Methylhydrazine → 3-(3-methoxyphenyl)-1-methyl-1H-thieno[3,2-c]pyrazole

Participants

Reaction Steps

Stir a mixture of (3-bromothiophen-2-yl)-(3-methoxyphenyl)methanone (20 g; 0.067 mol.; example 1, step A), ethylene glycol (134 mL) and methylhydrazine (17 g, 0.37 mol) under nitrogen at 120°-130° for 2.5 hours. Cool to room temperature, quench with water (200 mL) and extract with ether (4×200 mL). Dry the combined ether extracts (MgSO4), filter and evaporate the filtrate to an oil. Purify the oil by HPLC (3:1 hexane/ethyl acetate) to give a solid (9 g) and recrystallize from ether to give the title compound as crystals (8.2 g), m.p. 99°-101° C.

Provenance & Evidence