ONE-STEP SYNTHESIS OF 3-PHENYLCOUMARINS AND BENZYLIDENE COUMARAN-2-ONES

A Convenient and simple one step synthesis of 3-phenyl-coumarins and b enzylidenecoumaran-2-ones were carried out using a procedural modifica tion to Perkin reaction. Along with 3-phenyl coumarin (1a-k) small per centage of cis-2-phenylcinnamic acids (2a-p) were also formed. When an o-methoxy group is present in the aldehyde or acetophenone the alpha- phenylcinnamic acids are the exclusive products. On the other hand whe n o-hydroxy group is present both on the aldehyde and phenylacetic aci d, benzylidene coumaran-2-one (3q-u) and the corresponding 3-phenylcou rmarin (1q-t) were formed, and methoxy substitution on ortho position of aldehyde gave exclusively coumaran-2-one. Spectral-studies and/or c omparison with authentic samples confirmed the identities of the compo unds.