Studies on diazepines. VII. Syntheses of novel 1H-1,2-diazepines condensed with aromatic heterocyclic rings.

Annelated[1,2,4,5]Tetrazines

“…Similar treatment of 208 with potassium carbonate was reported to give [1,2,4,5]tetrazino[1,6-a:4,3-a']di [1,5]naphthyridine analog 210 (Scheme 60) [78]. The precursor 208 was also prepared by N-amination of 207 with O-mesitylene sulfonylhydroxylamine in chloroform [78].…”

“…Treatment of the N-iminonaphthyridinium salt 204 with potassium carbonate gave the respective fused tetrazine 206 derivative in 65% yield (Scheme 59) [78]. The precursor 204 was prepared by amination of 203 with O-arylsulfonylhydroxylamine in dichloromethane [78].…”

Electrocyclic aromatic substitution by the diazo group. Part 4. Periselectivity studies on the cyclisation of 1-thienyl-3-diazoalkenes: a route to 3H-thieno[1,2]diazepines

“…(30) * (31) compared to that for (5) -+ (6). The diazepine : pyrazole product ratio obtained in the cyclisation of the thienylalkenes (19b) and (23b) and the results of the diazepine pyrazole interconversion experiments indicate that the thiophene ring is less reactive to 1,7 cyclisation at its 2-than at its 3-position in the internal competition with 1,5 cyclisat ion.…”

“…158-159 "C as yellow crystals (Found: C, 61.75; H, 4.4; N, 10.25. Cl4HI2N2SZ requires C, 61.8; H, 4.4; N, 10.3%); 8" 2.0-2.8 (ni, 6 H), 3.0-3.2 (m, 1 H), 6.85 (d, 5.3 Hz, 2-H), 7.25 (dd, J 3 Hz, J' 1.3 Hz, 2'-H), and 7.35 (dd, 4,4-Di-2-rhienylbut-3-en-2-one tosylhydrazone. In this case after the preparation of the sodium salt further treatment was carried out as follows to ensure complete removal of the ethanol.…”