Water → 4-Benzyl-7-methoxy-1,3,4,5-tetrahydro-benzo[e][1,4]diazepin-2-one

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Reaction Conditions

Reaction Steps

To a solution of 2-benzyl-7-methoxy-2,3-dihydro-1H-isoquinolin-4-one (7.0 g, 26.2 mmol) in methanesulfonic acid (50 mL) was added sodium azide (3.4 g, 52.4 mmol) portionwise with stirring (Caution: mild exotherm, gas evolution). The mixture was heated to 65° C. for two hours before being cooled to ambient temperature. Water (100 mL) was added, the mixture was cooled in an ice-water bath, and the pH was adjusted to 7-8 (10N NaOH). The gummy precipitate was extracted (DCM), the organic phase was washed with brine, dried over magnesium sulfate, filtered and concentrated. Further purification by flash chromatography over silica gel (DCM/MeOH) gave 4-benzyl-7-methoxy-1,3,4,5-tetrahydro-benzo[e][1,4]diazepin-2-one (5.4 g, 73%) as a tan solid; 1H NMR (400 MHz, DMSO-d6) δ 9.80 (s, 1H), 7.33 (m, 5H), 6.97 (d, J=8 Hz, 1H), 6.87 (d, J=8 Hz, 1H), 6.82 (s, 1H), 3.73 (s, 3H), 3.67 (s, 4H), 3.09 (s, 2H); MS (m/e) 283 (M+1); mp 134° C.

Provenance & Evidence