4-Functionally Substituted 3-Hetarylpyrazoles: VI. 1,3-Diaryl-4-isocyanatopyrazoles

1,3-Diaryl-4-isocyanatopyrazoles were obtained by reaction of 1,3-diarylpyrazole-4-carboxylic acids with ethyl chloroformate and sodium azide or by reaction of 1,3-diarylpyrazole-4-carbonyl chloride with trimethylsilyl azide. The title compounds react with amines, hydrazine hydrate, alcohols, phenols, and monochloroacetic acid to afford 4-pyrazolyl-substituted ureas, semicarbazides, urethanes, and amides respectively.     

Conventional and microwave reactions of 1,3-diaryl-5,4-enaminonitrile-pyrazole derivative with expected antimicrobial and anticancer activities

The present study illustrates conventional and microwave reactions of 5-amino-1,3-diaryl-pyrazole-4-carbonitrile derivative with phenacyl bromide under different conditions, hydrazine hydrate, hydroxylamine hydrochloride, tetrahydrofuran, phthalic anhydride, and cyanoacetic acid. The product of the latter reaction condensed with hydrazine and cyclohexanone to give the pyrazolotriazepine acetonitrile and cyclohexylidene derivatives. The new cyclohexylidene is used as key intermediate to synthesize some new spiro compounds. The behavior of the starting compound with benzaldehyde, ethylenediamine, phenylenediamine, sodium azide, 1-amino-2-hydroxynaphthalene-7-sulphonic acid, diethylmalonate, terephthalaldehyde, acetyl chloride, and acetic anhydride were also investigated. The new compounds structures were established from spectroscopic data. Some of the new pyrazole derivatives showed antibacterial and anticancer activities.     

Synthesis of Spiropyrazolines via a Pseudo‐Six Component Reaction

A novel and eco‐friendly route for the synthesis of highly functionalized spiropyrazolines via a pseudo‐six component reaction of hydrazine hydrate, nitro ketene dithioacetal, isatin, and active methylene under mild condition at room temperature in ethanol media has been developed. The key steps in the synthetic strategy involve the formation of 1,1‐dihydrazino‐2‐nitroethylene from hydrazine hydrate with nitro ketene dithioacetal and its reaction with Knoevenagel adduct derived from the corresponding isatin and active methylene. The reaction is particularly attractive due to features such as high bond‐forming efficiency, optimum convergence, mild condition, atom economy, easy work‐up/purification, and reduced waste production without using any additive.     

Regiospecific Isomerization of 2‐Benzoxazinon‐2‐yl Benzoic Acid Toward Some Nitrogen Nucleophiles as Environmental Insecticide

Based on the strategies of receptor structure‐guided benzoxazinone design, a series of nitrogen nucleophiles such as benzyl amine, sodium azide, 4,4‐bis o‐toluidine, 4‐butanolamine, glucosamine, 2‐amino pyridine, 2‐picolinyl amine, hydroxyl amine, and hydrazine derivatives, for example, hydrazine hydrate, semicarbazide, thiosemicarbazide, methylhydrazide, phenylhydrazide, could be reacted with 2‐benzoxazine‐2‐yl benzoic acid 1 . According the basicity of nucleophiles, regiospecific isomerization of benzoxazinone has been considered through formation of the spiro derivatives. Organic reagents can be controlled on the course of reaction of benzoxazinonyl benzoic acid 1 . Preliminary bioassays indicated that the insecticidal spectra of the synthesized compounds were ecofriendly biodegradable materials due to isomerization. Among these analogues, the quinazoline 2 – 4 showed 100% mortality against Nilaparvata lugens (LC₅₀ = 0.087 mg/L). The insecticidal potency of our designed analogues was dual‐controlled by isomerization to quinazolinone and spiro derivatives that observed in vitro and shed light on the novel insecticidal mechanism. The chemical structure of the products can be confirmed by microanalytical, spectral data, optimized and stimulated by quantum chemical parameters.     

Synthesis of 3-cyano-2-pyridone derivative and its utility in the synthesis of some heterocyclic compounds with expecting antimicrobial activity

New 2-pyridone derivatives bearing p-methoxyphenyl and p-bromophenyl substituents at C-4 and C-6 were prepared smoothly by the one-pot reaction in high yield, and in a comparatively short time, it reacted with phosphorous oxychloride to produce the corresponding chloro compound. The latter was reacted with several nitrogen nucleophiles such as sodium azide, hydrazine, acetohydrazide, and benzohydrazide to give tetrazolo, hydrazino, and triazolo derivatives, respectively. The reaction of hydrazino derivative with cyclopentanone, furan-2-carbaldehyde afforded the corresponding hydrazone derivatives. Cyclocondensation of the latter compounds with thioglycolic acid afforded the nicotinamide derivatives. 2-Pyridone reacted with ethyl chloroacetate to afford chloroacetate and ethyl acetate derivatives. Ethyl acetate-derivative reacted with hydrazine hydrate and gave the acetohydrazide derivative, it was condensed with p-anisaldehyde and gave the 4-methoxybenzylidene acetohydrazide derivative. Also, 2-pyridone reacted with chloroacetic acid and or benzoyl chloride, afforded the benzoate derivative and 2-((6-(4-bromophenyl)-3-cyano-4-(4-methoxyphenyl) pyridin-2-yl) oxy) acetic acid, respectively. Structures of the products were confirmed using spectroscopic data and elemental analyses. Antibacterial activity of the synthesized compounds was evaluated against Escherichia coli and Staphylococcus aureus.     

Water-mediated one-pot synthetic route for pyrazolo[3,4-b]quinolines

First time one-pot water-mediated synthetic route has been developed by carrying condensation of 2-chloro-3-formyl quinolines and hydrazine hydrate/phenyl hydrazine using thermal/microwave energy resources. The route is convenient, eco-friendly, and scalable.     

改进的2-巯基-5-甲氧基咪唑并[4,5-b]吡啶合成法

以2,6-二氯吡啶为起始原料,经甲氧基化、硝化、氨基化、还原及成环5步反应得到2-巯基-5-甲氧基咪唑并[4,5-b]吡啶,总收率45.7%。重点比较了2-氯-6-甲氧基吡啶和2,6-二氯吡啶硝化反应条件及收率的差异,讨论了水合肼、NaOH的用量对目标产物收率的影响。用1HNMR、MS和IR测试技术对目标产物结构进行了表征。     

Ion-exchange resin catalysts in the liquid-phase hydrazinolysis of cinnamic acid

The catalytic activity of a synthetic ion-exchange resins has been studied in the reaction of cinnamic acid with hydrazine (aqueous medium, 363 K, 1.0–2.5 h) yielding the corresponding hydrazide. Efficient catalysts for the process are the anion-exchange resins AV-17-8 and AN-31. The modifying effect of the substrate—hydrazine hydrate—on the catalytic properties of the ion-exchange systems has been demonstrated. On the basis of IR spectroscopic studies, a plausible process mechanism was suggested. It involves polymer-bound quaternary ammonium ions of the anion exchanger.     

Synthesis and conversions of 2-substituted cinchoninic acid amides

Amides of 2-oxo- or 2-thiocinchoninic acid have been obtained by the reaction of substituted amides of 2-chlorocinchoninic acid with sodium acetate or sodium sulfide. The reaction of 2-thiocinchoninic acid amides with hydrazine hydrate or ethyl cyanoacetate leads to derivatives of 2-hydrazinocinchoninic acid or (4-carbamoyl-2-quinolyl)cyanoacetic ester respectively, which were also obtained from 2-chlorocinchoninic acid amides.Perm Pharmaceutical Academy, Perm 614600. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 697–700, May, 1997.     

Condensed pyridazines. Part IV. Reductive cyclization of (Z)-methyl 3-(6-azido-3-chloro-1-methyl-4-oxo-1,4-dihydropyridazin-5-yl)-2-rnethylacrylatc (I) to pyrido[2,3-c] pyridazines and the acid-catalysed cyclization of I to a pyrano[2,3-d] pyridazine

Reduction followed by cyclization of (Z)-methyl 3-(6-azido-3-chloro-1-methyl-4-oxo-1,4-dihydropyridazin-5-yl)-2-methylacrylate (I) to pyrido[2,3-c]pyridazines by treatment with triethyl phosphite or hydrazine hydrate as the reducing agents is described. Compound I was also reductively cyclized with sodium borohydride. Treatment of I with concentrated sulfuric acid gave 8-chloro-3,6-dimethyl-2,5-dioxo-5,6-dihydro-2H-pyrano[2,3-d] pyridazine (VII) which also could be synthesized by another independent route. A mechanism for the cyclization is proposed.     

Synthesis of new diheteroarylcarbazoles: a facile and simple route of 3,6-di(pyrazol-4-yl)carbazoles

A short and facile route to the synthesis of new 3,6-di(pyrazol-4-yl)carbazoles is reported. Dipyrazolylcarbazoles were synthesized in two steps from 3,6-diacetylcarbazoles through a Vilsmeier reaction which led to the formation of carbazolyl-β-chlorovinyl aldehydes, followed by cyclization with hydrazine hydrate. The reaction of the Vilsmeier reagent with hydrazones of diacetylcarbazoles yielded the corresponding pyrazole dicarbaldehydes in good yields.     

Some nucleophilic substitution reactions of 2-chloro-3-cyanopyridines

The chlorine atom in 2-chloro-3-cyanopyridines is readily replaced by primary and secondary aliphatic amines and heterocyclic amines to give 2-aminopyridines. 2-Chloro-3-cyanopyridines react with hydrazine hydrate and sodium azide to give hydrazinopyridines, pyridopyrazoles, azidopyridines, and pyridotetrazoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1085–1088, August, 1976.     

A facile and efficient method for hydroxylation of azabenzanthrone compounds

A novel and facile method of introducing 4-hydroxyl group into the aromatic ring of azabenzanthrone compounds was carried out by reacting azabenzanthrone compounds with hydrazine hydrate or hydroxylamine hydrochloride and sodium hydroxide in diethylene glycol(DEG) solvent.The mechanism of reaction may involve an amino intermediate and follow a hydroxyl substitution process.     

Polymer Catalysts

Catalysts of reduced and unreduced PdCl₂ with hydrazine hydrate deposited on polyaminochloroquinones or polyaminochlorohydroquinones were obtained. Polyaminochloroquinones were prepared by solution polycondensation of chloranil with benzidine in the presence of an acceptor, sodium acetate, for the resulting hydrochloric acid. Polyaminochlorohydroquinones were obtained by a reduction reaction of polyaminochloroquinones with 2,2′ -diphenyl hydrazine. The polymer catalysts were tested in the styrene hydro-genation reaction. The polymers and polymer catalysts were studied by IR spectroscopy.     

Synthesis of Pyrimidines,Thienopyrimidines, and Pyrazolopyrimidines

5-Ethoxycarbonyl-4-methyl-2-phenylpyrimidin-6(1H)-thione ( 3 ), which was prepared from the reaction of ethyl g -aminocrotonate 1 with benzoyl isothiocyanate ( 2 ) in refluxing acetone, was reacted with a series of halopgenated reagents to give S-alkyl derivatives 4a-g . Upon treatment of compounds 4a-c with sodium ethoxide were cyclized into thienopyrimidine 10a-c . Pyrimidinethione 3 was reacted with hydrazine hydrate to give hydroxypyrazolopyrimidine derivative 6 . The later compound was obtained by heating compound 4a with hydrazine hydrate under neat conditions, but when the reaction was carried using hydrazine hydrate in ethanol, the corresponding carbohydrazide 5 was produced.     

Synthesis of Novel Triazolyl Thiourea Derivatives and Their Antibacterial Activity

Russian Journal of Organic Chemistry - 4-Amino-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione was synthesized in three steps from carbon disulfide, hydrazine hydrate, and acetic acid. Its reaction...     

Synthesis of SnSe in various alkaline media under mild conditions

The synthesis of SnSe was systematically investigated in various alkaline media and at various temperatures with SnCl2.2H2O and selenium as source materials. The basicity of the alkaline media and the reaction temperature are two key factors considered in our process. The synthesis of SnSe in sodium hydroxide solution and aqueous ammonia is limited to a narrow temperature range, while the synthesis in hydrazine hydrate and ethylenediamine proceeds over a wider range. The final products were characterized by X-ray diffraction pattern (XRD), energy dispersive X-ray (EDX), and transmission electron microscopy (TEM). TEM results showed a variation of crystal morphology of SnSe obtained in different media. Two simple chemical mechanisms for the formation of SnSe are presented.     

Cycloaddition of Aroyl Isothiocyanate: A Novel Synthesis of Triazine,Oxazine, Pyrimidine,and Pyridine Derivatives

A simple and direct synthetic methodology for a novel series of azines and their annulated systems was performed. Heterocyclization of acyl isothiocyanate 2 with urea or malononitrile gave s‐triazine 4 and 1,3‐oxazine 7 derivatives, respectively. The reaction of heteroallene 1 with acetylacetone tolerated 2‐thioxopyridine derivative 9 . The latter compound underwent heterocyclization with urea, hydrazine hydrate, or phenyl hydrazine to give the annulated pyridines 10 – 12 . Pyrimidinethione 14 was resulted from reaction of acylisothiocyanate with enamine 13 . Condensation of compound 14 with hydrazine hydrate, phenyl hydrazine, urea, and 3‐nitrobenzaldehyde in the presence of ethyl cyanoacetate or sodium hydroxide afforded 15 – 20 , respectively.     

Synthesis of new pyrazole-1,2,3-triazole dyads

An efficient two step synthetic methodology of new 5(4)-aryl-4(5)-[3(5)-(2-hydroxyphenyl)-1H-pyrazol-5(3)-yl]-1H-1,2,3-triazole dyads was established. The reaction of (E)-2-styryl-4H-chromen-4-ones, used as building blocks, with sodium azide, gave 4(5)-aryl-5(4)-(chromon-2-yl)-1H-1,2,3-triazoles bearing either electron-donating or electron-withdrawing substituents in their styryl moiety which upon reaction with hydrazine hydrate afforded the expected pyrazoles in moderate to very good yields.     

Synthesis,characterization and antimicrobial study via new heterocyclic derivatives of trimethoprim

New compounds of trimethoprim heterocyclic derivatives were synthesized. These compounds were synthesized through the condensation reaction between trimethoprim with bromoacetic acid to yield compound 1. Several Schiff bases 2–7 have been synthesized by the condensation different aromatic aldehydes with compound 1. Compound 8 were formed from the reaction of sodium nitrite and acetyl acetone in presence of conc. hydrogen chloride to obtain the hydrazono derivative; then, Cyclocondensation of compound 8 with hydrazine hydrate, phenyl hydrazine and dinitrophenyl hydrazine respectively to yield compounds 9–11 in ethanol affording the pyrazoline derivatives. This work involves the synthesis of some 1,2,3-Triazoles derived from compound 1 by the action of sodium azide on the diazonium chloride salt to yield 5-azido-8-(3,4,5-trimethoxybenzyl)imidazo[1,2-c]pyrimidin-3(2H)-one 12. Finally, by reaction of 12 with acetyl acetone and ethyacetoacetate; respectively in sodium ethoxide/ethanol as a solvent to form compounds 13, 14. The structures of the compounds 1–14 were characterized by elemental analysis, spectral data and antimicrobial evaluation of the some newly synthesized compounds and found that the synthesized compounds are active against tested Gram positive and Gram negative bacteria like Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Proteus.