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Synlett 2007(18): 2868-2870  
DOI: 10.1055/s-2007-991095
LETTER
© Georg Thieme Verlag Stuttgart · New York

Synthesis of 2,4-Diaryl-3H-1-benzazepines

Keith Ramig*a, Shaan Allia, Myra Chenga, Richard Leunga, Rabail Razia, Michelle Washingtona, Linas V. Kudzmab
a Department of Natural Sciences, Baruch College, 17 Lexington Ave., New York, NY 10010, USA
Fax: +1(646)6606201; e-Mail: keith_ramig@baruch.cuny.edu;
b Baxter Anesthesia and Critical Care, 95 Spring St., New Providence, NJ 07974, USA
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Publikationsverlauf

Received 27 August 2007
Publikationsdatum:
12. Oktober 2007 (online)

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Abstract

Treatment of 2-fluoroaniline and some derivatives with aryl methyl ketones under acid catalysis gives the title compounds.

Key words

amines - annulations - bicyclic compounds - hetero­cycles - ketones

6

Typical Procedure
A solution of 6.7 mmol of the 2-fluoroaniline, 6.7 mmol of the aryl methyl ketone, and 40 mg of PTSA in 30 mL of toluene or xylenes in a Dean-Stark apparatus was heated at reflux until the initially formed imine was converted into benzazepine, as judged by silica gel TLC. After cooling, the solution was washed with 5% NaHCO3 solution and dried over MgSO4. Removal of the solvent under reduced pressure gave dark oil or solid, which was triturated with EtOAc-hexanes to isolate a first crop of benzazepine. Additional product can be obtained by taking a second crop, or purification by silica gel chromatography, eluting with EtOAc-hexanes. Analytically pure samples can be obtained by recrystallization from EtOAc-hexanes.
2,4-Bis(4-methoxyphenyl)-3 H -1-benzazepine (2a)
Mp 159-160 °C. 1H NMR (300 MHz, CDCl3): δ = 7.86 (d, 2 H, J = 9 Hz), 7.56-7.15 (m, 4 H), 7.49 (d, 2 H, J = 9 Hz), 6.98 (s, 1 H), 6.91 (d, 2 H, J = 9 Hz), 6.85 (d, 2 H, J = 9 Hz), 3.82 (s, 3 H), 3.78 (s, 3 H), 3.32 (br s, 2 H). 13C NMR (75 MHz, CDCl3): δ = 161.30, 159.43, 156.30, 146.88, 134.37, 132.63, 130.88, 130.45, 129.70, 128.08, 127.90, 126.61, 125.29, 123.53, 114.12, 113.84, 55.32, 55.31, 33.67. Anal. Calcd for C24H21NO2 (355.43): C, 81.10; H, 5.96; N, 3.94. Found: C, 80.95; H, 6.17; N, 3.78.
2,4-Bis(3-methoxyphenyl)-3 H -1-benzazepine (2b)
Mp 109-110 °C. 1H NMR (300 MHz, CDCl3): δ = 7.60-7.20 (m, 9 H), 7.08 (s, 1 H), 7.05-6.85 (m, 3 H), 3.79 (s, 3 H), 3.70 (s, 3 H), 3.36 (br s, 2 H). 13C NMR (75 MHz, CDCl3): δ = 159.96, 159.79, 157.13, 146.90, 141.47, 139.72, 134.83, 130.52, 130.13, 129.76, 129.48, 127.96, 127.00, 126.84, 123.97, 120.48, 119.37, 117.02, 113.64, 112.53, 112.48, 55.28, 55.19, 34.36. HRMS (EI): m/z calcd for C24H22NO2 [M + H+]: 356.1645; found: 356.1644.
2,4-Bis(4-methylphenyl)-3 H -1-benzazepine (2c)
Mp 147-149 °C. 1H NMR (300 MHz, CDCl3): δ = 7.79 (d, 2 H, J = 6 Hz), 7.56 (dd, 1 H, J = 8, 1 Hz), 7.49-7.43 (m, 3 H), 7.37 (td, 1 H, J = 8, 2 Hz), 7.23-7.13 (m, 5 H), 7.05 (s, 1 H), 3.36 (br s, 2 H), 2.37 (s, 3 H), 2.34 (s, 3 H). 13C NMR (75 MHz, CDCl3): δ = 157.04, 146.95, 140.32, 137.68, 137.12, 135.50, 134.84, 130.47, 129.68, 129.42, 129.21, 128.03, 127.94, 126.71, 126.69, 126.02, 123.69, 33.67, 21.29, 21.15. HRMS (EI): m/z calcd for C24H22N [M + H+]: 324.1746; found: 324.1749.
2,4-Bis(4-trifluoromethylphenyl)-3 H -1-benzazepine (2d)
Mp 142-143 °C. 1H NMR (300 MHz, CDCl3): δ = 7.95 (d, 2 H, J = 6 Hz), 7.64-7.25 (m, 10 H), 7.13 (s, 1 H), 3.39 (br s, 2 H). 19F NMR (300 MHz, CDCl3): δ = -63.05 (s), -63.35 (s). 13C NMR (75 MHz, CDCl3): δ = 155.45, 146.75, 143.08 (q, J = 3 Hz), 141.19 (q, J = 3 Hz), 133.06, 132.00 (q, J = 129 Hz), 130.75, 130.07 (q, J = 129 Hz), 129.05, 128.81, 128.27, 128.17, 127.76, 127.05, 125.96 (q, J = 15 Hz), 125.65 (q, J = 15 Hz), 124.72, 124.11 (q, J = 1083 Hz), 123.96 (q, J = 1083 Hz), 33.60. Anal. Calcd for C24H15NF6 (431.37): C, 66.82; H, 3.50; N, 3.25. Found: C, 66.61; H, 3.82; N, 3.12.


2,4-Bis(2-naphthyl)-3 H -1-benzazepine (2e) Mp 177-179 °C. 1H NMR (300 MHz, DMSO-d 6): δ = 8.70 (s, 1 H), 8.49 (s, 1 H), 8.19-7.88 (m, 8 H), 7.72-7.32 (m, 9 H), 3.66 (br s, 2 H). 13C NMR (75 MHz, CDCl3): δ = 157.08, 147.05, 137.12, 135.49, 134.87, 134.18, 133.50, 132.94, 130.64, 129.64, 128.93, 128.51, 128.28, 128.26, 128.21, 128.06, 127.65, 127.57, 127.35, 127.13, 127.09, 126.49, 126.30, 126.28, 125.86, 125.21, 124.91, 124.05, 33.88. Anal. Calcd for C30H21N (395.49): C, 91.11; H, 5.35; N, 3.54. Found: C, 90.81; H, 5.54; N, 3.44.