A study on 4-acylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones

Five novel 3-alkyl-4-phenylacetylamino-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) were synthesized by the reactions of 3-alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with phenylacetyl chloride and characterized by elemental analyses and IR, 1HNMR, 13C-NMR and UV spectral data. The newly synthesized compounds 2 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide, and the half-neutralization potential values and the corresponding pKa values were determined for all cases. In addition, these new compounds and five recently reported 3-alkyl-4-(pmethoxybenzoylamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (3) were screened for their antioxidant activities.     

Synthesis, acidity and antioxidant properties of some novel 3,4-disubstituted-4,5-dihydro-1H-1,2,4-triazol-5-one derivatives

3-Alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2a-g reacted with 4-diethylaminobenzaldehyde to afford the corresponding 3-alkyl(aryl)-4-(4-diethyl-aminobenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 3a-g. The acetylation reactions of compounds 3a-e were investigated and compounds 4a-e were thus obtained. The new compounds were characterized using IR, (1)H-NMR, (13)C-NMR, UV and MS spectral data. In addition, the newly synthesized compounds 3a-g were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents such as isopropyl alcohol, tert-butyl alcohol, acetone and N,N-dimethylformamide (DMF), and the half-neutralization potential values and the corresponding pKa values were determined for all cases. Moreover, 3 and 4 type compounds were also screened for their antioxidant activities.     

Synthesis and non-aqueous medium titrations of some new 4-benzylidenamino-4,5-dihydro-1H-1,2,4-triazol-5-one derivatives

The synthesis of 3-alkyl(aryl)-4-(3-ethoxy-4-hydroxybenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones 3 from the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones 2 with 3-ethoxy-4-hydroxybenzaldehyde is described.The acetylation and methylation reactions of the compounds 3 giving compounds of type 4 and 5, respectively, were investigated. The newly synthesized compounds were characterized using elemental analyses and IR, (1)H-NMR, (13)C-NMR and UV spectral data.In addition, to investigate the effects of solvents and molecular structure upon acidity,compounds 3 were titrated potentiometrically with tetrabutylammonium hydroxide in four non-aqueous solvents (isopropyl alcohol, tert-butyl alcohol, acetonitrile and N,N-dimethylformamide). The half-neutralization potential values and the corresponding pKa values were determined for all cases.     

Preparation of aminotriazole-thione derivatives from n-aryl-n-carboxyethyl-β-alanines

Depending on the substituents in the aryl moiety, the fusion of N-aryl-N-ethoxycarbonyl-β-alanines with thiocarbohydrazide gives di- or monotriazole derivatives, namely, 4-amino-(2-{[2-(4-amino-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)ethyl]anilino}ethyl)-4,5-dihydro-1H-1,2,4-triazole-5-thiones, 1-[2-(4-amino- 5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)ethyl]-2,3-dihydroquinolin-4(1H)-ones, 4-amino-3-[2-(4-methylanilino))ethyl]-4,5-dihydro-1H-1,2,4-triazole-5-thione and 4-amino-3-[2-(4-ethoxyanilino)-ethyl]-4,5-dihydro-1H-1,2,4-triazole-5-thione. A ditriazolethione derivative was also obtained from the diethyl ester of N-ethoxycarbonyl-N-(4-ethoxyphenyl)- β-alanine.     

Synthesis and GIAO NMR calculations for some new 4,5-dihydro-1H-1,2,4-triazol-5-one derivatives: comparison of theoretical and experimental 1H and 13C chemical shifts

Four novel 3-alkyl(aryl)-4-(4-methoxycarbonylbenzylidenamino)-4,5-dihydro-1H-1,2,4-triazol-5-ones (2) were synthesized by the reactions of 3-alkyl(aryl)-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones (1) with methyl 4-formylbenzoate and characterized by elemental analyses and IR, 1H NMR, 13C NMR and UV spectral data. In addition, isotropic 1H and 13C nuclear magnetic shielding constants of 2 were obtained by the gauge-including-atomic-orbital (GIAO) method at the B3LYP density functional level. The geometry of each compound was optimized using the 6-311G basis set.     

Aminolysis of 2-Aryl-5-R-5,6-dihydro-7H-[1,2,4]triazolo[5,1-<Emphasis Type="Italic">b</Emphasis>]1,3]thiazin-7-ones

We have established that the products of aminolysis of 2-aryl-5-R-5,6-dihydro-7H-[1,2,4]triazolo-[5,1-b][1,3]thiazin-7-ones in boiling ethanol are 3-R-3-(5-aryl-4H-1,2,4-triazol-3-ylsulfanyl)-propanamides, and at 180°C–210°C (depending on the structure of the substituent R): 3-phenyl-4,5-dihydro-1H-1,2,4-triazoline-5-thione and 3-arylacrylamides or 3-(3-aryl-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)propanamides. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1587–1592, October, 2005.     

Synthesis and characterization of metallodendritic palladium-biscarbene complexes derived from 1,1'-methylenebis(1,2,4-triazole)

The syntheses of first generation dendritic compounds bearing 1,1'-alkane-1,1-diylbis(4-butyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene)palladium(II) dibromide on the periphery are described. The metallabiscarbene moieties have also been studied separately from the dendrimer. These compounds display a non-symmetric boat-to-boat conformational equilibrium that has axial and equatorial arrangements. The predominance of the axial conformer in the equilibrium is supported by DFT calculations. The X-ray solid state structures of axial conformers of 3-hydroxy- and 3-mesyloxy-1,1'-propane-1,1-diylbis(4-butyl-4,5-dihydro-1H-1,2,4-triazol-5-ylidene)palladium(II) dibromide are reported. These complexes display modest catalytic activity in the Heck reaction with activated aryl bromides and the dendritic catalysts were more active than the corresponding non-dendritic mononuclear species, a finding indicative of a cooperative effect.     

Synthesis and Transformations of 2-R-5-Aryl-5,6-dihydro-7H-[1,2,4]-triazolo[5,1-b][1,3]thiazin-7-ones

A new procedure for preparation of 2-R-5-aryl-5,6-dihydro-7H-[1,2,4]triazolo[5,1-b][1,3]thiazin-7-ones by condensation of 5-R-1,2,4-triazole-3-thiones with 3-arylacryloyl chlorides was developed. The thiazine ring of the [1,2,4]triazolo[5,1-b][1,3]thiazin-7-ones is easily cleaved by treating with ammonia and hydrazine affording amides and hydrazides of 3-aryl-3-(1H-1,2,4-triazol-5-ylsulfanyl)propanoic acids. The latter react with isothiocyanates furnishing carbamoyl thiohydrazides of 3-aryl-3-(1H-1,2,4-triazol-5-ylsulfanyl)propanoic acids that in alkaline media undergo cyclization into 4-aryl-5-[2-(4H-1,2,4-triazol-5-ylsulfanyl)-2-phenylethyl]-2,4-dihydro-3H-1,2,4-triazole-5-thiones.     

Synthesis of 3-(3-Alkyl-5-thioxo-1H-4,5-dihydro-1,2,4-triazol-4-yl)aminocarbonylchromones

A series of 3-(3-alkyl-5-thioxo-1H-4,5-dihydro-1,2,4-triazol-4-yl)aminocarbonylchromones has been prepared by oxidation of 3-formylchromone with Jones' reagent followed by reaction with 3-alkyl-4-amino-4,5-dihydro-1,2,4-triazole-5(1H)-thione in the presence of POCl³. The structures of the compounds were confirmed by IR, LC-MS, and ¹H NMR spectra and elemental analyses.     

Synthesis of azoles from 3-[(3-hydrazino-3-oxopropyl)anilino]-and 3-[(3-hydrazino-3-oxopropyl)-4-methylanilino]propane hydrazides

Condensation of 3-[(3-hydrazino-3-oxopropyl)anilino]-and 3-[(3-hydrazino-3-oxopropyl)-4-methylanilino]propane hydrazides with 2,4-pentanedione, phenyl isocyanate or phenyl isothiocyanate (with subsequent work up of the semicarbazides obtained by base), and carbon disulfide gave respectively: 1-(3,5-dimethyl-1H-1-pyrazolyl)-3-[3-(3,5-dimethyl-1H-1-pyrazolyl)-3-oxopropylanilino]-1-propanone, 3-(2-{[2-(5-oxo-4-phenyl-4,5-dihydro-1H-1,2,4-triazol-3-yl)ethyl]anilino}ethyl)-4-phenyl-4,5-dihydro-1H-1,2,4-triazol-5-one and its thio analog, and 5-(2-{[2-(2-thioxo-2,3-dihydro-1,3,4-oxadiazol-5-yl)ethyl]anilino}ethyl)-2,3-dihydro-1,3,4-oxadiazole-2(3H)-thione plus their methyl derivatives. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1353–1358, September, 2007.     

Synthesis of 4-hydroxy-4,5-dihydro-1,2,4-triazol-5-ones

Summary A series of hydroxamic acid ethoxycarbonylhydrazides was obtained by reactions of ester ethoxycarbonylhydrazones with hydroxylamine. The corresponding 3-substituted 4-hydroxy-4,5-dihydro-1,2,4-triazol-5-ones were synthesized by cyclization of these hydroxamic acid derivatives in basic medium.

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Synthesen von 4-Hydroxy-4,5-dihydro-1,2,4-triazol-5-onen

Zusammenfassung Durch Reaktion von Esterethoxycarbonylhydrazonen und Hydroxylamin wurde eine Reihe von Hydroxamsäureethoxycarbonylhydraziden gewonnen; Cyclisierung dieser Verbindungen durch Base gab die entsprechenden 3-substituierten 4-Hydroxy-4,5-dihydro-1,2,4-triazol-5-one.

     

1,2,4-Triazines – products of reaction of thiocarbohydrazide and its alkyl(aryl)-substituted derivatives with 1,2-dicarbonyl compounds

The reaction of a series of 1,2-dicarbonyl compounds with thiocarbohydrazide and its 1- and 1,4-alkyl-(aryl)-substituted analogs has been studied. Treatment of diacetyl with the polynucleophiles indicated gives monohydrazones and/or 5-methylene-4,5-dihydro-2H-[1,2,4]triazine-3-thiones. Reaction of phenylglyoxal and benzil with thiocarbohydrazide yields 5-hydroxy- or 5-alkoxy-4,5-dihydro-2H-[1,2,4]triazine-3-thiones depending on the nature of the solvent. The products of condensation with 1,1-dimethylthiocarbohydrazide showed a thiocarbonohydrazone – 5-hydroxy-4,5-dihydro-2H-[1,2,4]tri-azine-3-thione ring-chain type equilibrium.     

Synthesis of new derivatives of 4-amino-2,4-dihydro-1,2,4-triazol-3-one as potential antibacterial agents

Thirty new 2-substituted-4-amino-5-alkyl or aryl-2,4-dihydro-1,2,4-triazol-3-ones and ten 2-substituted-5-alkyl or aryl-4-(5-nitro-2-furfurylidene)amino-2,4-dihydro-1,2,4-triazol-3-ones were synthesized and characterised by their sharp melting points, elemental analysis, ir and ¹H nmr spectra. These new derivatives of 5-nitro-2-furaldehyde were screened for their antibacterial activities. Most of the compounds showed good activity against one test organism, Staphylococcus aureus. For a few compounds, C.M.I. ranged from 4 to 8 μg/ml (higher results than nitrofurantoin).     

Microwave-assisted synthesis and antifungal activity of some new 1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazole derivatives

A number of 3-aryl-4-arylmethylideneamino-4,5-dihydro-1H-1,2,4-triazol-5-ones were synthesized by reaction of the corresponding aromatic aldehydes with 4-amino-3-aryl-1H-1,2,4-triazol-5-ones in anhydrous ethanol under microwave irradiation. The newly synthesized 1H-1,2,4-triazole derivatives were tested for antimicrobial activity. They showed no antibacterial activity but slight mycostatic activity against some Candida species. Published in Russian in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 12, pp. 1843–1847. The text was submitted by the authors in English.     

Reaction of acetylenedicarboxylic acids esters with 4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-1-carbothioamides and 3,4,5,6-tetrahydro-2<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazepine-3-thiones

The reactions of dimethyl acetylenecarboxylate with 3,4,5,6-tetrahydro-2H-1,2,4-triazepine-3-thiones and 4,5-dihydro-1H-pyrazole-1-carbothioamides are convenient methods for the synthesis of 7,8-dihydrothiazolo[3,2-b][1,2,4]triazepin-3-ones derivatives and methyl esters of (2Z)-[2-(4,5-dihydro-1H-pyrazol-1-yl)-4-oxo-1,3-thiazol-5(4H)-ylidene]acetic acids, respectively. The reaction of methyl propynoates with 4,5-dihydro-1H-pyrazole-1-carbothioamides or with 5,5,7-trimethyl-2,4,5,6-tetrahydro-3H-1,2,4-triazepine-3-thione gives 2-(4,5-dihydro-1H-pyrazol-1-yl)-4H-1,3-thiazin-4-ones.     

A new one-pot neat synthesis of 1,2,4-triazol-3-ones through 4-(N, N-dimethylamino) pyridine (DMAP) catalyzed cyclocondensation of ethyl carbazate with aryl nitriles

A new one-pot neat synthesis of some 5-aryl-2,4-dihydro-3H-1,2,4-triazol-3-ones through cyclocondensation of ethyl carbazate with aryl nitriles catalyzed by DMAP as an efficient and basic nucleophilic catalyst is described.     

新型三唑啉酮类化合物的合成及生物活性

分别以2,4,5-三氯苯胺和盐酸氨基脲、甲酸为起始原料, 设计并合成两个系列新型1,2,4-三唑啉酮类化合物(5, 7). 通过 1H NMR, MS和元素分析确证了其结构, 生物活性测定结果表明, 化合物5系列的除草效果优良, 而化合物7系列则基本没有除草活性, 但表现出很强的促进黄瓜子叶生根活性.     

Reactions of fused dihydro-1,2,4-thiadiazoles with isoselenocyanates giving 6aλ4-thia-1,3,4,6-tetraazapentalene derivatives and 5,10-dihydro-1,2,4-thiaselenazolo[4,5-b][2,4]benzodiazepines

3-Methyl-6,7-dihydro-5H-1,2,4-thiadiazolo[4,5-a]pyrimidine (1) reacted with isoselenocyanates with elimination of acetonitrile and concomitant addition of two molecules of the isoselenocyanate to give 2,3-di-substituted-6,7-dihydro-5H-2aλ⁴-thia-2,3,4a,7a-tetraazacyclopent[cd]indene-1(2H),4(3H)-diselones (6a)–(6j). 3-Methyl-5,10-dihydrobenzo[e]-1,2,4-thiadiazolo[4,5-a][1,3]diazepine (3) likewise reacted with alkyl isoselenocyanates to give the 2,3-dialkyl-5-10-dihydro-2aλ⁴-thia-2,3,4a,10a-tetraazapentaleno[3,3a,4-gh]benzocycloheptene-1,4-diselones (9a)–(9h), but reaction of (3) with aryl isoselenocyanates took place with elimination of acetonitrile and incorporation of one molecule of the aryl isoselenocyanate in the product to give 3-arylimino-5,10-dihydro-1,2,4-thiaselenazolo[4,5-b][2,4]benzodiazepines (10a)–(10h). Structure (10) is a new heterocyclic system. The pyrimidine (1) and the diazepine (3) reacted with aryl isoselenocyanates at room temperature in solvents of low polarity to give zwitterion 1:1 addition compounds (7) and (12), respectively. NMR studies reveal that the thiaselenazoles (10) react in solution with aryl isoselenocyanates to give diaryl diselones (11) in a reversible process involving a Dimroth rearrangement. © 1996 John Wiley & Sons, Inc.     

2-R-5-Ar(Het)-5,6-dihydro-7H-[1,2,4]triazolo[5,1-b][1,3]thiazin-7-ones

A novel method for synthesis of 2-R-5-Ar(Het)-5,6-dihydro-7H-[1,2,4]triazolo[5,1-b][1,3]thiazin-7-ones by condensation of 3-R-4,5-dihydro-1H-1,2,4-triazole-5-thiones with 3-aryl(heteryl)-2-propenoyl chlorides is proposed.     

Cu(II), Ni(II) and Fe(II) complexes with a new substituted [1,2,4] triazole Schiff base derived from 4-amino-5-(thien-2-yl ethyl)-2,4-dihydro-3H-1,2,4-triazol-3-one and 2-hydroxy-1-naphthaldehyde: synthesis,characterization and a comparison of theoretical and experimental results by Ab inito calculation

The synthesis and structural properties of two novel compounds, 4-amino-5-(thien-2-yl ethyl)-2,4-dihydro-3H-1,2,4-triazol-3-one and 4-{[(2-hydroxy-1-naphthyl)methyl-ene]amino}-5-(thien-2-ylmethyl) − 2,4-dihydro-3H-1,2,4-triazol-3-one have been described. 4-Amino-5-(thien-2-ylmethyl)-2,4-dihydro-3H-1,2,4-triazol-3-one was synthesized by treating N-propionyl-2-thien-2-ylethane-hydrazonoate with hydrazine hydrate and the Schiff base was obtained from condensation of substituted amine with 2-hydroxy-1-naphthaldehyde. The Cu(II), Ni(II) and Fe(II) complexes were prepared and characterized by elemental analyses, IR, magnetic moment, UV–Vis, mass spectral data and ¹H- and ¹³C-NMR IR spectra. The Schiff base is coordinated to the metal ions in a tridentate manner with OON donors of the phenolic O, carbonyl O and triazolic N. From the magnetic and UV spectral data, it was found the geometrical structure of Cu(II) and Fe(II) ions are octahedral while Ni(II) ion is square planar.Ab-inito 6-31 G* level calculations provided structural information and IR data that were in good agreement with experimental results.