Synthesis of a novel heterocyclic ring system: 2-thia-3,5,6,7,9-pentaazabenz[cd]azulenes

Synthesis of novel pyrazolo[3,4‐d]pyrimidines peri‐fused with 1,4‐diazepine, 1,4‐thiazepine, and 1,2,4‐triazepine rings

“…Nevertheless, performed long range 1 H‐ 1 H COSY NMR experiment did not show any interaction between protons of NCH 3 and NH groups. This together with the earlier obtained results on an analogous reaction in the thieno[2,3‐ d ]pyrimidine series [23] allowed to conclude that formation of derivative 13 took place.…”

Aliphatic aldehydes in the synthesis of carbo- and heterocycles: Part II. Synthesis of six- and seven-membered rings, bicyclic compounds, and macrocycles

“…6-Alkyl derivatives 204 showed vasoconstrictive activity and the ability to block K + ATP-dependent channels [229]. Tumkevicius et al [230] reported on a novel heterocyclic system, 2-thia-3,5,6,7,9-pentaazabenzo[cd]azulene 205, in which pharmacophoric thienopyrimidine fragment is perifused to 1,2,4-triazepine fragment (Scheme 76). Compound 205 in solution was found to exist in ring-chain tautomeric equilibrium with open hydrazone structure.…”

Synthesis of Novel Thieno- andPyrrolo[2,3-d]pyrimidinesperi-Fused with Pyrimidine­,1,4-Diazepine and 1,4-Thiazepine Rings

“…It is known that 6-chloropyrimidine-5-carbonitriles with mercaptoacetic acid esters in the presence of base usually undergo reactions of substitution of the chlorine atom and subsequent cyclisation to give the thienopyrimidine derivatives. [12][13][14][15][16][17][18][19] Compounds 2a and 2b behaved differently in the analogous reaction with mercaptoacetic acid esters. Heating 2a with ethyl mercaptoacetate in the presence of triethylamine afforded the expected thieno[2,3-d]pyrimidine derivative 3.…”

“…10,11 Previously, we described the preparation of novel peri-fused heterocycles, containing the thieno [2,3-d]pyrimidine skeleton, by the cyclocondensation of 4,5-diaminothieno [2,3-d]pyrimidines with nitrous acid or some one-and two-carbon C-electrophiles. [12][13][14][15] As an extension of this approach for the preparation of peri-annulated heterosystems with anticipated biological and pharmaceutical activities we report herein on the convenient and efficient method for the synthesis of novel heterosystems, namely 2,3,5,6,9-pentaazabenz[cd]azulene, 6-thia-2,3,5,9-tetraazabenz[cd]azulene, 2-thia-3,5,6,9-tetraazabenz[cd]azulene, and novel derivatives of 1-thia-3,5,6,8-tetraaza-and 1,3,5,6,8-pentaazaacenaphthylenes with natural amino acid fragment incorporated into their structure.…”