HCID 18444043, compound → HCID 17978864, compound

Participants

Reaction Steps

6.0 g (22.5 mmol) of 5-amino-1-(4-isopropylphenyl)-4-nitroso-1H-pyrazole hydrochloride from Step 2.2 in 150 mL of ethanol was hydrogenated for 6 hours on 0.6 g of Pd/C (10%) at 8 bar of hydrogen pressure. The catalyst was filtered off, and the filtrate was concentrated to a total volume of about 20 mL. After the addition of 40 mL of a 3-molar ethanolic hydrochloric acid solution and agitation in an ice bath, the product crystallized out. Suction filtration and washing with 50 mL of ethyl acetate gave 5 g (17.2 mmol, 77% of the theoretical) of 4,5-diamino-1-(4-isopropylphenyl)-1H-pyrazole dihydrochloride as a colorless product.

Provenance & Evidence