(2RS,3RS)-3-tert-butoxycarbonyl-5-oxotetrahydrofuran-2-carboxylic acid → (2RS,3RS)-2-[N-{(1RS,2RS,4E)-5-(2-benzoxazolyl)-1-methyl-2-(3,4-methylenedioxyphenyl)-4-pentenyl}-N-(2-naphthylmethyl)carbamoyl]-5-oxotetrahydrofuran-3-carboxylic Acid

Participants

Reaction Steps

47 mg of tert-butyl (2RS,3RS)-2-[N-{(1RS,2RS,4E)-5-(2-benzoxazolyl)-1-methyl-2-(3,4-methylenedioxyphenyl)-4-pentenyl}-N-(2-naphthylmethyl)carbamoyl]-5-oxotetrahydrofuran-3-carboxylate prepared in a manner similar to Example 27 except that (2RS,3RS)-3-tert-butoxycarbonyl-5-oxotetrahydrofuran-2-carboxylic acid obtained in Reference Example 4 was used, instead of the 1,2-di-tert-butyl (R*)-1,2,3,-propanetricarboxylate in Example 27, was dissolved in 1 ml of formic acid, and the solution was left to stand at room temperature overnight. The reaction solution was distilled under reduced pressure. Then, toluene was added to the residue, followed by distillation again. The product was purified by silica gel column chromatography (hexane/ethyl acetate=2/1)→chloroform/methanol=50/1) to obtain 20 mg (yield: 46%) of the above-identified compound as white solid.

Provenance & Evidence