An Efficient Protocol for the Liquid-Phase Synthesis of Methyl 3,4-Dihydro­pyrimidin-2(1H)-one-5-carboxylate Derivatives

Abstract

Methyl 3,4-dihydropyrimidin-2(1H)-one-5-carboxylate derivatives 7 were effectively synthesized on the soluble polymer of polyethylene glycol (PEG) 4000 by heating or solvent-free microwave irradiation through the Biginelli three-component cyclocondensation. Compared with the classical solution-phase Biginelli reactions, the yields could be considerably improved and the reaction time could be shortened dramatically under microwave promotion in a liquid-phase protocol. Moreover, the polymer-supported synthesis provided the target compounds in high purity.

Key words

Biginelli reaction - condensation - polymers - cyclizations - heterocycles - liquid-phase synthesis - polyethylene glycol - microwave irradiation

References

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26

The purity was determined by HPLC analysis on Agilent 1100 (250 × 4.6 mm C₁₈ Column, gradient elution 50% MeCN and 50% H₂O, 1 mL/min, UV detection at λ = 254 nm).