21634-42-4Relevant articles and documents
Nitrile Sulfides Part 16.1,2Synthesis of 1,2-benzisothiazolesvia nitrile sulfide cycloaddition reactions
Ross, John F.,Delipala, Christina,Watson, Matthew C.,Crosby, John,Paton, R. Michael
, p. 1 - 18 (2013/07/25)
The cycloaddition reactions of nitrile sulfides have been used to prepare benzisothiazole quinones and 1,2-benzisothiazole-5,6-dicarboxylates. The nitrile sulfides, generated by thermal decarboxylation of 1,3,4-oxathiazol-2-ones, reacted with 1,4-naphthoquinone to afford 3-substituted naphtho[2,3-d] isothiazole-4,9-diones (17), together with nitriles as by-products. The corresponding reactions with 1,4-benzoquinone yielded regioisomeric mixtures of 2:1 adducts. The 1,2-benzisothiazole-5,6-dicarboxylates were synthesised by a sequence involving both nitrile sulfide and Diels-Alder cycloaddition reactions. Dimethyl 3-phenylisothiazole-4,5-dicarboxylate (34), prepared from benzonitrile sulfide and dimethyl acetylenedicarboxylate (DMAD), was converted into the 4,5-bis(dibromomethyl) analogue 37 via the bis(dihydroxymethyl) compound 35. Treatment of 37 with sodium iodide in the presence of DMAD afforded dimethyl 3-phenyl-1,2-benzisothiazole-5,6-dicarboxylate (30) via the isothiazole o-quinodimethane 32. ARKAT-USA, Inc.
