(5-Amino-1H-pyrazol-4-yl)(thiophen-2-yl)methanone → Indiplon

Participants

Reaction Steps

A fifty liter flask is charged with 1.936 kg of (3-amino-1H-pyrazol-4-yl)-2-thienylmethanone, 2.450 kg of N-[3-[3-(dimethylamino)-1-oxo-2-propenyl]phenyl]-N-methylacetamide and 33.3 kg of acetic acid (Van Waters). The reaction mixture is heated at reflux for 6 hours. The reaction mixture is evaporated to a residue under reduced pressure while maintaining the temperature at approximately 45?C. The residue is dissolved in methylene chloride (8 L; Spectrum) then precipitated by the addition of 32 L of methyl-t-butyl ether. The solid is isolated by filtration and the cake washed with a small portion (3.6 L) of methyl-t-butyl ether (Van Waters). The solid is suspended in a mixture of hexanes (20 L) and ethyl acetate (20 L) and heated at reflux for 5 minutes. The mixture was allowed to cool to room temperature and the solid is isolated by filtration. The cake is washed with a small portion (6 L) of hexanes/ethyl acetate (1:1). The material is dissolved in hot methylene chloride (17 L) then the product is precipitated by the addition of hexanes (17 L). The mixture was allowed to cool to room temperature and the solid is collected by filtration. The solid may be further purified by crystallization from any one of a variety of known solvents and/or washing techniques.

Provenance & Evidence