| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject derivative expressed by a specific formula, free from substituent on the 3-site of theβ-lactam ring and useful for the arbitrary control of the steric structure of the 4-site in high production yield and selectivity. SOLUTION: The objective compound is expressed by formula I (A is phenyl or tolyl; (r) is an alkyl), e.g. 2-methyl-2-(N-p-toluenesulfinyl)iminomethyl-1,3- dioxolan. Preferably, the derivative of formula I is reacted with a metal ester enolate of formula II (Met is lithium, triisopropoxytitanium, diethylaluminum or potassium; R' is an alkyl) to obtain aβ-lactam derivative of formula III. The derivative of formula I is produced, e.g. by acetalizing an alkyl ester such as ethyl pyruvate in an alcohol solvent such as ethanol, reducing the ester part, subjecting to acetal exchange with ethylene glycol, converting to an aldehyde and iminating the product. |
