Ethanolamine → 3-Bromo-1-(2'-hydroxyethyl)-5-(2'-hydroxyethyl)amino-4-nitropyrazole

Participants

Reaction Steps

1.5 g (4.8 mmoles) of 3,5-dibromo-1-(2'-hydroxyethyl)-4-nitropyrazole are heated in a solution of 0.58 g (9.6 mmoles) ethanolamine in 30 ml ethanol for 15 hours at 80° C. After cooling, 50 ml of water are added to the reaction mixture which is then extracted three times with 70 ml of acetic acid ethyl ester. 200 ml n-hexane are added to the purified extraction solutions and the solvent mixture is vacuum distilled to a third of its original amount. Once again, n-hexane is added until the solution becomes cloudy. The crystallized product is then collected by filtration and washed with n-hexane (10 to 20 ml). 1.04 g (74 percent of theory) of 3-bromo-1-(2'-hydroxyethyl)-5-(2'-hydroxyethyl)amino-4-nitropyrazole are obtained in the form of bright yellow crystals with a melting point of 132° to 134° C.

Provenance & Evidence