Synthesis of novel tetra- and pentacyclic benzosultam scaffolds via domino Knoevenagel hetero-Diels-Alder reactions in water

摘要

An efficient catalyst-free and diastereoselective synthesis of novel dihydropyrano[2,3-d]pyrimidine and dihydropyrano[3,2-c]chromen-annulated benzosultams is described. A number of (E)-N-(2-formylphenyl)-N-methyl-2- phenylethenesulfonamides were synthesized and underwent a one-pot domino Knoevenagel hetero-Diels-Alder reaction, respectively, with N,N- dimethylbarbituric acid and 4-hydroxycoumarin in water, giving the desired products, in moderate to excellent yields.