Transacylation of cephalosporin; isolation and reactions of the imidate esters
作者:Toshinori Saito、Ken Nishihata、Syunzo Fukatsu
DOI:10.1039/p19810001058
日期:——
The reaction of the imidateester of methyl 7-acetamidoceph-3-em-4-carboxylate (2) and phenylacetyl chloride was followed by 13C n.m.r. spectroscopy, which disclosed the intermediacy of the adduct of (2) with the acyl chloride. Transacylations of methyl 7-([1-13C]acetamido)ceph-3-em-4-carboxylate (8) and methyl 7-±)-5-benzamido-5-methoxycarbonyl[1-13C]valeramido}ceph-3-em-4-carboxylate (9) were also
13 C nmr光谱分析随后的是7-乙酰氨基二甲基-3-em-4-羧酸甲酯的亚氨酸酯和苯乙酰氯的反应,该光谱揭示了(2)的加合物与酰氯的中间体。7-([[ 13 C]乙酰氨基)头孢-3-em-4-羧酸甲酯(8)和7- ±)-5-苯甲酰胺基-5-甲氧羰基甲基[1- 13 C]戊酰胺} ceph的酰基转移反应还发现-3-em-4-羧酸酯(9)是通过直接攻击相应的亚氨酸酯上的酰氯而进行的。
Amidines. VIII. A kinetic study of alcoholysis of N1-arenesulfonyl-N1,N2-diarylacetamidines.
作者:Machiko ONO、Reiko TODORIKI、Shinzo TAMURA
DOI:10.1248/cpb.39.558
日期:——
Alcoholysis of N1-Arenesulfonyl-N1, N2-diarylacetamidines (1-30) was studied kinetically. The rate of the reaction between the substrates and ethoxide ion depended on the electron-withdrawing resonance effect of the substituents on both the N1-aryl and N2-aryl groups to a similar extent. The rate of the neutral alcoholysis depended on the resonance effect of the N1-aryl substituent to a larger extent than in the former reaction, and depended hardly at all on the electron-releasing resonance effect of the N2-aryl substituent, showing that the reaction does not proceed by the solvolysis mechanism.A reaction mechanism is proposed in which the rate-determining attack of the nucleophile is accompanied by the concerted departure of the N-arylarenesulfonamide group.
申请人:Commonwealth Scientific and Industrial Research Organization
公开号:US04038405A1
公开(公告)日:1977-07-26
3-Trihalomethyl-1,2,4-triazoles either unsubstituted or having substituents in the 4 and/or 5, 1 and/or 5, and 2 and/or 5 positions; and methods for their preparation. Some of the compounds show biological activity; others have acaricidal activity.
申请人:Commonwealth Scientific and Industrial Research Organization
公开号:US04049815A1
公开(公告)日:1977-09-20
3-Trihalomethyl-1,2,4-triazoles either unsubstituted or having substituents in the 4 and/or 5, 1 and/or 5, and 2 and/or 5 positions; and methods for their preparation. The compounds show biological activity; at least some have acaricidal activity.