Sodium Azide → 2,3,4,5-Tetrahydro-1,4-benzoxazepin-5-one

Participants

Reaction Conditions

Reaction Steps

To a solution containing 4-chromanone (1, 2 g, 13.4 mmol) in 15 mL conc H2SO4 at 0° C. was added sodium azide (1.131 g, 17.4 mmol) and the reaction mixture was stirred initially at 0° C. for 1 hour and then stirred at room temperature for 2 hours. The reaction was quenched by the slow addition of water and then subsequently basified with 10% NaOH. The aqueous solution was extracted with ether (2×150 mL). The combined ether layers were dried (Na2SO4) and filtered. The solvent was removed under vacuo and the crude product was recrystallized from EtOAc/hexanes to afford 1.3 g, 61% of 2 as white needles. mp 118°-120° C. 1H NMR (CDCl3) d 8.0 (d, 1 H ArH), 7.6-7.7 (bs, 1H, NH), 7.4 (t, 1H, ArH), 7.2 (t, 1H ArH), 7.0 (d, 1H, ArH), 4.4 (t, 2H, CH2), 3.5 (t, 2H, CH2). EIMS M+ 163 (98), 134 (99), 105 (100).

Provenance & Evidence