10514-27-9Relevant academic research and scientific papers
Nitrile Sulphides. Part 9. Synthesis of 3-Arylisothiazoles
McKie, Marion C.,Paton, R. Michael
, p. 2051 - 2066 (2007/10/02)
3-Arylisothiazoles, unsubstituted at both 4- and 5-positions, have been prepared by two methods based on nitrile sulphide chemistry.Nitrile sulphides, generated by thermal decarboxylation of 5-aryl-1,3,4-oxathiazol-2-ones, react with norbornadiene to give 3-arylisothiazoles in one step, the best yields (50-80percent) being achieved under conditions of high dilution.The mechanism is believed to involve 1,3-dipolar cycloaddition to give dihydroisothiazole (6) followed by retro-Diels Alder extrusion of cyclopentadiene.With norbornene itself exo-dihydroisothiazole (8) is formed. 3-Arylisothiazoles also result from flash vacuum pyrolysis of 3-arylisothiazole-4- and 5-carboxylates and 4,5-dicarboxylates which are, respectively, the cycloadducts of nitrile sulphides with ethyl propiolate and diethyl acetylenedicarboxylate.
