198709-47-6Relevant articles and documents
Studies on the Synthesis and Cyclization Reactions of 2-(5-Amino-3-arylpyrazol-1-yl)-3-methylquinoxalines
El-Sherief, Hassan A.,Mahmoud, Abdalla M.,Ismaiel, Ahmed A.
, p. 2049 - 2061 (2007/10/03)
A series of 2-(5-amino-3-arylpyrazol-1-yl)-3-methylquinoxalines (2a-d) has been synthesized by condensation of 2-hydrazino-3-methylquinoxaline (1) with substituted benzoylacetonitriles.Reaction of 2 with various organic acids, acid chlorides or sulfonyl chlorides gave the corresponding 2-(5-acylamino-3-phenylpyrazol-1-yl)-3-methylquinoxalines (3a-e) and 2-(5-arylsulphonylamino-3-(p-tolyl)pyrazol-1-yl)-3-methylquinoxalines (4a,b) respectively.Condensation of 2 with aromatic aldehydes yielded 2-(1-aryl-4-arylmethylidene-5-imino-4,5-dihydro-1H-pyrazol-1-yl)-3-methylquinoxalines (5a-d) or 2-(3-aryl-5-arylmethylideneaminopyrazol-1-yl)-3-methylquinoxalines (6a-d) which in turn condensed with sylfanylacetic acid to give 3,4-diaryl-1-(3-methylquinoxalin-2-yl)-4,8-dihydro-1H-pyrazolothiazepin-7(6H)-ones (7a-d).A reaction mechanism is proposed and discussed.Cyclocondensation of 2 with formaldehyde and primary amines afforded 2-(3-aryl-4,5,6,7-tetrahydro-5-alkyl/aryl-1H-pyrazolopyrimidin-1-yl)-3-methylquinoxalines (8a-e) in good yield.All the synthesized compounds were characterized by elemental analysis and by using IR, NMR and mass spectrometry. - Keywords: Quinoxalines; Pyrazoles; Thiazepinones; Mannich reaction
