Three-component access to pyrroles promoted by the CAN–silver nitrate system under high-speed vibration milling conditions: a generalization of the Hantzsch pyrrole synthesis

Abstract

A sequential multicomponent process involving the high-speed vibration milling of ketones with N-iodosuccinimide and p-toluenesulfonic acid, followed by addition of a mixture of primary amines, β-dicarbonyl compounds, cerium(IV) ammonium nitrate and silver nitrate afforded polysubstituted, functionalized pyrroles. This one-pot, solid-state process can be considered as the coupling of an α-iodoketone preparation with a general version of the classical Hantzsch pyrrole synthesis.

Ceric Ammonium Nitrate (CAN)–Catalyzed Multicomponent Reactions: An Efficient Catalyst for Green Organic Synthesis

“…of silver nitrate (AgNO 3 ) was added and milling was continued for an hour under the same conditions to form the desired pyrroles 9. [22] Organic reactions without the use of harmful organic solvents are one of the current focuses of environmentally conscious society. So, a more facile way is the use of nonvolatile and low toxicity liquids, such as polyethylene glycol (PEG), as the reaction media to fulfil the demands of recyclability and environmental concerns.…”

Magnesium Incorporated White Sandstone as a Green and Efficient Heterogeneous Catalyst for One‐Pot Synthesis of 1,2,3,4‐Tetrasubstituted Pyrroles

“…Pharmacologically potent molecules which some examples are shown in Figure , and also the materials with high technology utilities for example conducting systems, fluorescent materials and supramolecules, have made the pyrrole derivatives as an attractive synthetic targets. In addition to numerous known routes for the synthesis of substituted pyrroles such as Clauson‐Kaas condensation, Hantzsch reactionand Paal–Knorr method, there are also various cyclocondensation and cycloaddition reactions for the construction of pyrrole rings . But these methods have significant drawbacks such as unavailability of the starting materials, multistep synthetic operations, and harsh reaction conditions which limit their scope.…”

Deep eutectic solvent based on choline chloride and malonic acid as an efficient and reusable catalytic system for one-pot synthesis of functionalized pyrroles

“…19 Next, the substrate scope of aldehydes with a variety of substituents was also investigated in 20 this 4CRs. The aromatic ring of benzaldehyde bearing electron-withdrawing or electron-donating 21 groups afforded the desired products in high yields, showing no significant influence on the reaction 22 time and the yield of the products. Notably, heteroaromatic aldehydes such as 2-furaldehyde and 23 2-thiophenealdehyde were tolerated and furnished the corresponding products 5r and 5s in excellent 24 yields.…”

“…Upon 19 completion of the reaction, the reaction mixture was cooled to room temperature and water (5 mL) 20 was added. The ChCl-malonic acid was dissolved in water and the products were extracted with 21 EtOAc (3 × 5mL). Pure products were obtained by evaporation of the solvent, followed by 22 recrystallization from ethanol or by column chromatography on silica gel using ethyl acetate/hexane 23 as the eluent.…”

“…A slightly lower yield was achieved using 1.5 g ChCl-malonic acid. 21 Thus, the most suitable reaction conditions for the model reaction were established (Table 1, entry 22 14). 23 To demonstrate the industrial applicability of this protocol, the model reaction was carried out 24 on a large scale (50 mmol).…”