Synthesis and Reactivity of Azidoximes: III. 1-Azido(4-amino-1,2,5-oxadiazol-3-yl)aldoxime in the Cycloaddition Reaction

By 1,3-dipolar addition of 1-azido(4-amino-1,2,5-oxadiazol-3-yl)aldoxime to propargyl alcohol and phenylacetylene bicyclic 4-amino-1,2,5-oxadiazol-3-yl(4-R-1,2,3-triazol-1-yl)ketoximes were obtained which in reaction with acetic anhydride afforded the corresponding O-acyl derivatives. Diazotization of 4-amino-1,2,5-oxadiazol-3-yl(4-R-1,2,3-triazol-1-yl)ketoximes furnished 4-azido derivatives. The treatment of 4-amino-1,2,5-oxadiazol-3-yl(4-hydroxymethyl-1,2,3-triazol-1-yl)ketoxime with SOCl₂ resulted in 4-amino-1,2,5-oxadiazol-3-yl(4-chloromethyl-1,2,3-triazol-1-yl)ketoxime, whose chlorine atom was readily replaced by azide ion affording 4-amino-1,2,5-oxadiazol-3-yl(4-azidomethyl-1,2,3-triazol-1-yl)ketoxime.     

Some Reactions of 3,6-Bis(4-amino-1,2,5-oxadiazol-3-yl)-1,4,2,5-dioxadiazine

Diazotization and nitration of 3,6-bis(4-amino-1,2,5-oxadiazol-3-yl)-1,4,2,5-dioxadiazine gave, respectively, 3,6-bis(4-azido-1,2,5-oxadiazol-3-yl)-1,4,2,5-dioxadiazine and 3,6-bis(4-nitroamino-1,2,5-oxadi-azol-3-yl)-1,4,2,5-dioxadiazine. The latter reacted with nitrogenous bases to form the corresponding salts.     

Synthesis of some sym-triazole derivatives

3,5-Di(hydroxyalkyl) derivatives of 4-amino-1,2,4-triazole and the corresponding derivatives of 1,2,4-triazole obtained by diazotizing them are converted by reaction with SOCl₂ into the hydrochlorides of 4-amino-3,5-di(chloroalkyl)-1,2,4-triazoles and 3,5-di(chloroalkyl)-1, 2,4-triazoles. The dinitrate of 3,5-di(hydroxymethyl)-1,2,4-triazole has been prepared. When the cyanohydrazide of glycolic acid is heated with hydrazine hydrate, 4,5-diamino-3-hydroxymethyl-1, 2,4-triazole is formed.     

Chiral 1,2,4-triazoles: stereoselective acylation and chlorination

Acyl groups are transferred from diverse N- and O-acyl derivatives of chiral 3,5-bis-(1-hydroxyethyl)-[1,2,4]-triazole to amino acid esters enantioselectively, with 7% to 68% ee, depending on the temperature conditions and nature of the reagents. Thionyl chloride replaced the hydroxyl groups of (S)-1-[4-amino-5-((S)-1-hydroxy-ethyl)-[1,2,4]-triazol-3-yl]-ethanol 3 stereospecifically with inversion, as confirmed by X-ray analysis, which also revealed unusual crystal structures with asymmetric units comprising three molecules of 4-amino-3,5-bis(R-1-chloroethyl)-1,2,4-triazole 5 and four of 3,5-bis((R)-1-chloroethyl)-1H-1,2,4-triazole 6.     

Construction of Coplanar Bicyclic Backbones for 1,2,4-Triazole-1,2,4-Oxadiazole-Derived Energetic Materials

Combining different nitrogen-rich heterocycles into a molecule can fine-tune its energetic performance and physical properties as well as its safety for use in energetic materials. Here, 1,2,4-oxadiazole was incorporated into 1,2,4-triazole to construct new energetic backbones. 3-(5-Amino-1H-1,2,4-triazol-3-yl)-1,2,4-oxadiazol-5-amine ( 5 ) was designed and synthesized. Nitramino-functionalized N-(5-(5-amino-1,2,4-oxadiazol-3-yl)-3H-1,2,4-triazol-3-yl)nitramide ( 6 ) and N-(5-(5-(nitramino)-1,2,4-oxadiazol-3-yl)-3H-1,2,4-triazol-3-yl)nitramide ( 7 ) were also obtained, and two series of corresponding nitrogen-rich salts were prepared, leading to the creation of new energetic compounds. All derivatives were fully characterized, and five of them were further confirmed by X-ray diffraction. The theoretical calculations, energetic performance, safety, and the main decomposition gaseous products of 1,2,4-triazole-1,2,4-oxadiazole-derived energetic materials were studied. Compound 7 and its dihydroxylammonium salt ( 7 c ) exhibited prominent detonation performance comparable to that of RDX while possessing satisfying thermal stabilities and mechanical sensitivities.     

4-Aminofurazan-3-carboxylic Acid Iminoester in Reactions with N,O-Nucleophiles

Reactions of 4-aminofurazan-3-carboxylic acid iminoester with o-aminophenol and ethylenediamine give rise respectively to 4-(1,3-benzoxazol-2-yl)- and 1-(4,5-dihydro-1H-imidazol-2-yl)-1,2,5-oxadiazol-3-amines, with aminoethanol arises 2-[(Z)-1-amino-1-(4-amino-1,2,5-oxadiazol-3-yl)methylideneamino]-1-ethanol. Treating of 3-amino-4-(1H-benzo[d]imidazol-2-yl)-1,2,5-oxadiazole with triethyl orthoformate in acetic anhydride yielded benzo[4,5]imidazo[1,2-c][1,2,5]oxadiazolo[3,4-e]pyrimidine, and alkylation with haloalkanes furnished 3-amino-4-(1-R-benzo[d]imidazol-2-yl)-1,2,5-oxadiazoles.     

Synthetic routes towards tetrazolium and triazolium dinitromethylides

Tetrazolium-5-dinitromethylide sodium salt has been prepared (91%) by cyclization of 1-amino-1-hydrazino-2,2-dinitroethene with nitrous acid in water. 5-Imino-1-(hydroxyiminonitromethyl) derivatives were obtained by nitration of 2-(5-amino-1,3-dimethyl-1H-1,2,4-triazol-4-ium-4-yl)- and 2-(5-amino-4-methyl-1H-tetrazolium-1-yl)acetate complex salts. Treatment of 4-methyl-1-(2-oxopropyl)-1-tetrazolium methylsulfate with nitric and sulfuric acid gave methyl (3-nitro-1,2,4-oxadiazol-5-yl)amine (27%) probably via dinitromethylide followed by cyclization and loss of nitrogen.__________Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 127–134, January, 2005.     

Synthesis of 5-aryl-3-carbazoyl-1,3,4-oxadiazol-2(3H)-one. Derivatives and their ring transformation into 5-benzamido-1,2,4-triazolidine-3,5-dione derivatives

Some 5-aryl-3-carbazoyl-1,3,4-oxadiazol-2(3H)-one derivatives 6 and 9 have been synthesized in two ways. The expected thermal ring transformation into 2,5-disubstituted 1,3,4-oxadiazoles did not occur but, by acid hydrolysis of 5-aryl-3-[3-benzylidene-2-methyl(or phenyl)carbazoyl]-1,3,4-oxadiazol-2(3H)-ones 6 , a new ring transformation took place and the corresponding 4-benzamido-1-methyl(or phenyl)-1,2,4-triazolidine-3,5-dione derivatives 11 were formed. The 4-amino-1-phenyl-1,2,4-triazolidine-3,5-dione ( 19 ) has been prepared and its structure was confirmed by some reactions.     

Fused Mesoionic Heterocycles: Synthesis of 1,2,4-triazolo(4,3-b)-1,2,4-triazole derivatives

A number of mesoionic compounds derivatives of the bicyclic system 1,2,4-triazolo(4,3-b)-1,2,4-triazole have been prepared from 4-amino-1-methyl-3,5-bis(methylthio)-1,2,4-triazolium iodide and aryl isothiocyanates.     

Touching the upper limit for ferromagnetic interactions in hetero-bridged dinuclear [Cu2(II)] complexes using a novel N5-dinucleating ligand bearing an endogenous monoatomic amido(R-NH(-))-bridging group

A novel N(5)-dinucleating ligand 4-amino-3,5-bis(bipyridine-2-yl)-1,2,4-triazole allows the preparation for the first time, and under mild conditions, of single and mixed amido(R-NH(-))-bridged copper(II) complexes, the latter exhibiting very strong ferromagnetic coupling.     

Synthesis of thiadiazoles and 1,2,4-triazoles derived from cyclopropane dicarboxylic acid

New heterocyclic derivatives of cyclopropane dicarboxylic acid comprising thiadiazole and 1,2,4-triazole moieties are reported. Reaction of 1,1-cyclopropane dicarboxylic acid (1) with thiosemicarbazide and phosphorous oxychloride resulted in 1,1-bis (2-amino-1,3,4-thiadiazol-5- yl)cyclopropane (2). Cyclopropane dicarboxylic acid thiosemicarbazide (6) was converted into 1,1-bis(3-thio-4H-1,2,4-triazol-5-yl) cyclo- propane (7) by ring closure in an alkaline medium. The thiadiazole 2 and the triazole 7 were converted into a variety of derivatives.     

N-Nitroimines: I. Synthesis,Structure, and Properties of 3,5-Diamino-1-nitroamidino-1,2,4-triazole

The reaction of 3,5-diamino-1,2,4-triazole with 2-methyl-1-nitroisothiourea gives 3,5-diamino-1-nitroamidino-1,2,4-triazole instead of the expected 1-[5(3)-amino-1,2,4-triazol-3(5)-yl]-2-nitroguanidine. Almost planar structure of the molecule of 3,5-diamino-1-nitroamidino-1,2,4-triazole gives rise for direct polar conjugation which is responsible for the low basicity of the amino groups.     

Synthesis of new modified aza heterocycles on the basis of 5-(2-chloro-1-nitroalkyl)-3-phenyl-and 5-(2-chloro-1-nitroalkyl)-3-methyl-1,2,4-oxadiazoles

3-Phenyl-and 3-methyl-5-(2-chloro-1-nitroalkyl)-1,2,4-oxadiazoles reacted with piperidine, pyrrolidine, and morpholine to give the corresponding 5-(2-amino-1-nitroalkyl) derivatives, while their reactions with sodium p-toluenesulfinate led to the formation of 2-[3-methyl(or phenyl)-1,2,4-oxadiazol-5-yl]-2-nitroethyl p-tolyl sulfones.     

4-Methyl-1,2,5-oxadiazole-3-carbonitrile in the synthesis of 1,2,5-oxadiazolyl-1,2,4-oxadiazoles

4-Methyl-1,2,5-oxadiazole-3-carbonitrile reacts with hydroxylamine to form 4-methyl-1,2,5-oxadiazole-3-carboxamidoxime, which turned out to be the useful starting compound in the synthesis of 3-(1,2,5-oxadiazol-3-yl)-1,2,4-oxadiazoles.     

Synthesis and study of heteroaromatic ligands containing a pyrimidine ring

5-Hexyl-3-[2-(1H-pyrazol-1-yl)pyrimidin-4-yl]amino-1(2)H-1,2,4-triazoles and 2-(3,5-dipropyl-4-ethyl-1H-pyrazol-1-yl)-6-methyl-4-(5-methyl-1H-pyrazol-1-yl)-aminopyrimidine were synthesized by the reaction of 4-chloropyrimidines with 3-araino-5-hexyl-1H-1,2,4-triazole and 3-amino-5-methyl-1H-pyrazole. Their IR, UV, and PMR spectra were investigated. New methods for the preparation of the intermediates, viz., 2-hydrazino-4(3H)-pyrimidinones and 2-(1H-pyrazol-1-yl)-4(3H)-pyrimidinones, that make it possible to obtain these compounds in higher yields are described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1673–1677, December, 1980.     

Synthesis of 1,2-Diazol-4-sulfonamides, 1,2,4- and 1,2,5-Oxadiazol-3-sulfonamides, 1,2,3-Triazol-4-sulfonamides, and Pyrimidine-5-sulfonamides starting from Cyanomethanesulfonyl Chloride

Summary. Cyanomethanesulfonyl chloride was reacted with amines yielding cyanomethanesulfonamides which could be transformed into alkoxymethylidene and aminomethylidene derivatives. The reaction of alkoxymethylidene derivatives with phenylhydrazine resulted in the formation of 5-aminopyrazol-4-sulfonamides, whereas from cyanomethanesulfonamides via the N-hydroxyamidine derivatives and their reaction with esters 1,2,4-oxadiazol-3-methanesulfonamides became accessible. Nitrosation of cyanomethanesulfonamides yielded 2-hydroxyimino derivatives which were then transformed into 2-hydroxyimino N-hydroxyamidine derivatives, and finally cyclized into 4-amino-1,2,5-oxadiazol-3-sulfonamides. On the other hand diazotation of cyanomethanesulfonamides gave the 2-arylhydrazono derivatives, which after transformation into N-hydroxyamidine derivatives gave by reaction with POCl₃ 5-amino-1,2,3-triazol-4-sulfonamides. Finally, the reaction between cyanomethanesulfonamides and formamidinium acetate opened an easy access to 4-aminopyrimidine-5-sulfonamides, which could be transformed by trialkyl orthoformiates into substituted pyrimidino[4,5-e][1,2,4]thiadiazine derivatives. All intermediates as well as transformation products of the heterocyclic systems were isolated and well characterized. Mechanisms were discussed, and the stereochemistry, when necessary and possible, was elucidated.     

2-Nitroguanidine Derivatives: V. Synthesis and Structure of 3,5-Bis(nitroamino)-1,2,4-triazole Salts. Acid–Base Properties of 3,5-Bis(nitroamino)-1,2,4-triazole

Heterocyclization of hydrazine-1,2-bis(N ²-nitrocarboximidamide) and salts derived therefrom provides a procedure for the synthesis of 3,5-bis(nitroamino)-1,2,4-triazole salts. The presence of two acceptor nitroamino groups conjugated with the triazole ring considerably enhances the acidity of 3,5-bis(nitroamino)-1,2,4-triazole (pK a¹= –2.0, pKa² = 4.8, pKa³ = 10.6) as compared to mononitroaminotriazole, so that formation of salts with the corresponding dianion becomes possible.     

Reaction of 3-formyl-2-methoxy-1,6-dioxaspiro[4.4]nonanes with 3-amino-1,2,4-triazole: synthesis of 2-(1,2,4-triazolo[1,5-a]pyrimid-6-yl)methylenetetrahydrofurans

The reaction of 3-formyl-2-methoxy-1,6-dioxaspiro[4.4]nonanes with 3-amino-1,2,4-triazole gives 2-(1,2,4-triazolo[1,5-a]pyrimid-6-yl)methylenetetrahydrofurans in 51–65% yields.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2004–2005, November, 1993.     

Regioselective single-reactor synthesis of arylsulfonyl derivatives of 3,5-diamino-1,2,4-triazole

Arylsulfonylation of 1-acetyl-3,5-diamino-1,2,4-triazole with arylsulfonyl chlorides in pyridine, with the subsequent hydrolysis of the acetyl group, was studied; a new regioselective method for synthesis of N-(5-amino-1H-1,2,4-triazol-3-yl)arylsulfonamides was developed.     

Synthesis and biological activity of some novel derivatives of 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole

To discover new 1,2,4-triazole derivatives which may possess significant biological activities, we synthesized a series of novel 6-aryl-3-(D-galactopentitol-1-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines and 4-(arylmethylidene)amino-5-(D-galactopentitol-1-yl)-3-mercapto-4H-1,2,4-triazoles from 4-amino-3-(D-galactopentitol-1-yl)-5-mercapto-1,2,4-triazole. All the title compounds were characterized by elemental analysis, IR, 1H- and 13C-NMR. Plant growth-regulating activity tests showed that these compounds have remarkable effects on the growth of radish and wheat.