Thiazetidines and their Derivatives

2-Thiazetidines and their Derivatives.—Carboxamides with an acidic cr-hydrogen react with thionyl chloride in the presence of pyridine to give l,2-thiazetidin-3-one 1-oxides (134). ° A-Phenyl-l,2-thiazetidin-3-one 1-oxide, prepared from keten and A-sulphinylaniline, is opened by anilines to give (135). Thiofluorenone reacts with (136) to give, amongst other things, a small yield of (137) this is oxidized to its sulphonamide by MCPBA.  

A-(Alkylsulphonyl)imides (138), prepared by treating A-alkylsulphamoyl chlorides with Et3,N, react with enamines that bear no hydrogens jS to the morpholino-group to give 1,2-thiazetidine 1,1-dioxides (139). The preparations and e.s.r. spectra of two relatively stable l,2-thiazet-2-yl radicals have been reported.  

Sokol skii, and I. L. Knunyants, Izv.Akad. Nauk SSSR, Ser. Khim., 1978, 2360. 

Mazzanti, G. Maccagnani, B. F. Bonini, P. Pedrini, and B. Zwanenburg, Gazz. Chim. Ital., 1980, 

Domschke, S. Bleisch, and A. Bartl, Tetrahedron Lett., 1978,4003. 

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Thiazetidines and their Derivatives.—Cyclization reactions yield (140) from benzenesulphonyl isocyanate and a thioamide, (141) from aroyl isothiocyanates and DCCI, (142) from dihydroisoquinoline and the CSj adduct of a Wittig reagent,and (143) from the BF3 EtjO-catalysed reaction of ethylenethiourea and aryl aldehydes. Thiazet (144) reacts with SbjTcs, presumably through the open thione-imine form, to give (145). 1,3-Thiazetidines have been proposed as intermediates. ... 

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