TITLE:
Conversion of Syringaldehyde to Sinapinic Acid through Knoevenagel-Doebner Condensation
AUTHORS:
Jack van Schijndel, Luiz Alberto Canalle, Jochum Smid, Jan Meuldijk
KEYWORDS:
Ligno-Phytochemicals, Sinapinic Acid, Knoevenagel-Doebner Condensation, 4-Vinylsyringol
JOURNAL NAME:
Open Journal of Physical Chemistry,
Vol.6 No.4,
October
27,
2016
ABSTRACT: Sinapinic
acid is a widespread compound in vegetable material and is as such common in
the human diet. Recently it has drawn attention because of its biological
activities. Sinapinic acid can be synthesized from syringaldehyde via the
Knoevenagel-Doebner condensation. However this reaction is limited by the
formation of 4-vinylsyringol after a second decarboxylation. To gain more
detailed information about this reaction and to improve control over the
formation of sinapinic acid, the concentration time history of syringaldehyde
and the reaction products of this reaction have been monitored over time at
different reaction temperatures. The formation of 4-vinylsyringol was found to
be inhibited by performing the reaction at temperature below 80°C. This allows
the reaction to be optimized for the production of sinapinic acid, with an optimal
yield of 78% after 2.5 hours at 70°C.