Chlorosulfonic acid coated on porous organic polymer as a bifunctional catalyst for the one-pot three-component synthesis of 1,8-naphthyridines.

The synthesis of six-membered oxygen- and nitrogen-containing heterocycles has been regarded as the most fundamental issue in organic chemistry and the chemical industry because these heterocycles are used in producing high-value products. In this study, an efficient, economic, sustainable, and green protocol for their multicomponent synthesis has been developed. The one-pot direct Knoevenagel condensation-Michael addition-cyclization sequences for the transformation of aromatic aldehydes, malononitrile, and 2-aminopyridine generate the corresponding 1,8-naphthyridines over a novel mesoporous bifunctional organocatalyst supported cholorosulfonic acid [poly(triazine-benzene sulfonamide)SOH (PTBSA-SOH)] under ambient conditions. The catalyst was used for the formation of 1,8-naphthyridine derivatives for six runs. The current strategy provided a wider substrate range, and short reaction times.