Efficient synthesis of 3-aroylcinnolines from aryl methyl ketones
作者:Nouria A Al-Awadi、Mohamed Hilmy Elnagdi、Yehia A Ibrahim、Kamini Kaul、Ajith Kumar
DOI:10.1016/s0040-4020(00)01141-8
日期:2001.2
An efficient synthesis of 3-aroylcinnolines starting from the appropriate arylmethylketones is described. The latter were converted in two steps to the corresponding 3-oxo-3-aryl-2-arylhydrazonopropanals, which upon acid catalyzed cyclization in conc. sulfuric acid or polyphosphoric acid (PPA) led to the corresponding 3-aroylcinnolines.
Flash vacuum pyrolysis of 3-aroylcinnolines 3 at 900 degreesC and 0.02 Torr yielded phenanthrene and arylacetylene derivatives as the major products beside anthracene, and diarylacetylene derivatives as minor products. Also, FVP of 3-(2-thienoyl)-cinnoline gave three isomeric naphthothiophenes, phenyl-2-thienylacetylene and phenylacetylene. On the other hand, 3-(2-furoyl)-cinoline gave dibenzofuran as a major product besides naphtho[1,2-b]furan and phenylacetylene. (C) 2001 Elsevier Science Ltd. All rights reserved.
A New Cyclization to Fused Pyrazoles Tunable for Pericyclic or Pseudopericyclic Route: An Experimental and Theoretical Study
作者:László Filák、Tibor András Rokob、Gyöngyvér Ágnes Vaskó、Orsolya Egyed、Ágnes Gömöry、Zsuzsanna Riedl、György Hajós
DOI:10.1021/jo800483a
日期:2008.5.1
2-Pyrazinyl (2) and 3-pyridazinylketone arylhydrazones (6) and their benzologues undergo a ring closure reaction to yield pyrazolo[3,4-b]pyrazines (4) and pyrazolo[4,3-c]pyridazines (7), respectively, in acceptable to good yields. The reaction was found to be accelerated by using acidic or basic conditions. Quantum chemical calculations suggest the key step of the mechanism to be a direct cyclization; analysis of aromaticity based on computed magnetic properties revealed its medium-dependent pericyclic or pseudopericyclic character. The cyclization reaction has also been extended for the synthesis of related ring systems (9, 12, 14).