An efficient synthesis of 2-substituted 6-methylpurine bases and nucleosides by Fe- or Pd-catalyzed cross-coupling reactions of 2,6-dichloropurines.
Fe-catalyzed cross-coupling reactions of 9-substituted or protected 2,6-dichloropurines with 1 equiv of methylmagnesium chloride gave regioselectively 2-chloro-6-methylpurines in good yields. The same reactions with 3 equiv of methylmagnesium chloride or Pd-catalyzed reactions with trimethylaluminum afforded 2,6-dimethylpurines. The 2-chloro-6-methylpurines underwent another coupling with phenylboronic acid to give 6-methyl-2-phenylpurines. All reactions were perfomed for Bn- and THP-protected purine bases as well as for acyl-protected ribosides and 2-deoxyribosides. After deprotection, free purine bases and nucleosides were obtained.
Hocek
Michal
M
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, CZ-16610 Prague 6, Czech Republic. hocek@uochb.cas.cz
Dvoráková
Hana
H
D002384:Catalysis; D007501:Iron; D010165:Palladium; D011684:Purine Nucleosides / Q000138:chemical synthesis*; D011687:Purines / Q000138:chemical synthesis* / Q000737:chemistry
D011684:Purine Nucleosides; D011687:Purines; C034051:6-methylpurine riboside; C031268:2,6-dichloropurine; D010165:Palladium; D007501:Iron