Sodium Dithionite → HCID 58747008, compound

Participants

Reaction Steps

1-(2-Chlorophenyl)-5-(4-chlorophenyl)4-nitroso-1H-pyrazole-3-carboxylic acid ethyl ester obtained from the last step was dissolved in ethyl acetate (200 ml) and water (200 ml). Sodium dithionite was added until the disappearance of 1-(2-chlorophenyl)-5-(4-chlorophenyl)-4-nitroso-1H-pyrazole-3-carboxylic acid ethyl ester was confirmed by TLC (ethyl acetate/hexane, 50/50). The organic layer was separated and the aqueous layer was extracted with ethyl acetate. The combined organic layers were dried over magnesium sulfate and the solvent was removed, in vacuo. The red solid obtained was further purified by plug filtration (silica, ethyl acetate/hexane, 50/50) to give 4-amino-1-(2-chlorophenyl)-5-(4-chlorophenyl)-1H-pyrazole-3-carboxylic acid ethyl ester I-2A-1a (21.86 g, 76%). MS: 376.1 (M+1)+.

Provenance & Evidence