Green methodologies in organic synthesis: Microwave assisted solvent- and catalyst-free synthesis of enaminones and their conversion into 1,3,5-trisubstituted benzenes as well as 3-aroyl-6-substituted pyridines

Enaminones were obtained in good yields via condensing methyl ketones with (N,N-dimethylformamide dimethyl acetal) DMF-DMA under microwave irradiation in absence of solvent. These enaminones were readily converted into 1,3,5-trisubstituted benzenes. Reacting enaminones in presence of ammonium acetate has afforded pyridine derivatives

Simple Efficient Routes for the Preparation of Pyrazoleamines and Pyrazolopyrimidines: Regioselectivity of Pyrazoleamines Reactions with Bidentate Reagents

Simple and efficient routes for the preparation of 2-amino-5-phenyl-4,5-dihydrofuran-3-carbonitrile (12), 2-oxo-5-phenyl-tetrahydrofuran-3-carbonitrile (13) and the 3,5-diaminopyrazole derivative 2h were developed. The results of the reactivity profiles of 12 and 2h are reported and the previously investigated reaction of pyrazole-3,5-diamine (2b) with acrylonitrile to yield compound (31), a N-1 acylation product, is currently justified by using X-ray crystallographic analysis. Taken together, the observation of alkenes and alkynes substitution when reacting with 3,5-diaminopyrazole derivative 2h is explained by the terminal electron withdrawing group. This pattern of substitution is attributed to involvement of sterically unhindered electrophiles primarily at the N-1 position. This work is licensed under a Creative Commons Attribution 4.0 International License

Arylazoazines and arylazoazoles as interesting disperse dyes: Recent developments with emphasis on our contribution laboratory outcomes

In this review, we report a survey on the synthesis and application of arylazoazines and arylazoazoles as versatile disperse dyes. Recent reports on the synthesis of arylazonicotinates via condensing arylhydrazonals with active methylene nitriles in acetic acid in presence of ammonium acetate is surveyed. The scope and limitations of this synthetic approach which in some cases afford pyridazinones or arylazonicotinates is defined. Microwave assisted as well as ultra sound assisted synthesis of arylazopyridones as established marketed dyes is also surveyed. Conversion of these arylazopyridones into arylazothienopyridones that can de converted into arylazoisoquinoline derivatives is discussed. Synthesis of arylazopyrazoles and pyrazolopyrimidines via microwave or ultra sound is discussed. The utility of the synthesized compounds as well as antimicrobial disperse dyes and efforts to define their potentialities are also covered

Reassignment of the Structures of Products Produced by Reactions of the Product Believed To Be 2-(1-Phenyl-2-Thiocyanatoethylidene)-malononitrile with Electrophiles

The reactivity of the product believed to be 2-(1-phenyl-2-thiocyanato-ethylidene)malononitrile toward a variety of electrophilic and nucleophilic reagents is reported

On the reaction of phenacylmalononitrile with hydrazines: A new route to pyrazolo[3,4-c]pyridazine, isoxazolo[5,4-c]pyridazine and pyrimido[4,5-c]pyridazine

AbstractThe reaction of arylmalononitiles 1a,b with hydrazine hydrate at room temperature has afforded 3-oxo-6-aryl-2,3,4,5-tetrahydropyridazine-4-carbonitrile 3a,b as the sole isolable product. These 3-oxopyridazin-4-carbonitriles underwent aromatization to 3-oxo-6-phenylpyridazine-4-carbonitrile 4 on attempted coupling with benzene diazonium chloride. Compound 3a reacted with hydrazine hydrate as well as urea to yield pyrazolo[3,4-c]pyridazine 5 and pyrimido[4,5-c]pyridazine 6. On the other hand, amidoximes 7a,b were isolated from reaction of 3a,b with hydroxylamine hydrochloride. Amidoximes 7a could be cyclized successfully into 5-phenylisoxazolo[5,4-c]pyridazin-3-amine 8 while 7b could not be cyclized on our hand

Enaminones in Heterocyclic Synthesis: A Novel Route to Tetrahydropyrimidines, Dihydropyridines, Triacylbenzenes and Naphthofurans under Microwave Irradiation

Condensation of phthalimidoacetone (1) with DMFDMA (N,N-Dimethylformamide dimethyl acetal) has afforded enaminone 2. Refluxing 2 with equimolecular amounts of benzaldehyde and urea in acetic acid afforded a mixture of tetrahydropyrimidine 5 and the dihydropyridine 6. Compound 2 undergoes self-condensation on heating in acetic acid or under microwave irradiation in presence of acidic zeolite to give 1,3,5-triacylbenzene 9. Reacting enaminone 11a with naphthoquinone 15 afforded the naphthofuran 18. The possible formation of the aldehyde 19 was excluded based on an HMQC experiment, which revealed that the carbonyl carbon is not linked to any hydrogen

Polyfunctional nitriles in organic syntheses: A novel route to aminopyrroles, pyridazines and pyrazolo[3,4-c]pyridazines

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