Reactivity of 3-alkynylthio-1-ethyl-1,2-4-triazinium salts in intramolecular Diels-Alder reactions
作者:Valery N. Charushin、Beb van Veldhuizen、Henk C. van der Plas、Casper H. Stam
DOI:10.1016/s0040-4020(01)89526-0
日期:1989.1
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 intramolecularDiels-Alderreaction into the corresponding thieno [2,3-b]- and thiopyrano