achieved in an organic-aqueous medium in the presence of palladium(II) acetate and the water-soluble sulfonated triphenylphosphine P(C6H4-m-SO3Na)3 (tppts). Similar reactions with 2-thiouracils are also drastically dependent on the solvent, taking place at N-1 and N-3 (in dioxane) or at sulfur (organic-aqueous medium). Probably reactions in the organic-aqueous medium are kinetically controlled whereas
DMSO中钯(0)催化的尿嘧啶烯丙基化发生在N-1和N-3处。与之形成鲜明对比的是,在乙酸钯(II)和水溶性磺化三苯膦P(C 6 H 4 - m -SO 3 Na)3(tppts )存在下,在有机水性介质中在N-1处实现了区域特异性烯丙基化)。与2-硫氧嘧啶的类似反应也完全取决于溶剂,该反应在N-1和N-3(在二恶烷中)或在硫(有机水溶液)中进行。可以动态控制有机-水性介质中的反应,而热力学控制DMSO或回流的二恶烷中的烯丙基化。
Palladium(0)-catalysed allylation of uracils and thiouracils. Influence of the solvent on the regioselectivity of the allylation
Uracil and 5-substituted uracils are monoallylated at N-1 in H2O-CH3CN with the catalytic (or tppts) although performing the reaction in H2O/THF with the system leads to diallylations at N-1 + N-3. 2-Thiouracil, 5-methyl-2-thiouracil (2-thiothymine) and 6-methyl-2-thiouracil are monoallylated at sulfur in with the catalytic system (or tppts). Performing the reactions in H2O/THF with the system leads
尿嘧啶和5-取代的尿嘧啶在H 2 O-CH 3 CN中的N-1处被催化(或tppts)单芳基化,尽管在H 2 O / THF中与该体系进行反应会导致N-1 + N-处的二烯丙基化3。2-硫氧嘧啶,5-甲基-2-硫氧嘧啶(2-硫胸腺嘧啶)和6-甲基-2-硫氧嘧啶在硫磺中通过催化体系(或tppts)被单芳基化。在系统中于H 2 O / THF中进行反应会导致2-硫尿嘧啶和2-硫胸腺嘧啶在N-1 + N-3处进行烯丙基化,而6-甲基-2-硫尿嘧啶则在S + N-3处进行二烯丙基化。