Domino Knoevenagel/Michael synthesis of 2,2’-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexen-1-one) derivatives catalyzed by silica-diphenic acid and their single crystal X-ray analysis

Abstract

An efficient and eco-friendly procedure has been developed for the synthesis of various 2,2'arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives which were isolated and characterized by melting point, IR, 1 H-NMR, 13 C-NMR and mass spectrometric techniques. Out of the fourteen compounds synthesized, four compounds yielded crystals suitable for single crystal X-ray analysis which showed that 2,2'-phenylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) crystallizes in the tetragonal system with space group I 4 1 /a, 2,2'-(3-nitrophenyl)methylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) crystallizes in the monoclinic system with space group P 2 1 /n, 2,2'-(4-nitrophenyl)methylenebis(3hydroxy-5,5-dimethyl-2-cyclohexene-1-one) crystallizes in the orthorhombic system with space group Pca21 and 2,2'-(4-chlorophenyl)methylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) crystallizes in the monoclinic space group P21/c.

Dimedone‐decorated conjugated polymer: Tandem knoevenagel‐michael post‐modification synthesis and its application as optical probe for Hg2+ and ClO− in high‐water‐fraction mediums

“…In the parallel experiment, the reaction conversion was much lower without the involvement of ammonium acetate, suggests the crucial role ammonium acetate played here. According to previous literatures, the 1,3‐dione was converted to enol‐form firstly and then via Knoevenagel condensation followed by Michael addition to get the target molecule . The introduction of ammonium acetate might facilitate the formation of enol‐form of 5,5‐dimethylcyclohexane‐1,3‐dione and sequentially promoted the reaction.…”

“…These compounds are important key synthons for the further synthesis of various xanthenes and acridinedione derivatives . What's more, the products also displayed significant biological and therapeutic activities such as antiviral, antibacterial, anti‐oxidant, skin melanoma and also action against disorders like asthma and inflammatory processes …”

Simple and efficient synthesis of 2,2′-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) derivatives

“…under different conditions (Scheme 2). Several synthetic methods have been reported for the synthesis in the literature applying different types of catalysts such as l-histidine in ionic liquid [12], silica-diphenic acid [13], Pd(0) nanoparticles in water [14], Ni(0) nanoparticles anchored on acid-activated montmorillonite [15], urea under ultrasound irradiation [16], Cu(0) nanoparticles on silica [17], immobilized Ni-Zn-Fe layered double hydroxide [18], and Yb(OTf) 3 -SiO 2 [19].…”

Caffeinium Hydrogen Sulfate: A Green Solid Acid Catalyst for Selective One‐Pot Domino Knoevenagel‐Michael Transformations

“…Furthermore they serve as valuable precursors for dyes, pH sensitive fluorescent materials for visualization of biomolecules, laser technologies and photodynamic therapy . Bis‐cyclohexenone compounds and their derivatives also exhibit various biological activities such as antioxidant, antibacterial and inflammatory problems . They also serve as biologically valuable key synthons for the synthesis of various xanthenes and acridinedione derivatives.…”