Synthesis of 2-alkyl-substituted chromone derivatives using microwave irradiation.

Maria Fridén-Saxin, Nils Pemberton, Krystle da Silva Andersson, Christine Dyrager, Annika Friberg, Morten Grøtli, Kristina Luthman

Index: J. Org. Chem. 74(7) , 2755-9, (2009)

Full Text: HTML

Abstract

A base-promoted condensation between 2-hydroxyacetophenones and aliphatic aldehydes has been studied. The reaction has been optimized to afford 2-alkyl-substituted 4-chromanones in an efficient manner using microwave heating. Performing the reaction using diisopropylamine in EtOH at 170 degrees C for 1 h gave moderate to high yields (43-88%). The 4-chromanones could be further converted into highly functionalized 2,3,6,8-tetrasubstituted chromones in which a 3-substituent (acetate, amine, or bromine) was introduced via straightforward chemical transformations.