Combined Experimental and Theoretical Study of the Synthesis of 5,7-Dihydroxy-4-methylcoumarin via a Pechmann Condensation in the Presence of UiO-66-SOH Catalysts.

An efficient synthesis of 5,7-dihydroxy-4-methylcoumarin from phloroglucinol with ethyl acetoacetate in the UiO-66-SOH metal-organic framework is reported. The potential of UiO-66-SOH as a solid catalyst was determined through optimized-condition experiments and quantum molecular calculations. The optimal conditions for the synthesis of 5,7-dihydroxy-4-methylcoumarin with UiO-66-SOH were as follows: phloroglucinol/ethyl acetoacetate molar ratio = 1:1.