The Crystal and Molecular Structure of (2Z)-2-[3-(4-Methoxybenzoyl)-4,4-dimethyl-1,2-oxazolidin-2-ylidene]-1-(4-methoxyphenyl)ethanone

The crystal and molecular structure of the title compound, viz., (2Z)-2-[3-(4methoxybenzoyl)-4,4-dimethyl-1,2,-oxazolidin-2-ylidene]-1-(4-methoxyphenyl)ethanone (4), is reported. Compound 4 crystallises from toluene/hexanes mixtures in the P21/c space group with eight molecules in the unit cell. The unit cell parameters are: a = 20.9410(11) angstrom, b = 8.7523(5) angstrom, c = 21.2291(9) angstrom; beta = 93.529(3)degrees and V = 3883.5(3) angstrom(3). There are two structurally distinct molecules of 4 found in the solid-state which differ primarily in terms of the observed torsion angles and the overall intramolecular spacing between the aromatic groups. Bond lengths and angles of this tertiary amide are otherwise typical. This is the first crystallographically characterised example of this class of oxazoline precursors, which have previously found application in the syntheses of other heterocycles. Density functional theory (B3LYP 6-311++G** level of sophistication) has likewise been applied to estimate the gas-phase structure of the title compound.