Structure and reactions of 4-(2,4,6-trimethyl)benzylidene-2-phenyloxazolin-5-one

The crystal structure of 4-(2,4,6-trimethyl)benzylidene-2-phenyloxazolin-5-one has been determined. Crystals of C 19 H 17 NO 2 , fw 291.35, are monoclinic, P2 1 /c, a = 10.207(2), b = 8.977(2), c = 17.123(4) Å, β = 92.66(1)°. For 2435 observed independent reflections the final R = 0.039 and R w = 0.042. The molecule has Z configuration about the exocyclic double bond, and the benzylidene ring is twisted 61.3° out of the oxazoline ring plane, thus relieving the overcrowding caused by the two ortho-methyl substituents. The reaction of this compound with benzylamine in acetonitrile occurs almost four times as fast as predicted using model reactions.