Robust synthesis and crystal-structure analysis of 7-cyano-7-deazaguanine (PreQ(0) base) and 7-(aminomethyl)-7-deazaguanine (PreQ(1) base)

We describe robust and efficient synthetic methods for the synthesis of the preQ(0) and preQ, bases. which are the biosynthetic precursors of the hypermodified RNA nucleoside queuosine. The X-ray crvstal-structure analysis of preQ(1) is also described.