Silica gel: A very cheap, reusable, and efficient catalyst for green preparation of some bis-4-hydroxycoumarin on water

摘要

Silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. The reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. This method is also simple and inexpensive and leads to high yield of products in short reaction times.