Photochemical synthesis and ring–chain–ring tautomerism of benzo[4,5]imidazo[1,2-a]cyclopenta[e]pyridines

Abstract

UV-mediated approach for the preparation of benzo[4,5]imidazo[1,2-a]cyclopenta[e]pyridine derivatives from allomaltols containing benzimidazole fragment was developed. The suggested method includes ESIPT-induced contraction of 3-hydroxypyran-4-one core and further intramolecular trapping of unstable...

1,1′-Carbonyldiimidazole-mediated transformation of allomaltol containing hydrazides into substituted 3-acetyltetronic acids

“…Previously, a series of studies devoted to the synthesis and photochemical reactions of 3-hydroxypyran-4-one derivatives were performed by our group. 10 As part of the ongoing research on the chemistry of substituted pyranones, herein, we disclose a transformation of allomaltol containing hydrazides 7 into substituted 3-acetyltetronic acids 8 under the action of CDI (Scheme 1D). It should be noted that only examples of recyclizations of 3-hydroxypyran-4-ones under the action of various nitrogen-containing nucleophiles are known.…”