Caspian Isinglass, a versatile and sustainable biocatalyst for domino synthesis of spirooxindoles and spiroacenaphthylenes in water

Abstract

Isinglass, derived from swim bladders of Caspian Sea fish and consisting predominantly of protein collagen, was found to be an effective, easily accessible heterogeneous biocatalyst for the synthesis of biologically important functionalized spirooxindoles and spiroacenaphthylenes in water. This facile and efficient one-pot, three-component synthesis route involving isatin or acenaphthenequinone, activated methylene reagent, and 1,3-dicarbonyl compounds provides a new strategy giving rise to spiro derivatives in quantitative yields in very short reaction times. Graphical abstract N CN X O O R 2 R 1 N O X H2N R 2 R 1 O O O O H2O, 60 °C H2O, 60 °C O O O O X H2N O 6 2 3 4 5 1 X= CN, CO2Et R 1 = H, Me, Et, Bn, Ph R 2 = H, Cl, Br, NO2 IG IG

CsF promoted rapid synthesis of spirooxindole‐pyran annulated heterocycles at room temperature in ethanol

“…In comparison to all given products, 4z completed with the lowest time (3 min) and 4f needed the highest reaction time (25 min) and products 4s, 4w, and 4aa were obtained in high yield up to 99%. The structures of the synthesized compounds were elucidated through IR, 1 H NMR, 13 C NMR, and HRMS analysis. The structure of product 4h was also confirmed by taking single crystal XRD (Figure 1).…”

“…These compounds are acknowledged for display of various biological activities like anti‐HIV, antitumor, antitubercular, antimalarial, and central nervous system (CNS) activities and effects . Therefore, different catalysts have been used to synthesize these spirooxindole scaffolds such as alum, l ‐proline, Caspian Isinglass, borax, and gold (III) chloride . Although such protocols reported by others find certain merits of their own.…”

Magnetic Isinglass a Nano‐Bio Support for Copper Immobilization: Cu–IG@Fe3O4 a Heterogeneous Catalyst for Triazoles Synthesis

“…The fish bladders were first washed in the manner previously mentioned . Then dried IG was ground in a ball mill machine to reach a fine powder.…”

Palladium on magnetic Irish moss: A new nano‐biocatalyst for suzuki type cross‐coupling reactions

“…[11] Therefore, the development of highly active heterogeneous ligandless catalysts has attracted considerable attention in recent years. [12] Thus, in continuation of our research toward the development of nano-biocatalytic systems, [5,13] Fe 3 O 4 @IM was designed and used as a novel nanobiosupport for immobilization of Pd NPs for Suzuki-Miyaura cross-coupling reactions under mild and green chemistry reaction conditions.…”