Abstract: Interaction of 3,4-di-tert-butyl-8-methylpyrazolo[5,1-c][1,2,4]triazine with RLi (R = n-Bu, t-Bu) at −110° ÷ −25 °C led to generation of (3,4-di-tert-butyl-8-methyl-1-R-1,4-dihydropyrazolo[5,1-c][1,2,4]triazin-4-yl)lithiums, while application of PhLi furnished a mixture of N(1)- and C(4)-addition products. Alkylation of (3,4-di-tert-butyl-8-methyl-1-R-1,4-dihydropyrazolo[5,1-c][1,2,4]triazin-4-yl)lithiums with MeI proceeded at the N(2) atom, but O2 and H3O+ selectively attacked the C(4) ring position. The protonation product could also be synthesized independently from (trans-)3-tert-butyl-8-methyl-3,4-dihydropyrazolo[5,1-c][1,2,4]triazine-3,4-diyl bispivalate and t-BuLi. 3,4-Di-tert-butyl-4-hydroperoxy-8-methyl-1-R-1,4-dihydropyrazolo[5,1-c][1,2,4]triazines underwent Criegee fragmentation at r.t. (for R = t-Bu) or transformed into C(4)-hydroxy derivative (for R = Ph). Structures of four of the isolated reaction products were established by single-crystal X-ray diffraction analyses.

Cite: Ivanov S.M. , Minyaev M.E.
Generation and chemical properties of (3,4-di-tert-butyl-1,4-dihydropyrazolo[5,1-c][1,2,4]triazin-4-yl)lithiums
Journal of Organometallic Chemistry. 2020. V.906. 121060 . DOI: 10.1016/j.jorganchem.2019.121060 WOS Scopus OpenAlex

Identifiers:

≡ Web of science:	WOS:000504038600006
≡ Scopus:	2-s2.0-85076023372
≡ OpenAlex:	W2993827945

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