Multi‐wall carbon nanotube supported Co (II) Schiff base complex: an efficient and highly reusable catalyst for synthesis of 1‐amidoalkyl‐2‐naphthol and tetrahydrobenzo[b]pyran derivatives

Abstract

An immobilized Co (II) Schiff base complex supported on multi‐wall carbon nanotubes was synthesized and characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact=8&ved=0CDoQFjAI&url=http%3A%2F%2Fen.wikipedia.org%2Fwiki%2FEnergy-dispersive_X-ray_spectroscopy&ei=8whJVfW_KMv4UJvQgOAH&usg=AFQjCNGukh_d_Co5x-jjjV9UjtGctkEYiA&sig2=ZreZksv_Yb7i3fliKYAfjg&bvm=bv.92291466,d.bGQ, thermogravimetric analysis and inductively coupled plasma mass spectrometry. It was shown that the supported complex is a facile, eco‐friendly, recyclable, reusable and green catalyst for three‐component condensation of 2‐naphthol and acetamide with various aldehydes for the synthesis of 1‐amidoalkyl‐2‐naphthol derivatives under solvent‐free conditions. Also, in a further study, the catalytic application was studied in the synthesis of tetrahydrobenzo[b]pyran derivatives via the condensation reaction of malononitrile and dimedone with several aromatic aldehydes. The procedures suggested here for the synthesis of 1‐amidoalkyl‐2‐naphthol and tetrahydrobenzo[b]pyran derivatives offer several advantages, such as stability, recyclability and eco‐friendliness of the catalyst, simple experimental conditions, short reaction times, high to excellent yields and easy work‐up.

Immobilization of novel inorganic nano-complexes onto MWCNT nanomaterials as a novel adsorbent and anti-inflammatory therapy in an induced model of rheumatoid arthritis

“…The proton nuclear magnetic resonace (NMR) spectra (DMSO-d6) were recorded on a Brucker FT-400 MHZ spectrometer using TMS as the internal standard. 13 C NMR (500 MHz) spectra were run in DMSO-d6. Chemical shifts were related to those of the solvent.…”

“…The 13 C NMR spectra of the Ag nano-complexes were recorded in DMSO-d6 (figure 3). The measured chemical shifts of all carbon atoms are listed in table 2.…”

“…The immobilization of transition metal complexes on solid supports could be used for catalyst preparation s that are easy to be isolated from, and reused in, a reaction system, and that probably have enhanced activities due to the support environment [13]. Different supports for the synthesis of a number of heterogeneous catalysts have been identified [14,15].…”

Facile One-Pot Synthesis of Amidoalkyl Naphthols and Benzopyrans Using Magnetic Nanoparticle-Supported Acidic Ionic Liquid as a Highly Efficient and Reusable Catalyst

“…These 1-amidoalkyl-2-naphthol and tetrahydrobenzo [b]pyran derivatives are of particular value because of their promising biological and pharmacological activities [7][8][9]. The preparation of amidoalkyl naphthols has been carried out by a three-component condensation of aldehydes, 2-naphthols and amides using different catalysts such as Ba 3 (PO 4 ) 2 [10], Nano Al 2 O 3 [11], supported heteropolyacid [12,13], magnetic sulfonic or phosphoric acid [14][15][16], β-CD-BSA [17], [C 6 [18], MWCNT@Co-complex [19], sulfonated polynapthalene [20] and grapheme oxide [21] in the last five years.Despite undeniable advantages of these methods, a great part of themsuffer from one or more shortcomings such as high reaction temperature, prolonged reaction time, low yield and difficult catalyst separation and recovery. In addition, most of them are limited to only aromatic aldehydes and the reactions with aliphatic aldehydes were reported to suffer from low yields and harsh reaction conditions.…”

“…In addition, most of them are limited to only aromatic aldehydes and the reactions with aliphatic aldehydes were reported to suffer from low yields and harsh reaction conditions. Meanwhile, the benzopyrans could also be prepared by multicomponent condensation of dimedone with aldehyde and malononitrile in the presence of newly reported catalysts such as SO4 2− /MCM-41 [22], NH4H2PO4/Al2O3 [23], THAM [24], urea [25], ionexchange resin [26], SO3H-functionalized nano-TiO2 [27], immobilized HPA [28,29], ionic liquid [30] and MWCNT@Co-complex [19]. Many of the reported procedures suffer from limitations yet, for example use of volatile organic solvent, prolonged reaction time, tedious work-up and additional ultrasonic irradiation.…”