Directed metalation of pyridinesulphonamides. Synthesis of pyridine??fused isothiazoles and 1, 2??oxathioles

BI Alo, OB Familoni, F Marsais…

Index: Alo, Babajide I.; Familoni, Oluwole B.; Marsais, Francis; Queguiner, Guy Journal of Heterocyclic Chemistry, 1992 , vol. 29, # 1 p. 61 - 64

Full Text: HTML

Citation Number: 10

Abstract

Abstract 4-Lithio-Nt-butylpyridine-3-sulphonamide reacted with benzophenone and carbon dioxide respectively to give the corresponding intermediates which on appropriate treatment gave isothiazolo [5, 4-c] pyridin-3-one 1, 1-dioxides. Metalation of 2-and 4-(N, N- dialkylaminosulphonyl) pyridines with lithium diisopropylamide (LDA) gave anions which reacted with benzophenone to give carbinols which thermally cyclised to 1, 2-oxathiolo [3, ...