PURPOSE: To obtain the subject compound useful as a synthetic intermediate for cephalosporin antibiotics in high yield by reacting a specific carboxylic acid derivative with phosphorus pentachloride in the presence of acetonitrile or nitromethane.
CONSTITUTION: The objective acid chloride of formula II having (Z)-configuration is produced by reacting a carboxylic acid derivative having (Z)-configuration and expressed by formula I (R1 is fluorine-substituted lower alkyl) [e.g. 2-(5- amino-1,2,4-thiadiazol-3-yl)-(Z)-2-fluoromethoxyiminoacetic acid] with phosphorus pentachloride in the presence of acetonitrile or nitromethane usually at -30 to +10°C for ≤1hr. The amounts of acetonitrile, etc., and phosphorus pentachloride are preferably 5-30mol and 1.5mol per 1mol of the compound of formula I, respectively.
KATO TADASHI
TAKEMOTO YOSHIJI
TACHIBANA SHINRO
KONISHI YUSUKE
EISAI KAGAKU KK