Cinnamic acids synthesis

Coumarin is usually prepared by heating salicylaldehyde with acetic anhydride and sodium acetate (i.e., the Perkin cinnamic acid synthesis, p. 23 6), whereby the 0" hydroxy-cinnamic acid (I) undergoes cyclisation to coumarin. Coumarins having substituents in the benzene ring can often be similarly prepared. 

Cinnamic acid synthesis from aryl aldehyde and acetic anhydride. 

Perkin Reaction (Perkin cinnamic acid synthesis) The Reaction ... 

Application of the Perkin cinnamic acid synthesis to salicylaldehydes provides a coumarin synthesis of some renown. The reaction itself has been reviewed <42OR(l)2l0) and some discussion of its value in coumarin synthesis is contained in other reviews (37CB(A)83, 45CRV(36)l). 

Ramazani, A., Abdian, B., Nasrabadi, F. Z., and Rouhani, M. (2013). The reaction of N-isocyaniminotriphenylphosphorane with biacetyl in the presence of ( )-cinnamic Acids Synthesis of fuUy substituted 1,3,4-oxadiazole derivatives via intramolecular aza-Wittig reactions of in situ generated iminophosphoranes. Phosphorus Sulfur Silicon Relat. Elem., 188, 642-648. 

Narasimhan, B., Belsare, D., Pharande, D., Mourya, V., 8c Dhake, A. (2004). Esters, amides and substituted derivatives of cinnamic acid synthesis, antimicrobial activity and QSAR investigations. European Journal of Medicinal Chemistry, 39,827. 

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