Carbon Dioxide → HCID 131712811, compound

Participants

Reaction Steps

To the freshly prepared methylene chloride solution of pivaloyloxymethyl 1-hydroxy-2-methylcarbapen-2-em-3-carboxylate of Example 4, cooled to -78° C. was added acetic anhydride (0.170 ml., 1.68 mmoles), pyridine (0.144 ml., 1.68 mmoles) and 4-dimethylaminopyridine (10.5 mg., 0.086 mmoles) in two aliquots over 2 hours. The reaction was monitored by tlc (3:1 chloroform:ethyl acetate). After maintaining the reaction mixture at dry ice temperature for approximately 16 hours, additional 4-dimethylaminopyridine (0.5 mg.) was added and reaction continued for 2 hours at -78° C. The reaction mixture was extracted twice with aqueous buffer (pH 7), dried over anhydrous sodium sulfate, filtered and evaporated in vacuo. The residue was chromatographed on 8 g. of silica gel (6:1 chloroform:ethyl acetate as eluant, monitored by tlc or ir spectral analysis) to yield pivaloyloxymethyl 1-acetoxy-2-methylcarbapen-2-em-3-carboxylate [15 mg,; ir (CH2Cl2) 1780, 1740 cm-1 ; Rf 0.75 (3:1 chloroform:ethyl acetate)].

Provenance & Evidence