Sodium Bicarbonate → HCID 131713625, compound

Participants

Reaction Steps

A solution of sodium bicarbonate (9.45 g.) in water (100 ml.) was added in portions to a stirred suspension of 3-acetoxymethyl-7-aminoceph-3-em-4-carboxylic acid (13.5 g.) in water (100 ml.) and acetone (50 ml.). The solid dissolved with effervescence. To this solution under nitrogen at 55° was added rapidly, drop by drop, a solution of 4,6-dimethyl-2-mercaptopyrimidine (10.5 g.) in water (100 ml.) and acetone (100 ml.), the pH being maintained between 7.4 and 7.8 by addition of 6 NHCl or 5% w/v aqueous NaHCO3. After 23 hours at 55°, the reaction mixture was cooled to 0° and acidified to pH 4.0. The resulting precipitate was filtered, washed with water and acetone, and dried over P2O5 to give 7-amino-3-(4,6-dimethylpyrimid-2-yl)thiomethylceph-3-em-4-carboxylic acid. A mixture of this acid (3.52 g.) and O-t-butyl-1,3-diisopropylisourea (6.0 g.) in dry CH2Cl2 (60 ml.) was stirred under nitrogen for 20 hours. The reaction mixture was filtered, the filtrate evaporated and the residue purified by chromatography on silica gel (200 g.) at -40° using CH2Cl2 /ether 6:4 v/v as eluant to give the t-butyl ester.

Provenance & Evidence