Reaction of 3-Amino-5H- and 3-Amino-5-sulfanyl-1,2,4-triazoles with 1,2,4-Triazine-5-carbonitriles

Russian Journal of Organic Chemistry - 1,2,4-Triazines with an unsubstituted (1,2,4-triazol-3-yl)amine residue in the C5 position were synthesized by the solvent-free ipso-amination reaction...     

Solid-phase synthesis of 3-amino-1,2,4-triazoles

A solid-phase synthesis of 3-amino-1,2,4-triazoles is described. Reaction of resin bound S-methylisothiourea 2 with carboxylic acids yielded resin-bound S-methyl-N-acylisothioureas 3, which reacted with hydrazines under mild conditions to afford the corresponding resin-bound 3-amino-1,2,4-triazoles 4 with regioselectivity. Following cleavage, the desired products 5 were obtained in good yields and purities.     

Reactions of 3-amino-1,2,4-triazoles with cinnamic aldehydes

The reaction of 3-amino- and 3-amino-5-methylthio-1,2,4-triazoles with cinnamaldehyde takes two directions to form mixtures of 5-[N-(3-phenylpropenylideneamino)]-1H-1,2,4-triazoles and 5-phenyl-4,5,6,7-tetrahydro[1,2,4]triazolo[1,5-a]pyrimidin-7-ols.     

Zinc complexes with 3-Pyridinyl-5-(2-salicylideneiminophenyl)-1H-1,2,4-triazoles

New coordination compounds of zinc with 3-(pyridine-2-yl)-5-(2-salicylideneiminophenyl)-1H-1,2,4-triazole (H₂L¹) and 3-(pyridine-4-yl)-5-(2-salicylideneiminophenyl)-1H-1,2,4-triazole (H₂L²) are obtained. According to X-ray diffraction data, binuclear zinc complexes with L¹, namely, [Zn₂L₂¹]. 0.5EtOH and [Zn₂L₂¹] · 2C₄H₈O₂ · 2H₂O obtained in different solvents, are structurally related molecular complexes. The product of the reaction with H₂L² is the {[ZnL²(Py)] · CHCl₃} _n coordination polymer. The 1,2,4-triazoles under study and the complexes on their basis luminesce in solutions with emission maxima ranging from 412 to 503 nm. These coordination compounds in the solid state emit in the green range of the spectrum (λ_max = 496 and 485 nm).     

Reaction of 3(5) -diazo-1,2,4-triazoles with nitroalkane anions

The 1,2,4-triazolylhydrazones of the corresponding nitro aldehydes were obtained by the reaction of the anions of nitromethane, nitroethane, and 1-nitropropane with diazo-1,2,4-triazoles. 2-Nitropropane, 1,1-dinitroethane, 1,1-dinitropropane, and trinitromethane form 1,2,4-triazolylazonitro compounds.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 713–717, May, 1972.     

Aroylation of 5-amino-2H-1,2,4-thiadiazolin-3-one

2-Aroyl-5-aroylamino-1,2,4-thiadiazolin-3-ones 2 have been synthesized through aroylation of 5-amino-2H-1,2,4-thiadiazolin-3-one ( 1 ) as an analog of cytosine. The aroylation was carried out with a substituted aroyl chloride in pyridine at 56–58°. It has been established that the intermediates of the reactions are 2-aroyl-5-amino-1,2,4-thiadiazolin-3-ones 3 on the basis of the spectral data, additional experimental information and ab initio molecular orbital calculations.     

Aroylation of 5-amino-2H-1,2,4-thiadiazolin-3-ones

2-Aroyl-5-aroylamino-1,2,4-thiadiazolin-3-ones ( 2 ) have been synthesized through aroylation of 5-arruno-2H-1,2,4-thiadiazolin-3-one ( 1 ) as an analog of cytosine. The aroylation was carried out with a substituted aroyl chloride in pyridine at 56～58°C. It has been established that the intermediates of the reactions are 2-aroyl-5-amino-1,2,4-thiadiazolin-3-ones ( 3 ) on the basis of the spectral data, additional experimental information and ab initio molecular orbital calculations.     

Diphenylmethyl Protective Group in the Synthesis of 5-Substituted 3-Nitro-1H-1,2,4-triazoles

A diphenylmethyl protective group is suggested for use in the synthesis of 5-R-3-nitro-1H-1,2,4-triazoles unsubstituted at the cyclic nitrogen atom, via nucleophilic substitution of 5-bromo- and 5-methylsulfonyl groups.     

A convenient synthesis of 4-amino-3,5-dialkyl-4H-1,2,4-triazoles

Ester tert-butoxycarbonylhydrazones 2 were reacted with some carboxylic acid hydrazides to give 4 -terrtutoxycarbonylamino-3,5-dialkyl-4H-1,2,4-triazoles 3–6 . Treatment of 3–5 with 6 N hydrochloric acid under mild conditions resulted in the formation of 4-ammo-3,5-dialkyl-4H-1,2,4-triazole hydrochlorides 7–9 in good yields. Compound 7a was converted to the free 4 -amino compound 10a upon treatment with ethanolic sodium ethoxide solution.     

1,2,4-Triazoles,II Synthesis of 1,5-diphenyl-3-trifluoromethyl-1H-1,2,4-triazoles

Reaction of substituted phenylhydrazines1 a–f with methyl trifluoroacetimidate2 gives via the amidrazones3 after treatment with benzoyl chlorides4 the triazoles5 a–f which showed an anti-inflammatory effect.Presented at the 1st Belgian Organic Synthesis Symposium, Namur, 19–23 May, 1986.     

5-substituted 3-nitro-1-trinitromethyl-1,2,4-triazoles

A number of 5-R-substituted 3-nitro-1-trinitromethyl-1H-1,2,4-triazoles (R = Me, Cl, Br, N₃, NH₂, NO₂) were synthesized by nitration of the corresponding ω-(5-R-3-nitro-1H-1,2,4-triazol-1-yl)alkan-2-ones with mixtures of concentrated sulfuric and nitric acids.     

5-Substituted 3-Nitro-1-vinyl-1,2,4-triazoles

A series of 5-substituted 3-nitro-1-vinyl-1,2,4-triazoles were synthesized by alkaline treatment of the corresponding 1-(2-haloethyl- or 2-nitroxyethyl)-3-nitro-1,2,4-triazoles and by transvinylation of NH acids of the same series with vinyl acetate. The scope of applicability of the transvinylation procedure was established with respect to the azole pK _a value. The vinylic double bond on the nitrogen was shown to be inactive toward both nucleophilic and electrophilic reagents, whereas the halogen atom in position 5 exhibits enhanced reactivity. The latter factor provides the possibility for versatile structural modification via nucleophilic replacement of the 5-halogen atom by various groups, including triazolate ion.     

3-芳基-5-巯基-1,2,4-三唑衍生物的亲核反应研究

研究了碱性条件下3-芳基-5-巯基-1,2,4-三唑与丙烯腈或丙烯酸甲酯的亲核反应,得到31个新的3-芳基-1,2,4-三唑-5-硫酮类衍生物,其结构经NMR, IR, MS和元素分析表征.     

Reaction of Diethyl Chloroethynylphosphonate with 3-Amino-1,2,4-triazoles

Russian Journal of General Chemistry - A series of new 6-phosphonylated 1H-imidazo[2,1-c][1,2,4]triazoles was synthesized by the reaction of diethyl chloroethynylphosphonate with 2-substituted...     

Synthesis of 3-pyridyl-substituted 5-amino-1,2,4-triazoles from aminoguanidine and pyridinecarboxylic acids

Effect of the molar ratio between reagents, temperature, and synthesis duration on the yield of 3-pyridylsubstituted 5-amino-1,2,4-triazoles in the reaction of aminoguanidine hydrochloride with pyridinecarboxylic acids under acid catalysis conditions was studied. A single-reactor method for synthesis of 3-pyridyl-substituted 5-amino-1,2,4-triazoles and their hydrochlorides was developed.     

Rapid, microwave-assisted synthesis of N1-substituted 3-amino-1,2,4-triazoles

A robust, regioselective synthesis of 3-amino-1,2,4-triazoles is described. This reaction employs a key intermediate 2, which is coupled to carboxylic acids in good yields to afford intermediates 3a-d. These entities, in turn, react with a variety of hydrazines or hydrazine hydrochlorides to provide proposed intermediates 4a-j, which under microwave conditions cyclize to the desired 3-amino-1,2,4-triazoles (compounds 5a-j). This approach permits the rapid synthesis of regioselective N1-substituted 3-amino-1,2,4-triazoles, and is shown to afford a variety of such compounds in 34-70% isolated yields.     

Crystal structures of an isomeric pair of 3-methylthio-5-amino-1,2,4-triazoles

The structures of an isomeric pair: 1-[2-(2,6-dichlorophenoxy)-ethyl]-3-methylthio-5-amino-1H-1,2,4-triazole (IV) and 2-[2-(2,6-dichlorophenoxy)-ethyl]-3-methylthio-5-amino-2H-1,2,4-triazole (V) have been established by X-ray crystallography from diffractometer data. Crystals of IV are monoclinic, space group P2₁/c with a = 11.220(1), b = 10.005(3), c = 12.784(3) Å, β = 91.99(1)°, Z = 4, D_c = 1.478 g cm⁻³. Crystals of V are orthorhombic, space group Pbca with a = 7.618(2), b = 14.289(4), c = 26.494(7) Å, Z = 8, D_c = 1.470 g cm⁻³. The structures determined by direct methods were refined to R = 0.060 for 1931 reflections of IV and R = 0.061 for 1315 reflections of V. The X-ray analysis corroborated the structures assigned to the isomeric pair on the basis of proton coupled ¹³C-NMR spectra. The features (i.e. the sequence of the endocyclic bond angle magnitudes) of the planar s-triazole rings are governed by the same rules reported recently by Kálmán and Argay [J. Mol. Struct., 102 (1983) 391] discussing the structures of the related I, II and III compounds. In contrast to I, II, III and IV the S(6)---C(7) bond of V is almost perpendicular to the best plane of the s-triazole ring C(7)---S(6)---C(3)---N(4) = −79.0(7)°. This unusual orientation of the S-methyl bond is created by the steric hindrance of the very same vicinal 2-ethyl (C(9)H₂---C(10)H₂) moiety once within the molecule V and the second time as the part of a symmetry equivalent molecule at a distance of −a (7.618 Å). These molecules are fixed together by two infinite helices of hydrogen bonds formed around the screw axis 2, (X, 1/4, 1/2) via an intermediate V molecule at (x − 1/2, 1/2 − y, 1 − z).     

On the lead tetraacetate oxidation of 4-amino-1,2,4-triazoles, 1-amino- and 2-amino-1,2,3-triazoles

Lead tetraacetate oxidation of 4-amino-1,2,4-triazoles, 1-amino- and 2-amino-1,2,3-triazoles affords mainly fragmentation to nitriles or acetylenes, even in the presence of intramolecularly attached double bonds.

---

Über die Bleitetraacetatoxidation von 4-Amino-1,2,4-triazolen, 1-Amino- und 2-Amino-1,2,3-triazolen (Kurze Mitteilung)

Zusammenfassung Bei der Oxidation von 4-Amino-1,2,4-triazolen, 1-Amino- und 2-Amino-1,2,3-triazolen mit Bleitetraacetat entstanden hauptsächlich Nitrile bzw. Acetylene durch Fragmentierung — trotz der Gegenwart von intramolekularen Doppelbindungen.

     

A survey of the lone pair effect on the ring geometry of 1,2,4-triazoles and analogous 1,2,3-triazoles and imidazoles : The structures of 1-methyl-5-amino-3-methylthio-1,2,4-triazole, 1-phenyl-5-amino-3-methylthio-1,2,4-triazole and 1-(4-methylbenzyl)-3-amino-5-methylthio-1,2,4-triazole

The structures of the title compounds have been established by X-ray crystallography from diffractometer data. Crystals of the first (I), C₄H₈N₄S, are monoclinic, space group P2₁/c, with a = 8.166(2), b = 10.481(1), c = 8.585(1) Å, β = 109.33(2)°, Z = 4, D_c = 1.381 g cm⁻³. Crystals of the second (II), C₉H₁₀N₄S, are monoclinic, space group P2₁/c, with a = 11.850(4), b = 7.898(1), c = 23.981 (6) Å, β = 117.23(2)°, Z = 8, D_c = 1.373 g cm⁻³. Crystals of the third (III), C₁₁H₁₄N₄S₁ are also monoclinic, space group P2₁/c with a = 12.829(3), b = 8.348(1), c = 11.088(4) Å, β = 94.40(4)°, Z = 4, D_c = 1.314 g cm⁻³. The structures, determined by direct methods (I, III) and Patterson synthesis (II) were refined to R = 0.039 for 1070 reflections of I, R = 0.040 for 2792 reflections of II and R = 0.041 for 1900 reflections of III. The characteristic features of the planar five-membered rings are studied in comparison with the analogous 1,2,3-triazoles and imidazoles. It is shown that these planar rings exhibit only two patterns of the endocyclic bond angles induced dominantly by the number and relative position of the N-lone pairs. A similar effect of the double bonds (attached to C atoms) is also discussed.