Metal-free greener method for the synthesis of densely functionalized pyrroles via a one-pot three-component reaction

Recent Advances for the Synthesis of N‐Unsubstituted Pyrroles

“…2‐Methyl‐ N ,4,5‐triphenyl‐1 H ‐pyrrole‐3‐carboxamide 23 was obtained via a convenient acid‐promoted one‐pot three‐component transformation with the use of acetoacetanilide 22 , benzoin 11 , and ammonium acetate 2 [11] . This strategy includes simple reaction conditions, no toxic transition‐metal catalysts and readily available starting materials with 92 % yield (Scheme 8).…”

“…2-Methyl-N,4,5-triphenyl-1H-pyrrole-3-carboxamide 23 was obtained via a convenient acid-promoted one-pot threecomponent transformation with the use of acetoacetanilide 22, benzoin 11, and ammonium acetate 2. [11] This strategy includes simple reaction conditions, no toxic transition-metal catalysts and readily available starting materials with 92 % yield (Scheme 8). Formation of 4-thioarylpyrroles 27 was carried out via thiol-Michael/Paal-Knorr reaction of 1,4-enediones 24 with thiols 25, and ammonium formate 26 in one-pot procedure.…”

A Practical Synthesis of Densely Functionalized Pyrroles via a Three-Component Cascade Reaction between Carbohydrates, Oxoacetonitriles, and Ammonium Acetate

“…45,46 Several pyrrole-based drugs are commercially available including the blockbuster atorvastatin 1, 47 sunitinib 2, 48 and aloracetam 3 (Figure 2). 49 Therefore, the development of practical and sustainable methods for the synthesis of densely functionalized pyrroles that are amenable to easy transformations to useful intermediates or final products is of great interest. Herein, we disclose an efficient, one-step synthesis of densely functionalized pyrroles via a three-component cascade reaction between unprotected sugars, oxoacetonitriles, and ammonium acetate in excellent yields.…”

A convenient route toward one‐pot multicomponent synthesis of spirochromenes and pyranopyrazoles accelerated via quinolinic acid

“…To address the above‐mentioned issues and in partial fulfillment of our ongoing projects in terms of developing an efficient protocol for the synthesis of heterocyclic molecules, herein, we have designated an efficient one‐pot, three‐component strategy for the synthesis of spirochromenes by condensation of enolizable C–H activated compounds 1 , malononitrile or ethyl cyanoacetate 2 , and various 1,2‐diketones 3 in aqueous ethanol at 70°C and also an efficient one‐pot, four‐component strategy for the effective synthesis of dihydropyrano[2,3‐c]pyrazoles and spiroindoline‐pyranopyrazoles from the condensation of hydrazine monohydrate 5 , ethyl acetoacetate 6 , malononitrile 2, and aldehydes 7 or isatins 3 under solvent‐free conditions in the presence of QUIN as an effective catalyst at 90°C (Scheme ).…”