A Facile Route to Triazolopyrimidines Using a [3+2] Cycloaddition and Continuous-Flow Chemistry
Journal of Flow Chemistry, 4(3), pp 140-147, 2014-9
A facile and benign route to N-heterocycles, including triazoles and triazolopyrimidines, has been developed. Using continuous-flow microreactor technology, organic azides are prepared in situ and reacted with cyanoacetamide in a [3 + 2] cycloaddition to produce a variety of substituted 1,2,3-triazoles, which can be elaborated into useful building blocks. A benzyl-substituted triazole was further functionalized to an analog of the core structure of the antiplatelet agent Brilinta (R). The methodology lends itself well to flow chemistry, where reaction volumes are minimized, heating and mixing are consistent, and the need for intermediate azide isolation bypassed. The scope of the process is wide, and the efficiency is high, suggesting this as a practical, green route for the production of triazolo-based heterocycles.
[3+2] cycloaddition; azide; continuous flow; triazole; triazolopyrimidine; one-pot reaction