Hydrochloric Acid → 5-(Propan-2-yl)-1,2-oxazol-3-amine

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Reaction Conditions

Reaction Steps

N′-Hydroxy-2-(2-isopropyl-1,3-dioxolan-2-yl)acetimidamide (1.8 g, 9.57 mmol) was dissolved in ethanol (12 ml) and acidified to pH=1 with 37% aqueous hydrochloric acid. The mixture was subjected to microwave heating at 120° C. for 30 minutes. After concentration under reduced pressure the residue was diluted with dichloromethane, a solution of saturated sodium bicarbonate was added until the solution became basic (pH=11) and the organic layer separated. After multiple extractions of the water phase with dichloromethane, the organic layers were combined, dried (MgSO4), filtered and concentrated under reduced pressure. The crude material was purified by silica gel chromatography (hexane/ethyl acetate 1:1) to afford 5-isopropylisoxazol-3-amine (819 mg, 68%). 1H NMR (300 MHz, CDCl3) δ 5.52 (s, 1H), 3.89 (bs, 2H), 2.96-2.91 (m, 1H), 1.27 (d, 6H); LC-MS (ESI) m/z 127 (M+H)+.

Provenance & Evidence