzyl)-1-(R,S), 4(R,S)-methanonaphthalene and 1,2,3,4-tetrahydro-2(R,S), 3(R,S)-cis-phenylboronate-5, 8-dimethoxy-2-methyl-7-(21-carboxybenzy'&.)-1(R,S), 4(R,S) methanonaphthalene (11b):

W OCH 3 CH 3 Z (:VT CH llb: T = COOH W = H 2 which, by reaction at OOC and for 5 minutes with a mixture of trifluoroacetic anhydride and trifluoroacetic acid, is transformed to the anthrone mixture (12):

1 0 OCH 3 CH 3 CH 3 CH 3 Z + 0 OCH OCH 3 12 oxidizing said mixture, in methanolic solution in the presence of N-benzyl-trimethylammonium hydroxide with a 1 stream of oxygen, at room temperature for 4 hours, to isolate, after chromatographic purification on silica gel using as eluting system toluene-acetone (10:1 v/v)-and.subsequent crystallization from diethyl ether, the pure k I 4 12 - novel anthraquinone derivative (13):

0 CH - 3 CH 3 %, 1 11% Z G1 z p H 3 13 removing the phenyl boric protecting group by treamtment, in methylene dichloride solution, with 2-methyl-pentane-2,4- diol in acetic acid at room temperature and for 48 hous, to obtain the 7(R,S), 8(R,S), 10(R,S)-4-demethoxy-6,11dimethoxy-7-deoxy-7,10-methano-8-hydroxy-g-desacetyl-9methyl-daunomycinone (14):

0 OCH 3 CH 3 OH t!". OH 0 OCH 3 14 which is treated, at room temperature, in methylene dichloride solution, with an aqueous solution of sodium periodate to give 4-demethoxy-6, 10-dimethoxy-7,9-dideoxy7-formyl-10-nor-daunomycinone (15a) 0 CH 0 0..- 1 1 9 7 - -G c 4 0 CH' I 15a: G = CHO 4 submitting said intermediate to a selective reduction of the 7-formyl group, in anhydrous benzene, at reflux temperature for 2 hours, by means of tetra-n-butyl-ammonium-tri-acetoxyborohydride, to obtain a diastereomeric mixture of 7(R,S), 9(R,S)-4-demethoxy-6,10-dimethoxy-7,9dideoxy-7-hydroxymethyl-10-nor-daunomycinone (15 b): 0 CH 3 0 0 OCH 3 G 15b: G = CH 2 OH which dissolved in anhydrous dimethylformamide, is first reacted with- potassium t-butyloxide in the presence of triethylphosphite while a stream of oxygen is bubbled through for 30 minutes and subsequently treating the obtained crude product, at the reflux temperature in methylene dichloride and for 40 minutes with anhydrous aluminium trichloride, to obtain finally, after chromatographic purification on silica gel using as eluent system methylene-dichloride: methanol (95:5 v/v), the wanted racemic mixture of 7(R,S), 9(R,S)-4-demethoxy-7-deoxy- 7hydroxymethyl-10-nor-daunomycinone (3).

In an embodiment for the prearation of the glycosides I and II and their salts, the 7(R,S), 9(R,S)-4demethoxy-7-deoxy-7-hydroxymethyl-10-nordaunomycinone of formula (3), dissolved in anhydrous methylene dichloride is reacted, at room temperature and for two hours, with 2,3,6-trideoxy-3trifluoroacetamido-4-0-trifluoroacetamidoa-L-lyxyranosyl chloride of formula (4) in the presence of sym-collidine and an ethereal solution of silver trifluoromethanesulfonate to obtain a diastereoisomer mixture of N, O-protected glycosides which, after treatment with methanol, at room temperature for 30 minutes, gives the corresponding diastereomeric Nprotected trifluoroacetyl derivatives of formula (17): 0 HO 0--OH 0 HG CH 2 0 CH 3!z 0 NHCOCF., 17 OH 3 from which, after mild alkaline hydrolysis, at OOC and for minutes with aqueous 0.1N sodium hydroxide for removing the N-trifluoroacetyl protecting group, a mixture of the diastereomeric free bases I(a) and II(a) (X = H) is obtained; isolating the free bases by treatment with methanolic hydrogen chloride as ther hydrochlorides; submitting the diasteromeric mixture of the hydrochlorides to a chromatographic separation on a column of silica gel using as eluting system methylene dichloride: methanol:

-water (100:20:2: v/v) so as to obtain, separately, the pure diastereomeric hydrochlorides of formula I(a) and II(a) (X H); and treating, if desired, each pure diastereomer with a solution of bromine in chloroform, submitting the so obtained 14-bromo derivatives to hydrolysis with an aqueous solution of sodium formate and finally isolating the obtained free bases I(b) and II(b) (X - OH), by treatment with methanolic hydrogen chloride, as their corresponding hydrochlorides.

As is apparent from the foregoing, these processes involve the preparation and use of several novel intermediates. These too are within the scope of the present invention.

In yet another aspect thereof, the invention provides pharmaceutical compositions comprising an anthracycline glycoside of formula I or II or pharmaceutically acceptable acid addition salt thereof in admixture with a pharmaceutically acceptable diluent or carrier. Conventional carrier and diluents and conventional formulation techniques may be employed.

Finally, the invention provides methods of treating certain mammalian tumors using the new anthracycline glycosides and salts of the invention. A therapeutically effective amount of a compound of the invention is administered to a patient in need of it. Conventional routes of administration, in particular parenteral routes such as intravenously, may be employed.

The following Examples illustrate the invention.

16 - Example 1 Preparation of: 5,8-dimethoxy-2-methyl-1,4-dihydro-I(R,S),4(R, S)methanc naphthalene (8) 9 (0.462 moles) of p-benzoquinone (5) in 1000 mi of methanol cooled at C. was added with & freshly distilled Isomeric mixture of 50 =1 (0.5 mmoles) of methylcyclopentadiene (6) following the procedure described by A.P.Marchand [J.Org.Chem., jLg, 670 (1984)1. The solution was allowed to warm slowly to room temperature, after 3 hours the reaction mixture was concentrated to small volume and 2-methyl-1,4,4a,Ba-tetrahydro-endc-1 4methanonaph-.ha- lene-5,8-dione (7) was isolated after crystallization from methanol. Yield 45ch r compound (7), dissolved in 900 r.1 cf, 33.6 g (0.18 moles) cd.

aqueous 10% sodium. hydrox---.

methanol and 540 mI, c..' Lde, was cooled at 0. C and bubbled with nitrogen for one hour. After that, 60 ml of methyl iodide, diluted in 140 rnl of methanol, was added dropwise and the mIxture was stirred overnight.

Then the reaction mixture was neutralized by adding aqueous IN hydrochloric acid and the solvent removed in vacuc. The crude product was chromatographed on a column of silica gel eluting with petroleum ether and diethyl ether (100:1 by volune) to give the title product (8) as oil, 299 yield'75%.

TLC kieselgel plates Merck F 254 (petroleum ether:diethyl ether 20:1 by volume) Rf 0.28.

El-MS: m/e 216 (M+) PMR (200 rHz, WC-1 3) 6, inter alia:

6.52 (s, 2H, B-6, B-7); 6.24 (m, 1H, E-3); 4.07 (m, 1H, B-4); 3.85 (M, 1H, B-1); 3.78 (s, 6H, 2X0CH3); 2. 24-2.15 (two m, 2H, CH 2 -9) Example 2 Preparation of:

1-,2,3,4-tetrahydro-2(R,S),3(R,S)-cis-phenylboronate-S,B-dim ethoxy-2methyl-l(R,S),4(R,S)methanonaphthalene (10) To a.solution of 20 g (0.092 moles) of compound (8) in 1000 ml of methylene dichloride, a freshly prepared solution of 21.9 g (0.138 moles) of potassium permanganate and 31.5 g (0.138 moles) of triethylbenzylammonium chloride in 1200 M of methylene dichloride was added dropwise In two hour at O&C under stirring. After two hour of additional stirring at O'C, the dark-brown solution was treated with 250 ml of aqueous 10% sodium hydroxide under nitrogen at O6C for two hours. The manganese dioxide, generated by the alkaline treatment, was removed by filtration and the organic phase was washed with satured aqueous sodium metabisulfite. After conventional work up, the crude product was purified through chromatographyc column of silica gel eluting with methylene dichloride/acetone (95:5 by volume) to give 13.8 g of pure 1,2,3,4-tetrahydro-2(R,S),3(R,S)-cis-hydroxy-5,8dimethoxy-2-methyl-I(R,S),4(R,S)-methanonaphthalene (9) Yield 60%. TLC kieselgel plates Merck F 254 (methylene dichloride:acetone 10:1 by volume) Rf 0.2 FD-MS: m/e 250 (M+). PEM (200 MHz, CDCl.) 6, inter alia:

6.6 (s, 2H, H-7 H-8); 3.76 (s, 6H, 2x0CH 3); 3.63 (Broad signal, 1H, OH3); 3.38 (m, 1H, H-3); 3.35-3.28 (two m, 2H, H-1, H-4); 2.31-1.86 (two m, 2H, H-9a. H-9s); 0.99 (s, 3H, C113) 129 (48 mmoles) of compound (9) was dissolved in 150 ml of trifluoroacetic acid, cooled at OOC and added with 7.8g of phenylboronic acid. The mixture was stirred for two hours at O&Cand four hours at room temperature. After that the reaction mixture was poured in a separator funnel and washed with aqueous sodium hydrogen carbonate and water. The organic phase was dried over anhydrous sodium sulphate, filtered off and the solvent removed in vacuo to give, after crystallization from methanol, 12.5 g of the benzeneboronate derivative (10), yield 78%. Melting point 9f C.

TLC kieselgel plates Merck F 254 (methylene dichloride: acetone 20:1 by volume) Rf 0.66. FD-MS: m/e 336 (M+).

Example 3 Preparation of: 1,2,3,4-tetrahydro-2(R,S),3(R,S)-cisphenylboronate-5,8-dim ethoxy-2-methyl-6-(21-carboxybenzyl)-1(R,S),4(R, S)methan onaphthalene and 1,2,3,4-tetrahydro-2(R,S),3(R,S)cisiphenylboronate-5,8-dinethoxy-2-methyl-7-(21-carboxybenzyl)I(R,S),4(R, S)methanonaphthalene (11b) 12 9 (35.7 mmoles) of compound (10), prepared as described in Example 2, and 9.72 9 (54 ffLmoles) of phthalic acid momomethyl ester, dissolved in a mixture of 200 ml of trifluoroacetic anhydride and 100 ml of trifluoroacetic acid, was refluxed for twelve hours. The residue, obtained by evaporating off the solvents under reduced pressure, was purified on a column of silica gel, using methylene dichloride as the eluting solvent, to give, after crystallization from diethyl ether, 13.8 g of the isomeric mixture (11a), yield 78% Melting point 169-1720C.

TLC kieselgel plates Merck F2,4 (methylene dichloride: acetone 20:0.1 by volume) Rf 0.32. El-MS: m/s 470 (M+). 13 g (26 mmoles) of compound (11a) was dissolved in 240 mi of ethanol, cooled at DOC and added with 150 ml of acraeous potassium hydroxide. After 30 minutes the mixture was acidified with 2N hydrochloric acid and extracted with methylene dichloride. The organic phase was separated and the solvent removed in vacuo. After that, the residue was dissolved in 50 ml of tifFIjoroace-ic acid and ad--ed dropwise with 12 ttl of triethylsilane.

- 19 The reaction mixture was warmed at ST C for twentyfour hours, then cooled, diluted with water and extracted with methylene dichloride. The organic phase was separated and the solvent removed in vacuo. The residue was chromatographed on a column of silica gel, using methylene dichloride:methanol (20:0A by volume) as eluting system, to afford an Isomeric mixture of (lib) (8.5 9, yield 70%). Melting point 17r C.

TLC on kieselgel plates Merck F 2,4 (methylene dichloride: methanol 20:1 by volume) Rf 0.62. EI-MS: m/e 470 (M+).

PMR: (200 MHz, WC13) 8. inter alia:

8.0-7.1 (m-, 9H, aromatics); 6.40 (s, iH, H-6); 4.43-4.37 (two d, j=16.0 Hz, 2F. Ar-CH 2 -Ar); 4.18 (m, 1H, H-3); 3.70 (s, 6H, 2x0CH 3); 3.66 (m, 1H, H-4); 3.47 (m, 1H, H-1); 2.18-1.99 (two d, j=10.0 Hz, 2H, H-9a, H-9b) Example 4 Preparation of: 7 (R, 5) B (R, S) 9 (R, S) -10 (R, S) -4demethoxy-6,11-demethoxy -7-de oxy-7,10-methano-8-hydroxy-g-desacetyl-gmethyl-daunomycino ne (14).

To a solution of 8 g (16.6 mmoles) of compound (lib), prepared as described in Example, 3, in 100 ml of trifluoroacetic anhydride was added dropwise 40 rnl of trifluoroacetic acid at OOC under stirring. After 5 minutes the reaction was completed, the solvent mixtures was evaporated off and the residue was dissolved in methylene dichloride and washed with aqueous saturated solution of sodium hydrogen carbonate and then with water. The organic phase was dried over anhydrous sodium sulphate to give, after evaporating off the solvent the isomeric mixture of c=pound (12) - z - 20 T1C kieselgel plates Merck F 254 (toluene:acetone 95:5 by volume) Rf 0.53.

FD-MS: m/e 548 (M+).

7.6 g (7.5 mmoles) of (12) was dissolved in 800 ml of methanol, added with 14 rnl of a 40% inethanolic solution of Triton B (Nbenzyltrimethylammoniumhydroxyde) and bubbled with a stream of oxygen at room temperature. After four hours the reaction mixture was brought to pH 5 by adding aqueous 0.1N hydrochloric acid and extracted with methylene dichloride. After conventional processing, the crude product was chromatographed on a column of silica gel, using a mixture of toluene:acetone (10:1 by volume) as eluting system, to afford, after crystallization from diethyl ether, 5 9 of the novel anthraquinone system derivative (13).

Yield 68%, melting point 2040C TLC kieselgel plates Merck F 2,4 (toluene:acetone 95:5 by volu.,n,e) Rf 0. 31 FD-MZ: m/e 467 (M+) The phenylboric protecting group was removed by dissolving compound (13) in 300 ml of methylene dichloride and treating with 80 ml of 2 -methyl pentane - 2, 4 -diol diluted with 15 mi o acetic acid. The reaction mixture was stirred at room 4.

temperature for 48 hours. After that, the mixture was brought to pH 7 with aqueous 0.1N sodium hydroxide, and the product was extracted with methylene dichloride. The solvent removed in vacuo to afford, after crystallization from diethyl ether, the title compound (14) (3.6 g, yield 87%). Melting point 205C with decomposition. TLC kieselgel plates Merck F2.4 (methylene dichloride: acetone 90:10 by volume) Rf 0.2 FD-MS: m/e 380 (M+) PM (200 MHz, WC13) 6, inter alia: 8.2-8.1 (m, 2H, H-1, H-4); 7.8- 7.7 (m, 2H, H-2, H-3); 3.99-3.98 (s, 6H, OCH 3_ 6 OCH 3_ 11); 3.58 (rn, 1H, H-10); 3.52 (m, 1H, H-8); 3.50 (m, 1H, H-7); 3.11 (d, j=6.0 Hz, 1H, CH-8); 2.80 (s, 1H, OH-9); 2.47-1.99 (two m, 2H, CH2) - 21 Example 5 Preparation of 7(R,S),9(R,S)-4-demethoxy-6,10-dinethoxy-7,9dideoxy7-hydroxymethyl-10-nordaunomycinone (15b) 3.5 9 (9 mmoles) of compound (14), prepared as described in Example 3, dissolved in 400 ml of methylene dichloride, was treated with a solution of 2.8 g (9.3 mmoles) of sodium periodate in 120 mI of water and stirred for two hours at room temperature to give, after conventional work up the isomeric inixture of 4 -deme thoxy- 6, 10 -dime thoxy -7, 9 -dideoxy7-formyl-10-nordaunomycinone (15a), which was used in the next step without purification.

TLC kieselgel plates Merck F 254 (methylene dichloride: acetone 10:1 by volume) Rf 0.43 FD-MS: m/e 378 (M,+) P1,M (200 r,.tJz, CDCI 3) 6, inter alia:

9.82 (d, j=1.9Hz, 1H, CHO); 8.2-8.1 (m, 2H, H-1, H-4); 7.8-7.7 (m, 2H, H2, 1-3); 4.36 (dd, j=5.1, 8.9HZ, 1H, h-9); 4.25 (ddd, j=1.9, 4.9, 8.7Hz, 1H, H-7); 3.94-3.87 (two s, 6H, OCIM 3_ 6, OCH 3_ 11); 2.7-2.3 (m, 2H, CH 2_ 8); 2.33 (s, 3H, COCH 3) Compound 15a, dissolved in 50 ml of anhydrous benzene, was added in one portion to a solution of 4.3 g (10 mmoles) of te tra-n -butyl - ammonium - tri -ace toxy-borohydride, prepared as described by G.W.Gribble et al. [Tetrahedron Letters, 24, 4287 (1983)], in 30 ml of anhydrous benzene warmed it 80 0 C.

The reaction mixture was refluxed for two hours and then processed by pouring into water, then was extracted with diethyl ether, dried over anhydrous sodium sulphate and the solvent removed in vacuo. The residue was purified by chromatography on a column of silica gel, using as Cluting a mixture of methylene dichloride acetone 90:10 by volume, to afford the title compound 15b as a diastereoisomeric mixture (2.4 g, yield 7M. TLC kieselgel plates Merck F 254 (methylene dichloride:acetone 8:2 by volume) Rf 0.49.

FD-MS: rnle 380 (M+).

JP - 22 PMR: (200 MHz, CDC1 3) 6, inter alia: 8.2-8.1 (m, 2H, L-1, 1L-_4); 7.8-7. 7 (m, 2H, R-2, H-3); 4.31 (dd, j=10.2, 4.8Hz, 1H, H-9); 3.86-3.87 (two s, 6H, OCH -6 OCH3- 11); 3.92 (m, 2H, CH 2 OH); 3.8-3.7 (m, 1H, B-7, L65' (ddd, j=13.9, 10.2, 9.6Hz, 1H, H-8a); 2.35 (s, 3H, COCH 3); 2.17 (ddd, J=13.9, 4.8, 4.7Hzo. 1H, H-8b) Example 6 Preparation 7(R,S),9(R,S)-4-demethoxy-7-deoxy-7-hydroxymethyl- 10-nordaunomycinone (.1) of:

2.2 g (5.7 mmoles) cl. compound 15b, prepared according to Example 5, was dissolved in 50 rnl of anhydrous dimethylformamide and added to a solution of 100 mi of anhydrous dimethylfornazide containing 1 g of potassixLT,, t-butoxy and 1 ml of triethylphosphite cooled at -15'C. The mixture was bubbled with a stream of oxygen. The colour of the reaction mixture began brown. After 30 minutes the reaction was completed, since it was quenched in water, extracted with methylene dichloride. After evaporating of the organic solvent, the crude product was dissolved in 200 ml of anhydrous methylene dichloride and refluxed with 2 g of anhydrous alum-Jn--u:n trichloride for 40 minutes. The ---ate- reaction mixture was quenched with 200 rr,l of aq.ueojs sa--, e.

oxalic acid, then extracted with methylene dichloride to give, after purification on a column of silica gel eluting with a mixture of methylene dichloride:acetone (90:10 by volume), ihe title compound 15 (0.42g 20% yield).

TLC kieselgel plates Merck F 2,4 (methylene dichloride: methanol 95:5 by volume) Rf 0.34 FD-MS: m/e 392 (M+) PMR: (200 MHz, DY,50) 8, inter alia:

13.00-12.96 (s, 2H, OH-6, OH-11); 8.3-8.2 (m, 2H, H-1, H-4); 8-0-7.9 (m, 2H, H-2, H-3); 5.95 (1H, 2H-9); 5.35 (m, 1H, CH 27-C)1), 3.6D (m, 1H, R7); 2.57 (dd, j=8.3, 14.0Hz, 1H, H-Sal; 2.34 (s. 3H, COCH 3); 2.15 (dd, j=1.9, 14.0 HZ, 1Ho H-Bbl i lk - 23 Example 7 Preparation of (7S,9R)-4-demethoxy-7-deoxy-7- daunosarninyloxvmethyl-10-nordaunomycinone (la,Y =H) and -(7R,9S)-4demethoxy-7-deoxy-7daunosaminylox.vmethyl-10-nordaunomycinone (Ila,X =H) To a solution of 0.320 g (0.081 rnmoles) of racemic 7(R,S),9(R,S)-4demethoxy-7-deoxy-7-hydroxymethyl-10-nor- daunomycinone (3), prepared as described in Example 1, in 200 ml of anhydrous methylene dichloride, there were added 1 9 of molecular sieves (41 Merck), 0.5 g of 2,3,6-trideory3-trifluoroacetamido-4-0-trifluoroacetamido-.ct-L-lyxopyranosyl-chloride (4), 0.200 ml of sym-collidine and 0.250 g of silver trifluoromethanesulphonate dissolved in 2 ml of anhydrous diethyl ether. After 2 hours at room temperature the reaction mixture was filtered and washed with aqueous O.IN hydrochloric acid, water, aqueous saturazed hydrogen carbonate, and water. Then the residue obtained by the evaporation =E the solvent was taken up in methanol and after 30 minutes at room temperature the hydrolysis of the C-C-O-trifluoroacetyl group was completed. This afforded a mixture of the N-trifluoroacetyl diastereoisomers (17).

TLC on kieselgel plates (Merck F 254) using the solvent system methylene dichloride:methanol (95:5 by volume) Rf 0.28.

FD-MS: m/e 457 (M+) The hydrolysis of the N-protecting group was performed by dissolving the N-trifluoroacetyl derivative in aqueous O.IN sodium hydroxyde. After 30 minutes at O&C the solution was adjusted to pH 8 and extracted with methylene dichloride. Evaporation of the solvent to a small volume, followed by addition of methanolic 0.1N hydrogen chloride in order to adjust the pH to 4.5, afforded the title compounds Ta and Ma, as the hydrochlorides (0.2 g, 50% yield). TLC on silica gel plates (Merck F 254) using the solvent system methylene dichloride.-methanol.-acetic acid:water (30:4:1:0.5 by volume) RI 0.26. FD-HIS.. W/5 498 (MH+); 497 (M+ ) The pure diastereoisomers are obtained by chromatographic separation on a column of silica gel using, as eluent, the solvent system methylene dichloride:methanol:water (100;20:2 by volume).

PMR of the diastereoisomeric mixture (50:50) of compounds 'Ta,Sa (200 MHz, DMSO) 6, Inter alia:

12.94-13.01 (S, 2.H-6, 2.H-11); 83-8.2 (M, 2H, g-1, h-4); 8.0-7.9 (m, 2H, H-2, M-3); 6.06-5.99 (s, 1H, 2jH--9); 5.45-5.42 (d,j=6.6 Hz, 1H, OH-41); 4.89 (m, 1H, H-19); 4-0-3.2 (m, 6H, M-7, h-51, H-41, H-31, CH 20); 2.7-2.2 (m 2H, CH2-8); 2. 30 (s, 3H, COCH 3); 1.8-1.6 (m, 2H, CH-21); 1.11-1.02 (d, j=6.6 Ez, 3H, CH 3-CS')- Exc-on.ple 8 Preparation of(7S,9R)-4-dernetho3-y-7-deo>rv-7-daunosarr, inyloxymethyl-10-nordoxorub--c-n (7b) Following the process described in U.S. Pat. No.3,803,124 and using as starting material the lo-nor-daunorubicin derivative Ta, prepared according to Example 7, the title compound was isolated as the hydrochloride.

Ex amm 1 e 9 Preparation of (7R,9S)-4-demethoxy-7-deoxy-7daunosaminyloxymethyl-10-nordoxorubicin (lib) 1 Following the process described in U.S. Pat. No.3,803,124 and using as the starting material compound T_ja, prepared according to Example 7, the title compound was isolated as the hydrochloride.

f

Claims (14)

- 25 CLAIMS

1. An anthracycline glycoside having the general formula I (a,b) or II (a, b):

X 0 HO H CH 0 H 2 0 HO OJ ,,OH 9 7 0 HO CH 2 1 U CH 3 0 7NHOH 2 Ia, b a: X=H b: X=OH U CH 3 0 3 ? OH 2 IIa,b wherein X represents a hydrogen atom or a hydroxy group, and their pharmaceutically acceptable acid addition salts.

2. A compound according to claim 1, which is (7S, 9R)-4-demethoxy-7-deoxy7-daunosaminyloxymethyl-10-nordaunomycinone or its hydrochloride.

3. A compound according to claim 1, which is (7S, 9R)-4-demethoxy-7-deoxy7-daunosaminyloxymethyl-10-noradriamycinone or its hydrochloride.

4. A compound according to claim 1, which is (7R, 9S)-4-demethoxy-7-deoxy7-daunosaminyloxymethyl-10-nordaunomycinone or its hydrochloride.

1 A i - 26

5. A compound according to claim 1, which is (7R, 9S)-4-demethoxy-7-deoxy- 7-daunosaminyloxymethyl-10-noradriamycinone or its hydrochloride.

6. A process for the preparation of an anthracycline glycoside of formula I or II as defined in claim 1 or a pharmaceutically acceptable acid addition salt thereof, which process comnprises (i) reacting 7(R,S), 9(R,S)-4-demethoxy-7-deoxy-7hydroxymethyl-10-nor- daunomycinone of formula (3):

OJ 0 HO OH 4 0 HO CH 2 OH 3 with 2,3,6-trideoxy-3-trifluoroacetamido-4-0-trifluoroacetamido-a-Llyxopyranosyl chloride of formula (4) CH_ CF 3 COO NHCOCF 3 4 in the presence of silver trifluoromethanesulfonate to obtain a diastereomeric mixture of N,O-protected glycosides; (ii) removing the N- and 0-trifluoroacetyl groups to obtain the diastereomeric free bases of formula Ia and IIa; (iii) if desired, converting the said free bases into -pharmaceutically acceptable acid addition salts thereof; i (iv) separating the diastereomeric free bases of formula Ia and IIa or pharmaceutically acceptable acid addition salts thereof; (v) if desired, brominating a said free base or pharmaceutically acceptable acid addition salt thereof and hydrolysing the 14-bromo derivative thus obtained to form thereby a free base of formula Ib or 11b; and (vi) if desired, converting a said free base of formula Ib or Ilb into a pharmacueitcally acceptable acid addition salt'thereof.

7. A process according to claim 6, wherein the 7(R,S), 9(R,S)-4-demethoxy7-deoxy-7-hydroxymethyl-10-nordaunomycinone of formula (3), dissolved in anhydrous methylene dichloride is reacted, at room temperature and for two hours, with 2,3,6-trideoxy-3-trifluoroacetamido-4-0trifluoroacetamidoix-L-lyxopyranosyl chloride of formula (4) in the presence of symcollidine and an ethereal solution of silver trifluoromethanesulfonate to -obtain a diastereoisomeric mixture of N,O-protected giycosides which, after treatment with methanol, at room temperature for 30 sainutes, gives the corresponding diastereomeric N-protected trifluoroacetyl. derivatives of formula (17):

0 HO 0--OH 0 HO H j 2 0 CH PNHCOCF, OH 3 17 from which, after mild alkaline hydrolysis, at OOC and for 30 minutes with aqueous O.IN sodium hydroxide for removing the N-trifluoroacetyl protecting group, a mixture of the diastereomeric free bases I(a) and II(a) (X-H) is obtained; isolating the free bases by treatment with methanolic hydrogen chloride as their hydrochlories; submitting the diasteromeric mixture of the hydrochlories to a chromatograhic separation on a column of silica gel using as eluting system methylene dichloride: methanol: water (100:20:2: v/v) so as to obtain, separately, the pure diastereomeric hydrochlorides of formula I(a) and 11(a) (X-H); and treating, if desired, each pure diastereomer with a solution of bromine in chloroform, submitting the so 1 obtained 14-bromo derivatives to hydrolysis with an aqueous solution of sodim formate and finally isolating the obtained free bases I(b) and II(b) (X=OH), by treatment with methanolic hydrogen chloride, as their corresponding - 29 hydrochlorides.

8. A pharmaceutical composition comprising an anthracycline glycoside of formula I or II as defined in claim I or a pharmaceutically acceptable acid addition salt thereof in admixture with a pharmaceutically acceptable diluent or carrier.

9. The racemic 7(R,S), 9(R,S)-4-demethoxy-7-deoxy7-hydroxymethyl-10-nordaunomycinone or formula (3):

H H H CHIOH 3

10. A process for the preparation of the racemic 7(R,S), 9(R,S)-4- demethoxy-7-deoxy-7-hydroxymethyl-10-nor- daunomycinone of formula (3):

H H CHlOH 3 which process comprises reacting a diastereoisomeric mixture of ERtS), 9(R,S)-4-demethoxy-6,10-dimethoxy-7,9-dideoxy-7hydroxyaethyl-10-nordaunomycinone with potassium t!-butoxide and oxygen followed by treatment with aluminium trichloride.

11. A process according to claim 10, in which a 1 - 30 methanolic solution of p-benzoquinone (5):

cooled at -500C, is treated with an isomeric mixture of raethyl cyclopentadiene 6):

allowing the solution to warm slowly at room temperature and after 3 hours, isolating the so formed 2-methyl-1,4,4a, 8a-tetrahydro-endo -1,4-methanaphtalene-5,8-dione (7):

CH 3 1 Oti 0 7 which, after crystallization from methanol, is reacted in methanolic solution at VC and under nitrogen atmosphere with an aqueous solution of 10% sodium hydroxyde and with methyl iodide to give 5,8-dimethoxy-2methyl- ] 4-di hydro-] (R, 5), 4 (R,S) ni--thano4-,ap.,)tialene (8):

OCH 3 ooCH 3 OCH 3 8 from which, after treatment in methylene dichloride solution, with potassium permanganate and triethylbenzylammonium chloride at OOC, and after purification of the crude reaction product by chromatography on silica gel using as eluent,system methylene dichloride-acetone (95:5 v/v), the 1 pure 1,2,3,4-tetrahydro-2(R,S), 3(R,S)-cis-hydroxy-5,8-dimethoxy-2-methyl- OCH 3 CH 3 OH OH CH 3 9 is obtained, i 1k and subsequently reacted, at CC and in trifluoroacetic acid solution, with phenylboronic acid, isolating from the reaction mixture, after stirring at room temperature for 4 hours, the wanted 1,2,3,4tetrahydro2(R, S), 3(R, 5)-cis-phenylboronate-5,8-dimethoxy-2-methyl-]-(R, S), 4(R,S) methanonaphtalene (10):

OCH 3 CH 3 1 Z CH, 0^% B-C H 6 5 which, dissolved in a mixture of trifluoroacetic acid and trifluoroacetic anhydride, is treated at reflux temperature for 12 hours, with phthalic acid monomethyl ester:

COOCH 3 COOH to give an isomeric mixture of the compound (11 a):

W CH 3 CH 3 Z dT CH 3 IIa: T = COOCH 3 W 0 1 hydrolyzing the monomethyl ester, at 01 and for 30 minutes with a hydroalcoholic mixture of potassium hydroxide, reducing the hydrolyzed product in trifluoroacetic acid solution, with triethylsilane, at 5 r and for 24 hours, to obtain an isomeric mixture of 1,2,3,4-tetrahydro-2 (R,S), 3(R,S) cis-phenylboronate-5,8-dimethoxy-2-methyl-6-(2'-carboxy benzyl)-I-(R,S), and 3(R,S)-cis-phenylboronate-5,8-dimethoxy-2-methyl-7-(2Lcarboxybenzyl)-1(R,S), 4(R,S/' (11b):

W OCH 3 CH 3 cl 1 Z OCH 3 llb: T = COOH W = H,) which, by reaction at OOC and for 5 minutes with a mixture of trifluoro- acetic arn,,d,-ide a-nd tri-fl.joroacezic acid, is -.ran.sfc-.7-,r=-d --c the anthrone rr.ixz,a-,e ( 12):

- 3 4 - 1 9 0 OCH OCH 3 CH 3 CH 3 Z + 00 0 OCH OCH 3 12 i oxidizing said mixture, in methanolic solution in the presence of N- benzy] trimethylammonium hydroxide with a stream of oxygen, at room temperature for 4 hours, to isolate, after chromatographic purification on silica gel using as eluting systerr toluene-acetone (10:1 v/v) and subsequent crystallization frorr, diethyl ether, the pure novel 0 OCH 3 CH 3 1 1 - 0 OCH 3 13 removing the phenyl boric protecting group by treatment, in methylene dichloride solution, with 2-methyl-pentane-2,4-diol in acetic acid at room temperature and for 48 hours, to obtain the 7(R,S), 8 (R,S)-10 (R,S)4-demethoxy-6,11-dimeftxy-7-deoxy-7,10-methano-8-hydroxy-g-desacetil-9methyl-daunomycinone (14):

0 CH 3 CH 3 OH OH CH3 0 CH #_ 0 CH, 14 which is treated, at room temperature, in methylene dichloride solution, with an aqueous solution of sodium periodate to give 4-demethoxy-6,10dimetfloxy-7,9-dideoxy-7-formyl-10-nor-daunomycinone (15a) 0-1 CH 3 0 0 1 7 0 CH- G 3 1 5a: G CHO submitting said intermediate to a selective reduction of the 7-formyl group, in anhydrous benzene, at reflux temperature for 2 hours, by meais of tetra-n-butyl-ammonium-tri-acetoxy-borohydride, to obtain a diastereomeric mixture of 7(R,S), 9(R,S)-4-demethoxy-6,10-dimethoxy-7,9dideoxy-7-hydroxymethy]-10-nor-daunomycinone (15 b):

0 CH 3 0 0 0 OCH3 G 15b: G = CH 2 014 - 36 which dissolved in anhydrous dimethy1formamide, is first reacted with potassium t-butyloxide in the presence of triethylphosphite while a stream of oxygen is bubbled through for 30 minutes and subsequently treating the obtained crude product, at the reflux temperature in methylene dichloride and for 40 minutes with anhydrous aluminium trichloride, to obtain finally, after chromatograhic purification on silica gel using as eluent system methylene-dichloride: methanol (95:5 v/v), the wanted racemic mixture of 7(R,S), 9(R,S)-4-demethoxy-7-deoxy-7- hydroxymethyl-10-nordaunomycinone (3).

12. An anthracycline glycoside of formula I or II as defined in claim 1 or a pharmaceutically acceptable salt thereof for use as an antitumor agent.

13. A process for the preparation of an anthracycline glycoside of formula I or II as defined in claim 1 or a pharmaceutically acceptable salt thereof, said process being substantially as hereinbefore described in any one of Examples 7 to 9.

14. A process for the preparation of racemic 7(R,S), 9(R,S)-4-demethoxy-7deoxy-7 hydroxymethyl-10-nordaunomycinone, said process being substantially a hereinbefore described in Example 6 or in Examples 1- to 6 taken together.

PtLlj,i--he!d 1990atThePatentOffice, State House, 66171 1-hghHolborn. London WCIR4TP. Further copies maybe obtainedfrom The Patent OfficeP-t,.d bv Multin2ex technicues ltd. St Mary Cray. Kent. Con. 1187