合成路线1

A new procedure for the synthesis of acivicin has been reported: The photochlorination of L-glutamic acid (I) gives 3-chloroglutamic acid (II); the corresponding diastereomers were separed by ion-exchange chromatography over Dowex-50 (H+). The reaction of (II) with benzyl chloroformate (III) affords N-carbobenzoxy-3-chloroglutamic acid (IV), which is anhydrized with dicyclohexylcarbodiimide to the corresponding protected anhydride (V). The reaction of (V) with lithium N-hydroxyphthalimide (VI) yields the phthalimidoxy derivative (VII), which is converted to the protected hydroxamic acid (VIII) by a treatment with hydroxylamine. The cyclization of (VIII) with triethylamine affords N-carbobenzoxytricholomic acid (IX), which is esterified with diphenyldiazomethane (X) giving the corresponding protected benzhydryl ester (Xl). The reaction of (XI) with dichloro-trisdimethylaminophosphorane (XII) yields the deprotected final compound (XIII), which is finally treated with trifluoroacetic acid and thioanisole (A).

合成路线2

The reduction of N-benzyloxycarbonylprolinamide (I) with H2 over Pd/c in methanol gives prolinamide (II), which is condensed with N-benzyloxycarbonylhistidyl hydrazide (III) by means of NaNO2 - HCl in ethyl acetate yielding N-benzyloxycarbonylhistidylprolinamide (IV), The hydrolysis of (IV) with HBr in acetic acid affords histidylprolinamide (V), which is finally condensed with gamma-carboxy-gamma-butyrolactone (VI) by means of pentachlorophenol and dicyclohexylcarbodiimide in DMF. Compound (VI) is prepared by reaction of alpha-aminoglutaric acid (VII) with NaNO2 and 2N H2SO4 in water.

合成路线3

The condensation of glutamic acid (I) with 3,4-dichlorobenzoyl chloride (II) by means of Na2CO3 in water gives N-(3,4-dichlorobenzoyl)glutamic acid (III), which is treated with acetic anhydride in refluxing isopropyl ether to afford N-(3,4-dichlorobenzoyl)glutamic anhydride (IV). Finally, this compound is treated with dipentylamine (V) in water.

合成路线4

D,L-Glutamic acid (I) was sequentially protected as the gamma-allyl ester (III), upon treatment with allyl alcohol (II) and chlorotrimethylsilane, followed by conversion to the trichloroethyl carbamate (V) by means of chloroformate (IV), and then reaction of (V) with benzyl bromide to afford the alpha-benzyl ester (VI). Deprotection of the trichloroethyl carbamate of (VI) by treatment with zinc dust and HOAc and subsequent condensation of the resulting amine with decanoyl chloride (VII) furnished amide (VIII). The allyl ester of (VIII) was then selectively cleaved by using tetrakistriphenylphosphine palladium(0) and morpholine to give carboxylic acid (IX). trans-1,2-Diaminocyclohexane (X) was protected as the mono tert-butyl carbamate (XI) and then coupled with acid (IX) in the presence of diethylphosphoryl cyanide to yield amide (XII). After acidic Boc cleavage of (XII), coupling of the resulting amine with 2,5-diphenyloxazole-4-carboxylic acid (XIII) by means of bromo-tris(pyrrolidino)phosphonium hexafluorophosphate (PyBroP) afforded (XIV). Finally, hydrolysis of the benzyl ester of (XIV) with LiOH provided the corresponding carboxylic acid.

合成路线5

D,L-Glutamic acid (I) was sequentially protected as the gamma-allyl ester (III), upon treatment with allyl alcohol (II) and chlorotrimethylsilane, followed by conversion to the trichloroethyl carbamate (V) by means of chloroformate (IV), and then reaction of (V) with benzyl bromide to afford the alpha-benzyl ester (VI). Deprotection of the trichloroethyl carbamate of (VI) by treatment with zinc dust and HOAc and subsequent condensation of the resulting amine with decanoyl chloride (VII) furnished amide (VIII). The allyl ester of (VIII) was then selectively cleaved by using tetrakistriphenylphosphine palladium(0) and morpholine to give carboxylic acid (IX). trans-1,4-Diaminocyclohexane (X) was protected as the mono tert-butyl carbamate (XI) and then coupled with acid (IX) in the presence of diethylphosphoryl cyanide to yield amide (XII). After acidic Boc cleavage of (XII), coupling of the resulting amine with 2,5-diphenyloxazole-4-carboxylic acid (XIII) by means of bromo-tris(pyrrolidino)phosphonium hexafluorophosphate (PyBroP) afforded (XIV). Finally, hydrolysis of the benzyl ester of (XIV) with LiOH provided the corresponding carboxylic acid.

合成路线6