Substituted coumarins are synthesized from phenols and β-ketoesters by the Pechmann reaction, using a Wells–Dawson heteropolyacid (H6P2W18O62· 24H2O) as catalyst by a solvent-free procedure. This one requires low reaction times, 130° C temperature and as little as 1mol% of Wells–Dawson acid, obtaining good to excellent yields of coumarins. The catalyst showed to be reusable with no differences in the yields. The results are compared ...
