Yu. A. Strelenko

On the structure and spectra of dinitramide salts

Abstract The preparation for the isotopically substituted dinitramide salts has been proposed. The 14 N and 15 N NMR spectra of the 15 N-enriched dinitramide anion in solution are measured and interpreted for the first time. New experimental IR and Raman spectra are obtained for the NH 4 + and K + salts of dinitramide in the solid state and in solution. The assignments are made with the help of quantum-mechanical force field calculations and normal-coordinate analysis. The harmonic vibrational spectrum of the dinitramide anion calculated at the B3LYP/6-31+G(d) level in the presence of solvent correlates best with the experimental data. The structure and spectra of the M + CH(NO 2 ) 2 − and M + N(NO 2 ) 2 − (M denotes a counterion) are compared and discussed. Topology of the electron charge density in the dinitramide anion is analyzed within the framework of Baders theory of atoms in molecules.

New approach to the synthesis of benzo[e][1,2,3,4]tetrazine 1,3-dioxides

A new approach to the synthesis of benzo[e][1,2,3,4]tetrazine 1,3-dioxides involves the treatment ofN-nitroanilines containing anortho-(tert-butyl-NNO-azoxy) group with phosphoric anhydride or phosphorus pentachloride. The reaction is supposed to proceed through an intermediate diazonium oxide cation.

A New Approach to the Synthesis of Dithienylethanediones and Dithienylacetylenes

Abstract1,2-Dithienylethanediones were synthesized by modified acylation of thiophene and its homologs in the presence of aluminum chloride and pyridine. The bishydrazones of the products were converted into dithienylacetylenes by oxidation with atmospheric oxygen in pyridine in the presence of CuCl.

1H, 13C, and 14N NMR study of 3-methylfurazans with nitrogen-containing substituents at position 4

Abstract3-Methylfurazans with nitrogen-containing substituents at position 4 were studied by 1H, 13C, and 14N NMR spectroscopy. A correlation between the chemical shifts in 13C NMR spectra of these furazans and monosubstituted benzenes with the same substituents was found. The increments for a number of furazan-containing substituents were determined for the first time.

Synthesis of 1H-[1,2,3]triazolo[4,5-e][1,2,3,4]tetrazine 4,6-dioxide and its methyl derivatives

Abstract1H-[1,2,3]Triazolo[4,5-e][1,2,3,4]tetrazine 4,6-dioxide (3) was synthesized by reduction of 1-hydroxy-1H-[1,2,3]triazolo[4,5-e][1,2,3,4]tetrazine 5,7-dioxide (1) with PCl3, reduction of 1-methoxy-1H-[1,2,3]triazolo[4,5-e][1,2,3,4]tetrazine 5,7-dioxide (4) with Na2S2O4, and by the reaction of compound 4 with Et3N. Both methylation of compound 3 with diazomethane and reaction of Ag-salt of compound 3 with MeI occur at the triazole cycle to give all three possible isomers. The structures of the synthesized compounds were confirmed by 1H, 13C, 14N, and 15N NMR spectroscopy.

Amino(tert-butyl-NNO-azoxy)furoxans: synthesis, isomerization, and rearrangement of N-acetyl derivatives

Abstract3-Amino-4-(tert-butyl-NNO-azoxy)furoxan (1a) and 4-amino-3-(tert-butyl-NNO-azoxy)-furoxan (1b) and their acetyl derivatives 6a,b were obtained. The equilibria 1a ai 1b and 6a ⇒ 6b were studied. Furoxan 6b can undergo thermal rearrangement into 3-[(tert-butyl-NNO-azoxy)(nitro)methyl]-5-methyl-1,2,4-oxadiazole (7), prolonged heating of which gives N-(2-tert-butyl-5-nitro-1-oxido-2H-1,2,3-triazol-4-yl)acetamide (8). With the transformation 7 → 8 as an example, the possibility of participation of the azoxy group in the Boulton-Katritzky rearrangements was demonstrated for the first time.

Synthesis and structure of bis-crown-containing stilbenes

An improved procedure was proposed for the synthesis of stilbenes fused to two crown ether fragments at both benzene rings. The structure of new homologous symmetric bis-crown-containing stilbenes was determined by X-ray analysis. Relations were revealed between the size of the crown ether moiety and stilbene conformation in crystal and the mode of crystal packing. Conformational analysis of the prepared stilbenes in solution and in the solid state was performed by 1H and 13C NMR spectroscopy and by DFT quantum-chemical calculations.

2-Alkyl-4-amino-5-(tert-butyl-NNO-azoxy)-2H-1,2,3-triazole 1-oxides: synthesis and reduction

A new approach to the synthesis of 4-amino-5-(tert-butyl-NNO-azoxy)-2-R-2H-1,2,3-triazole 1-oxides 1 was developed. Compounds 1 were obtained by reactions of 3-amino-4-(tert-butyl-NNO-azoxy)furoxan with aliphatic amines RNH2 (R = Me, Et, Pri, Bu, and But). 4-Amino-5-(tert-butyl-NNO-azoxy)-2-tert-butyl-2H-1,2,3-triazole 1-oxide was transformed under the action of acids into 4-amino-5-(tert-butyl-NNO-azoxy)-1-hydroxy-1H-1,2,3-triazole. Methylation of the latter with diazomethane mainly involves the O atom of the triazole oxide ring. Reduction of compounds 1 gave 4-amino-5-(tert-butyl-NNO-azoxy)-2-R-2H-1,2,3-triazoles and 4-amino-5-(tert-butyldiazenyl)-2-R-2H-1,2,3-triazoles (R = Me, Pri, and But). The structures of the compounds obtained were confirmed by 1H, 13C, and 14N NMR spectroscopy.

Synthesis of first nonannulated 1,2,3,4-tetrazine 1,3-dioxides

Thermolysis of o-diazidobenzotetrazine 1,3-dioxides was accompanied by cleavage of the C-C bond of the benzene ring to give nonannulated 1,2,3,4-tetrazine 1,3-dioxides. The structures of these first representatives of nonfused 1,2,3,4-tetrazines were confirmed by 13C and 14N NMR spectroscopy.

Reaction of 1,2-dialkyldiaziridines with ketenes as a new approach to cyclic and linear systems containing the N— C—N fragment

The reaction of 1,2-dialkyldiaziridines with ketenes proceeds through the N—N bond cleavage to form three types of structures containing the N—C—N fragment, viz., 1,3-dialkylimidazolidin-4-ones, 3,5-diacyl-3,5-diazahept-1-enes, and β-lactams. The reaction pathway depends on the reaction conditions and the structures of the starting compounds.