Synthesis of Purine‐based Triazoles by Copper (I)‐catalyzed Huisgen Azide–Alkyne Cycloaddition Reaction

An efficient protocol for the synthesis of substituted 1,2,3‐triazol‐9H‐purines via copper (I)‐catalyzed click chemistry of 2,6‐dichloropurine with aromatic azide has been reported. A wide range of 1,4‐disubstituted triazoles ( N‐9 substituted purines) was accessible in good‐to‐excellent yields with remarkable functional group tolerance. The base‐catalyst ratio was tuned to achieve optimum reaction condition (>95% conversion and purity in most cases). Furthermore, the structure of 4i has been unambiguously assigned by X‐ray crystallographic study to yield structural information on the 1,3‐dipoles entering the reaction.