A Simple Method for the Preparation of Di-, Tri- and Tetrasubstituted Non-Symmetrical Ureas

Abstract

The synthesis of a series of di-, tri- and tetrasubstituted non-symmetrical ureas is described. Di- and trisubstituted ureas are prepared in excellent yield by treatment of a phenyl carbamate in a self-tunable single-mode microwave synthesizer with a primary or secondary amine. The synthetically more challenging tetrasubstituted urea can be prepared using the 4-nitrophenyl carbamate and a secondary amine.

Key words

urea - microwave-assisted synthesis - carbamate

References and Notes

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11

All compounds prepared were characterised by mp, ¹H NMR, ¹³C NMR, IR, MS and HRMS.