合成路线1

The acylation of 11beta,16alpha,17alpha,21-tetrahydroxypregna-1,4-diene-3,20-dione (I) with isobutyric anhydride in pyridine gives the 16,17,21-triester (III), which is condensed with cyclohexanecarbaldehyde (IV) by means of HCl and HClO4 in dioxane yielding the cyclic ketal (Va-b) as a diastereomeric mixture. Finally, this mixture is resolved by preparative HPLC over Lichrosorb RP-18 affording the desired (R)-isomer, the target compound. Alternatively, the monoacylation of the ketal 11beta,16alpha,17alpha,21-tetrahydroxypregan-1,4-diene-3,20-dione 16,17-O-cyclohexylmethylene ketal (VI) with isobutyric anhydride (II) by means of K2CO3 in acetone gives the previously described diastereomeric mixture (Va-b), which is resolved by crystallization in ethanol/water.

合成路线2

Treatment of cyclohexanecarboxaldehyde (I) with sulfur monochloride produced the dimeric disulfide (II). After condensation of (II) with 3-amino-1-propanol (III), reduction with NaBH4 afforded diamine (IV). Subsequent N-methylation of (IV) to give (VI) was achieved by condensation with formaldehyde, followed by NaBH4 reduction of the resulting oxazine (V). Reductive cleavage of the disulfide group of (VI) using LiAlH4 provided thiol (VII). Optionally, nitrosation of the sulfhydryl group of (VII) by means of tert-butyl nitrite gave rise to the nitrosothio derivative (VIII). Further coupling of this compound with diclofenac (IX) in the presence of DCC and DMAP furnished the title ester. Alternatively, the title compound was prepared by esterification of mercapto alcohol (VII) with diclofenac, followed by S-nitrosation of the resulting ester (X).

合成路线3

Coupling between ethyl 3-aminopropionate (I) and N-Boc-glycine (II) by means of EDC and HOBt affords the protected dipeptide (III). After acidic Boc group cleavage in (III), the N-deprotected dipeptide (IV) is acylated by 3,3,3-triphenylpropionic acid (V) to produce amide (VI). Saponification of the ethyl ester group of (VI) yields acid (VII). This is coupled with (R)-1-Boc-3-(aminomethyl)piperidine (VIII) to afford amide (IX), which is further subjected to acidic N-Boc group cleavage. The resultant piperidine derivative (X) is then reductively condensed with cyclohexanecarboxaldehyde (XI) in the presence of NaBH(OAc)3 to furnish the title compound.

合成路线4

The primary amino group of 4-(aminomethyl)piperidine (I) was protected by conversion to the phthalimide (III) upon heating with phthalic anhydride (II). After coupling of piperidine (III) with 1-naphthylacetic acid (IV) to give amide (V), hydrazinolysis of the phthalimido group of (V) liberated the primary amine (VI). Alkylation of (VI) with N-(4-bromobutyl)phthalimide (VII) furnished the secondary amine (VIII), which was further protected with a tert-butoxycarbonyl group to provide (IX). The phthaloyl group of (IX) was then removed by hydrazinolysis, yielding amine (X). This was subjected to reductive alkylation with cyclohexanecarboxaldehyde (XI) in the presence of NaBH4 to afford the cyclohexylmethyl amine (XII). After purification as the di-Boc derivative, acid cleavage of the tert-butyl carbamate groups provided the title compound.

合成路线5

Saponification of ethyl adamantyloxyacetate (I), followed by treatment of the resultant carboxylic acid (II) with oxalyl chloride gives rise to acid chloride (III). This is then condensed with benzyl (triphenylphosphoranylidene)acetate (IV) to produce the phosphoranylidene keto ester (V). Subsequent oxidative cleavage of phosphorane (V) with oxone under phase transfer conditions leads to diketo ester (VI). Cyclization between diketo ester (VI), cyclohexanecarboxaldehyde (VII) and ammonium acetate in hot AcOH affords imidazole (VIII). The benzyl ester group of (VIII) is removed by catalytic hydrogenolysis, yielding acid (IX), which is further coupled with benzyl 3-aminobenzoate (X) to furnish amide (XI). Finally, benzyl ester hydrogenolysis in the presence of Pd/C provides the target compound (1,2).

合成路线6

合成路线7