The Knoevenagel reaction: analysis and recycling of the ionic liquid medium

A study involving the scope of substrate in the Knoevenagel reaction in an IL medium has been conducted. Reactivity trends favor formation of the condensation product using electron deficient aryl aldehydes. Use of electron rich aldehydes and ketones lead to lower levels of conversion and no measurable amounts of condensation products, respectively. A recycling study confirmed that the reaction medium could be used multiple times affording, with each run, the desired condensation product 1a in excess of 90% conversion. Post-run analyses of the IL documented that the IL medium was unaltered upon reuse.