Nitropyrazoles

The double Vilsmeier formylation of theC-methyl group in pyrazole derivatives has been shown to occur when a nitro-group is in the adjacent position of the ring. A method for the synthesis ofC-(diformylmethyl)nitropyrazoles based on this reaction has been developed.For the previous communication, see Ref. 1; for Part 2, see Ref.2 Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1273–1276, July, 1993.     

Nitropyrazoles

A preparative method ofN-amination of pyrazoles bearing nitro groups and other electron withdrawing substituents in the pyrazole ring with hydroxylamine-O-sulfonic acid involving control of the pH of the medium has been elaborated. A series of previously unknown pyrazoles has been prepared. Basicities of 1-aminopyrazole and 1-amino-4-nitropyrazole have been measured and differences between the basicities of theC- andN-amino groups for the pyrazole series have been revealed.For part 3, see ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1434–1436, August, 1993.     

Quaternization of tetrazoles under high pressure and establishment of the structures of quaternary tetrazolium salts by 13C NMR spectroscopy

The quaternization of 1- and 2-acetonyl-5-R-tetrazoles, as well as dimethyltetrazole, was accomplished under high pressure conditions (5000–14,000 kgf/cm²) by means of bromoacetone and methyl iodide and at atmospheric pressure and room temperature under the influence of methyl fluorosulfate. The structure of the salts were ascertained by ¹³C NMR spectroscopy, and the principles of the change in the chemical shifts and the spin-spin coupling constants during quaternization and protonation of the tetrazoles were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1118–1124, August, 1982.     

Nitropyrazoles

A method for the synthesis of bi-, ter-, and quaterpyrazoles by cyclization ofC-(diformylmethyl)nitropyrazoles with hydrazine has been elaborated. Some of theirC- andN-derivatives have been obtained. The compounds prepared have been characterized by¹H,¹³C,¹⁴N, and¹⁵N NMR spectra.For communication 6, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1941–1945, November, 1993.     

Regiospecificity of nucleophilic substitution in 4,6-dinitro-1-phenyl-1H-indazole

The reactions of 4,6-dinitro-1-phenyl-1H-indazole with anionic nucleophiles RS^– and N₃ ^– lead to the regiospecific replacement of the nitro group at position 4. The reaction with N₂H₄·H₂O + FeCl₃ also results in reduction of only the 4-NO₂ group. Based on this fact, a procedure was developed for the preparation of previously unknown 3-unsubstituted 4-X-6-nitro-1-phenyl-1H-indazoles (X is a residue of a nucleophile or NH₂). Comparison of the data on the selective nucleophilic substitution (4-NO₂ group) in 3-Z-1-aryl-4,6-dinitro-1H-indazoles shows that in the case of Z = H, the regiospecificity of substitution is determined by the electronic effect of the annelated pyrazole ring.     

Gem-dinitro compounds in organic synthesis. 4. Use of the condensation product of glyoxal and dinitromethane in the synthesis of nitro-1,2,3-triazoles

The condensation of dinitromethane with glyoxal has been investigated and it has been demonstrated that 1,1,4,4-tetranitro-2,3-butandiol, -hydroxy-,-dinitropropionic acid or their mixture may be formed. Interaction of 1,1,4,4-tetranitro-2,3-butandiol or 1,4-dibromo-1,1,4,4-tetranitro-2,3-butanediol diacetates with sodium azide leads to bis(5-nitro-1,2,3-triazol-4-yl) via intermediate 1,1,4,4-tetranitro-1,3-butadiene.For communication 3, see [1].N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2123–2131, September, 1992.     

Alkylation of the silver salt of trinitromethane with secondary and tertiary alkyl halides

Conclusions In the reaction of isopropyl iodide or tert-butyl chloride with the silver salt of trinitromethane, the trinitromethane anion is alkylated only at the oxygen atom of a nitro group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2117–2121, September, 1968.