合成路线1

The reaction of pregnenolone (I) with I2 and pyridine at 90 C gives (3beta-hydroxypregn-5-en-20-one-21-yl)pyridinium iodide (II), which by treatment with sodium methoxide in refluxing methanol is converted into methyl 5-androsten-3beta-ol-17beta-carboxylate (III). The Meerwein-Poundorf oxidation of (III) with cyclohexanone (A) and aluminum isopropoxide in refluxing toluene yields methyl 4-androsten-3-one-17beta-carboxylate (IV), which is hydrolyzed with KOH in refluxing methanol - water to the corresponding free acid (3-oxo-4-etienic acid) (V). The reaction of (V) with oxalyl chloride (B) and diethylamine in refluxing toluene affords 17beta-(N,N-diethylcarbamoyl)-4-androstene-3-one (VI), which is oxidized with O3 or with NaIO4 and KMnO4 giving 17beta-(N,N-diethylcarbamoyl)-5-oxo-3,5-secoandrostan-3-oic acid (VII). The cyclization of (VII) with methylamine ethylene glycol at 180 C in a pressure vessel affords 17beta-(N,N-diethylcarbamoyl)-4-methyl-4-aza-5-androsten-3-one (VIII), which is finally reduced with H2 over Pt in acetic acid. The cyclization of the acid (VII) with NH3 in ethanol at 180 C in a pressure vessel gives 17beta-(N,N-diethylcarbamoyl)-4-aza-5-androsten-3-one (IX), which is reduced with H2 over Pt in acetic acid yielding 17beta-(N,N-diethylcarbamoyl)-4-aza-5alpha-androstan-3-one (X). Finally, this compound is methylated with CH3I by means of NaH in toluene.

合成路线2

The oxidation of 3-oxo-4-etienic acid (V) with NaIO4 and KMnO4 in tert-butanol - water gives 5-oxo-3,5-secoandrostane-3,17beta-dioic acid (XI), which is cyclized with methylamine in ethanol at 180 C in a pressure vessel yielding 17beta-carboxy-4-methyl-4-aza-5-androsten-3-one (XII). The hydrogenation of (XII) with H2 over Pt in acetic acid affords 17beta-carboxy-4-methyl-4-azaandrostan-3-one (XIII), which is finally treated with oxalyl chloride (B) and diethylamine in toluene-THF. The amidation of (XIII) with oxalyl chloride (B) and NH3 in toluene-THF gives 17beta-carboxamide-4-methyl-4-azaandrostanone (XIV), which is alkylated with ethyl bromide and NaH in toluene. The amidation of (XIII) with ethylamine and oxalyl chloride (B) in toluene-THF gives 17beta-(N-ethylcarbamoyl)-4-methyl-4-azaandrostan-3-one (XV), which is finally alkylated with ethyl bromide and NaH in toluene.

合成路线3

2) By the reaction of 3-oxoandrost-4-ene-17beta-carboxylic acid (III) with diisopropylcarbodiimide (II) in refluxing ethyl acetate and subsequent A-ring opening of compound (IV) by treatment with the Lamieux-von Rudloff reagent (permanganate-periodate) in isopropanol. The cyclization of the secoacid (V) so obtained, with methylamine in dioxane under pressure, followed by the hydrogenation under pressure, on 10% Pd/C in ethanol, affords turosteride. This method is used for the large scale production of turosteride.

合成路线4

Methyl 3-oxoandrost-4-en-17beta-carboxylate (I) was converted to methyl 3-bromoandrosta-3,5-diene-17beta-carboxylate (II) by treatment with phosphorus tribromide in glacial acetic acid. Saponification of (II) in methanolic potassium hydroxide afforded 3-bromoandrosta-3,5-diene-17beta-carboxylic acid (III), which was further converted to 3-bromo-N-(1,1-dimethylethyl)androsta-3,5-diene-17beta-carboxamide (IV) by treatment with oxalyl chloride and quenching with tert-butylamine. Treatment of (IV) with ethyl magnesium bromide, followed by halogen metal-exchange with sec-butyllithium and gassing with carbon dioxide afforded crude epristeride (V). Alternatively, 3-bromo-N-(1,1-dimethylethyl)androsta-3,5-diene-17beta-carboxamide (IV) was prepared in one step by treatment of 17beta-androst-4-en-3-one carboxylic acid (VI) with bromomethylenedimethylammonium bromide, followed by quenching with tert-butylamine. Crude epristeride was purified and converted to the desired polymorph by heating a suspension in ethyl acetate.

合成路线5

The synthesis of [14C]-labeled epristeride has been reported: The oxidation and decarboxylation of 3-oxo-4-androstene-17beta-carboxylic acid methyl ester (I) gives the 3-oxo-4-oxasteroid (II), which is methylated with [14C]-labeled methyl magnesium iodide, yielding labeled 3-hydroxy-3-methyl-4-oxa-5-androstene-17beta-carboxylic acid methyl ester (III). The cyclization of (III) by means of NaOH affords labeled 3-oxo-4-androstene-17beta-carboxylic acid methyl ester (IV), which is hydrolyzed with KOH to the corresponding acid (V). The reaction of (V) with trifluoromethanesulfonic anhydride gives the androstadiene triflate (VI), which by reaction first with SOCl2 and then with tert-butylamine is converted to the amide (VII). The carboxylation of (VII) with CO and triphenylphosphine palladium diacetate complex in methanol affords [14C]-labeled 17beta-(N-tert-butylcarbamoyl)androsta-3,5-diene-3-carboxylic acid methyl ester (VIII), which is finally treated with K2CO3 in refluxing methanol/water.

合成路线6

1) The reaction of 3-oxo-4-androstene-17beta-carboxylic acid (I) with SOCl2/pyridine in THF gives the acyl chloride (II), which is condensed with 2,5-bis(trifluoromethyl)aniline (III) by means of pyridine in refluxing THF, yielding amide (IV). The oxidation of (IV) with KMnO4/NaIO4/Na2CO3 in refluxing tert-butanol/water affords the seco-steroid (V), which is cyclized with NH3 in ethylene glycol at 180 C to give the 5-unsaturated azasteroid (VI). The hydrogenation of (VI) with H2 over PtO2 in acetic acid yields the saturated azasteroid (VII), which is finally dehydrogenated by means of 2,3-dichloro-5,6-dicyanobenzoquinone (DCQ)/bis(trimethylsilyl)trifluoroacetamide in dioxane.

合成路线7

2) The oxidation of 3-oxo-4-androstene-17beta-carboxylic acid (I) with KMnO4/NaIO4/Na2CO3 in refluxing tert-butanol/water affords the seco-steroid (VIII), which is cyclized with NH3 in ethylene glycol at 180 C, giving the 5-unsaturated steroid (IX). The hydrogenation of (IX) with H2 over PtO2 in acetic acid yields the saturated azasteroid (X), which is esterified with 2,2-dimethoxypropane/HCl in methanol to afford the corresponding methyl ester (XI). The dehydrogenation of (XI) with phenylseleninic anhydride in refluxing chlorobenzene gives the 1-unsaturated azasteroid (XII), which is hydrolyzed with KOH in refluxing methanol/water to yield the corresponding unsaturated free acid (XIII). The esterification of (XIII) with 2,2'-dipyridyl disulfide (XIV) by means of triphenylphosphine in toluene affords the 2-pyridyl thioester (XV), which is finally amidated with 2,5-bis(trifluoromethyl)aniline (III) by means of silver trifluomethanesulfonate in dichloromethane. 3) The previously obtained unsaturated free acid (XIII) can also be treated with SOCl2 in pyridine to give the corresponding acyl chloride (XVI), which is then condensed directly with 2,5-bis(trifluoromethyl)aniline (III) in pyridine.

合成路线8