Effect of substituent in pyridine-2-carbaldehydes on their heterocyclization to 1,2,4-triazines and 1,2,4-triazine 4-oxides
作者:A. P. Krinochkin、D. S. Kopchuk、N. V. Chepchugov、I. S. Kovalev、G. V. Zyryanov、V. L. Rusinov、O. N. Chupakhin
DOI:10.1134/s1070428017070016
日期:2017.7
A series of substituted pyridine-2-carbaldehydes were brought into heterocyclization with isonitrosoacetophenone hydrazones, followed by aromatization by the action of oxidants or by dehydration in boiling acetic acid. As a result, substituted 3-(pyridin-2-yl)-1,2,4-triazines or 3-(pyridin-2-yl)-1,2,4-triazine 4-oxides were formed. 6-Formylpyridine-2-carbonitrile failed to undergo heterocyclization
作者:D. N. Kozhevnikov、I. S. Kovalev、A. M. Prokhorov、V. L. Rusinov、O. N. Chupakhin
DOI:10.1023/a:1025601311393
日期:——
Nucleophilic substitution of hydrogen in pyrazine N-oxides under the action of CH-active compounds requires activation with acylating agents. This activation facilitates aromatization of intermediate sigma(H) adducts via elimination of the acid residue to form substituted pyrazines. More electrophilic 1,2.4-triazine 4-oxides react with carbanions derived from CH-active compounds without additional activation according to a scheme, which has previously been unknown for azine N-oxides. This scheme involves aromatization of a H adducts through elimination of water by the E1cb mechanism. The reaction products occur in DMSO-d(6) Solutions predominantly as 6-methylene-1,6-dihydropyrazines and 5-methylene-4,5-dihydro-1,2,4-triazines.
Prokhorov; Kozhevnikov; Rusinov, Polish Journal of Chemistry, 2003, vol. 77, # 9, p. 1157 - 1161
作者:Prokhorov、Kozhevnikov、Rusinov、Chupakhin
DOI:——
日期:——
Kozhevnikov; Kozhevnikov; Rusinov, Russian Journal of Organic Chemistry, 1998, vol. 34, # 3, p. 393 - 399