Other Seven-Membered Heterocycles Fused to a Benzene Ring

other Seven-Membered Heterocycles Fused to a Benzene Ring 

Fused tricyclic compounds have a venerable history as antidepressant drugs. A number of carbocyclic representatives are considered in Chapter 3 while those that consist of dibenzo heterocyclic compounds are noted in Chapter 13. Antidepressant activity is retained in a benzodiazepine in which the third ring occurs in an unfused 

SEVEN-MEMBERED HETEROCYCLIC RINGS FUSED TO BENZENE 

Yet a further variation of this theme consists in the replacement of the bridging methylene group by sulfur to give a thiadiazepine as the central ring. The starting thiophene ether (26-3) is obtained by the nucleophilic aromatic displacement of fluorine in nitrobenzene (26-1) by the anion from imidazole-2-thiol (26-2). The nitro 

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