4-phenylbutylphosphonous acid benzyl ester 、 methyl (8S)-7-[(2S)-2-aminopropanoyl]-1,4-dithia-7-azaspiro[4.4]nonane-8-carboxylate 生成 methyl (8S)-7-[(2S)-2-[[ethoxy(4-phenylbutyl)phosphoryl]amino]propanoyl]-1,4-dithia-7-azaspiro[4.4]nonane-8-carboxylate