Microwave-Assisted Synthesis of Fluorescent 8-Aryl-7-deazaguanines

Microwave-assisted conditions were adapted to our previously published synthesis of 8-aryl-7-deazaguanines via cyclocondensation of phenacyl bromides with 2,4-diamino-6-hydroxypyrimidine in refluxing 1,4-dioxane. Upon microwave irradiation at 150-225 degrees C, 8-aryl-7-deazaguanines were obtained in high yield above 90% and within 15-60 min, compared to the 24-72 h that are required under reflux conditions. Three new fluorescent 8-heteroaryl-7-deazaguanines were additionally produced and characterized confirming our hypothesis that compounds of this class typically exhibit fluorescence properties, regardless of the aryl substituent.