Hydrochloric Acid → 10-Methyl-8,9-dihydropyridazino[1',6':1,2]imidazo[4,5-c]quinoline

Participants

Reaction Steps

A solution of tert-butyl 2-(3-{[3-(2-methyl-1,3-dioxolan-2-yl)propanoyl]amino}quinolin-4-yl)hydrazinecarboxylate (6.83 g, 16.4 mmol) and pyridinium p-toluenesulfonate (0.10 g, 0.41 mmol) in 1-butanol (125 mL) was heated to 140° C. under an atmosphere of nitrogen. After 3 h, the reaction mixture was cooled to ambient temperature, treated with HCl (38 mL, 4.3 M in ethanol) and heated (115° C.). After 1 h, the reaction mixture was concentrated under reduced pressure to give a brown solid. The solid was dissolved in water (50 mL) and treated with 50% NaOH aqueous solution until the pH of the liquid was 13. A tan solid was collected by vacuum filtration. The solid was dissolved in dichloromethane (150 mL) and washed with water (2×30 mL) and brine (30 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure to yield 1.96 g of 10-methyl-8,9-dihydropyridazino[1′,6′:1,2]imidazo[4,5-c]quinoline as a light brown solid.

Provenance & Evidence