title: Regioselective direct C-H arylations of protected uracils. Synthesis of 5- and 6-aryluracil bases.
abstract: A new regioselective synthesis of 5- and 6-aryluracil bases based on direct C-H arylations of diverse 1,3-protected uracils has been developed. Benzyl-protected uracils were selected as the most practical in terms of stability during the arylation and facile cleavage of the benzyl groups. Pd-catalyzed C-H arylations in the absence of CuI gave preferentially 5-aryl-, whereas the reactions in the presence of CuI gave 6-aryl-1,3-dibenzyluracils. Final deprotection either by transfer hydrogenolysis over Pd/C or by treatment with BBr(3) gave the desired free arylated uracil bases in good yields.
authors: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead Sciences & IOCB Research Center, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic.
authors: Miroslava
authors: M
authors: Čerňová
authors: Igor
authors: I
authors: Čerňa
authors: Radek
authors: R
authors: Pohl
authors: Michal
authors: M
authors: Hocek