Background:
In recent years, 3,4-dihydro-pyrimidin-2-(1H)-ones (DHPMs) have attracting significant attention due to their diverse range of biological properties such as antibacterial, antiviral, antitumor, anti-inflammatory, calcium channel block etc. Taking into account, in this present work a polymer based solid acid catalyst is employed for the microwave-assisted synthesis of DHPMs.
Introduction:
Multicomponent reactions (MCRs) are attracting utmost attention as it promotes the formation of several bonds in a single process with diverse advantages. Biginelli reaction is the top-ranked example of MCR for the synthesis of dihydropyrimidinones (DHPMs). Solid catalysts are considered as a significant tool for MCRs as they are non-toxic, easy to handle, high selectivity, easy separation process and reusable.
Methods:
DHPMs synthesis was carried out using acid functionalized mesoporous polymer (AFMP) catalyst under microwave irradiation and solvent-free condition.
Results:
AFMP showed good to excellent DHPMs yield (89-98%) under the optimized reaction conditions: 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (with respect to aldehyde), the temperature of 80 °C and microwave power of 500 W.
Conclusion:
We have successfully utilized microwave-assisted AFMP catalyzed the synthesis of DHPMs under solvent-free condition via Biginelli approach. The catalyst is recyclable and reusable up to 5 consecutive reaction cycles with no significant loss in catalytic activity.