Synthesis of exclusive N2-(isobutyryl)-9-(carboxymethyl)guanine, an important moiety for peptide nucleic acid synthesis has been reported through a high-yielding reaction scheme starting from 6-chloro-2-amino purine. Crystal structures of two intermediates confirmed the formation of N9-regioisomer. This new synthetic route can potentially replace the conventional tedious method with moderate overall yield.
Keywords: N9-regioisomer; Peptide nucleic acid; crystal structure; guanine.