Unusual and stereoselective ring closure of unsaturated monohydrazones with β-ketoesters in a solvent-free reaction

Chemistry of 2-Arylhydrazonals: Utility of Substituted 2-Arylhydrazono-3-Oxoalkanals as Precursors for 3-Oxoalkanonitriles, 3-Aminoisoxazole and 1,2,3- and 1,2,4-Triazoles

“…199-200 °C; IR (KBr): n/cm -1 : 3447 (OH), 3338 and 3275 (NH 2 ), 3062 (NH) and 1639 (CO); MS: m/z = 296 (M + );1 H NMR (DMSO-d 6 ): d (ppm) = 2.45 (s, 3H, CH 3 ), 6.51 (br s 2H, D 2 O exchangeable NH 2 ), 7.45 (d, 2H, J = 8.4 Hz, p-tolyl-H), 7.55-7.32 (m, 2H, phenyl-H), 7.60 (t, 1H, J = 7.6 Hz, phenyl-H), 7.94 (d, 2H, J = 7.6 Hz, phenyl-H), 8.08 (d, 2H, J = 8.4 Hz, p-tolyl-H), 10.02 (br s, 1H, OH, D 2 O exchangeable). 13.79 (br s, 1H, NH, D 2 O exchangeable).…”

Microwaves in Heterocyclic Chemistry

“…When the active methylene compound is a keto ester the reaction follows a different pathway [73]. With the dry media procedure it was possible to isolate the intermediate alkene, which was not obtained in the previously reported procedure.…”

“…with Active Methylene Compounds Several 3-(2H)pyridazinones have been prepared from monophenyl hydrazones of 1,2-dicarbonyl compounds and a variety of active methylene compounds within 1± 20 min without solvent under focused irradiation in the presence of carefully adjusted amounts of piperidine or solid potassium tert-butoxide (isolated yields 50± 89 %), in accordance with Scheme 8.49 [72,73].…”

“…73 can be selectively alkylated[110] (Scheme 8.75) by benzyl bromide to give 74 in high yield (>90 %) when the reactants were mixed with 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]) as polar solvent and the reaction was performed with brief (1 min) microwave irradiation at 180 8C. Product 74 was fully extracted with diethyl ether and [bmim][PF 6 ] was reused in another cycle of synthesis.…”

The effective reaction of 2-chloro-3-formylquinoline and acetic acid/sodium acetate under microwave irradiation

“…Microwave irradiation using commercial domestic oven has been recently used to accelerate organic reactions, the high heating efficiency giving remarkable rate enhancement and dramatic reduction in reaction time (Jolivet et al, 1996). As a part of a research project to develop environmentally benign organic reactions, we have recently reported (Nadaraj et al, 2010;2011) the synthesis of simple quinolines, pyrimido-and pyrazoloquinolines under microwaves.…”