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

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Reaction Steps

(2R,4S)-1-(p-Nitrobenzyloxycarbonyl)-2-carboxymethyl-4-acetylthiopyrrolidine (125 mg) was dissolved in 1 ml of dry methylene chloride, and 0.1 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 to the residue, followed by distillation of benzene. After two times repetition of the above procedure, the resulting residue was dissolved in 2 ml of dry methylene chloride. The resultant mixture was added to a solution of 45 mg of dimethylamine in 1.5 ml of dry methylene chloride and 0.2 ml of dry tetrahydrofuran under nitrogen stream at 0° C., followed by stirring at the same temperature for 30 minutes. The reaction mixture was diluted with methylene chloride, washed successively with water, dilute hydrochloric acid, water, a saturated sodium bicarbonate solution and water, dried over anhydrous sodium sulfate and distilled to remove the solvent. The residue was purified by silica gel thin layer chromatography to obtain (2R,4S)-1-(p-nitrobenzyloxycarbonyl)-2-dimethylaminocarbonylmethyl-4-acetylthiopyrrolidine.

Provenance & Evidence