Acetic Acid → (2E)-2-(1H-Indazol-5-ylmethylidene)-3-oxobutanenitrile

Participants

Reaction Steps

10 g (68.4 mmol) 1H-indazole-5-carbaldehyde [preparation described in US 2005/0227968-A1 (Intermediate 1)], 7.91 g (75.2 mmol) sodium (1Z)-1-cyanoprop-1-en-2-olate, 4.89 ml (85.5 mmol) acetic acid and 0.68 ml (6.84 mmol) piperidine in dry dichloromethane (500 ml) were stirred at reflux temperature for 7 h using an inverse water separator. Upon cooling, a precipitate was formed which was collected by filtration and washed with dichloromethane. The solid was dried in vacuo to afford the crude title compound (19 g, 75% purity by LC-MS, 96% of th.) which was used in subsequent steps without further purification.

Provenance & Evidence