180145-63-5Relevant academic research and scientific papers
Palladium(0)-catalysed allylation of uracils and thiouracils. Influence of the solvent on the regioselectivity of the allylation
Goux, Catherine,Sigismondi, Silvana,Sinou, Denis,Perez, Montserrat,Moreno-Manas, Marcial,Pleixats, Roser,Villarroya, Merce
, p. 9521 - 9534 (2007/10/03)
Uracil and 5-substituted uracils are monoallylated at N-1 in H2O- CH3CN with the catalytic systemPd(OAc)2/P(C6H4-m -SO3Na)3 (or tppts) although performing the reaction in H2O/THF with the system Pd2(dba)3/dppb 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 H2O/CH3CN with the catalytic system Pd(OAc)2/P(C6H4-m-SO3Na)3 (or tppts). Performing the reactions in H2O/THF with the system Pd2(dba)3/dppb leads to diallylations at N-1 + N-3 of 2-thiouracil and 2-thiothymine whereas 6-methyl-2-thiouracil is diallylated at S + N-3.
Palladium(0)-catalyzed allylation of uracils and 2-thiouracils drastic effect on an aqueous reaction medium on the regioselectivity
Sigismondi,Sinou,Perez,Moreno-Manas,Pleixats,Villarroya
, p. 7085 - 7088 (2007/10/02)
Palladium(0)-catalyzed allylation of uracils in DMSO takes place at N-1 and at N-3. In sharp contrast, regiospecific allylation at N-1 is 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 allylation in DMSO or refluxing dioxane are thermodynamically controlled.
