Abstract
Benzyl 2-oxazolecarbamates (I), 2-aminoxazoles (II), 1-benzyloxycarbonyl-3-alkylureas (III), alkylureas (IV), (E)-alkenylureas (V), and 2-amino-2-oxazolines (VI) were treated with trifluoroacetic anhydride, and determined by programmed temperature gas chromatography. Acetyl derivatives (VIIa-Xa) of IIa, IVa, Va, and VIa were converted into trifluoroacetyl derivatives by treatment with trifluoroacetic anhydride. To examine the route of hydrogenation of I, 5-phenyl (Ia), 5-methyl (Ib), 5-isopropyl (Ic), 5-tert-butyl (Id), 4-methyl-5-phenyl (Ie), and 4-isopropyl-5-phenyl derivative (If) of I were submitted to catalytic reduction over palladium-carbon or platinum oxide, and then these products were determined at appropriate intervals. The bulkiness of substituents was found to give some marked effect on ring fission.
