Hydrochloric Acid → 2-(Piperazin-1-yl)nicotinaldehyde

Participants

Reaction Steps

A solution of 2-chloro-3-pyridinecarboxaldehyde (VI; 6.4 g, 0.05 mole) and piperazine (19.4 g, 0.23 mole) was refluxed 5 hr in isopropanol (250 mL). The reaction mixture was concentrated in vacuo to a syrup which was partitioned between methylene chloride and water. The organic phase was isolated, washed with water (3×500 mL), dried (MgSO4), filtered, and concentrated in vacuo to a syrup which was flash chromatographed (10% methanol-methylene chloride). The appropriate fractions were combined, concentrated in vacuo, dissolved in ethanol and treated with 1 equivalent of ethanolic HCl. Crystallization of the crude hydrochloride salt gave 8.8 g (87%) of the appropriate IIIc intermediate.

Provenance & Evidence