Hydrochloric Acid → Pirbuterol hydrochloride

Participants

Reaction Steps

To a solution of methanol (11.3 l.)--hydrogen chloride gas (620 g., 17 moles) at 20° C. is added, with stirring, 2-phenyl-6-(1-hydroxy-2-t-butylaminoethyl)-4-H-pyrido-[3,2-d]-1,3-dioxin maleate (1880 g., 4.24 moles) over a five minute period. The resulting solution is then stirred for 2 hours at 20°-25° C. and is then concentrated under reduced pressure to a volume of about 3 liters. Acetone (16 liters) is added to the concentrate and the resulting precipitate granulated at 25° C. for a half-hour. The white crystalline solid is separated by filtration and washed with acetone (4 liters). Yield = quantitative. M.P. 183°-187° C. (dec.).

Provenance & Evidence