Synthesis of 1-alkyl-1,2,4-triazolium 4-nitroimides by alkylation of 4-nitramino-1,2,4-triazole salts

A method for the synthesis of 1-alkyl-1,2,4-triazolium 4-nitroimides was developed based on alkylation of 4-nitramino-1,2,4-triazole Na and Ag salts with halo- and dihaloalkanes.     

Synthesis of 1-amino-1,2,4-triazolium 4-nitroimides and their reactions with electrophiles

A procedure was developed for the preparation of 1-amino-1,2,4-triazolium 4 nitroimides by amination of triethylammonium salts of 4-nitramino-1,2,4-triazoles with O-picrylhydroxylamine. The resulting nitroimides reacted with electrophilic reagents (acyl chlorides, aldehydes, phenyl isocyanate, NO₂BF₄, etc.) at the amino group.     

Thermal decomposition of 4-amino-1,2,4-triazolium nitrate under infrared laser heating

The objective of this work is to study the behavior of an ionic liquid, 1-H-4-amino-1,2,4-triazolium nitrate, during thermal decomposition driven by an infrared laser (10.6 μm). The focus was to understand the initial decomposition reactions and subsequent reactions that lead to ring decomposition and eventually to ignition. A triple quadrupole mass spectrometer with molecular beam sampling was used to obtain gaseous decomposition species of the sample. The principal mass peaks that may contain multiple masses were analyzed through tandem mass techniques. The experiments were conducted at a laser heat flux of 100 W/cm² in helium at 1 atm. To assist in interpreting the data, three other materials were also tested, 4-amino-1,2,4-triazolium hydrochloride, 4-amino-1,2,4-triazole, and 1-H-1,2,4-triazole. The results show that the most probable route to initiate the decomposition of the 1-H-4-amino-1,2,4-triazolium nitrate is through proton transfer from N₁ site to the nitrate forming a neutral pair, nitric acid and amino-triazole. Subsequent reactions involve decomposition of the neutral pair and their interactions.     

Assessment of Thermal Stability and Detonation Performance of 4-Amino-1,2,4-triazolium Nitrate as compared to 2,4,6-Trinitrotoluene for Melt-cast Explosives

4-Amino-1,2,4-triazolium nitrate (4-ATN) is an energetic and non-sensitive ionic liquid, which was introduced as a good candidate in previous works for the replacement of 2,4,6-trinitrotoluene (TNT) in melt-cast explosives. Since previous studies used pure nitric acid for nitration of 4-ATN, the effect of the use of low price industrial nitric acids (50 %, 70 % and 98 %) is investigated on the percent yields of 4-ATN. The thermogravimetric and differential scanning calorimetry (TGA/DSC) are done on the synthesized 4-ATN with impure nitric acid at a heating rate of 10 K · min^–1 by the vacuum system. The obtained TGA/DSC curves confirm decomposition of 4-ATN involving melting and dissociation. Derivative thermogravimetric (DTG) curves of 4-ATN at various heating rates are applied to obtain activation energy of thermolysis by several model-free techniques. The calculated activation energies are in the range 78.7–87.7 kJ · mol^–1, which are about 10 kJ · mol^–1 more than the reported activation energy of industrial TNT (purity 98.2 %), i.e. 66–70 kJ · mol^–1. Assessments of detonation performance of 4-ATN are also compared with TNT, which show higher detonation performance of 4-ATN. Thus, 4-ATN can be used with nitramine compounds as melt-cast explosives with higher thermal stability and detonation performance than corresponding nitramine compound/TNT explosives.     

Synthesis, crystal structure, IR-spectral data and some properties of 3,5-diamino-1,2,4-triazolium tetrafluoroborate and hexafluorosilicate

3,5-Diamino-1,2,4-triazolium tetrafluoroborate (LH)BF₄ and hexafluorosilicate (LH)₂SiF₆ have been isolated and characterized by single-crystal X-ray structure determination, IR spectroscopy, mass spectrometry, solubility data, potentiometry. The N-H?F and N-H?N hydrogen bonds play an important role in a formation of 3-D structures of two compounds. The relationship between the salts structure and some properties is discussed.     

Acidic N-dealkylation in nitrotriazolium salts

New selective synthesis of 1-alkyl-5-nitro-1,2,3-triazoles and 1-alkyl-4-nitro-1,2,3-triazoles has been developed, involving acid N-dealkylation of the relative 4-nitro-1,2,3- and 3-nitro- 5-R-1,2,4-triazolium salts. The assortment of novel 1-alkyl- 4(5)-nitro-1,2,3-triazoles has been thus essentially expanded. Treatment of relative 3-nitro-1,2,4-triazolium salts with HCl or HBr proceeds mostly as S_N^ipso-substitution of the nitro group.     

Reactions of 3-nitro-1,2,4-triazoles with alkylating agents. 3. Alkylation of a neutral heterocycle by diethyl sulfate

The reaction of 3-nitro-5-R-1,2,4-triazoles with diethyl sulfate gives 1-ethyl-3-R-5-nitro-, 4-ethyl-3-nitro-5-R-1,2,4-triazoles, 1,4-diethyl-, 1,4-diethyl-3-methyl-1,2,4-triazol-5-ones, and 1,4-diethyl-3-nitro-5-R-1,2,4-triazolium salts. When compared with the use of dimethyl sulfate as alkylating agent the ethylation products have a markedly increased fraction of triazolones (up to 30–37%) and a somewhat lowered yield of nitrotriazolium salts (up to 6–10%). The reaction time is increased by an order. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1378–1381, September, 2006.     

The first 1-alkyl-3-perfluoroalkyl-4,5- dimethyl-1,2,4-triazolium salts

Syntheses of quaternary 1-alkyl-3-perfluoroalkyl-4,5-dimethyl-1,2,4-triazolium iodides have led to a variety of new quaternary salts via metathesis reactions. 1,4,5-Trimethyl-3-trifluoro-methyl-1,2,4-triazolium iodide (6) with LiN(SO(2)CF(3))(2), KSO(3)CF(3), AgClO(4), AgBF(4); 1-(3-fluoropropyl)-3-trifluoromethyl-4,5-dimethyl-1,2,4-triazolium iodide (7) with LiN(SO(2)CF(3))(2); and 1,4,5-trimethyl-3-perfluorooctyl-1,2,4-triazolium iodide (8) with LiN(SO(2)CF(3))(2), AgClO(4), AgBF(4) gave excellent yields of new thermally stable and relatively low melting quaternary salts. The structure of 1,4,5-trimethyl-3-perfluorooctyl-1,2,4-triazolium tetrafluoroborate (11c) was confirmed by single-crystal X-ray analysis. Although the molecular weight of 11c (cation) is 3-fold greater than that of the 3-trifluoromethyl derivative 9d, its melting point is 32 degrees C lower.     

Synthesis of 1,2,4-triazolium 4-nitrimides with polyfunctionalized substituents

Methods for the synthesis of 1,2,4-triazolium 4-nitrimides with nitraminoalkyl-, hetaryl-methyl, nitro ether, and dinitroalkyl substituents are developed. These compounds are useful models for evaluation of the effect of relative positions of the nitro groups on the properties of substances.     

Conversion of 4-amino-4H-1,2,4-triazole to 1,3-bis(1H-azol-l-yl)-2-aryl-2-propanols and 1-phenacyl-4-[(benzoyl or 4-toluenesulfonyl)-imino]-(1H-1,2,4-triazolium) Ylides

A series of 1,3-bis(1H-azol-1-yl)-2-aryl-2-propanols 17 were synthesized in an one-pot procedure by reacting l-aryl-2-(1H-1,2,4-triazol-l-yl)- or l-aryl-2-(1H-imidazol-l-yl)ethanones with dimethylsulfoxonium methide in the presence of either 1,2,4-triazole or imidazole. The aromatic groups in 17 were either 4-bromo-, 4-chloro-, 2,4-dichloro- or 2,4-difluorophenyl. 4-Amino-4H-1,2,4-triazole was acylated with either benzoyl or 4-toluene-sulfonyl chloride to afford [4-(benzoyl or 4-toluenesulfonyl)amino]4H-1,2,4-triazole. Subsequent alkylations with 4-bromo- or 4-chlorophenacyl bromide produced 1-(4-bromo- or 4-chlorophenacyl)-4-[(benzoyl- or 4-toluenesulfonyl)amino]-1H-1,2,4-triazolium bromides. Neutralizations of these salts provided the corresponding ylides.     

Synthesis of anhydro-3-mercapto-5-pyrazinyl-1,2,4-triazolium hydroxides

The synthesis of some novel anhydro-3-mercapto-5-pyrazinyl-1,2,4-triazolium hydroxides 5 is described. The appropriate 1-methylhydrazides 3 were condensed with isothiocyanates to give the thiosemicarbazides 4 which were cyclized to 5 under mildly basic conditions. A few 1,2,4-triazole-3-thiones 8 were synthesized for comparison, starting with the 2-methylhydrazides 6 and then carrying out analogous synthetic transformations.     

Synthesis of 1,4-diphenyl-3-phenylimino-1,2-dihydro-1,2,4-triazolium hydroxide (Nitron)

1,4-Diphenyl-3-phenylimino-1,2-dihydro-1,2,4-triazolium hydroxide (Nitron) is prepared by the reaction of Pb₃O₄ with diphenylthiourea, followed by the reaction of the obtained diphenylcarbodiimide with phenylhydrazine to form triphenylaminoguanidine, whose heterocyclization yields 1,4-diphenyl-3-phenylimino-1,2-dihydro-1,2,4-triazole, which is subsequently oxidized.     

The degradation of carboxylic acids into aldehydes : Regioselective α-acetoxylation of 1,2,4-triazolium salts with diacetoxyiodate(1)anion

A novel method was developed for degradation of carboxylic acid into aldehydes containing one C atom less whose key step consists in α-acetoxylation of 5-alkyl-3-methylthio-1,4-diphenyl-1,2,4-triazolium iodides by (diacetoxyiodo)benzene. The mechanism of the regioselective α-acetoxylation was studied and the diacetoxyiodate(1)anion was shown to be the actual oxidising agent. Further oxidation reactions of tetraethylammonium diacetoxyiodate(1) were investigated.A novel method was developed for the oxidation of primary alkyl amines into aldehydes by the novel heterocyclic reagent 5-bromo-3-methylthio-1,4-diphenyl-1,2,4-triazolium bromide and diethyl azodicarboxylate.     

1H-thiazolo[3,2-b]-1,2,4-triazolium salts

The alkylation of 4H-triazole-5-thiones with -halo ketones takes place at the sulfur atom. 1H-Thiazolo[3,2-b]-1,2,4-triazolium — a new heteroaromatic cation — derivatives were obtained by intramolecular cyclization of the resulting -keto sulfides.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1132–1134, August, 1977.     

Synthesis of 1,2,4-triazolium salts: Reaction of 1-azo-2-azonia-allene salts with nitriles

Summary Alkyl ketone hydrazones1 are oxidized withtert-butylhypochlorite to give geminal chloro azo compounds2. These react with SbCl₅ to give 1-aza-2-azonia-allene salts3 as reactive intermediates which are intercepted with nitriles to yield 3H-1,2,4-triazolium salts5. In most cases these salts rearrange spontaneously to form 1H-triazolium salts6. Hydrolysis of6e–g by NaOH provide bases7a–c, which react with picric acid to give 1H-pyrazolium picrates8.

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Synthese von 1,2,4-Triazoliumsalzen: Reaktion von 1-Azo-2-azonia-allensalzen mit Nitrilen

Zusammenfassung Alkylketonhydrazone1 werden durchtert-Butylhypochlorit zu geminalen Chlorazoverbindungen2 oxidiert. Diese reagieren mit SbCl₅ zu 1-Aza-2-azonia-allensalzen3, welche mit Nitrilen unter Bildung von 3H-1,2,4-Triazoliumsalzen5 abgefangen werden. In den meisten Fällen lagern diese spontan zu 1H-Triazoliumsalzen6 um. Hydrolyse von6e–g mit NaOH führt zu den Basen7a–c, welche mit Pikrinsäure 1H-Pyrazoliumpikrate8 bilden.

     

Synthesis of 4-Amino-6-R-4,5-dihydro-3-phenacylthio-1,2,4-triazin-5-ones and 8H-3-R-7-Aryl-1,2,4-triazino[3,4-b][1,3,4]thiadiazin-4-ones

A study was carried out on the reaction of 4-amino-6-R-2,3,4,5-tetrahydro-3-thioxo-1,2,4-triazin-5-ones with halo ketones in alkaline media to yield 4-amino-6-R-4,5-dihydro-3-phenacylthio-1,2,4-triazin-5-ones, which then convert to 8H-3-R-7-aryl-1,2,4-triazino[3,4-b][1,3,4]thiadiazin-4-ones.     

Synthesis,characterization and energetic properties of novel 1-methyl-1,2,4-triazolium N-aryl/N-pyridinyl ylids

Synthesis, characterization and energetic properties of novel, nitrogen-rich 1-methyl-1,2,4-triazolium N-aryl/N-pyridinyl ylids 3a–m are reported.     

Unexpected Direction of Iodocyclization of 3-Allylthio-5-phenyl-4H-1,2,4-triazole

The reaction of 3-allylthio-5-phenyl-4H-1,2,4-triazole with iodine to give a mixture of 5,6-dihydro-5-iodomethyl-3-phenyl[1,3]thiazolo[2,3-c][1,2,4]triazole, 6,7-dihydro-6-iodo-3-phenyl-5H-[1,2,4]triazolo[3,4-b][1,3]thiazine, 5,6-dihydro-6-iodomethyl-2-phenyl[1,3]thiazolo[3,2-b][1,2,4]triazole, and 6,7-dihydro-6-iodo-2-phenyl-5H-[1,2,4]triazolo[5,1-b][1,3]thiazine has been studied. The structure of the products obtained was established using ¹H NMR spectroscopy of their dehydriodination products.     

A Convenient Synthesis of 1,2,4-Triazolo-1,3,5-triazin-4-ones and 1,2,4-Triazolo-1,3,5-triazin-4-thiones

The imidates derived from 3-aminotriazole 1 react with isocyanates and isothiocyanates to give corresponding 1,2,4-triazolo-1,3,5-triazin-4-ones and 1,2,4-triazolo-1,3,5-triazin-4-thiones in a 60–75% overall yield. If the condensation is realized at r.t., then the intermediate 2 can be isolated.     

Study of the Products of Iodocyclization of 4-Allyl-5-phenyl-1,2,4-triazole-3-thione

The interaction of 4-allyl-5-phenyl-1,2,4-triazole-3-thione with iodine proceeds with the formation of a mixture of 6-iodomethyl-3-phenyl-5,6-dihydrothiazolo[2,3-c]-1,2,4-triazole and 6-iodo-3-phenyl-6,7-dihydro-5H-1,2,4-triazolo[3,4-b]-1,3-thiazine. The structures of the cyclization products obtained were established on the basis of the ¹H NMR spectra of their dehydroiodinated derivatives. 6-Methyl-3-phenylthiazolo[2,3-c]-1,2,4-triazole, 3-phenyl-5H-1,2,4-triazolo[3,4-b]-1,3-thiazine, and 3-phenyl-7H-1,2,4-triazolo[3,4-b]-1,3-thiazine are formed on eliminating HI from the cyclization products.