Sulfuric Acid → 4-Amino-1-(2'-hydroxyethyl)-5-(2'-hydroxyethyl)aminopyrazole

Participants

Reaction Conditions

Reaction Steps

0.8 g (2.7 mmoles) of 3-bromo-1-(2'-hydroxyethyl)-5-(2'-hydroxyethyl)amino-4-nitropyrazole are hydrogenated over a period of 4 hours according to method (1). After filtering the catalyst, 0.27 g (2.7 mmoles) sulfuric acid (97-percent) is added. After cooling to -30° C., 630 mg (82 percent of theory) of 4-amino-1-(2'-hydroxyethyl)-5-(2'-hydroxyethyl)aminopyrazole hydrosulfate are obtained in the form of colorless crystals with a melting point of 140° to 142° C.

Provenance & Evidence