# Sustainable and Safe N-alkylation of N-heterocycles by Propylene Carbonate under Neat Reaction Conditions

## TL;DR

A new eco-friendly method uses propylene carbonate to safely alkylate heterocycles without toxic reagents.

## Contribution

Propylene carbonate acts as both solvent and reagent for N-alkylation without genotoxic alkyl halides.

## Key findings

- Propylene carbonate enables N-alkylation of N-, O-, and S-containing heterocycles under neat conditions.
- The process avoids genotoxic alkyl halides and auxiliary reagents in anhydrous conditions.
- The method produces nucleophilic substitution with water and carbon dioxide as byproducts.

## Abstract

A new, eco-friendly process utilising the green solvent propylene carbonate (PC) has been developed to perform N-alkylation of N-, O- and/or S-containing heterocyclic compounds. PC in these reactions served as both the reagent and solvent. Importantly, no genotoxic alkyl halides were required. No auxiliary was necessary when using anhydrous PC. Product formation includes nucleophilic substitution with the concomitant loss of water and carbon dioxide. Substrates prepared, including the newly invented PROTAC drugs, are widely used.