Hydrochloric Acid → Imidazo-[1,2-a]quinoxaline-2-methanol

Participants

Reaction Steps

A solution of 7.2 g of ethyl imidazo-[1,2-a]-quinoxaline-2-carboxylate in 140 ml of anhydrous tetrahydrofuran and 1.0 g of lithium borohydride was refluxed with stirring for 20 hours and was then cooled to room temperature. 2N hydrochloric acid was added dropwise to the mixture until effervescence ceased and the clear solution was stirred for one hour and made alkaline with saturated sodium bicarbonate solution. The mixture was concentrated under reduced pressure to evaporate the tetrahydrofuran and the mixture was poured into 500 ml of water. The mixture was cooled in an ice bath and filtered to obtain 4.9 g of imidazo-[1,2-a]-quinoxaline-2-methanol in the form of a colorless solid. The filtrate was extracted with chloroform and the organic phase was dried over magnesium sulfate and evaporated to dryness to obtain an additional 0.60 g of the desired compound in the form of needles melting at 158°-159° C. after crystallization from an ether-ethyl acetate mixture.

Provenance & Evidence