One-pot preparation of 2-(alkyl)arylbenzoselenazoles from the corresponding N-(acetyl)benzoyl-2-iodoanilines via a microwave-assisted methodology

We report here the first example of a one-pot synthesis of 2-(alkyl)arylbenzoselenazoles from N-(acetyl)benzoyl-2-iodoanilines. The reaction was carried out in the presence of Woollins’ reagent under microwave irradiation and resulted in moderate to good yields.     

Cycloaddition profile of pentafulvenes with 3-oxidopyrylium betaine: experimental and theoretical investigations

A detailed investigation on the effect of solvent polarity, temperature, and microwave irradiation on periselectivity in cycloaddition reactions of pentafulvenes with 3-oxidopyrylium betaine is described. The base catalyzed generation of 3-oxidopyrylium betaine in CHCl₃ resulted in the exclusive formation of [6+3] adducts. With increase in solvent polarity and temperature, mixtures of [6+3] and [3+2] adducts were formed, where as under microwave irradiation, [3+2] adducts were formed exclusively. The experimental results have been rationalized on the basis of theoretical calculations.     

Application of microwave-assisted micellar extraction combined with solid-phase microextraction and high-performance liquid chromatography with UV detection for the determination of organochlorine pesticides in different mud samples

Abstract

A sequential injection analysis method for the simultaneous spectrophotometric determination of phosphate and silicate has been developed. The method is based on the different reaction rates of the heteropolymolybdate formation reactions. Concentrations within the range 0.026—0.485 mmol P l^?1 and 0.125—2.848 mmol Si l^?1 have been determined at a frequency of 30 samples per hour. An R.S.D. of 2.1% was obtained for 0.162 mmol P l^?1 and of 1.1% for 1.424 mmol Si l^?1. The method was found to be suitable for the determination of phosphate and silicate in wastewater.     

Old Reagent,New Results: Aromatization of Hantzsch 1,4-Dihydropyridines with Supported Bismuth Nitrate under Microwave Irradiation in Solventless System

Hantzsch 1,4-dihydropyriines were rapidly and efficiently oxidized using bismuth nitrate supported onto silica gel under microwave irradiation.     

Microwave Thermolysis: A Rapid and Selective Method for the Cleavage of THP Ethers Using CrO 3 Supported onto Zeolite in Solventless System

Oxidative deprotection of tetrahydropyranyl ethers (THP ethers) using chromium trioxide supported onto zeolite under microwave irradiation in solvent free condition is described.     

One-pot synthesis of N-aryl propargylamine from aromatic boronic acid,aqueous ammonia,and propargyl bromide under microwave-assisted conditions

A facile,one-pot synthesis of N-aryl propargylamine from aromatic boronic acid,aqueous ammonia,and propargyl bromide has been achieved under microwave-assisted conditions.The reactions can be smoothly completed within a total 10 min through a two-step procedure,including copper-catalyzed coupling of aromatic boronic acids with aqueous ammonia and following propargylation by propargyl bromide.     

海蛎壳粉废弃物负载CuCl_2作为高效、廉价以及可回收催化剂合成炔胺类化合物(英文)

发展了一种经济、简单的海蛎壳粉负载的CuCl2异相催化剂OSP-CuCl2,用来催化醛-炔-胺之间的A3偶联反应.OSP-CuCl2容易通过简单的方法从海蛎壳粉以及CuCl2制备,且显示出高的催化活性以及良好的可循环回收性.在微波辅助以及无溶剂条件下,以OSP-CuCl2为催化剂,能够以高产物收率制备出一系列炔胺类化合物.OSP-CuCl2可通过简单的过滤方式进行回收,并至少可循环使用6次.初步放大实验表明,炔胺类化合物能够以150 mmol的规模制备(87%收率).     

Microwave-assisted lipase-catalyzed synthesis of polyethylene glycol stearate in a solvent-free system

Polyethylene glycol stearate, a condensation esterification product of stearic acid and polyethylene glycol 600, was widely applied in the biomedical and healthcare industries. The current work focuses on the enzymatic synthesis of PEG stearate using CALB_ex10000, a commercial Lipase enzyme in solvent-free conditions using microwave irradiation. The influence of various reaction parameters such as temperature, molar ratio of reactants, and enzyme loading was studied to obtain the highest conversion. Maximum conversion of 85% was attained under molar ratio 1:1 (PEG 600 to stearic acid using 0.7% (w/w) enzyme loading at 60 ​°C of temperature in 70 ​min of reaction time. Further, the thermodynamic parameters were analyzed and compared with the conventional and ultrasound-assisted synthesis of PEG stearate. The enzyme was recycled up to 5^th cycle giving more than 35% of the initial activity.     

Microwave-Assisted Method for Synthesis of 1,3-Disubstituted Pyrroles

1,3-Disubstituted pyrroles were prepared by a microwave-assisted reaction of pyrrolidine and aldehydes in toluene as well as in solvent-free conditions. Reactions were completed in a few minutes in the solvent-free condition but a long time (up to 30 min) was necessary to complete reactions in toluene. Yields of products depended considerably on the aldehyde used.