Grindstone Telescopic Approach for Pyrrolodiazepines Through Pictet‐Spengler‐Type Reaction and Solvent‐Free Synthesis of Quinazolines

We have established Pictet-Spengler-type telescoping strategy under eco-friendly, cost effective, and energy efficient mechanochemical activation for the first time to construct pyrrolodiazepines and quinazolines in moderate to excellent isolated yields with minimum E-factor.

Abstract

Hypervalent iodine activated Pictet-Spengler-type telescoping strategy under grindstone technology has been reported for the first time to construct pyrrolodiazepine with minimum E-factor. The same hypervalent iodine is also applicable to the synthesis of quinazoline cores in moderate to excellent yields under neat conditions. This greener approach for N-centered heterocycles is superior compare to the traditional methods due to its shorter reaction time, eco-friendly conditions, reduced cost, lower energy consumption, higher yields of desired products, and broader substrate scope. The scale-up experiment for the Pictet–Spengler-type reaction and the extension of protocol to the Bischler–Napieralski reaction give a new feather of the sustainable chemistry.

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