A New Synthesis of 2-Benzazepines

Abstract

AlCl₃-mediated intramolecular cyclization of N,N-bis(1H-1,2,3-benzotriazol-1-ylmethyl)-3-phenyl-1-propanamine (5) gave 2-benzotriazolylmethyl-2,3,4,5-tetrahydro-1H-2-benzazepine (6). Subsequent nucleophilic substitution of the benzotriazolyl group in 6 with Grignard reagents, triethyl phosphite and sodium borohydride afforded 2,3,4,5-tetrahydro-1H-2-benzazepines 1a-e, 2 and 3. Similarly, TiCl₄-mediated cyclization of 8 and 10 gave 5,6,7,13b-tetrahydro-9H-isoindolo[1,2-a][2]benzazepin-9-one (9) and 1,2,5,6,7,11b-hexahydro-3H-pyrrolo[2,1-a][2]benzazepin-3-one (11), respectively.

Key words

benzotriazole - 2-benzazepine - cyclization - synthesis

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