HCID 118511093, compound → 4-amino-2-cyclohexyl-1,5-dimethyl-2,3-dihydro-1H-pyrazol-3-one

Participants

Reaction Steps

To 2-cyclohexyl-1,5-dimethyl-4-nitro-1H-pyrazol-3(2H)-one (415 g, 1.73 mol) in MeOH (4500 ml) and THF (4500 ml) was added 10% Pd/C (70 g) and the reaction mixture was hydrogenated at 0.1 bar and RT for 57.5 hrs. The resulting mixture was filtered through a pressure strainer and washed with methanol (1×1 L) and THF (2×1 L). The filtrate was concentrated under reduced pressure to give a dark red oil. The oil was dissolved immediately in TBME (4 L), concentrated under reduced pressure to ca. 2 L and seeded (100 mg). The suspension was stirred for 2 hrs at RT and cooled in an ice bath for 1 hr. The solid was collected by filtration and washed with ice cold TBME in portionwise until the filtrate was colourless and dried under vacuum to give the title compound as yellow/pale orange crystals.

Provenance & Evidence