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 intramolecular Diels-Alder reaction into the corresponding thieno [2,3-b]- and thiopyrano
室温下,在CH 2 Cl 2中用四氟硼酸三乙基氧鎓对3-(3-丁炔硫基)和3-(4-戊炔基)取代的1,2,4-三嗪进行季铵化仅在N-1处产生3-炔基硫基-1-乙基13 C NMR和X射线晶体学数据明确显示了-1,2,4-三嗪鎓盐。3-炔基硫基-1-乙基-5-苯基-1,2,4-三嗪鎓盐在分子内经历Diels-Alder反应,生成相应的噻吩并[2,3-b]-和噻喃并[2,3-b]吡啶比相应的中性1,2,4-三嗪要温和得多。