Amberlyst A21 catalyzed one-pot three-component coupling of aldehyde and malononitrile with active methylene compounds such as acetylacetone and ethyl acetoacetate for the synthesis of pharmaceutically important polyfunctionalized 4H-pyrans has been reported. Simple experimental procedure. no chromatographic purification. no hazardous organic solvents. https://www.markbroyard.com/super-save-whole-wheat-phyllo-pastry-sheets-jufka-sa-integralnim-brasnom-12pcs-x-450g-jami-supply-great-choice/