Single step incorporation of carboxylic acid groups in the lower rim of calix[4]arenes: a recyclable catalyst towards assembly of diverse five ring fused acridines

Abstract

Library synthesis of five ring fused acridines using a carboxylic acid incorporated calixarene catalyst.

One-Pot, Catalyst-Free Synthesis of Spiro[dihydroquinoline-naphthofuranone] Compounds from Isatins in Water Triggered by Hydrogen Bonding Effects

“…An intramolecular nucleophilic attack (carbonyl addition) of 9 in which the hydroxyl of naphthol ring adds to the 2-position carbonyl group of isatin, essentially leads to the unusual ring-opening process. − The reactive intermediate 11 experiences an intramolecular cyclization process to give the unusual 4a . The hydrogen-bonding effects play a dual role in the reaction: − ,, (1) enhancing the nucleophilicity of enol’s β-carbon ( 3a′ and 2a ) and the hydroxyl of naphthol ring ( 9 ) via the generation of HBs between water and the hydroxyl groups; (2) increasing the eletrophilicity of carbonyl carbon ( 1a and 9 ) by the formation of HBs between water and the carbonyl groups.…”

“…Several reports have mentioned that enaminones can attack the 2-position carbonyl carbon of isatins to generate pyrrolo­[2,3,4- kl ]­acridinone derivatives through sequential ring-opening and cyclizing processes (Figure ). − Based on these results, we reason that 2-naphthol as a nucleophile can also add to the 2-position carbonyl carbon of isatin to form the naphthofuranone, moreover the free amine group in situ generate by the ring-opening route can cycle with 1,3-dicarbonyl compounds to derive dihydroquinolines (Figure ).…”

Calix[n]arenes in Action: Recent Applications in Organocatalysis

“…Sarkar and Mukhopadhyay (2015) reported the synthesis of carboxylic acid calix[4]arene CX30-CX33 (Figure 14) and evaluated its catalytic activity in the synthesis of acridine. [34] Acridines are alkaloids with high inhibiting power against tumor, fungal and bacterial activities. [35] The model reaction to test the catalytic activity of CX30-CX33 was a multicomponent reaction using 5,5-dimethyl-1,3cyclohexanedione, p-toluidine, isatin and dimethylacetylenedicarboxylate as the starting material in water (Table 16).…”

Pyrrolo[3,4-c]pyridine-Based Fluorescent Chemosensor for Fe3+/Fe2+ Sensitivity and Their Application in Living HepG2 Cells

“…Then, it was stirred at room temperature (25–30 °C) for 12 h and the progress of the reaction was monitored by TLC. The spot for pyrrolo­[3,4- c ]­pyridine-1,3,6­(5 H )-trione disappeared after 12 h. After that, the reaction mixture was extracted with ethyl acetate and it was subjected to column chromatography using 60–120 mesh silica gel and petroleum ether–ethyl acetate mixture as the eluent and the pure products 3xy were obtained at 10–12% ethyl acetate in petroleum ether and 4xy at 20–25% ethyl acetate in petroleum ether, respectively …”