Acetic Acid → Benzoxazole

Participants

Reaction Steps

Sodium cyanoborohydride (0.17 g) was added portionwise to a solution of 2-ethylamino-5-(3-formylphenoxymethyl)benzoxazole (0.80 g), piperidine (0.23 g) and acetic acid (0.76 ml) in methanol (10 ml) at 0° C. with stirring. The mixture was stirred at the same temperature for 2 hours and for further 6 hours at ambient temperature. The solvent was evaporated in vacuo. The residue was mixed with a saturated sodium bicarbonate solution and extracted with ethyl acetate. The extract was washed with water, dried over magnesium sulfate and evaporated in vacuo. The residue was chromatographed on silica gel by eluting with a mixture of chloroform-methanol (20:1, V/V). The pure base was converted to the hydrochloride in a usual manner. The salt was dissolved in ethanol and reprecipitated with diethyl ether to give 2-ethylamino-5-3-piperidinomethylphenoxymethyl)benzoxazole (0.35 g) dihydrochloride.

Provenance & Evidence