Reactions of Aldehydes with Monosubstituted Malonic Acids
OA Version
Citation
Abstract
The primary purpose of the present work was the extension of the Doebner modification of the Knoevenagel reaction to mono-substituted malonic acids. The Doebner modification has
been limited in the past to the reactions of malonic acid
with aliphatic and aromatic aldehydes
malonic acids. Since the Doebner modification of the Knoevenagel
reaction usually gives high yields of a unsaturated
acids directly, it was hoped that extension to monosubstituted
malonic acids would make available a general and possibly
superior method of preparing substituted and unsaturated
acids.The reaction of benzaldehyde and ethylmalonic acid in
pyridine solution in the presence of piperidine was studied
in an effort to find acceptable general conditions for the
reaction. The conditions found satisfactory involved treating
ethylmalonic acid and piperidine in equimolar amounts
with benzaldehyde in pyridine solvent at steam bath temperature. The
molar ratio of ethylmalonic acid to benzaldehyde was two to
one. These conditions were applied to the reactions of
methylmalonic acid with twenty-nine aromatic aldehydes. The
yields of methyleinnamic acids were generally excellent
and were superior in all cases to those reported using other
preparative methods. The electronic nature of the ring
substituent of the aldehydes investigated did not markedly
influence the yields of methylcinnamic acids. There
appeared to be a tendency toward improved yields when electron
withdrawing groups, e.g., nitro, chloro, bromo, were present
in the benzenoid nucleus. At least in the two cases tested
viz., 2,4,6-trimethylbenzaldehyde and 2,4,6-trimethyl-3,5-
dintrobenzadehyde, the presence of two ortho methyl groups
resulted in a decreased yield.[Truncated]
Description
Thesis (Ph.D)--Boston University
License
Based on investigation of the BU Libraries' staff, this work is free of known copyright restrictions.