A. B. Sheremetev

Synthesis of secondary and tertiary aminofurazans

Reactions of nitrofurazans with primary and secondary amines were studied. Conditions were found which allow the efficient replacement of the nitro group with these nucleophiles. Transformations of the amidoxime fragment, which is bound to the furazan ring and contains an amino substituent, enable one to substantially expand the spectrum of polyfunctional derivatives. The structures of the amines synthesized were studied by X-ray diffraction analysis.

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 3-alkyl-4-aminofurazans

A “one-pot” method for the synthesis of 3-alkyl-4-aminofurazans from ethyl β-alkyl-β-oxopropionates was developed. The multistep process involves hydrolysis of the ester, nitrosation at the activated methylene group, and treatment of the resulting intermediate with an alkaline solution of hydroxylamine in the presence of urea.

Reactions of 3-amino-4-methylfurazan with nitrating agents

Depending on the type of nitrating agent and the reaction temperature, nitration of 3-amino-4-methylfurazan 1 gives either nitramine or the products of formal oxidation of the amino group, namely, nitroso-, nitro-, azo-, and azoxyfurazans. The methyl group of compound 1 is resistant against all the nitrating agents studied.

3-(1-Adamantyl)Furazans

The reactivity of 3-(1-adamantyl)-4-aminofurazan was studied. Upon treatment with oxidizing reagents the amino group is oxidized to azo, azoxy, and nitro groups. The nitration of 3-(1-adamantyl)-4-aminofurazan with nitric acid provided the corresponding nitroamine. The reaction of 3-(1-adamantyl)-4-nitrofurazan with nitrating and bromination agents takes place at the bridgehead position of the adamantane fragment and gives the corresponding nitroxyl and bromo derivatives. An X-ray structural analysis of 4,4′-di(1-adamantyl)azofurazan was undertaken.

Synthesis of 4-amino-6-chloro-1,3,5-triazin-2(1H)-ones

Conditions for selective substitution for one chlorine atom in 2-(R,R′-amino)-4,6-dichloro-1,3,5-triazines with a hydroxide ion were elaborated. Spectral and calculation methods showed that the products formed are in the lactam form, i.e., have the structure of 4-chloro-6-(R,R′-amino)-1,3,5-triazin-2(1H)-ones.

Bromoacetyl derivatives of furazan and furoxan

Bromination of acetylfurazans and furoxans has been studied. The conditions for the synthesis of bromoacetyl derivatives have been found.

NMR spectroscopic study of 3-nitrofurazans

Abstract3-Nitrofurazans with different substituents at position 4 were studied by 1H, 13C, and 14N NMR spectroscopy. A correlation between chemical shifts (CS) in the 13C NMR spectra of furazans and benzene with similar substituents was revealed. Increments for a series of new substituents were determined. The 13C and 14N CS values presented can be used as a reliable set of reference data.

One-pot synthesis of 3-amino-4-aryl- and 3-amino-4-hetarylfurazans

A “one pot” method for the synthesis of 3-amino-4-aryl- and 3-amino-4-hetarylfurazans from β-aryl- and 4-β-hetaryl-β-oxo acid esters was developed.

(Pyrrol-1-yl)furazans

Short-time reactions of 3-amino-4-R-furazans with 2,5-dimethoxytetrahydrofuran in boiling acetic acid afford (pyrrol-1-yl)furazans. One of the products was characterized by X-ray diffraction analysis.