R 30 Reactivity of 3-alkynylthio-1-ethyl-1,2-4-triazinium salts in intramolecular Diels-Alder reactions [Electronic resource] / V. N. Charushin, Beb Van Veldhuizen, Henk C. van der Plas, Casper H. Stam // Tetrahedron. - 1989. - Vol. 45. - С. 6499-6510. - Bibliogr. : p. 6510 (20 ref.) Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): 1,2,4-TRIAZINES -- TRIETHYLOXONIUM TETRAFLUOROBORATE -- DIELS-ALDER REACTIONS Аннотация: Quaternization of 3-(3-butynylthio) and 3-(4-pentynyltio) substituted 1,2,4-triazines with triethyloxonium tetrafluoroborate in CH2Cl2 at room temperature occurs exclusively at N-1 yielding 3-alkynylthio-1-ethyl-1,2,4-triazinium salts, as unequivocally shown by the 13C NMR and X-ray crystallographic data. 3-Alkynylthio-1-ethyl-5-phenyl-1,2,4-triazinium salts undergo the intramolecular Diels-Alder reaction into the corresponding thieno [2,3-b]- and thiopyrano [2,3-b]pyridines under considerably milder conditions than the corresponding neutral 1,2,4-triazines. \\\\expert2\\nbo\\Tetrahedron\\1989, v. 45, p. 6499.pdf |