Ethanol → 1,1-dimethylethyl N-[4-(1H-imidazo[4,5-c][1,5]naphthyridin-1-yl)butyl]carbamate

Participants

Reaction Steps

Triethylorthoformate (2.8 mL, 16.6 mmol) was added to a solution of 1,1-dimethylethyl N-{4-[(3-amino[1,5]naphthyridin-4-yl)amino]butyl}carbamate (5.0 g, 15.1 mmol) in toluene (150 mL). The reaction was heated at reflux overnight with ethanol being collected in a Dean Stark trap. The reaction mixture was heated at reflux for an additional 6 hours and then p-toluenesulfonic acid (1.4 g, 7.5 mmol) was added and the reaction was refluxed overnight. A dark orange/brown oil had formed. The toluene supernatant was decanted off and concentrated under vacuum to provide 1.1 g of 1,1-dimethylethyl N-[4-(1H-imidazo[4,5-c][1,5]naphthyridin-1-yl)butyl]carbamate. The oil was identified as 4-(1H-imidazo[4,5-c][1,5]naphthyridin-1-yl)butaneamine. This material was reacted with 1,1-dimethylethyl-dicarbonate to provide an additional 1 g of 1,1-dimethylethyl N-[4-(1H-imidazo[4,5-c][1,5]naphthyridin-1-yl)butyl]carbamate. The two lots were combined and carried on to the next step.

Provenance & Evidence