Facile and regioselective synthesis of novel 2,4-disubstituted-5-fluoropyrimidines as potential kinase inhibitors

2,4-Disubstituted-5-fluoropyrimidine is a biologically active molecular core seen in various anticancer agents such as 5-fluorouracil (5-FU). As part of a programme aimed at discovering kinase inhibitors, routes to two series of novel compounds (5-fluoropyrimidine-2-carboxamides and 5-fluoropyrimidine-4-carboxamides) were successfully executed. For the first series, regioselective substitution at the 4-position of the pyrimidine with an amine (HNR1R2) was achieved, followed by preparation of the amide at the 2-position. The route to the second series involved introduction of the methoxy protecting group at the 4-position, which allowed subsequent amine substitution to occur at the 2-position. The 4-amide substituent was finally introduced by direct conversion of the 4-methoxy into a 4-chloro group followed by transformation into an amide by palladium catalysis.