Abstract
In order to examine the reductive cleavage of aminoxazoles, benzyl 5-phenyl-2-oxazolecarbamate (I), 2-amino-5-phenyloxazole (II), and few related compounds were submitted to catalytic reduction at ordinary pressure, using various catalysts, and following observations were made. 1) I is converted to phenethylurea (IV) via II when using palladium-carbon catalyst in ethanol, and via 1-carbobenzyloxy-3-phenethylurea (VI) when using platinum oxide catalyst. However, II is obtained selectively when using palladium-barium sulfate catalyst in ethanol, and VI, when using platinum oxide catalyst in acetic acid. 2) II affords IV when using either palladium-carbon or platinum oxide catalyst in ethanol or acetic acid. 3) Hydrochloric acid promotes ring cleavage but alkali markedly inhibits fission. 4) Raney nickel is inactive as a catalyst in this reaction. 5) Ring cleavage of ethyl 5-phenyl-2-oxazolecarboxylate (IX) and 5-phenyloxazole (X) do not progress under these conditions.
