Boron tribromide → HCID 178424050, compound

Participants

Reaction Steps

To a stirred solution of 3-methoxy-6-methyl-1H-1-benzazepine-2,5-dione (350 mg, 1.61 mmol) in dry CH2Cl2 (25 mL, distilled from CaH2) under N2, there was added a solution of BBr3 in CH2Cl2 (5 mL, 1M, Aldrich) in one portion over 30 seconds at rt. The reaction solution immediately became orange, then an orange precipitate formed during the addition. The reaction was allowed to stir under N2 at rt for 65 min. The reaction was added to saturated NaHCO3 (50 mL) and the resulting mixture was vigorously stirred for 15 min to give biphasic system containing some solid material. The phases were separated and the aqueous portion vacuum filtered. The clear, pale yellow, aqueous portion was extracted with CH2Cl2 (1×10 mL). The aqueous portion was acidified with concd HCl (pH 2). The resulting precipitate was collected by filtration, washed to neutrality with water (6×2 mL) and dried in vacuo to yield a highly electrostatic, colorless powder (mass could not be determined). Crystallization from EtOAc (dissolved in 15 mL, hot filtered, concd to 7 mL, allowed to cool to rt) initially yielded near colorless needles, which upon standing overnight at rt, transformed into beige cubes (146 mg, 45%, pure by 1H NMR); mp 187.5°-188.5° C. (dec.); 1H NMR (DMSO-d6) δ2.34 (s, 3H), 6.30 (s, 1H), 7.09 (d, J=7.2 Hz, 1H), 7.21 (d, J=8.1 Hz, 1H), 7.37 (t, J=7.8 Hz, 1H), 10.39 (s, 1H), 11.20 (s, 1H); IR (KBr) 3207 (m), 3047 (m), 1642 (s), 1607 (s), 1598 (s), 1348 (m), 789 (m); Anal. Calcd for C11H9NO3 : C, 65.02, H, 4.46, N, 6.89. Found: C, 65.26; H, 4.54; N, 6.89. Concentration of the mother liquor yielded an additional portion of orange cubes (30 mg, 9%, pure by 1H NMR); mp 184.5°-188° C. In one crystallization, the above mentioned needles were collected; mp 177°-179° C. (dec); IR (KBr) 3389 (m), 3193 (m), 1661 (s), 1646 (s), 1601 (m), 1580 (m), 1350 (m), 1204 (m).

Provenance & Evidence