Penicillin으로부터 유도된 4-mercaptoazetidin-2-one(2a)은 염기조건에서 불안정하지만 Et3N이나 pyridine 염기하에서 acetyl chloride, methyl chloroformate, ethyl iodoacetate, diethyl azodicarboxylate 등의 친전자체와 반응하여 sulfur에 acetyl, methoxycarbonyl, ethoxycarbonylmethyl, diethoxycarbonylhydrazineo원자단이 부착된 화합물이 된다. 반면 thiol의 methylation은 methyl iodide와의 반응으로 얻을 수 없고 diazomethane을 사용해야 한다. 또한 화합물 2a의 이성질체인 화합물 3a의 반응성도 화합물 2a와 거의 비슷하다.
The penicillin-derived 4-mercaptoazetidin-2-one(2a) was unstable in basic media, but it reacted with electrophiles such as acetyl chloride, methyl chloroformate, ethyl iodoacetate, diethyl azodicarboxylate in the presence of triethylamine or pyridine to give the products such as S-acetyl, S-methoxycarbonyl, S-ethoxycarbonylmethyl, and S-diethoxycarbonylhydrazino compounds. However S-methylation could not be done with methyl iodide, but with diazomethane. The reactivity of isomer 3a toward electrophiles was almost the same as that of compound 2a.
