Layland, Nicola J.; Laws, Andrew P.; Vilanova, Bartolome, Journal of the Chemical Society. Perkin transactions II, 1995, # 5, p. 869 - 870
作者:Layland, Nicola J.、Laws, Andrew P.、Vilanova, Bartolome、Page, Michael I.
DOI:——
日期:——
Importance of the C(3) substituent of the penam derivative in interconversion reactions of penam and cepham systems
作者:Aldo Balsamo、Paola Maria Benedini、Bruno Macchia、Franco Macchia、Armando Rossello
DOI:10.1039/p19840000413
日期:——
a structural analogue of Kamiya's disulphide (1a), has been synthesized. Some cyclization reactions of the disulphides (1)(Br2 in CH2Cl2 and AcOAg in ClCH2CO2H–CH2Cl2) leading to penam and cephamderivatives through episulphonium ions (2), have been studied. The data obtained show that changing the substituent X in (1a) and (1b) brings about changes in the distribution of the positive charge in the