Studies on the syntheses of heterocyclic compounds. Part DCXXIX. A ready synthesis of indeno[2,1-a][3]benzazepines

Abstract

The 3′,4′-dihydrospiro[indan-2,1′(2′H)-isoquinoline]-1,3-diones (6)–(9) were transformed into a mixture of cis-(10)–(13) and trans-(14)–(17) hexahydroindeno[2,1-a][3]benzazepines under reductive conditions (zinc and acetic acid). 5-(3,4-Dimethoxybenzoyl)-2,3-dihydro-7,8-dimethoxy-3-methyl-1H-3-benzazepine (18) was converted into 12-chloro-5,6,7,7a-tetrahydro-2,3,9,10-tetramethoxy-7-methylindeno[2,1-a][3]benzazepine (20) with phosphoryl chloride in hot toluene, and the product was reduced with sodium borohydride to give 5,6,7,12-tetrahydro-2,3,9,10-tetramethoxy-7-methylindeno[2,1-a][3]benzazepine (21).