A Convenient Synthesis of N 2 -Alkylated Guanines

An improved three-step synthesis of N2-alkylated guanines has been developed starting from N2-Boc-protected 2-amino-6-chloropurine which was treated with Boc2O, and the resulting doubly N2,9-protected derivative was subjected to N2-alkylation with alkyl halides, followed by hydrolysis. The advantages of this procedure include short reaction steps, simple operations, and good yields.