The mechanism of the condensation of 5-fluorouracil and 2-acetoxytetrahydrofuran (3), giving 1-(tetrahydro-2-furyl)-5-fluorouracil, was studied. An equilibrium between 2-acetoxytetrahydrofuran (3) and 2, 3-dihydrofuran (4) was observed at 120-170°C in dimethylformamide. It was found by the use of 1, 3-dideuterio-5-fluorouracil that the condensation of 5-fluorouracil with 3 occurred both by direct substitution and by the formation of 4 from 3 followed by addition of the uracil to it. The contribution of the latter path increased with increase of the reaction temperature.
研究了 5-
氟尿
嘧啶和
2-乙酰氧基四氢呋喃(3)缩合生成 1-(四氢-2-
呋喃基)-5-
氟尿
嘧啶的机理。在二甲基甲酰胺中,
2-乙酰氧基四氢呋喃(3)和 2,3-二氢
呋喃(4)在 120-170°C 的温度下达到平衡。通过使用 1,3-二氚基-5-
氟尿
嘧啶发现,5-
氟尿
嘧啶与 3 的缩合既可以通过直接置换发生,也可以通过由 3 生成 4,然后加入尿
嘧啶的方式发生。随着反应温度的升高,后一种途径所占的比例增大。