Efficient synthesis of N9-alkylguanines : & evaluation of a more highly conjugated analog of guanidinium-rich molecular transporters using a pH dependent fluorescence assay

Synthesis of N9-(2-chloroethyl)guanine from 2-amino-6-chloropurine was accomplished in three steps with an overall yield of 83%. All products were purified via crystalli7.ation and no chromatography was required. Selective crystallization of the desired N9 isomer subsequent to the key alkylation step completely and efficiently removed the N7 isomer. This compound was shown to be a versatile reagent in the synthesis of various N9-substituted guanines