Sodium gluconate: An efficient organocatalyst for the synthesis of dihydropyrano[2,3-c] pyrazole derivatives

Abstract

Sodium gluconate presented as a category of biomolecule found to be a proficient and recyclable organocatalyst for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives via one-pot multicomponent reaction of aryl aldehyde, malononitrile, ethyl acetoacetate and hydrazine hydrate in water as a solvent. The catalyst is nontoxic in nature, commercially available, biodegradable and easily separated from the reaction mixture. Present protocol avoids the use of the heavy metal catalyst, harsh reaction condition and the reusability of catalyst, broad substrate scope, simple work-up procedure and excellent yield of products make this protocol greener.

Applications of pyrazolone in multicomponent reactions for the synthesis of dihydropyrano[2,3-c]pyrazoles and spiro-pyrano[2,3-c]pyrazoles in an aqueous medium

“…85 In 2019, Khandebharad et al has synthesized several dihydropyrano[2,3-c]pyrazole derivatives 37 in good to excellent yield from the four-component reaction of aldehydes 10, malononitrile 2, ethyl acetoacetate 13, and hydrazine hydrate 9 by using sodium gluconate as recyclable organocatalyst in presence of water as a reaction medium under reflux of 15-45 minutes (Scheme 38b). 86 All aryl, as well as heteroaryl aldehydes with electron-withdrawing and electron releasing group on the different position, were smoothly worked under the optimized reaction condition and a total of 13 compounds were synthesized in 85-92% yield. In the same year, several novel dihydropyrano[2,3-c]pyrazole derivatives 67 in 80-90% yield has been synthesized by Chate et al from the reaction of aldehydes 10, malononitrile 2, ethyl acetoacetate 13, and isoniazid 66 in the presence of 2-aminoethanesulfonic acid (taurine) as a bio-organic catalyst in water medium at 70 °C (Scheme 38c).…”

Greener and Environmentally Benign Methodology for the Synthesis of Pyrazole Derivatives

“…Amol Khandebharad et al [84] . carried out synthesis of dihydropyrano [2,3‐c] pyrazole (72) in presence of biodegradable catalyst such as sodium gluconate.…”

“…Amol Khandebharad et al [84] carried out synthesis of dihydropyrano [2,3-c] Madhuri Barge et al [85] develop greener and ecofriendly approach for synthesis of pyrazole (73) in presence of hydrotropic aqueous medium. Hydrotrope increases solubility of practically insoluble organic reactant, therefore reactants interact with each other and reaction goes to proceed.…”

Preparation and catalytic application of two different nanocatalysts based on hexagonal mesoporous silica (HMS) in synthesis of tetrahydrobenzo[b]pyran and 1,4-dihydropyrano[2,3-c]pyrazole derivatives

“…Also, in opposite of MCM and SBA mesoporous silica, HMS has indicated commendable outputs in the catalysis research area 6 . Design and development of multicomponent synthetic strategies which are in accordance with the principle of green chemistry and using novel and heterogenous catalyst led to the integration of a variety of novelty in their line of investigation 7 .…”

“…This synthetic strategy does not need to separation and purification of the intermediates. In comparison to traditional multistep protocols, one-pot multi-component reactions have both economic and environmental benefits such as decreasing time, saving costs, energy 12 , increasing atom economy 7 , reducing waste production, high efficiency and experimental simplicity 13 . Therefore, they are economically and environmentally suitable methodology 12 and often proceed with excellent chemoselectivities 13 .…”