Editing Cinnamic acid (section)

===Synthesis===
Cinnamic acid was first synthesized by the base-catalysed condensation of [[acetyl chloride]] and [[benzaldehyde]], followed by [[hydrolysis]] of the [[acid chloride]] product.<ref name="Garbe-2012">{{Ullmann|first=Dorothea|last=Garbe|title=Cinnamic Acid|doi=10.1002/14356007.a07_099|year=2012}}</ref> In 1890, [[Rainer Ludwig Claisen]] described the synthesis of [[ethyl cinnamate]] via the reaction of [[ethyl acetate]] with benzaldehyde in the presence of [[sodium]] as base.<ref>{{cite journal|last=Claisen|first=L.|date=1890|url=https://babel.hathitrust.org/cgi/pt?id=uc1.b3481786;view=1up;seq=992|title=Zur Darstellung der Zimmtsäure und ihrer Homologen|trans-title=On the preparation of cinnamic acid and its homologues|journal=Berichte der Deutschen Chemischen Gesellschaft|volume=23|pages=976–978|doi=10.1002/cber.189002301156}}</ref> Another way of preparing cinnamic acid is by the [[Knoevenagel condensation]] reaction.<ref>{{cite book|first=L.|last=Tieze|title=Reactions and Synthesis in the Organic Chemistry Laboratory|location=Mill Vall, CA|date=1988|page=1988}}</ref> The reactants for this are benzaldehyde and [[malonic acid]] in the presence of a weak base, followed by acid-catalyzed [[decarboxylation]].  It can also be prepared by oxidation of [[cinnamaldehyde]], condensation of [[benzal chloride]] and sodium acetate (followed by acid hydrolysis), and the [[Perkin reaction]]. The oldest commercially used route to cinnamic acid involves the [[Perkin reaction]], which is given in the following scheme<ref name="Garbe-2012"/>
:[[File:Zimtsäure nach Perkin.svg|450px|center|thumb|Synthesis of cinnamic acid via the [[Perkin reaction]].<ref>{{cite journal |doi=10.15227/orgsyn.005.0083|author=F. K. Thayer|title=m-Nitrocinnamic Acid|journal=Organic Syntheses|year=1925|volume=5|page=83}}</ref>]]