14428-35-4Relevant academic research and scientific papers
New synthesis of pyrazolo[3,4-b][1,4,5]benzothiadiazepine, -[1,4,5]benzoxadiazepine, -[1,4,5]benzotriazepine and pyrazolo[3,4-b]quinoxaline derivatives
El-Rady, Eman A.
, p. 859 - 862 (2004)
New pyrazolo[3,4-b][1,4,5]benzothiadiazepine and its analogues 3 have been obtained by reaction of 4-nitrosopyrazoles 1 with 2-aminothiophenol 2a and its analogues 2b,c. Under fused conditions, dipyrazolyl derivatives 7a was obtained with a trace amount of quinoxaline 5a. On the other hand, 5b and 7b were obtained in equal amounts. A proposed pathway is presented.
A new regiospecific synthesis method of 1H-pyrazolo[3,4-b]quinoxalines – Potential materials for organic optoelectronic devices, and a revision of an old scheme
Danel, Andrzej,Wojtasik, Katarzyna,Szlachcic, Pawe?,Gryl, Marlena,Stadnicka, Katarzyna
, p. 5072 - 5081 (2017/07/28)
A series of 6-substituted-1,3-diphenyl-1H-pyrazolo[3,4-b]quinoxalines were prepared using a new synthetic pathway: reductive cyclization of appropriate 5-(o-nitrophenyl)-pyrazoles with ferrous oxalate or triphenylphosphine. The main advantage of this procedure is that, contrary to the older protocols of pyrazolo[3,4-b]quinoxaline synthesis, this method allows for a substituent to be introduced to the carbocyclic ring without the formation of isomers. The pyrazole ring can also be modified to some extent. Furthermore, we propose a new mechanism for the oldest reported pyrazolo[3,4-b]quinoxaline synthesis, based on the condensation between o-phenylenediamine and 3,4-pyrazolin-5-diones.
Fused Nitrogen-Containing Heterocycles: IV. 3-Benzoyl-2-oxo-1,2- dihydroquinoxaline Hydrazones and Flavazoles Derived Therefrom
Mamedov,Kalinin,Gubaidullin,Rizvanov,Chernova,Doroshkina,Litvinov,Levin
, p. 131 - 140 (2007/10/03)
3-Benzoyl-1,2-dihydroquinoxalin-2-one reacts with hydrazine and thiosemicarbazide to give the corresponding hydrazone and thiosemicarbazone. The reaction with arylhydrazines yields 3-(α-arylazobenzylidene)-1,2,3,4- tetrahydroquinoxalin-2-ones which are tautomeric to the respective arylhydrazones. On heating in boiling acetic acid, the products of both types undergo intramolecular cyclocondensation with formation of 3-phenylpyrazolo[3,4- b]quinoxalines (3-phenylflavazoles). 3-Benzoyl-1,2-dihydroquinoxalin-2-one thiosemicarbazone gives rise to flavazole structure only in the presence of methyl 3-chloro-2-oxo-3-phenylpropionate as a trap of thiocarbamoyl moiety. The cyclization of 3-(α-hydrazonobenzyl)-1,2-dihydroquinoxalin-2-one is accompanied by formation of quinoxalyl ketone azine.
Phenylation and Dephenylation Reactions: Formation of 1H-Pyrazoloquinoxalines
Pillai, P. Madhavan,Ramabhadran, P.
, p. 901 - 904 (2007/10/02)
1,3-Diphenyl-1H-pyrazoloquinoxaline (9) has been isolated as a byproduct in the conversion of quinoxaline-2-carboxaldehyde phenylhydrazone (1) into 1-phenyl-1H-pyrazoloquinoxaline (5) using stored phenylhydrazine as the dehydrogenating agent
