Phenylacetic anhydride

Here the phenylacetic anhydride, possessing more reactive a-hydrogen atoms, condenses with benzaldehyde to give a-phenylcinnamic acid. The preparation of the latter is an example of the Oglialoro modiflcation of the Perkin reaction. 

The preparation of a-phenylclnnamlc acid from benzaldehyde, phenylacetic acid, acetic anhydride and triethylamine is described. Presumably equilibria are set up between phenylacetic acid and acetic anhydride to form phenylacetic anhydride, a mixed anhydride or both ... 

A modified Perkin procedure is illustrated in the synthesis of a-phenyl-cinnamic acid in which benzaldehyde is condensed with phenylacetic acid in the presence of acetic anhydride and triethylamine. Presumably equilibria are set up which result in the formation of either a mixed anhydride, phenylacetic acetic anhydride or the symmetrical phenylacetic anhydride. 

Phthalic anhydride, when used as the carbonyl component in the Peikin reaction, affords, on treatment with acetic anhydride and potassium acetate, phthalylacetic acid (15 equation 12) a-Arylacetic acids also react with aromatic aldehydes to afford a-arylcinnamic acids (Ogliaro modirication of the Pericin condensation, equation 7) this type of reaction presumably involves the formation of the mixed anhydride of phenylacetic acid and acetic acid and/or phenylacetic anhydride. This modirication is also illustrative of the equilibrium that is established between acid, acid salt and acid anhydrides under the conditions of the reaction. 

Irradiation (254 nm) of phenylacetic anhydride (169) in acetonitrile results in elimination of COa and CO and formation of bibenzyl (170) and 1,3-diphenyl-propanone (171).97 The ketone is known to eliminate CO rather efficiently via a short-lived triplet, and at least part of the bibenzyl may therefore originate in this way. 

The reaction of 3-7V-(6-amino-2-pyridyl)amino-2-cyano-2-butenenitrile (72) with phenylacetic anhydride led to the unexpected tricyclic triazepine (73) (12% yield), in addition to the expected tetraazaphenalene derivative (74) (56% yield) (Equation (2)) <88JHC1837>. 

Picoline-l-oxide (s), 723 reaction with, ketene, 723 phenylacetic anhydride, 721 rearrangement of anhydro base, 720... 

Preparation by reaction of phenylacetic anhydride with resorcinol,... 

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