Deuterated dicondensed indolinobenzospiropyran formed from the reaction of Fischer base-d(2) and salicylaldehyde: Mechanism involving a carbinol intermediate

Abstract

From the deuterium content (x-value) of deuterated molecules obtained from the reaction of an excess of Fischer base-d(2) with salicylaldehydes, it is found that the formation of the dicondensed indolinobenzospiropyrans occurred via a carbinol intermediate, rather than an open merocyanine form of spiropyran. H-1 NMR behavior supported this proposed mechanism, indicating that a carbinol intermediate was simultaneously, and not consecutively, formed prior to the transformation to both spiropyrans and dicondensed indolinobenzospiropyran. (C) 2008 Elsevier Ltd. All rights reserved.