Synthesis of 5-azido-3-nitro-1H-1,2,4-triazole by using a cyanoethyl activating group
作者:Vladimir V. Tolstyakov
DOI:10.1007/s10593-017-2115-8
日期:2017.6
A new method is proposed for the preparation of 5-azido-3-nitro-1H-1,2,4-triazole, based on cyanoethylation of 5-bromo-3-nitro-1H-1,2,4-triazole, nucleophilic substitution of bromide with azide ion, and removal of cyanoethyl protecting group.
A series of 5-substituted 3-nitro-1-vinyl-1,2,4-triazoles were synthesized by alkaline treatment of the corresponding 1-(2-haloethyl- or 2-nitroxyethyl)-3-nitro-1,2,4-triazoles and by transvinylation of NH acids of the same series with vinyl acetate. The scope of applicability of the transvinylation procedure was established with respect to the azole pK(a) value. The vinylic double bond on the nitrogen was shown to be inactive toward both nucleophilic and electrophilic reagents, whereas the halogen atom in position 5 exhibits enhanced reactivity. The latter factor provides the possibility for versatile structural modification via nucleophilic replacement of the 5-halogen atom by various groups, including triazolate ion.
A number of 5-R-substituted 3-nitro-1-trinitromethyl-1H-1,2,4-triazoles (R = Me, Cl, Br, N(3), NH(2), NO(2)) were synthesized by nitration of the corresponding omega-(5-R-3-nitro-1H-1,2,4-triazol-1-yl)alkan-2-ones with mixtures of concentrated sulfuric and nitric acids.