1-Azetines, 1,2-Thiazetin-1,1-dioxides and Isothiazol-1,1-dioxides as Building Blocks in Heterocyclic Synthesis: the Attempted Synthesis of Bicyclic -Sultams

Abstract This thesis is concerned with the synthesis of -sultams and the development of new routes for the synthesis of bicyclic versions of these molecules as potential anti-bacterials. The synthesis of 1-azetines, 1,2-thiazetin-1,1-dioxides and isothiazol-1,1-dioxides as precursors of bicyclic heterocycles is described. 1-Azetines were synthesised from azetidin-2-ones prepared via the [2+2] cycloaddition of alkenes with N-chlorosulfonyl isocyanate (CSI). They reacted with diphenylcyclopropenone or nitrile oxides to afford bicyclic systems whose reactivity was explored and afforded a range of heterocycles such as 1,2,4-oxadiazoles, pyridines or pyrimidines via novel reaction pathways.This thesis is concerned with the synthesis of -sultams and the development of new routes for the synthesis of bicyclic versions of these molecules as potential anti-bacterials. The synthesis of 1-azetines, 1,2-thiazetin-1,1-dioxides and isothiazol-1,1-dioxides as precursors of bicyclic heterocycles is described. 1-Azetines were synthesised from azetidin-2-ones prepared via the [2+2] cycloaddition of alkenes with N-chlorosulfonyl isocyanate (CSI). They reacted with diphenylcyclopropenone or nitrile oxides to afford bicyclic systems whose reactivity was explored and afforded a range of heterocycles such as 1,2,4-oxadiazoles, pyridines or pyrimidines via novel reaction pathways. R1 R2 R3 R4 N O R 1 R2 R3 R4 H N SR5 R 1 R2 R3 R4 1) [2+2] with CSI 2) deprotection 1) thionation 2) alkylation diphenylcyclopropenone nitrile oxide N R1 R2 R3 R4 O