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Synlett 2006(2): 243-246  
DOI: 10.1055/s-2005-923584
LETTER
© Georg Thieme Verlag Stuttgart · New York

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

Eve Bridgeman, Nicholas C. O. Tomkinson*
School of Chemistry, Main Building, Cardiff University, Park Place, Cardiff, CF10 3AT, UK
Fax: +44(29)20874030; e-Mail: tomkinsonnc@cardiff.ac.uk.;
Further Information

Publication History

Received 30 September 2005
Publication Date:
23 December 2005 (online)

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