Sulfuric Acid → HCID 46836960, compound

Participants

Reaction Steps

9-Benzyl-3,7-dioxa-9-azabicyclo-(3.3.1)nonane (650 mg, 2.96 mmol, see: JOC, Vol. 71, No. 1, 2006, 413-415) was dissolved in methanol (20 ml) and formic acid (4 ml). 10% Pd/C (0.3 g) was added and the mixture was hydrogenated over night. The solids were filtered off, and the solvent evaporated. The residue was dissolved in methanol (20 ml) and a solution of HCl in dioxane (2 ml, 4N) was added and the solvent evaporated. The residue was dissolved in dichloromethane (80 ml), THF (20 ml) and triethylamine (3 ml) and a solution of [2,1,3]-benzoxadiazole-5-carbonylchloride (1.0 g, 5.5 mmol) in dichloromethane (10 ml) was added. After stirring the mixture for 0.5 h, water (100 ml) and H2SO4 (→pH 2) were added and the organic phase extracted with sodium bicarbonate solution (100 ml), the aqueous was re-extracted with dichloromethane (50 ml) and the combined organics were dried over magnesium sulfate, and concentrated under vacuum. The crude product was purified by silica gel chromatography eluting with hexane/THF (50/50). The product was crystallized from dichloromethane/ethanol, which gave the title compound as an off white solid (590 mg): mp=197-199° C., LC-MS, MH+=276.2; 1H NMR (300 MHz, CDCl3) δ 7.98 (dd, 2H, J=9.0 and 1.2 Hz); 7.94 (t, 1H, J=1.2 Hz); 7.50 (dd, 1H, J=9.0 and 1.2 Hz); 4.52 (s, 2H); 4.21 (d, 2H, J=11.4 Hz); 4.09-4.02 (m, 4H); 3.90 (dd, 2H, J=10.8 and 2.4 Hz); 3.61 ppm (s, 2H).

Provenance & Evidence