Synthesis and transformations of N -butyl-3(5)-nitro-1,2,4-triazoles under the conditions of acid-catalyzed alkylation o
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Synthesis and transformations of N-butyl-3(5)-nitro-1,2,4-triazoles under the conditions of acid-catalyzed alkylation of 3(5)-nitro-1H-1,2,4-triazoles with butyl alcohols Gennady T. Sukhanov1, Irina А. Krupnova1, Yuliya V. Filippova1*, Yurii V. Gatilov2, Anna G. Sukhanova1, Konstantin K. Bosov1, Ekaterina V. Pivovarova1 1
Institute for Problems of Chemical and Energy Technologies, Siberian Branch of the Russian Academy of Sciences, 1 Sotsialisticheskaya St., Biysk 659322, Russia; е-mail: [email protected] 2 N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 9 Akademika Lavrentieva Ave., Novosibirsk 630090, Russia; е-mail: [email protected]
Submitted September 17, 2020 Accepted October 15, 2020
Translated from Khimiya Geterotsiklicheskikh Soedinenii, 2020, 56(11), 1440–1448
The directions of thermodynamically controlled rearrangements and transformations of alkyl substituents under the conditions of acidcatalyzed alkylation of unsubstituted and 5(3)-substituted 3(5)-nitro-1H-1,2,4-triazoles with butyl alcohols (n-, i-, tert-, sec-BuOH) were studied. Keywords: 1-(tert-butyl)-4-(sec-butyl)-3-nitro-1,2,4-triazolium salt, 1-(sec-butyl)-3,5-dinitro-1H-1,2,4-triazole, N-(sec-butyl)-3(5)-nitro1,2,4-triazole, alkylation, isomers, transformation of alkyl substituent, X-ray structural analysis.
Derivatives of 1,2,4-triazoles are an exciting class of polynitrogen compounds that combine energetic properties and biological activity.1 N-substituted 1,2,4-triazoles are widely used as starting compounds in the synthesis of some pharmaceuticals (such as maraviroc, sitagliptin, triazolam),2 ligands of coordination compounds,3 as well as components of energetic materials.4 The problem of synthesizing new N-substituted 1,2,4-triazoles with different substituents, the variation of which gives the compound a given set of characteristics, remains urgent. Synthetically important reactions such as alkylation of azoles have attracted close attention. Alkylation of ambident (polydental) heterocyclic systems is associated 0009-3122/20/56(11)-1440©2020 Springer Science+Business Media, LLC
with the problem of regioselectivity, the solution of which remains an important area of modern organic synthesis and is associated with the need for a deep study and identification of the main rules of the reaction of electrophilic reagents with the nitrogen atoms of the triazole ring. Alkylation of nitro-1,2,4-triazole derivatives usually leads to the formation of a mixture of isomers. To date, the reactions of 3(5)-nitro-1H-1,2,4-triazoles in alkaline medium, where a highly nucleophilic anion is generated from the corresponding azole containing the NH group, are the most studied. Such transformations usually result in the formation of N1-substituted nitro-1,2,4-triazoles5 or their
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Chemistry of Heterocyclic Compounds 2020, 56(11), 1440–1448
mixtures with N2-substituted isomers.5f The exceptions are reactions using some reagents, where in all cases mixtures of three isomeric N
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