A facile synthesis of pyrrolo[3,2‐d]pyrimidines from 6‐azidouracils and ylide phosphoranes

A series of the title compounds, 9‐deazaxanthines, was regioselectively prepared in reasonable yields as major products from the reactions of 6‐azidouracils 1a,b with stabilized ester‐ 2a,b or keto‐ 2c ylide phosphoranes and a moderated phosphorus ylide 3 , instead of the expected triazoles. Side products were also observed wherein pyrimido[5,4‐g]pteridine‐2,4,5,7‐tetrone ( 15 ) and other fused ring systems or acyclic‐substituted uracil derivatives were isolated. A comparative study on the reactivity of 1a in analogy to 1b toward phosphoranes is also described. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:357–365, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10048