Studies on annelated 1,4-benzothiazines and 1,5-benzothiazepines. VIII-Synthesis and inhibition of benzodiazepine receptor binding of some derivatives of triazino[3,4-c]-1,4-benzothiazine and triazino[3,4-d]-1,5-benzothiazepine, two new heterocyclic ring systems.

Several series of triazino[3,4-c]-1,4-benzothiazines and triazino[3,4-d]-1,5-benzothiazepines were synthesized. Tentative syntheses performed to obtain 5H-as-triazino[3,4-c]-1,4-benzothiazin-1,2-diones and 5,6-dihydro-as-triazino[3,4-d]-1,5-benzothiazepin-1,2-diones gave rise to s-triazolo derivatives. Only in one case was the reaction successful, affording the 3,5-dihydro-as-triazino[3,4-c]-1,4-benzothiazin-1,2-dione 9a. All the final compounds were tested for their ability to displace [3H]flunitrazepam from bovine brain membranes.