合成路线1

合成路线2

The reaction of 17beta-hydroxy-17-methylandrost-4-en-3-one (I) with thiophenol (A) and formaldehyde by means of triethylamine in refluxing ethanol gives 17beta-hydroxy-17-methy-4-(phenylthiomethyl)androst-4-en-3-one (II), which is desulfurized by treatment with Raney-Ni in water yielding 17beta-hydroxy-4,17-dimethylandrost-4-en-3-one (III). The reaction of (III) with methyl formate by means of sodium methoxide in methanol affords 17beta-hydroxy-4,17-dimethyl-2-hydroxymethyleneandrost-4-en-3-one (IV), which by cyclization with hydroxylamine in acetic acid-sodium acetate is converted into 4,17-dimethylandrosta-2,4-dieno[2,3-d]isoxazol-17beta-ol (V). The epoxidation of (V) with m-chloroperbenzoic acid in methylene chloride gives 4alpha,5alpha-epoxy-4,17-dimethylandrost-2-eno [2,3-d]isoxazol-17beta-ol (VI), which is finally isomerized by treatment with sodium methoxide in THF.

合成路线3

The protected hydroxyproline tosylate (I) was condensed with the sodium derivative of thiophenol (II) to produce thioether (III). After saponification of the methyl ester function of (III), the N-benzyloxycarbonyl group of (IV) was removed by means of HBr in refluxing HOAc, yielding cis-4-(phenylthio)-L-proline (V). Acylation of (V) with (S)-3-(benzoylthio)-2-methylpropionyl chloride (VI) afforded zofenopril (VII), which was finally converted to the corresponding calcium salt by treatment with calcium oxide in EtOH/H2O. The intermediate (S)-3-(benzoylthio)-2-methylpropionyl chloride (VI) was obtained by enzymatic resolution of racemic 3-(benzoylthio)-2-methylpropionic acid (VIII) with Pseudomonas fluorescens (Amano lipase P-30) to yield (S)-3-(benzoylthio)-2-methylpropionic acid (IX), which was activated with oxalyl chloride to afford the chiral acyl chloride (VI).

合成路线4

The reaction of 1-bromo-3-chloropropane (I) with thiophenol (II) by means of NaOH in refluxing water gives 1-(phenylthio)-3-chloropropane (III), which is condensed with piperazine (IV) by means of NaOH in refluxing ethanol-water yielding 1-(3-phenylthiopropyl)piperazine (V). Finally, this compound is condensed with 7-(2,3-epoxypropyl)theophylline (VI) in refluxing ethanol.

合成路线5

A new efficient synthesis of 2-acetylbenzothiophene (I), the key starting material for the previously reported synthesis of zileuton, has been described: Thiophenol (II) is dilithiated with butyllithium and tetramethylethylenediamine in cyclohexane to compound (III), which is then cyclized by successive treatments with DMF and chloroacetone (IV) in THF to afford (I) in high yield.

合成路线6

The condensation of thiophenol (II) with 3-methyl-2-butenyl bromide (I) by means of NaOH in refluxing acetone gives 3-methyl-2-butenyl(phenyl)sulfide (III), which is cyclized by means of P2O5 and H3PO4 in refluxing benzene to yield 4,4-dimethyl-3,4-dihydro-1H-1-benzothiopyran (IV). The acylation of (IV) with acetyl chloride catalyzed by SnCl4 in benzene affords the corresponding 6-acetyl derivative (V), which by dehydration with lithium diisopropylamide and diethyl chlorophosphate in THF is converted into 6-ethynyl-4,4-dimethyl-3,4-dihydro-2H-1-benzothiopyran (VI). Finally, this compound is condensed with ethyl 6-chloropyridine-3-carboxylate (VII) by means of butyllithium in THF. The ester (VII) is obtained by esterification of the corresponding acid (VIII) with ethanol by means of dicyclohexylcarbodiimide (DCC) and dimethylaminopyridine (DMAP).

合成路线7

The addition of thiophenol (II) to N-(benzyloxycarbonyl)-L-serine beta-lactone (I) by means of NaH in THF gives N-(benzyloxycarbonyl)-(S-phenyl)-L-cysteine (III), which is treated with isobutyl chloroformate, diazomethane and N-nitro-N-nitrosoguanidine in ethyl acetate/ethyl ether to yield the diazo intermediate (IV). The treatment of (IV) with dry HCl in ethyl ether affords the chloromethyl derivative (V), which is reduced with NaBH4 in THF giving the secondary alcohol (VI). The dehydrochlorination of (VI) with KOH in ethanol yields the corresponding epoxide (VII), which is submitted to ring opening with (3S,4aS,8aS)-N-(tert-butyl)decahydroisoquinoline-3-carboxamide (VIII) in hot isopropanol to afford the condensation product (IX). The deprotection of (IX) with 30% HBr in acetic acid gives compound (X) with a free amino group, which is finally acylated with 3-hydroxy-2-methylbenzoic acid (XI) by means of dicyclohexylcarbodiimide (DCC) and hydroxybenzotriazole (HOBT) in THF. The benzoic acid (XI) has been obtained by the following sequence: The condensation of 3-methoxybenzoyl chloride (XII) with aniline (XIII) gives the corresponding anilide (XIV), which is methylated with butyllithium and methyl iodide in THF yielding 2-methyl-3-methoxybenzanilide (XV). Finally, this compound is treated with 5N HCl and 30% HBr in refluxing acetic acid.

合成路线8

A new synthesis of nelfinavir has been described: The protection of the amino group of the dioxolane derivative (I) with benzyl chloroformate and K2CO3 in toluene gives the carbamate (II), which is mesylated with MsCl and triethylamine in toluene yielding the mesylate (III). Reaction of compound (III) with thiophenol (IV) by means of tetrabutylammonium bromide and NaOH in toluene/water affords the thioether (V), which is treated with HCl in methanol/water to provide diol (VI). Protection of the primary OH group of (VI) with p-nitrobenzoyl chloride and 2-picoline yields the p-nitrobenzoate (VII), which is mesylated as before to afford the protected compound (VIII). The reaction of (VIII) with KOH in dioxane gives epoxide (IX), which is condensed with N-tert-butylperhydroisoquinoline-3-carboxamide (X) in refluxing methanol to yield the addition product (XI). This compound (XI) can also be obtained by direct condensation of compound (VIII) with isoquinoline (X) by means of K2CO3 in methanol/water. Removal of the benzyloxycarbonyl group of (XI) with KOH in hot isopropanol affords compound (XII), which is condensed with 3-acetoxy-2-methylbenzoyl chloride (XIII) by means of NaHCO3 in ethyl acetate to give the corresponding amide (XIV). Finally, this compound is deacetylated with ammonia in methanol.

合成路线9

A new concise synthesis of nelfinavir has been reported: The asymmetric desymmetrization of the meso-epoxide (I) by means of azidotrimethylsilane and a chiral (R,R)-(salen)chromium(III) complex as catalyst gives the chiral 3-(trimethylsilyloxy)-4-azidotetrahydrofuran (II), which is deprotected with TFA in methanol yielding the chiral 4-azidotetrahydrofuran-3-ol (III). Hydrogenation of (III) with H2 over PtO2 affords the chiral 4-aminotetrahydrofuran-3-ol (IV), which is condensed with 3-acetoxy-2-methylbenzoyl chloride (V) by means of NaHCO3 in dichloromethane to provide amide (VI). The mesylation of the OH group of (VI) with Ms-Cl gives mesylate (VII), which is isomerized with Ac2O and H2SO4 to yield oxazoline (VIII). Condensation of compound (VIII) with the perhydroisoquinoline-3-carboxamide derivative (IX) by means of K2CO3 in methanol affords the oxazoline-adduct (X). Finally, the oxazoline-ring opening of compound (X) is performed with thiophenol (XI) and KHCO3.

合成路线10

The reaction of D-tartaric acid (I) with 2,2-dimethoxypropane (II) and Ts-OH gives the acetonide (III), which is reduced with NaBH4 in ethanol to yield the diol (IV). The reaction of (IV) with Ts-OH and TEA affords the ditosylate (V), whose acetonide is cleaved with HCl to provide the diol (VI). The reaction of (VI) with SOCl2 in dichloromethane gives the cyclic sulfite (VII), which is oxidized with NaIO4 and RuCl3 to yield the cyclic sulfate (VIII). The reaction of (VIII) with sodium azide in acetone/water affords the azide (IX), which is treated with sulfuric acid in THF/water to provide the azido alcohol (X). The reduction of the azido group of (X) with H2 over Pd/C affords the amino alcohol (XI), which is condensed with 3-acetoxy-2-methylbenzoyl chloride (XII) by means of TEA in THF, providing the intermediate amide (XIII). Spontaneous cyclization of the amide (XIII) under the reaction conditions gives the oxazoline (XIV), which is condensed with the perhydroisoquinoline (XV) by means of K2CO3 in isopropanol to yield the oxazoline intermediate (XVI). Finally, the cleavage of the oxazoline ring of (XVI) by means of thiophenol (XVII) affords the target compound.

合成路线11

Alternatively, the reaction of the cyclic sulfate (VIII) with potassium phthalimide (XVIII) gives the N-substituted phthalimide (XIX), whose sulfate group is cleaved with sulfuric acid to yield the alcohol (XX). The reaction of (XX) with the perhydroisoquinoline (XV) by means of K2CO3 in acetonitrile/methanol affords the oxazoline (XXI), whose ring is opened with thiophenol (XVII) and KHCO3 in THF, providing a mixture of the two sulfides (XXII) and (XXIII) that are not isolated. The cleavage of the phthalimido group with refluxing ethanolamine followed by a treatment with benzoic acid gives a mixture of ammonium salts that is separated by crystallization, yielding the desired isomer (XXIV). The reaction of (XXIV) with acid chloride (XII) affords the precursor (XXV), which is finally deacetylated with NaOH to provide the target compound.

合成路线12

The Friedel-Crafts condensation of 4-chlorobiphenyl (I) with 3-methylenetetrahydrofuran-2,5-dione (II) by means of AlCl3 in tetrachloroethane gives 4-(4'-chlorobiphenyl-4-yl)-2-methylene-4-oxobutyric acid (III), which is treated with thiophenol (IV) and K2CO3 in DMF/water, yielding racemic 4-(4'-chlorobiphenyl-4-yl)-4-oxo-2-(phenylsulfanylmethyl)butyric acid (V). Finally, racemic (V) is resolved by means of crystallization with (+)-cinchonine in acetone.

合成路线13

Alkylation of 4-fluorothiophenol (I) with 3-chloropropanol (II) in the presence of K2CO3 in DMF provided thioether (III), which was oxidized to sulfone (IV) using Oxone(R). Fluorine displacement in (IV) with thiophenol and K2CO3 gave phenylsulfanyl derivative (V). The hydroxyl group of (V) was converted to mesylate (VI) and then displaced by potassium thioacetate to afford thioacetate ester (VII). Finally, hydrolysis with methanolic NaOMe furnished the target thiol.

合成路线14

Condensation of 7-methoxytetralone (I) with diethyl carbonate in the presence of NaH afforded ketoester (II), which was alkylated with ethyl 4-bromobutyrate (III) to give (IV). Hydrolysis and decarboxylation of (IV) using KOH in boiling MeOH provided ketoacid (V). Subsequent addition of thiophenol to (V) with concomitant esterification in the presence of ethanolic HCl, followed by oxidative aromatization with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) gave rise to the (phenylthio)naphthalene (VI). Addition of methylmagnesium bromide to the ester function of (VI) yielded carbinol (VII), which was cyclized to the tetrahydroanthracene (VIII) employing ethereal H2SO4. After reductive removal of the phenylthio group of (VIII) by means of Raney Ni yielding (IX), its methyl ether group was cleaved with BBr3, providing phenol (X). Treatment with trifluoromethanesulfonic anhydride gave triflate (XI).

合成路线15

Condensation of 7-methoxytetralone (I) with diethyl carbonate in the presence of NaH afforded ketoester (II), which was alkylated with ethyl 4-bromobutyrate (III) to give (IV). Hydrolysis and decarboxylation of (IV) using KOH in boiling MeOH provided ketoacid (V). Subsequent addition of thiophenol to (V) with concomitant esterification in the presence of ethanolic HCl, followed by oxidative aromatization with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) gave rise to the (phenylthio)naphthalene (VI). Addition of methylmagnesium bromide to the ester function of (VI) yielded carbinol (VII), which was cyclized to the tetrahydroanthracene (VIII) employing ethereal H2SO4. After reductive removal of the phenylthio group of (VIII) by means of Raney-Ni yielding (IX), its methyl ether group was cleaved with BBr3, providing phenol (X). Treatment with trifluoromethanesulfonic anhydride gave triflate (XI).

合成路线16

Thiophenol (I) is treated with mesityl oxide (II) in CHCl3 and Et3N to yield derivative (III), which is then converted into alcohol (IV) by means of methylmagnesium iodide in Et2O. Cyclization of (IV) by means of AlCl3 in CS2 affords benzothiopyrane derivative (V) (1), which is nitrated by means of HNO3 and Ac2O or HOAc followed by treatment with Na2CO3 to provide (VI). Nitro derivative (VI) is then reduced with TiCl3 and HOAc or HCl and treated with NaOH to yield (VII). Amine (VII) is finally acylated with acid chloride (VIII) in benzene and pyridine.

合成路线17

Deoxy rhamnopyranoside derivative (I) was acetylated to (II) and subsequently reacted with thiophenol in the presence of boron trifluoride etherate to afford the phenylthio glycoside (III). Acetate hydrolysis of (III) with methanolic K2CO3 gave alcohol (IV). Inversion of the configuration of position 4 to provide the required epimeric alcohol (VII) was achieved via conversion of (IV) to triflate (V), followed by displacement with potassium benzoate and basic hydrolysis of the benzoate ester (VI). The sulfoxide monomer (IX) was obtained from (VII) by protection with trimethylsilyl triflate yielding (VIII), and then oxidation with m-chloroperbenzoic acid to (IX). Coupling of monomers (VII) and (IX) using the sulfoxide glycosylation method in the presence of triflic anhydride produced a mixture of disaccharide (X), its desilylated analogue (XI), and trisaccharide (XII), which were separated by flash chromatography. Oxidation of disaccharide sulfide (X) with m-chloroperbenzoic acid provided sulfoxide (XIII). On the other hand, trisaccharide (XII) was desilylated with HF.Pyr to afford the corresponding alcohol (XIV).

合成路线18

Displacement of the 4-fluoro group of (IX) with thiophenol (X) in the presence of K2CO3 led to the diaryl sulfide (XI). Acid (XII), prepared by alkaline hydrolysis of ester (XI), was then coupled to O-tetrahydropyranyl hydroxylamine (XIII) by means of EDC to furnish (XIV). Finally, acidic cleavage of the tetrahydropyranyl moiety produced the corresponding hydroxamic acid.