A Facile Synthesis of [1] Benzopyrano [4, 3??b] pyridin??5??ones

…, SK Karagiosov, MF Simeonov

Index: Ivanov, Ivo C.; Karagiosov, Stoyan K.; Simeonov, Mario F. Liebigs Annalen der Chemie, 1992 , # 3 p. 203 - 208

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Citation Number: 19

Abstract

Abstract The title compounds 5a-c and 7a-m have been prepared by Vilsmeier formylation of 4-aminocoumarins 1 yielding aldehydes 2, and subsequent condensation of 2 with CH acids in the presence of piperidine. This condensation probably proceeds via the intermediate ylidenemalonic esters 4. By means of detailed 1 H-and 13 C-NMR studies a Dimroth-type rearrangement of intermediates 6f-m has been found to take place in the course of the ...