Journal of Heterocyclic Chemistry

Synthesis via pummerer intermediates. IV. Synthesis of 1??(4??hydroxy??2??oxo??2H??1??benzopyran??3??yl) pyridinium hydroxide inner salt derivatives and 3??(2H) …

DT Connor, RJ Sorenson

Index: Connor, David T.; Sorenson, Roderick J. Journal of Heterocyclic Chemistry, 1981 , vol. 18, p. 587 - 590

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Citation Number: 8

Abstract

Abstract The treatment of ketosulfoxide 1 with phosgene in pyridine gave a mixture of 1-(4- hydroxy-8-methoxy-2-oxo-2H-1-benzopyran-3-yl) pyridinium hydroxide inner salt (4) and 7- methoxy-2-(methylthio)-3-(2H) benzofuranone (7). Ketosulfoxides 8 and 11 behaved similarly. The inner salt structure assigned to compounds 4, 10, and 13 was confirmed by the unambiguous synthesis of 10 and 13 from hydroxycoumarins 15 and 18.