Reactions of α-phenylglycinamide with some carbonyl compounds. Formation of 5,7-diisopropyl-8,8-dimethyl-2-oxo-3-phenylimidazolidino-[1,2-c]-tetrahydro-[1,3]-oxazine, and determination of structure and stereochemistry by nuclear Overhauser effect difference measurements

α-Phenylglycinamide 5 reacts with ketones to give either the Schiff base 3 or the 4-imidazolidone 4, but reacts with boiling isobutyraldehyde to give the bicyclic compond 6. The structure and stereochemistry of 6 have been established by 1H nuclear Overhauser effect difference measurements, supported by molecular mechanics calculations. Keywords: structure, stereochemistry, nuclear Overhauser effect, molecular mechanics, α-phenylglycinamide reactions.