Efficient atom economical one-pot multicomponent synthesis of densely functionalized 4H-chromene derivatives

Functionally Substituted 1,2,4-Triazoloquinoline, Tetrahydro-quinolinone and Benzotriazolotriazine Derivatives from 5,5-Dimethylcyclohexan-1,3-Dione and Arylmethylenemalonic Acid Derived Michael Acceptors

“…The precipitate formed was collected by filtration and recrystallized from ethanol to give 5 as colorless crystals (85% ) General procedure for preparation of 5-aryl-1,5,6,7,8,9-hexahydro-8,8-dimethyl-6-oxo-2-phenyl- [1,2,4] triazolo [1,5-…”

“…The solids formed were collected by filtration, recrystallized from the proper solvents and then identified as 8a-c. 1 H NMR spectra of 8a,b could not be obtained due to the insolubility of the samples in DMSO.…”

“…Yellow crystals from ethanol/1,4-dioxane, yield (80%), m. 1,5,6,7,8,9-hexahydro-8,8-dimethyl-6-oxo-2-phenyl- [1,2,4]triazolo [1,5-a] quinoline-4-carboxamides (12a,b) A sample of compound 5 (0.01 mol) in ethanol (50 ml) containing piperidine (0.1 ml) was heated with 0.01 mol each of arylmethylene cyanoacetamides 2d,e under reflux for 3 hr. The reaction mixture was left to cool at room temperature.…”

“…5,5-Dimethylcyclohexan-1,3-dione (1) is a versatile reagent that has been extensively used for preparation of a variety of aromatic and heteroaromatic compounds (1)(2)(3)(4)(5)(6)(7) . These compounds are interesting as potential biodegradable agrochemicals (8) , pharmaceuticals (9) , as nonpeptide human deficiency virus (HIV) protease inhibitors, blood anticoagulants (10) and as plant growth regulating agents (11) .…”

“…The present work resulted in the formation of functionally substituted quinoline, 1,2,4-triazoloquinoline and benzotriazolotriazne derivatives of potential biological importance utilizing 5,5-dimethyl-1,3-cyclohexanedione (1) and activated nitriles 2a-e and 3a,b as starting materials. (5) 15 , prepared via condensing 5,5-dimethylcyclohexane-1,3-dione (1) with benzoylhydrazine (4), readily reacted with the arylmethylenemalononitriles (2a-c) in ethanol containing piperidine as catalyst to afford 5-aryl-1,5,6,7,8,9-hexahydro-8,8-dimethyl-6-oxo-2-phenyl [1,2,4]triazolo [1,5-a]quinoline-4-carbonitriles (8a-c) rather than Nʹ-(2-amino-4-aryl-3-cyano-5,6,7,8-tetrahydro-7,7-dimethyl-4H-chromen-5-ylidene) benzo hydrazide (9, Ar = phenyl). The triazoloquinoline structures 8 were preferred over the possible alternative chromene derivatives 9 based on elemental analyses and spectral data.…”