Mass-spectrometric study of isomeric 5-amino-1,2,3-thiadiazoles and 5-mercapto-1,2,3-triazoles

The behavior of the isomeric 5-amino-1,2,3-thiadiazoles and 5-mercapto-1,2,3-triazoles under electron impact was studied. It was shown that mass spectrometry can serve as a rapid and reliable method for the identification of these compounds. Key factors in the assignment of a compound to one or the other class are the peaks of the [M-N₂]⁺ ions, which are more intense in the case of the thiadiazoles, and the ions determined by the decomposition of the prototropic forms of the triazoles. The compositions of the ions were determined by the high-resolution mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 681–689, May, 1987.     

Acylation of 2-aryl-5-imino-2,5-dihydro-1,2,3-thiadiazoles

A large series of new 5-acyl-and 5-sulfonylthiadiazolimines was prepared by acylation of 2-aryl-5-imino-2,5-dihydro-1,2,3-thiadiazoles. Compounds obtained are more stable than the initial substances and do not transform into 1,2,4-thiadiazoles.     

5-卤代1,2,3,-三唑互变异构的密度泛函理论研究

用密度泛函B3LYP/6-311 G**方法,对气相和水相中的1,2,3三,-唑及5-卤(-F、C l和-B r)代1,2,3,-三唑互变异构体进行了几何构型全自由度优化,获得了它们在气相和水相中的几何结构和电子结构。计算结果显示,在气相和水相中1,2,3三-唑和5-卤代1,2,3三-唑的N2-H型要比对应的N1-H型和N3-H型稳定。讨论了不同的取代基团和溶剂化效应对互变异构体的几何结构、能量和电荷分布以及互变异构反应活化能的影响带。并进一步研究了N1-H、N2-H和N3-H型三唑之间的互变异构机理:(a)分子内质子转移;(b)水助质子转移。计算结果表明,途径(b)所需要的活化能较小,为120.06KJ/mol,途径(a)为204.12KJ/mol。     

Structure of the UV irradiation product of 5-methyl-2-phenyl-1,2,3-diazaphosphole

Conclusion UV irradiation of 5-methyl-2-phenyl-1,2,3-diazaphosphole leads to 4,4-didehydro-bis(5-methyl-2-phenyl-1,2,3-diazaphosphole).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 633–636, March, 1987.The authors thank A. V. Il'yasov and K. M. Enikeev for discussion of the¹³C NMR spectra.     

2-乙酰基-5-甲基-1,2,3-二氮磷杂环戊二烯同丙炔醇反应研究

用付里叶变换红外光谱及³¹PNMR,探索了2-乙酰基-5-甲基-1,2,3-二氮磷杂环戊二烯同丙炔醇的动态反应过程,推测了可能的反应机理,并通过对二配位磷化物对应的三配位磷化物(2-乙酰基-3-氯-5-甲基-1,2,3-二氮磷杂环戊烯)同丙炔醇反应的研究,验证了二配位磷化物反应机理的可能性。     

Selenium-catalyzed oxidative carbonylation of 1,2,3-thiadiazol-5-amine with amines to 1,2,3-thiadiazol-5-ylureas

With cheap and easily available 1,2,3-thiadiazol-5-amine and amines as raw materials, cheap and reusable selenium as the catalyst, CO as the carbonylation reagent and O₂ as the oxidizing agent, the selenium-catalyzed oxidative carbonylation reaction of 1,2,3-thiadiazol-5-amine can proceed smoothly with a series of amines in one-pot manner in the presence of triethylamine, affording 1,2,3-thiadiazol-5-ylureas mostly in moderate to good yields.     

Synthesis of 5-amino-1,2,3-thiadiazole

A convenient method is proposed for the synthesis of ethyl phthalimidoethylideneaminocarbamate, an intermediate in the synthesis of 5-amino-1,2,3-thiadiazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 112–113, January, 1989.     

5-Methyl-2-phenyl-2H-1,2,3-diazaarsole in reaction with ethyl diazoacetate

5-Methyl-2-phenyl-2H- 1,2,3-diazaarsole 1 reacts with ethyl diazoacetate to form a 1:1 bicyclic product 3a , 8-ethoxycarbonyl-4-methyl-2-phenyl-1-arsa-2,3,6,7-tetraazabicyclo[3.3.0]octa-3.7-diene. The latter isomerizes to a two-coordinate arsenic compound 5 , 3-ethoxycarbonyl-5-[α-(phenylhydrazono)ethyl] 1-1,2,4-diazaarsole. The X-ray crystal structure analyses of both products 3a and 5 have been carried out.     

Reactions of 2,4-disubstituted 5-nitro-1,2,3-triazole 1-oxides. 2. Oxidation of 2-substituted 4-amino(alkylamino)-5-nitro-1,2,3-triazole 1-oxides

The oxidation of substituted aminonitrotriazole oxides to the corresponding dinitro derivatives of triazole and azotriazole oxides has been studied. Communication 1, see ref. [1]. N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow, Russia; e-mail: cheminst@mail.psu.ru. Institute of Chemical Physics at Chernogolovka, Russian Academy of Sciences, 124432 Chernogolovka, Russia. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1356–1362, October, 1999.     

4-Aryl(benzyl)sulfonyl-2-chloro-5-polyfluoroalkyl-1,2,3-triazoles. The first monocyclic N-chloro-1,2,3-triazoles

Treatment of 4-aryl(benzyl)sulfonyl-5-polyfluoroalkyl-v-triazoles with NaOCl gave the 4-aryl(benzyl)-sulfonyl-2-chloro-5-polyfluoroalkyl-v-triazole derivatives which contain a chlorine atom only on the N₍₂₎ atom of the heterocycle. The structure of 2-chloro-5-(1,1,2,2,3,3-hexafluoropropyl)-4-(p-tolyl-sulfonyl)-2H-[1,2,3]triazole has been established by X-ray structural investigation. The presence of a highly polarized N—Cl bond with a positive halogen atom causes the N-chlorotriazoles to react with KCN and KF as strong acids to form the potassium salts of the triazoles and to form 4-arylsulfonyl-2-(2-chloro-1-ethoxyethyl)-5-polyfluoroalkyl-2H-[1,2,3]triazoles with vinyl ethyl ether. It was found that chlorination of 4-arylsulfonyl-5-polyfluoroalkyl-v-triazoles in the presence of KF gives 4-chloro-5-polyfluoroalkyl-2H-[1,2,3]triazoles. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1342–1352, September, 2007.     

Crystal Structure and Solid-State Packing of 4-Chloro-5H-1,2,3-dithiazol-5-one and 4-Chloro-5H-1,2,3-dithiazole-5-thione

The crystal structure and solid-state packing of 4-chloro-5H-1,2,3-dithiazol-5-one and two polymorphs of 4-chloro-5H-1,2,3-dithiazole-5-thione were analyzed and compared to structural data of similar systems. These five-membered S,N-rich heterocycles are planar with considerable bond localization. All three structures demonstrate tight solid-state packing without voids which is attributed to a rich network of short intermolecular electrostatic contacts. These include S^δ+…N^δ−, S^δ+…O^δ−, S^δ+…Cl^δ− and S^δ+…S^δ− interactions that are well within the sum of their van der Waals radii (∑_VDW). B3LYP, BLYP, M06, mPW1PW, PBE and MP2 were employed to calculate their intramolecular geometrical parameters, the Fukui condensed functions to probe their reactivity, the bond order, Bird Index and NICS(1) to establish their aromaticity.     

Dimroth rearrangement of 5-hydrazino-1,2,3-thiadiazoles

The reversible isomerization of 5-hydrazino-1,2,3-thiadiazoles and 1-amino-5-mercapto-1,2,3-triazoles has been established for an ester function at the 4-position ( 4a ? 5a ). Thus, 4a was isolated by reacting 3a with two equivalents of hydrazine, whereas 5a resulted when an excess of hydrazine was used. Acid treatment of 5a yielded 4a again, and its hydrazone 8 was obtained from 5a and benzaldehyde. Compound 5a was also converted into the derivatives 6a, 7, 9 and 10a-c. The less reactive 5-chloro-1,2,3-thiadiazoles 3b,c afforded the bis-heterocycles 6b,c on heating with hydrazine.     

Synthesis of 2-(1,2,3-Thiadiazol-5-yl)-1H-benzimidazoles

We have developed a convenient preparative method for synthesis of previously unknown 2-(1,2,3-thiadiazol-5-yl)-1H-benzimidazoles based on reaction of benzoylhydrazones of 2-acylmethyl-1H-benzimidazoles with thionyl chloride. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1391–1393, September, 2005.     

5-醛基-1,2,3-三唑互变异构的理论研究

用密度泛函B3LYP/6-311++G**方法,对气相和水相中的5-醛基-1,2,3-三唑互变异构体进行了几何构型全自由度优化,获得了它们在气相和水相中的几何结构和电子结构.讨论了不同的取代基团和溶剂化效应对互变异构体的几何结构、能量以及互变异构反应活化能的影响.并进一步研究了N1-H、N2-H和N3-H型三唑之间的互变异构机理:(a)分子内质子转移;(b)水助质子转移.计算结果表明,途径(b)所需要的活化能较小,平均为101.31kJ/mol,途径(a)为211.70kJ/mol.     

2,2-Difluor-1,2,3-trimethyl-1,3-diaza-2λ5-phospholidin

2,2-Difluoro-1,2,3-trimethyl-1,3-diaza-2λ⁵-phospholidine The title compound 1 is obtained in about 50% yield by oxidative fluorination of 1,2,3-trimethyl-1,3-diaza-2λ³-phospholidine, 6 , with IF₅. 1 is characterized by its nmr, mass, and ir spectra.     

The photolysis of the l-cycloalkoxy-5-chloro-1,2,3-benzotriazole system

Three l-cycloalkoxy-5-chloro-1,2,3-benzotriazoles were photolyzed at 254 nm. The major photolytic pathway yielded the corresponding cyclic ketone and 4,4′-dichloroazobenzene.