Tricyclic 1,3,6-thiadiazepines

A symmetrical tricyclic 1,3,6-thiadiazepine derivative 152 (Scheme 48) has been synthesized [68,69] in 54% yield starting from 5-bromo-thiadiazole derivative 144 and 1,2-diaminobenzene 145. The synthesis embraces two types of molecular rearrangements Smiles and Dimroth s. 

Heating the 2-(acylamino)sulphonamide (17.3) with phosphorus oxychloride gives a good yield of a tricyclic thiadiazepine a new C—C bond is formed between the acyl carbonyl and the pyrrole C-2 atom. 

The AfA/ -diacetylphenylhydrazine derivatives 2 are converted into 5,6-diacetyl-5,6-dihy-drodibenzo[ft,/][l,4,5]thiadiazepines 3 in the presence of potassium carbonate. (The reaction fails in the absence of the chlorine substituents.) Hydrolysis of the products 3 results in the tricyclic hydrazines 4, which are transformed quantitatively into dibenzothiadiazepines 5 in... 

The reaction of l-(2-aminobenzenesulfonyl)-17/-pyrrole 336 with methyl 3,3-dimethoxypropionate in AcOH afforded the tricyclic 1,2,5-thiadiazepines 73 and 74, which were converted into several other heterocycles (Scheme 69) <1996FES425>. The starting 336 was synthesized according to previous reports <1994JHC867, 1994JHC1033>. 

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