[N,N'-di-(tert-butoxycarbonyl)]-2-ethoxyguanidine   、                                                                                      3-(3-Chlorobenzylsulfonyl)amino-6-methyl-1-carboxymethyl-2-pyridinone                                                                                                                                                                                                                                                                                                          以57%的产率得到3-(3-chlorobenzylsulfonyl)amino-6-methyl-1-{[N,N'-di(tert-butoxycarbonyl)][2-(guanidinooxyethyl)aminocarbonylmethyl]}-2-pyridinone