A theoretical (AM1) and experimental dipole moment study of 5(4H)- oxazolones

Experimental and calculated (AM1) dipole moments have been determined for a series of Z and E-isomers of 4-phenylmethylene-5(4H)-oxazolones (1) and 4(a-phenylethylidene)-5(4H)- oxazolones (2) in order to study the conformation in solution of the phenyl group in position 4. The comparison between experimental and calculated values for the Z-isomers indicates a planar conformation of the phenyl group. In the case of E-isomers the agreement is good for lE, which is probably planar, but not so good for ZE, although the perpendicular form shows better agreement. These results have been confirmed by IH-NMR.Peer reviewe