Potassium Carbonate → N-(2-hydroxytetrahydro-2H-pyran-4-yl)-[2,1,3]-benzoxadiazole-5-carboxamide

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-aminopentane-1,5-diol (2.38 g, 20 mmol) (Helv. Chim. Acta 1964, 47(8), 2145-2153) and triethylamine (4 ml), in dichloromethane (30 ml), was slowly added, at 0° C., a solution of [2,1,3]-benzoxadiazole-5-carboxylic acid chloride (1.82 g, 10 mmol), in dichloromethane (20 ml), and the mixture stirred for 1 h. A mixture of methanol (30 ml) and 4N potassium carbonate solution (20 ml) was added and stirred for 3 h. The mixture was evaporated onto silica gel and purified by silica gel chromatography eluting with ethyl acetate/chloroform/methanol (60:30:10) to give, after crystallization from dichloromethane/ethyl acetate/diethyl ether, N-(1,5-dihydroxypentan-3-yl)-[2,1,3]-benzoxadiazole-5-carboxamide as a white solid (Mp: 87-88° C.). N-(1,5-Dihydroxypentan-3-yl)-[2,1,3]-benzoxadiazole-5-carboxamide (0.5 g, 1.9 mmol), suspended in chloroform (20 ml), was warmed to 45° C. and periodinane (Dess Martin reagent; 1.6 g) added and stirred for 1 h. The reaction mixture was evaporated onto silica gel and purified by chromatography, eluting with ethyl acetate/chloroform (60:40) to give N-(2-hydroxytetrahydro-2H-pyran-4-yl)-[2,1,3]-benzoxadiazole-5-carboxamide (0.12 g) as a white solid after trituration with diethyl ether and as the less polar of two components (Rf: 0.55). Mp=91-92° C., 1H NMR (300 MHz, CDCl3) δ 8.22 (s, 1H); 7.96-7.81 (m, 2H); 7.10-7.00 and 6.40-6.05 (m, 2H); 4.65-4.40 (m, 1H); 4.15-3.70 (m, 2H) and 2.15-0.60 ppm (m, 4H).

Provenance & Evidence