DABCO catalyzed rapid one-pot synthesis of 1,4-dihydropyrano [2,3-c] pyrazole derivatives in aqueous media

Abstract

A simple and efficient protocol is developed for the synthesis of dihydropyrano[2,3-]pyrazole derivatives by a one pot, four component reaction of ethylacetoacetate, hydrazine hydrate, malanonitrile and various aldehydes in the presence of catalytic amount of DABCO in aqueous medium. This method provides several advantages such as high yield, shorter reaction time, mild reaction condition, operational simplicity, easy work-up procedure with environment friendly nature and purification of products by non-chromatographic methods have been developed.

Synthesis of pyrano[2,3‐c]pyrazoles: A review

“…In that respect, Pandit et al and Debache et al presented the synthesis of 1,4 and 2,4‐dihydropyran[2,3‐c]pyrazoles 35 , 36 using DABCO. [ 56 ] and PPh 3 , [ 57 ] respectively, in a one‐pot four‐component reaction in aqueous medium with excellent yields (up to 92%) of the products.…”

A Review on the Recent Multicomponent Synthesis of Pyranopyrazoles

“…Waghmare et al 94 In 2018, 95 DABCO was applied as a reusable solid base catalyst for the synthesis of bis-spiro pyranopyrazoles via the condensation reaction between bis-isatins, malononitrile, hydrazine hydrate and b-ketoester derivatives in ethanol at reflux conditions (Scheme 57). The desired bisisatins were obtained via the reaction between isatin (2 mmol) and dibromoalkane (1 mmol) in PEG-400 in the presence of K 2 CO 3 at room temperature.…”

Recent Advance in Development of 3-Methyl-4-Arylmethylene Isoxazole-5(4h)-Ones and 6-Amino-1,4-Dihydropyrano[2,3-C]-Pyrazole-5-Carbonitriles: Synthetic Applications and Pathways

“…. [72] www.wjpps.com [78] All synthesized compounds shows potent activity in Alzheimer's disease therapy.…”