Synthesis of 2-Alkyl-Substituted Chromone Derivatives UsingMicrowave Irradiation

摘要

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 usingmicrowave heating. Performing the reaction using diisopropylamine in EtOH at 170 °C for 1 h gavemoderate to high yields (43-88%). The 4-chromanones could be further converted into highlyfunctionalized 2,3,6,8-tetrasubstituted chromones in which a 3-substituent (acetate, amine, or bromine)was introduced via straightforward chemical transformations.