PURPOSE: To obtain a new compd. useful as a synthesis intermediate of new compds. and having a very good antibiotic activity against penicillin-resistant staphylococcus bacteria, E. coli Klebsiella, Salmonella, Proteus bacteria, etc.

CONSTITUTION: The compd. is a compd. of formula I [wherein R' is a 2-4C alkyl; A is H or an alk (alk is a 1-4C alkyl), OR' is in syn position], e.g. syn isomer of ethyl 2-(2-amino-4-thiazolyl)-2-ethoxyimino acetate. The compds. of the formula I, e.g. a compd. of formula II among them, is obtd. by reacting thiourea with a compd. of formula III and then treating with a base. The compd. of the formula I is useful as an intermediate for prepn. of an oxime deriv. of a novel 7-aminothaiazolyl acetoamide cephalosporanic acid of formula IV (wherein R is H or trityl; A' is H, an alkali metal, alkaline earth metal, etc.).