2,5-Dihydrothiophene 5,5-dioxides 8 and 6 have been obtained by interception of flash-pyrolytically produced 2,3-dihydro-2,3-bis(methylene)thiophene with sulfur dioxide and from methyl 4,5-bischloromethylthiophene-2-carboxylate by reaction with sodium sulfide and oxidation. Pyrazole fused analogues 15 and 16 (R = Me and COPh) were prepared from 3-phenylsulfonyl-2,5-dihydrothiophene S,S-dioxide by cycloaddition
2,5-Dihydrothiophene 5,5-dioxides 8 and 6 have been obtained by interception of flash-pyrolytically produced 2,3-dihydro-2,3-bis(methylene)thiophene with sulfur dioxide and from methyl 4,5-bischloromethylthiophene-2-carboxylate by reaction with sodium sulfide and oxidation. Pyrazole fused analogues 15 and 16 (R = Me and COPh) were prepared from 3-phenylsulfonyl-2,5-dihydrothiophene S,S-dioxide by cycloaddition
A new route to heterocyclic fused 2,5-dihydrothiophene S,S-dioxides: formation of pyrazole analogues of o-xylylenes
作者:Lynne M. Chaloner、Andrew P.A. Crew、Richard C. Storr、Michael Yelland
DOI:10.1016/0040-4039(91)80547-j
日期:1991.12
Addition of diazomethane to 3-phenylsulphonyl-2,5-dihydrothiophene S,S-dioxide 3, followed by base induced aromatisation gives the sulphone 7, a precursor to pyrazole analogues of o-quinodimethane).