(10) Typically, &hydroxy ketones and their derivatives cyclize with 1, 2-diaminobenzene in the absence of metal ions to 1, 5-diazepines: FD Popp and A. Catala Noble, Adv. Heterocycl. Chem., 8, 66 (1967).(1 1) This approach has been used by Neidlein and Behzadi for 4b and 8 independently from our investigations: R. Neidlein and Z. Behzadi, Chem. Zfg., 102, 199 (1978).
