Bioglycerol-Based Sulfonic Acid-Functionalized Carbon Catalyst as an Efficient and Reusable Catalyst for One-Pot Synthesis of 3- Substituted-2H-1,4-Benzothiazines

Abstract

A simple and efficient synthetic protocol has been developed for the synthesis of 3-substituted-2H-1,4-benzothiazines by using bioglycerol-based sulfonic acid-functionalized carbon catalyst, devoid of corrosive acidic and basic reagents. The developed method has the advantages of good to excellent yields, short reaction times, operational simplicity, and a recyclable catalyst.     

Chemoselective acetylation of amines and thiols using monodispersed Ni-nanoparticles

Abstract

We report here a method by which Ni-nanoparticles can be used efficiently to catalyze the acetylation of a variety of amines and thiols under ambient conditions at room temperature. However in a competitive reaction, the thiol was acetylated selectively while the amine remained almost unaffected. The demonstrated chemoselectivity could have multiple potential synthetic applications. Some of the major advantages of this method are high yields, selectivity, short reaction times (<40 min), ease of operation, and compatibility with other protecting groups. Additionally, the process reported is environmentally benign.     

Highly selective synthesis of single-walled carbon nanotubes from methane in a coupled Downer-turbulent fluidized-bed reactor

For the synthesis of single-walled carbon nanotubes (SWCNTs) from CH₄ over a Fe/MgO catalyst, we proposed a coupled Downer-turbulent fluidized-bed (TFB) reactor to enhance the selectivity and yield (or production rate) of SWCNTs. By controlling a very short catalyst residence time (1–3 s) in the Downer, only part of Fe oxides can be reduced to form Fe nano particles (NPs) available for the growth of SWCNTs. The percentage of unreduced Fe oxides increased and the yield of SWCNTs decreased accordingly with the increase of catalyst feeding rate in Downer. SWCNTs were preferentially grown on the catalyst surface and inhibited the sintering of the Fe crystallites which would be formed thereafter in the downstream TFB, evidenced by TEM, Raman and TGA. The coupled Downer-turbulent fluidized-bed reactor technology allowed higher selectivity and higher production rate of SWCNTs as compared to TFB alone.     

Nickel-catalyzed synthesis of 9-monoalkylated fluorenes from 9-fluorenone hydrazone and alcohols

A practical protocol was disclosed for the nickel-catalyzed C-alkylation of 9-fluorenone hydrazone with alcohols using t-BuOK as the base, and 9-monoalkylated fluorene derivatives were obtained in good yields under the benign conditions.     

Improved Protocol for Thorpe Reaction: Synthesis of 4‐Amino‐1‐arylpyrazole using Solid–Liquid Phase‐Transfer Conditions

Solid–liquid phase‐transfer conditions were employed for the first time in the Thorpe reaction to synthesize 4‐amino‐1‐aryl‐3,5‐substituted‐1H‐pyrazoles 3. Aryl amines were diazotized and coupled with various active methylene compounds such as cyano acetamide, cyanoacetophenone, malononitrile, and ethyl cyanoacetate, resulting into α‐arylhydrazononitriles 1. Cyclization of 1 using α‐bromo ketones or esters resulted in compounds 3.     

Micron Particles of AlN/Al: Efficient,Novel, and Reusable Heterogeneous Catalyst for the Synthesis of Bis(indolyl)methanes

The present work introduces for the first time the catalytic utility of micron particulate aluminium nitride (AlN/Al) as a novel and reusable heterogeneous catalyst for the synthesis of bis(indolyl)methanes involving the electrophilic substitution of indoles on aldehydes. The catalyst is recyclable and works without any significant change in its catalytic activity.     

SiO2-NHC-CuI–Catalyzed N-Arylation of Imidazoles with Arylboronic Acids Under Base-Free Reaction Conditions

N-Arylation of imidazoles with arylboronic acids was efficiently carried out in the presence of a catalytic amount of SiO₂-NHC-Cu^I in methanol at room temperature under base-free reaction conditions. The reactions of a variety of arylboronic acids with imidazoles generated the corresponding products N-arylimidazoles in good to excellent yields. In addition, SiO₂-NHC-Cu^I could be recovered and recycled for six consecutive trials without significant loss of its reactivity.     

Benzylation and Allylation of Naphthols Using Amberlyst-15

A simple and efficient method has been developed for benzylation and allylation of naphthols by treatment of the compounds with benzylic and allylic alcohols, respectively, in the presence of amberlyst-15. Several heterogeneous catalysts were screened for the reaction, and amberlyst-15 was found to be most effective.     

Bromamine-B/PdCl2 is an Efficient System for the Synthesis of Anthranilic Acids from Indoles and Indigos

A convenient method has been developed for the conversion of indoles and indigos into anthranilic acids in good to excellent yields using a bromamine-B/PdCl₂ system. The general process utilizes our efficient method for the oxidation of indoles and indigos in alkaline (pH 12) acetonitrile/water (1:1) at 60 °C.