Dimethylformamide → (2R,4S)-1-(p-nitrobenzyloxycarbonyl)-2-methoxycarbonylmethyl-4-acetylthiopyrrolidine

Participants

Reaction Steps

(2R,4S)-1-(p-Nitrobenzyloxycarbonyl)-2-carboxymethyl-4-acetylthiopyrrolidine (148 mg) was dissolved in 2 ml of dry methylene chloride, and 0.2 ml of oxalyl chloride and a catalytic amount of dimethylformamide were added thereto, followed by stirring at room temperature for 2 hours. The reaction mixture was distilled to remove the solvent, and dry benzene was added thereto, followed by distillation of benzene. After two times repetition of the above procedure, the residue was dissolved in 2 ml of dry methylene chloride. The solution was added to a mixture of methanol (125 mg), triethylamine (81 mg) and dry methylene chloride (1 ml) under nitrogen stream with ice-cooling and stirred at the same temperature for 2 hours. The reaction mixture was washed successively with water and dilute hydrochloric acid, dried over anhydrous sodium sulfate and distilled to remove the solvent to obtain (2R,4S)-1-(p-nitrobenzyloxycarbonyl)-2-methoxycarbonylmethyl-4-acetylthiopyrrolidine.

Provenance & Evidence