FR2664277A1 - Sinefungin derivatives, their preparation and their application in therapeutics - Google Patents

Abstract

The subject of the present invention is the total synthesis of natural (S)-sinefungin derivatives. This is a nucleoside antibiotic which displays a twofold anti-HIV and antiparasitic activity. The strategy which we describe for the synthesis of natural (S)-sinefungin 1a and its (R) epimer in the C6' position 1b involves the additon of the C4' radical of adenosine, resulting from the decarboxylation of the thiohydroxamic ester 129, to the olefin 192. This olefin is activated in the alpha position by an electron-withdrawing group suitable for its subsequent conversion to an amine functional group. This radical addition to the olefin 192 is carried out with retention of configuration on the 4' carbon of the adenosine in order to lead to the addition product 194, a key intermediate in the synthesis of sinefungin. The advantage of this method lies in the fact that it lends itself to the preparation, in only a few stages, of a great variety of derivatives. It is compatible with various purine and pyrimidine bases and with modifications to the sugar part.

Description

 The present invention relates to sinefungine derivatives, their preparation and their therapeutic application.

Sinefungin is a naturally occurring substance that has been isolated from cultures of
Streptomyces griseolus, and syntheses of which have been described in Nucleic Acid Rets.

(1982), 10, 6223 and in J. Am. Chem. Soc., (1983), 105, 7638. Its chemical formula (Ia) is given in Scheme 1 below. The carbon atom in the 6 'position is chiral and of S configuration. On the other hand, the epimer of configuration R (formula Ib) is new and forms part of the invention.

 Both compounds can be prepared by a process illustrated in Scheme I below.

 The thiohydroxamic ester of formula 129 is first prepared from the acid of formula 32 (formulas wherein Bz is benzoyl), according to the mixed anhydride method described in J. Am. Chem. Soc. (1967), 895012 followed by treatment with the sodium salt of N-hydroxythione-2-pyridine, and then irradiating the latter in the presence of the olefinic amide of formula (in which Z represents a benzyloxycarbonyl group and Bn represents a benzyl group). An addition product of formula 194 is thus obtained in the form of two C-6 'diastereoisomers and a rearrangement product of formula 235 (formulas in which Spy represents a (pyridyl-2-ylthio) group. the pyridyl-2-ylthio group of the compound of formula 194 by means of tributyltin hydride, by thermolysis and in the presence of a radical initiator such as α, α'-azoisobutyronitrile (AIBN) or a peroxide.

 A mixture of two compounds of formulas 195a and 195b, epimers at the C-6 'position, is obtained which can be separated, for example, by medium pressure chromatography on a column of silica gel.

 The amide function of each of the compounds 195a and 195b is then converted into a primary amine function, by Hoffmann rearrangement, according to the conditions described in Synthesis (1981), 266-268, that is to say by the [bis ( trifluoroacetoxy) iodo] benzene in a mixture of dimethylformamide and water, and in the presence of a stoichiometric amount of pyridine.

 The primary amine functions are then protected in the presence of t-butyloxycarbonyl in the presence of di-t-butyl carbonate and triethylamine to give compounds 185a and 185b, respectively.

 Finally, these compounds are deprotected successively by hydrogenolysis in the presence of palladium on carbon, by treatment with ammonia in methanol, and by acid hydrolysis. There is thus obtained, respectively, the compound of formula la, identical to natural sinefungine, and its epimer (R) at C-6 ', of formula lb.

Schema 1

<tb><SEP> IBBz <SEP> ~ <SEP> EI? NBz
<tb><SEP> HOOC <SEP>ÈÇÉI;;
<tb><SEP> Oo <SEP> oO
<tb><SEP> 32 <SEP>) <<SEP> 129
<tb><SEP> ZONEZ
<tb><SEP> HNBz <SEP> EINBz
<tb><SEP> ZEN: <SEP> CONE1 <SEP> N <SEP> Spy <SEP> N <SEP> N
<tb><SEP> 0N
<tb><SEP> 19 '<SEP> H <SEP> COOBn <SEP> Rus <SEP> oN
<tb><SEP> ZEN <SEP> o <SEP> O <SEP> O <SEP> O <SEP> oOt
<tb><SEP> E <SEP> COOBn <SEP> 194 <SEP> ffi <SEP> 23S
<tb><SEP> Bu, SnH
<tb><SEP> AIBN
<tb><SEP> Benzenc. <SEP> reflux
<tb><SEP> HNBz <SEP> H: NB
<tb><SEP> I <SEP> r
<tb><SEP> NI! <SEP> NN
<tb><SEP> COJHî <SEP> 0NN <SEP><NH1
<tb> ZIIN <SEP> O <SEP> O <SEP> ZEN
<tb> ZEN <SEP> R <SEP> ZEN
<tb><SEP> COOBri <SEP> H
<tb><SEP> 19b <SEP> l9Sa
<tb><SEP> i: <SEP> cc, coj1rcji5 <SEP> t: (CF, CO21C5
<tb><SEP> Pyridine
<tb><SEP> li: <SEP> 3oc, O <SEP> Pyridine <SEP> i: <SEP> DIMF-EI30 (1: r)
<tb><SEP> HL, N, <SEP> DMF, <SEQ> TA <SEP> DMF-H1O (1: 1) <SEQ> Ei, N, <SEP> DMF, <SEP> TA <SEP> TA
<tb><SEP> TA
<tb><SEP> VENRI <SEP> V <SEP> ENBZ
<tb><SEP> N
<tb><SEP>; 1oc <SEP>zip; NBBoe <SEP> II
<tb> ZEN <SEP> R <SEP> Y <SEP> ZHN <SE> O <SEP>
<tb><SEP> H <SEP> COOBn <SEP> g <SEP> COOBn <SEP> K
<tb><SEP> IS5b
<tb><SEP> ISSa
<tb><SEP> 10% PdIC, <SEP> E,
<tb><SEP> EtOR <SEP> EtOHi: <SEP> 10% PdIC, <SEP> H1
<tb><SEP> ii: <SEP> NHXlMeOH <SEP> ii:
<tb><SEP> iii: <SEP> CFxCOOHIHxO <SEP> 1 <SEP> r <SEP> X <SEP> r <SEP> iil: NEeOE
<tb><SEP> NE, <SEP> it: <SEP> CCOOH! H1O
<tb><SEP> NN <SEP> NE1
<tb><SEP> RNH10 <SEP> ^ <SEP> NX <SEP> AT) ÉI) N
<tb> H <SEP> s- <SEP> 0NN
<tb> OH <SEP> HO <SEP> OH
<tb><SEP> H <SEP> COOff <SEP> H1N <SEP> - <SEP> HO <SEP> OH
<tb><SEP> lb <SEP> H <SEP> COOH
<tb><SEP> lb <SEP> la
<Tb>
Figure 2

<tb><SEP> O <SEP> COOEt <SEP> COOEt
<tb><SEP> II <SEP> CE, 01E10
<tb><SEP> (Eto) ,? <SEP> COOEt <SEP> ~ H- <SEP> / <SEP> PBr,
<tb><SEP> SzCON <SEP> itherTA <SEP> ~ Br
<tb><SEP> 202 <SEP> 203 <SEP> 204
<tb><SEP> (PhS) :: JNnH4
<tb><SEP> EtOH
<tb><SEP> COOEt
<tb><SEP> CHssAICINH5 <SEP> COOEt
<tb><SEP> Bcmnc <SEP> -SPh
<tb><SEP> 205
<tb><SEP> CONS1
<tb><SEP> mSPh <SEP> CONHX
<tb><SEP> R <SEP> Fi <SEP> 197 <SEP>) =
<tb><SEP> C-ONv <SEP> S
<tb> ZH <SEP>ZHN'C
<tb><SEP> H <SEP> COO3n <SEP> COOBn
<tb><SEP> 216 <SEP> 192
<Tb>
Figure 3

The olefinic amide of formula 192 can be prepared as illustrated in Scheme 2, from commercial ethyl triethylphosphonoacetate of formula 202, by reaction of
Wittig-Horner on formaldehyde in the presence of potassium carbonate, followed by bromination of the intermediate of formula 203 by phosphorus tribromide.

 The bromide of formula 204 thus obtained is described in Synthesis (1982), 924-926.

The latter is then treated with one equivalent of sodium thiophenolate prepared from diphenyldisulfide and sodium borohydride. The ester of formula 205 (wherein Ph represents a phenyl group) is obtained which is converted to amide of formula 197 by means of methylchloroaluminum amide prepared in situ from trimethylaluminium and ammonium chloride in benzene.

Finally, the amide of Formula 197 is reacted with the ester of Formula 216 (wherein Z is benzyloxycarbonyl and Bn is benzyl) by irradiation at 0 C. The ester of Formula 216 is described in Y HERVE, Thesis, 1986,
Orsay. The acid of Formula 32 can be prepared as illustrated in Scheme 3, from the alcohol of Formula 30 (wherein Bz is benzoyl) described in J. Arn.

 Dear. Soc., (1979), 101, 1554-1564, first by an oxidation to aldehyde of formula 31 as described in J. Med. Chem., (1987), 30, 888-894 and in J. Am. Soc., (1976), 98 3346-3357, followed by acid oxidation with 3-chloro-peroxybenzoic acid in dichloromethane.

 The following example illustrates the invention in detail. The elemental microanalyses and the IR, NMR and mass spectra confirm the structures of the compounds obtained.

Ethyl Example 1. 2-IPhenyltio) methylprop-2-enoate (Formula 205).

 19.2 g (100 mmol) of ethyl 2- (bromomethyl) prop-2-enoate are reacted with a solution of 11.99 g (55 mmol) of diphenyldisulphide in 200 ml of ethanol and 4.18 g. (110 mmol) sodium borohydride at room temperature for 18 hours.

 After chromatography on a column of silica gel, 15.65 g of colorless oil are isolated (yield: 76%).

2. 2-IPhenylthio) methyl-prop-2-enamide (Formula 197).

 To a suspension of 10.7 g (200 mmol) of ammonium chloride in 200 ml of anhydrous benzene is added dropwise, under argon at 0 ° C, 100 ml (200 mmol) of trimethylaluminium (2M in toluene), the reaction mixture is stirred at room temperature for 2 hours, then transferred to a flask containing 14.65 g (66 mmol) of α-thiophenylacrylate 205 and 300 ml of anhydrous benzene, and the mixture is stirred at 50 ° C under argon for 5 hours. 16 hours.

 The mixture is cooled to 0 ° C. and 50 ml of 5% hydrochloric acid is added. The organic phase is separated, the aqueous phase is extracted with three times 100 ml of ethyl acetate, the organic phases are combined, dried over sodium sulfate, filtered and evaporated under reduced pressure. After purification of the residue on a column of silica gel (eluent ethyl acetate / hexane, 1/1), 10.45 g of amide are isolated (yield: 82%).

 Phenylmethyl 5-amino-2-aryl-2 - [[phenylmethoxy) carbol-5-enoate (Formula 192).

 A solution of 4,284 g (12 mmol) of 1,2-dihydro-2-thioxopyridin-1-yl and phenylmethyl 2 L [phenylmethoxy) carbonylamino] succinate (Formula 216, Y. HERVE, Thesis, Orsay, 1986) and 11.58 g (60 mmol) of 2 - ((phenylthio) methyl] prop-2-enamide (Formula 197) in 60 ml of anhydrous tetrahydrofuran for 30 minutes at 0 ° C. Then the mixture is diluted with dichloromethane and washed successively with a saturated solution of sodium bicabonate, with water, and with saturated sodium chloride solution, the organic phase is dried over magnesium sulfate, filtered and evaporated at room temperature. The residue is purified by chromatography on a column of silica gel (eluent ethyl acetate / hexane, 6/4), and 2,947 g are isolated in crystalline form (yield: 62%). 93-95 C.

4. 1 '- [6- (Benzoylmino) -9H-puran-9-yl] -1'-deoxy-2', 3'-O- (isopropylidene) -ridofuranuronic acid (Formula 32).

 To a solution of 9.8 g (24 mmol) of N-benzoyl-2 ', 3'-O- (isopropylidene) adenosine and 14.88 g (72 mmol) of dicyclohexylcarbodiimide in 54 ml of dimethylsulfoxide is added dropwise. The mixture is stirred at 0 ° C., 0.96 ml (12 mmol) of dichloroacetic acid, and the mixture is stirred at room temperature for 1 hour 30 minutes. The dicyclohexylurea formed is filtered off and the filtrate is extracted four times with 100 ml of cyclohexylurea. hexane to remove excess dicyclohexylcarbodiimide. The dimethylsulfoxide solution is diluted with 400 ml of chloroform and then washed with twice 200 ml of water. It is dried over sodium sulphate, filtered and evaporated to dryness under reduced pressure.

 The residue (aldehyde of formula 31) is dissolved in 240 ml of anhydrous dichloromethane and 8.28 g (48 mmol) of 3-chloroperbenzoic acid are added. The mixture is stirred at room temperature for 30 minutes, the dichloromethane is evaporated under reduced pressure, the residue is triturated with diethyl ether, the precipitate formed is filtered off and washed with diethyl ether. 7.14 g of product is obtained which is recrystallized from a large volume of methanol (yield 70%). M.p. 235-238 ° C.

5. 6'-Aminocarbonyl-1- [6- (benzoylamino) -9H-purin-9-yl-1 ', 5', 6 ', 7', 8 ', 9'-hexa-deoxy-2', Phenylmethyl 3'-O- (isopropylidene) -9 '- [[(phenylmethoxy) carbonyl] smino] -1H- (pyridin-2-ylthio) furanuronate (formula 194).

 0.11 ml (1 mmol) of 4-methylmorpholine and 0.14 ml (1 mmol) of isobutyl chloroformate are added, under argon and at 0 ° C., to a solution of 0.425 g (1 mmol) of acid 1 6- (benzoylamino) -9H-purin-9-yl] -1-deoxy-2 '' - 3 - O- (isopropylldene) ribofuranuronic acid in 12 ml of anhydrous tetrahydrofuran After 15 minutes stirring at 0 ° C 0.178 g (1.2 mmol) of sodium salt of 4-hydroxypyridine-2-thione. The mixture is stirred at 0 ° C. for 30 minutes under argon and protected from light, then a solution of 2.366 g ( 6 mmol) of phenylmethyl 5-aminocarbonyl-2 - [(phenylmethoxy) carbonylamino) hexano-5-enoate (Formula 192) in 6 ml terahydrofuran, and the solution was irradiated with a 250 W tungsten lamp at 00C for 30 minutes. The mixture is diluted with 100 ml of chloroform, washed successively with 50 ml of saturated sodium bicarbonate solution and 50 ml of water, the organic phase is dried over magnesium sulfate, filtered and filtered. ev The residue is purified by chromatography on a column of silica gel, eluting with a 95/5 mixture of ethyl acetate / methanol. 0.381 g of 6 aminocarbonyl-1- [6- (benzoylamino-9H-purin-9-yl] -1 ', 5', 6 ', 7', 8 ', 9'-hexadésoxy-2', 3 are thus isolated. Phenylmethyl-O- (isopropylidene) -9 - [[(phenylmethoxy) carbonyl] amino] -6 '- (pyridin-2-ylthio) -furanuronate (formula 194) and 0.098 g of rearrangement product of formula 235.

6. 6'-Aminocarbonyl-1 '- [6- (benzoylamino) -9H-purin-9-yl] 1', 5 ', 6', 7 ', 8', 9'-hexadésoxy-2 ', 3' Phenylmethyl-O- (isopropylidene) -9- [[phenyl-methoxy) carbonyl] amino] furanuronate, 6S and 6R (formulas 195a and 195b)
0.024 g (0.15 mmol) of α, α'-azoisobutyronitrile and 1.21 ml (4.5 mmol) of tributyltin hydride are added to a solution of 1.329 g (15 mmol) of 6'-aminocarbonyl- 1- (6- (benzoylamino) -9H-purin-9-yl] -1 ', 5', 6 ', 7', 8 ', 9'-hexadesoxy-2,3-O- (1-methylethylidene) - Phenylmethyl 9- [[phenylmethoxy) carbonyl] amino] -6- (pyridin-2-ylthio) furanuronate in 15 ml of anhydrous and degassed benzene, and the mixture is refluxed for 3 hours under argon. It is evaporated under reduced pressure and the residue is chromatographed on a column of silica gel, eluting with a 9/1 mixture of ethyl acetate / butanol-3, thus isolating 0.443 g of 6S-configuration compound. and 0.420 g of compound of configuration 6R, each recrystallized from a mixture of dichloromethane and pentane.

Composed of formel95a
F: 95-96 ° C (CH 2 Cl 2 -pentane) [a 3 D 2 = + 14 "(c = 1, CHCl 3)
Compound of formula 195b
F: 92-95 C (CH2CQ-pentane) [os] D20 = +6.5 (c = 1, CHCl3) 7. 1 '(6-Benzoylamino-9H-purin-9-yl) -1', 5 ' 6 ', 7', 8 ', 9'-hexadesoxy-6' - [[(t-butyloxy) carbonyl] amino] -2 ', 3'-O- (isopropylidene) -9- [phenylmethoxy] carbonyl] amino ] Phenylmethyl furanuronate, 6S (Formula 185a)
0.195 g (0.25 mmol) of 6'-aminocarbonyl-1 '- [6- (benzoylamino) -9H-purin-9-yl] -1', 5 ', 6', 7 ', 8' are dissolved Phenylmethyl 6'-hexadoxy-2 ', 3'-O- (isopropylidene) -9- [(phenylmethoxy) cabonyl] amino] furanuronate, 6S (Formula 195a) in 4 ml of a 1: 1 mixture of dimethylformamide and water, 0.162 g (0.375 mmol) of [bis (trifluoroacetoxy) iodo] benzene was added, the mixture was stirred for 30 minutes at room temperature, then 41 ml of pyridine was added; the mixture is stirred for 2 hours at room temperature, then evaporated under reduced pressure, and the residue is taken up and the residue is evaporated with toluene to remove traces of pyridine.

 The amine obtained is treated with a solution of 0.066 g (0.3 mmol) of di-t-butyl dicarbonate in 2 ml of dimethylformamide and 35 ml of triethylamine, the mixture is stirred for 2 h, evaporated under pressure. reduced, the residue is purified by column chromatography on silica gel eluting with 8/2 ethyl acetate / hexane, and recrystallized from a mixture of dichloromethane / hexane. 0.140 g of purified compound is finally isolated.

185a
F: 94-97 C (CH 2 Cl 2 -pentane) L 0 JD 2 O = + 110 (c = 0.5, CHCl 3) 8. 1 '- (6-Benzoylamino-9H-purin-9-yl) -1', 5 ', 6 Phenylmethyl 7 ', 7', 8 ', 9'-hexadésoxy-6 - [[(t-butyloxy) carbonyl] aminol-2', 3 '-O- (isopropylidene) - [(phenylmethoxy) carbonyl] amino] furanuronate , 6R (Formula 185b).

 Starting from 0.195 g of 6-aminocarbonyl-1'-t6- (benzoylamino) -9H-purin-9-yll-1 ', 5', 6 ', 7', 8 ', 9'-hexadésoxy-2', Phenylmethyl 6H-6- (O-phenylmethoxy) carbonyl] amino] -furanuronate (Formula 195b) and 0.1145 g of the purified compound were finally isolated as above.

F: 90-93 C (CH2Cl2-pentane) (oe) D20 = + 2 (c = 0.5, CHCl3) 9. 6 ', 9'-diamino- (6-amino-1-diamino) - (6) -inino-9H-purin-9-yl) -1 ', 5', 6 ', 7', 8 ', 9'-hexadesoxy-D-glycero-α-tlso-decafuranuronic (formula la).

 0.068 g (0.08 mmol) of 1 '- (6-benzoylamino-9H-purin-9-yl) -1', 5 ', 6', 7 ', 8', 9'-hexadesoxy is hydrogenolyzed Phenylmethyl 6S 6-isopropylidene phenylmethoxycarbonylaminofuranuronate in methanol in the presence of 70 mg of phenylmethyl-phenylmethoxycarbonylammonium [6-isopropylidene] carbonyl] amino] -2 ', 3'-O- (isopropylidene) -9 - [[phenylmethoxy) carbonyl] aminofuranuronate 10% palladium on carbon, under a pressure of 2 bars of hydrogen for 12 hours. The mixture is filtered, the filtrate is evaporated, the residue is washed with diethyl ether and treated with a saturated solution of ammonia in methanol for 16 hours at room temperature. The methanol is evaporated and the residue is hydrolysed with 80% trifluoroacetic acid for 1 h at room temperature. After evaporation, the residue is purified by high performance liquid chromatography, eluting with a 0.03 M solution. ammonium acetate in a 99/1 mixture of water / acetonitrile. After evaporation of the solvents and lyophilization, 0.024 g of compound is finally isolated.

 (<xJD20 = + 11.11 (c = 0.18, H2O).

10. 6 ', 9'-diamino-1' - (6-amino-9H-purin-9-yl) -1 ', 5', 6 ', 7', 8 ', 9'-hexadésoxy-o gly acid cero-bd-allo-decafuranuronic (formula lb).

 Starting from 0.0764 g of 1 '- (6-benzoylamino-911-purin-9-yl) -1', 5 ', 6', 7 ', 8', 9'-hexadésoxy-6 - [[t phenylmethyl [(phenyl- [methoxy) carbonyl] amino] furanuronate, 6R (Formula 185b), and proceeding as above, one obtains a phenylmethyl-N-butyloxy) carbonyl] amino] -2,3-O (1-methylethylidene) -9 [(phenyl- [methoxy] carbonyl] amino] furanuronate. finally isolates 0.026 g of compound.

The] D20 = + 32 (c = 1.1, H20)

Claims (5)

 1. Method of synthesis leading to the compounds of formula la, lb and their analogues  The analogs mentioned above are obtained by the same sequence of reactions (decarboxylation-alkylating addition) as that used for natural sinefungine but from uronic acids derived from uridine, thymidine and guanidine.  Analogues: B = Uracil, Thymine, Guanine; R1 = H or OH, R = H or OH; n = 1-3  B = Adenine; R1 = R2 = OH; n = 0 lb 3 = Adenine; R1 R OH; n = 0 2. Process for the preparation of sinefungine and its epimer of formula Ib as well as their analogues.

Bz represents a benzoyl group) via its thiohydroxamic ester 129 (prepared by reaction of 4-methylmorpholine / isobutyl chloroformate / 4-hydroxypyridine-2-thione sodium salt). This process is characterized by a decarboxylation reaction of acid 32 (in which

The latter is reacted by irradiation in the presence of the amide olefin of formula 192.

 then, on each epimer, a rearrangement of Hoffmann followed by a primary amine protection reaction with a t-butyloxycarbonyl group is carried out to obtain the two epimers of formulas 185a and 185b.

 (Formulations in which Spy represents a pyridin-2-ylthio group), the compound of formula 235 is separated by column chromatography on silica gel and the mixture of epimers of formula 194 is subjected to a reduction by means of hydride of tributyltin in the presence of α, α'-azo-isobutyronitrile, then the two epimers of formula 195a and 195b are separated by chromatography

 and a compound of formula 235

(wherein Z represents a (phenylmethoxy) carbonyl group and Bn represents a phenylmethyl group), to obtain a mixture of epimers of formula 194. (Formulations in which Boc represents a t-butyloxycarbonyl group) and finally deprotect each epimer 185a and 185b, successively by hydrogenolysis, by action of ammonia, and by acid hydrolysis to obtain compounds 1a and 1b. 3. Compounds necessary as intermediates in the process according to claim 2, corresponding to one of the following formulas

 4. Drug containing sinefungin, or an analogue or a synthetic intermediate associated with a pharmaceutical excipient. 5. The medicament of claim 4 having antiparasitic and antiviral (HIV) activities.