Reactions of 3-Nitro-1,2,4-Triazole Derivatives with Alkylating Agents. 2. Alkylation of a Neutral Heterocycle by Dimethyl Sulfate

Reactions of 3-nitro-1,2,4-triazole derivatives with alkylating agents. 5. Selective synthesis of 1,4-dialkyl-and 1,4,5-trialkyl-3-nitro-1,2,4-triazolium salts from 1-alkyl-and 4,5-dialkyl-3-nitro-1,2,4-triazoles and dialkyl sulfates

“…According to our previous findings [5,6], a complex mixture is formed in the reaction of N-unsubstituted 3-nitro- (9) and 5-methyl-3-nitro-1,2,4-triazoles (10) with excess dialkyl sulfate (DAS) including products of N-monoalkylation and 1,4-dialkylation of the 3-nitro-5-R-1,2,4-triazoles and 1,4-dialkyl-5-R-1,2,4-triazol-5-ones. The major products of the alkylation of nitrotriazoles 9 and 10 by dimethyl sulfate (DMS) are N-monomethyl-3-nitro-5-R-1,2,4-triazoles (the overall yield of the isomer mixture is 53-73% and the ratio of the products, N (1) -, N (2) -, and N (4) -methyl-3-nitro-5-R-1,2,4-triazoles is, on the average, 0.035:1.0:7.75).…”

“…When diethyl sulfate (DES) was used [6], the N-monosubstituted 3-nitro-5-R-1,2,4-triazoles gave only N (2) -isomers, namely, 1-ethyl-5-nitro-and 1-ethyl-3-methyl-5-nitro-1,2,4-triazoles, and N (4) -isomers 6 and 8 (the overall yield of the mixture was 26.3 and 45.3% and the ratio of the N (2) -and N (4) -isomers was 1.0:2.7 and 1.0:2.3, respectively). The yield of the ethylated triazolones, 1,4-diethyl-(36.7%) and 1,4-diethyl-3-methyl-1,2,4-triazol-5-ones (29.4%) was much greater when compared to the methyl analogs.…”

“…Thus, in light of the rather high activity of dialkyl sulfates in the formation of quaternary salts from N-unsubstituted nitrotriazoles [5,6], it appeared desirable to employ these alkylating agents for the further study of the quaternization of the indicated N-alkylnitrotriazoles.…”

“…We obtained similar results in the synthesis of 1,4-dialkyl-3-nitro-5-R-1,2,4-triazolium salts. For example, nitrotriazolium salts 13, 14, 17, and 18 were obtained by convergent synthesis from N (1) -(1-4) and N (4) -isomeric nitrotriazoles (5)(6)(7)(8) in varying yield (Table 1). The quaternization products are identical in their physicochemical and spectral data and correspond to 1,4-dimethyl-3-nitrotriazolium salts 13, 14, 17, and 18 also obtained by alkylation of N-unsubstituted nitrotriazoles 9 and 10 by DAS [5,6].…”

Selective synthesis of 1,4-dimethyl-1,2,4-triazol-5-one from 1-methyl-5-nitro-1,2,4-triazole and dimethyl sulfate

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The alkylation of unsubstituted 3-nitro-1,2,4-triazole with dimethyl sulfate takes place nonselectively with the formation of a complex mixture of products from N-monosubstitution (1-, 2-, and 4-methyl-3-nitro-1,2,4-triazoles) and N,N-disubstitution (nitrotriazolium salts) and 1,4-dimethyl-1,2,4-triazol-5-one (1) [2]. The latter is formed here in a very small amount.

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