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Pyrazolo[3,4-b]pyridinediazonium chlorides react with a variety of active methylene-containing reagents (e.g., cyanoacetic acid arylidenehydrazide derivatives) to afford the corresponding 3-hydr-azonopyrazolo[3,4-b]pyridine derivatives. The diazonium chlorides react with N'-acyl-2-cyanoaceto-hydrazide derivatives to give the corresponding 3-hydrazonopyrazolopyridine derivatives. The latter affords the corresponding 3-hydrazonopyrazolo[3,4-b]pyridine derivatives on reflux in acetic acid. Diazo coupling of 2,4-dimethylpyrazolo[3,4-b]pyridinediazonium chloride with ketoester, e.g., ethyl benzoylacetate, is followed by cyclization to afford pyrido[2',3':3,4]pyrazolo[5,1-c]triazine derivative. Diazo coupling of the same dimethylpyrazolo[3,4-b]pyridinediazonium chloride with unsymmetrical β-diketone, e.g., benzoylacetone, was also studied to afford the corresponding hydrazono derivative, which undergoes in situ cyclization to furnish the pyrido[2',3':3,4]pyrazolo[5,1-c]triazine derivative.

A series of some new substituted 5-antipyrinylazo-4-phenyl-2-aminothiazole disperse dyes was synthesized by diazocoupling of 4-antipyrinyldiazonium chloride with aminothiazole derivatives. The synthesized dyes were characterized by UV-Vis absorption, IR, 1H NMR, and MS spectroscopy. The dyes gave orange to reddish-violet shades with very good depth and levelness when applied to polyester fabrics as disperse dyes and their fastness properties were evaluated on polyester fibers. Also the position of color in CIELAB coordinates (L*, a*, b*, H*, and C*) was assessed.

New substituted 5-(pyridine-3-yl)-1,3,4-thiadiazoles, their sugar hydrazones and acyclic C-nucleoside analogs as well as the corresponding thioglycoside derivatives were synthesized. The synthesized compounds were tested for their antimicrobial activity against Escherichia coli, Bacillus subtilis, Staph aureus, Aspergillus niger, and Candida albicans The obtained results indicated that most of tested compounds exhibited moderate to high antimicrobial activity while few compounds were found to exhibit little or no activity against the tested microorganisms.

Aminothiazole derivatives (I) and (XIV) are used as starting materials for the synthesis of a variety of heterocyclic compounds.

This review summarizes results from the literature concerning on tautomerism, synthetic approaches and chemical properties of title compounds as well as their chemical reactions since the pyrazolone chemistry began in 1883 by Ludwig Knorr to date are reported. Emphasis is placed on pinpoining old literature reports that need reinspection in light of modern techniques. The most eye catching features of this structure are their greatest utility resides in pharmaceuticals (analgesic, antibacterial, antifungal, antagonists, antiinflammatory, antimicrobial, antidiabetic, antihyperglycemic and anxiolytic), agrochemicals, dyes (textile and photography), and to a lesser extent in analytical chemistry are discussed with the help of adequate examples.

The chemistry of thiohydantoins has gained increased interest in both synthetic organic chemistry and biological fields. Many of these compounds exhibit considerable biological activities in various fields. This review covers the literature regarding the synthesis, reactions, and applications of such compounds.

Thiosemicarbazides are convenient precursors which have been extensively utilized in heterocyclic synthesis. From the point of view of biological activity, thiosemicarbazide derivatives are useful ...

The products of the reaction of diazaspiro[2.4]heptane-4,7-dione derivatives (II) with nucleophilic reagents depend on the type of the diazaspiro compound and/or the nucleophile used.

The chemistry of aminobenzo[b]thiophenes has gained increased interest in both synthetic organic chemistry and biological fields and has considerable value. Some of the reactions have been successfully applied for the production of various fused heterocycles. The present review covers the literature up to date for the synthesis, reactions and applications of such compounds.

Methods for the synthesis of 2-amino-4-thiazolidinones and their chemical properties are reviewed for the first time. 2-Amino-4-thiazolidinones are synthetically versatile substrates, as they can be used for the synthesis of a large variety of biologically active compounds, such as thiazolodihydropyrazoles, thiazolotriazines, and thiazolotetrahydropyrimidones, and as a raw material for drug synthesis. The high reactivity of amino and active methylene groups next to the carbonyl of the thiazolidin ring represents useful targets for many organic reactions.

Starting from benzothiazole derivative (I) a series of new heterocyclic derivatives of type (IV), (VII), (X), (XII), and (XIV) containing the benzothiazole moiety are prepared and their antimicrobial activities are tested.

Various derivatives of 3,5-pyrazolidinedione are synthesized based on either the Knoevenagel reaction of carbonyl derivatives with 3,5-pyrazolidinedione, cyclization of malonic acid hydrazides with glacial acetic acid or by coupling of aryldiazonium salts with 3,5-pyrazolidinedione.

The effect of various electron-withdrawing halo substituents is studied using analogues such as (VIb), (VId), and (VIe), whereas the derivatives (VIa) and (VIc) enable the investigation of electron-donating substituents.

A number of title heterocyclic compounds were prepared by the reaction of 6-amino-1,4,5,6-tetrahydro-5-imino-3-methyl-1,4-diphenylpyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidine with ethyl 2-cyano-3-ethoxy-2-propenoate, ethoxymethylenemalononitrile, ethyl cyanoacetate, malononitrile, ethyl pyruvate, oxalyl chloride, ethyl chloroformate, and 3-methyl-4-nitroso-1-phenylpyrazol-5(4H)-one, respectively

Pyrazine derivatives show a wide range of biological activities. Some derivatives are used for tuberculosis treatment1). Pyrazinosulfonamides are long acting sulfonamides2) and in combination with certain pyrimidine derivatives have shown dramatic effects in clinical trials against resistant falciparum malaria3). A group of diuretics has been found among substituted amidinocarbamoyl-aminopyrazines4).

α,β-Unsaturated nitriles are versatile reagents and their chemistry has received considerable attention. The reactivity of cinnamonitriles I toward active methylene reagents has been extensively utilised for synthesis of pyranes.

α-Amino acids react with aryl aldehydes in the presence of N-substituted maleimides to yield stereospecific cycloadducts ( 3a,b ) and with dimethyl fumarate to give isomeric mixtures of ( 4a-i ) and ( 5a-i ). The relatively low yield in the case of dimethylfumarate is presumably due to the steric interaction between the dipolarophile and the substituents at both ends of the dipole.

Condensation of the title compounds (1) with hydroxylamine hydrochloride, hydrazines and/or aromatic amines resulted in the formation of the benzisoxazoles 2, oximes 3, indazolines 4 and beta-keto anilides 6. The oxime derivatives and anilides underwent cyclization to compounds 2. The interaction between 1 and thiourea gave the benzothiazines 7 and thiouracils 8. Compounds 8 on treatment with monochloroacetic acid gave the dioxo compounds 9, while their reaction with hydrazine hydrate afforded the hydrazino derivatives 10, which upon treatment with nitrous acid gave the azido or tetrazolo derivatives 11 and 12. Treatment of 1 with 2,3-diaminopyridine and/or 2-amino-3-hydroxy-pyridine gave the pyrimidoquinazolines 13 or 14. Some of the synthesized compounds were screened to test their antimicrobial properties.

The dimerization of dinitrile (I) is accompanied by a rearrangement to afford dihydropyrimidine derivative (II).

Novel derivatives of 2,4,5,6-tetrasubstituted pyrimidine cyclin-dependent kinase (CDK2) inhibitors was designed and synthesized. We built a library of proposed pyrimidine derivatives and by using pharmacophore and docking techniques we made our selections. We modified the proposed compounds due to the interaction of docked structures with the protein to achieve the best fit. The newly synthesized compounds showed potent and selective CDK2 inhibitory activities and inhibited in-vitro cellular proliferation in cultured human tumor cells. The design, synthesis and biological evaluation of these 2,4,5,6-tetrasubstituted pyrimidine derivatives are reported.

α-(Bromothiocyanatomethyl)benzylidenemalononitrile (1) reacts with the hydrazides 2a–c, cyanoacethoydrazide (2d,) cyanoacetamide (3a) and cyanoacetanilides 3b–d to afford pyrrolo[2,1-b]thiadiazolines 5a–c, pyrrolo[2,1-b]thia-diazolo[3,2-a]pyrimidine (8) and the pyridone derivatives 11a–d. Structures and conceivable mechanisms are discussed.

A series of different novel nonclassical nucleosides have been synthesised and evaluated for their inhibitory activity against human immunodeficiency virus (HIV) replication in MT-4 cells.

Reactions of sodium salts of 3-(hydroxymethylene)alkan-2-ones with enamines afford 3-cyano-2-(disubstituted-methylene)-1,2-dihydropyridines.

A novel synthesis of 5-amino-1-arylsulfonyl-4-pyrazolin-3-ones via intramolecular cyclization of cyanoaceto-N-arylsulfonylhydrazides is reported and the synthetic potential of the method is demonstrated.