Citric Acid → (5,7-Difluoroquinolin-6-yl)methanamine

Participants

Reaction Conditions

Reaction Steps

Diphenyl phosphoryl azide (0.5 ml, 2.32 mmol), triethylamine (0.34 ml, 2.43 mmol) and tert-butanol (1.3 ml, 13.78 mmol) were added to a solution of the product from step 1 (0.5 g, 2.24 mmol) in dioxan (6.5 ml) and heated at 110° C. for 4 h. The mixture was cooled to RT and distributed between ethyl acetate and aq. 10% citric acid. The organic layer was separated, dried over Na2SO4 and concentrated to leave a brown residue which was dissolved in dioxane (5 ml) and dichloromethane (1.5 ml) and treated with ether saturated with HCl (10 ml) and stirred at RT overnight. After removing the solvents completely, aq. NaHCO3 was added to the residue and extracted into ethyl acetate, the organic layer dried over Na2SO4 and the solvent was removed. Purification of the residue by column chromatography gave the title compound as a mixture containing ca. 35 mol % of 1,3-bis((5,7-difluoroquinolin-6-yl)methyl)urea, which was used as such in the next step. 1H-NMR (δ ppm, DMSO-d6, 400 MHz): δ 8.95 (d, J=3.8 Hz, 2H); 8.45 (dd, J=7.5, 5.2, 2H); 7.65 (d, J=10.9, 2H); 7.59 (dd, J=8.29, 4.2, 2H); 6.50 (t, J=5.6, 1H), 4.44 (d, J=5.6, 2H); 3.90 (s, 2H).

Provenance & Evidence