[CONTRIBUTION FROM THE DEPARTMENT OF CHEMISTRY, WAYNE STATE UNIVERSITY, DETROIT 2, MICH.] Aromatic and Pseudoaromatic Non-benzenoid Systems. 111. The Synthesis of Some Ten n-Electron Sy~temsl-~ ... BY NORMAN L. XLLINGER AND GILBERT A. ~TOUNGDSLE4 RECEIVED JULY 13, 1961 ... The synthesis of 2,3,6,7-dibenzo- 1-methyl-1,4,5-triazacyclohepta-2,6-die1ie ... (IIb) and the 1-oxa, 1-thia, and 1-methylene