A facile and efficient procedure for one-pot four-component synthesis of polysubstituted spiro pyrano[2,3-c]pyrazole and spiro 1,4-dihydropyridine catalyzed by a Dabco-based ionic liquid under mild conditions

Abstract

Spiro pyrano[2,3-c]pyrazoles and spiro 1,4-dihydropyridines were obtained in high yields from different amine components under Dabco-based ionic liquid catalysis.

Ultrasound-Engineered fabrication of immobilized molybdenum complex on Cross-Linked poly (Ionic Liquid) as a new acidic catalyst for the regioselective synthesis of pharmaceutical polysubstituted spiro compounds

“…This straightforward approach was extended in a series, using phenyl hydrazine instead of hydrazine hydrate component, which formed the desired spiro pyranopyrazole derivatives in excellent yield. We found that reactions with hydrazine hydrate could afford the desired products within shorter times because of its low steric hindrance [13] . Furthermore, to gain more insight into the effect of US on the synthetic pathway, the reactions were performed under two green protocols including microwave (MW) and ultrasound (US) irradiations without any undesirable byproducts in good to excellent yields and short reaction times.…”

“…can influence the main product of reactions. For example, a one-pot four-component reaction of isatin, DMAD, malononitrile, and aromatic amines using different iodine sources as catalyst selects rout (III) [43] While the same four-component reaction in the presence of Dabco-based IL crosses rout (II) [13] .…”

“…1 . Both functionalized spiro 1,4-dihydropyridines and spiro pyranopyrazoles are important branches of biologically active organic compounds [12] , [13] . Recently, owing to their great biological properties, some straightforward methods have been reported for their preparation using one-pot four-component reactions.…”

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

“…Isatin, is a versatile chemical building block, which is able to form a large number of heterocyclic molecules [102–104] . The strategy for the use of multicomponent reactions of isatin with malonic acid derivatives, [105–108] acetylacetone, acetoacetic ester in the presence of aromatic amines, aminouracils or phenols remains an efficient way to build spirocyclic compounds [109–113] . The three‐component reaction of isatins 22 , malononitrile (or 2‐(phenylsulfonyl)acetonitrile) and 6‐aminouracils in aqueous ethanol, catalyzed by sodium formate and leads to spiro heterocycles 23 .…”

In the Mists of a Fungal Metabolite: An Unexpected Reaction of 2,4,5-Trimethoxyphenylglyoxylic Acid

“…Thereby, we encountered several unexpected and unprecedented reactions yielding 3,3-diaryl substituted benzofuranones which undergo retro-Friedel-Crafts alkylation in hydrochloric acid forming the p-QM structure. These molecules are similar to 3,3-diaryloxoindoles and 3,3-substituted oxoindoles that have lately been studied quite extensively yielding pharmacological interesting molecules [23][24][25][26][27][28]; they are also known intermediates from isatines and a prominent motif in natural product products, as for example in azonazine [29]. In contrast to isatines, benzofuran-2,3-diones are widely overlooked [28,30].…”