Sulfonic organic resin as catalyst for the synthesis of substituted pyrano[4,3-b]pyrazolo[4,3-e]pyridin-5(1H)-one derivatives.

An efficient domino approach for the synthesis of new pyrano[4,3- b ]pyrazolo[4,3- e ]pyridin-5(1 H )-one derivatives has been developed using reusable sulfonic organic resin as catalyst in water. The unique feature of sulfonic organic resin makes the formation of pyrano[4,3- b ]pyrazolo[4,3- e ] pyridin-5(1 H )-ones be possible, and avoids generating ring opening products. The plausible mechanism for this domino reaction is proposed. [ABSTRACT FROM AUTHOR]