High intensity ultrasound-assisted reduction of sterically demanding nitroaromatics
摘要:
Sterically demanding nitroaromatic compounds have been prepared and reduced to their corresponding amines with high intensity ultrasound using hydrazine in the presence of a Raney nickel catalyst. These reactions were dependent on catalyst quality, solvent and ultrasonic amplitude and, in comparison to their silent reactions, proceeded much faster and afforded higher yields. (c) 2005 Elsevier Ltd. All rights reserved.
High intensity ultrasound-assisted reduction of sterically demanding nitroaromatics
摘要:
Sterically demanding nitroaromatic compounds have been prepared and reduced to their corresponding amines with high intensity ultrasound using hydrazine in the presence of a Raney nickel catalyst. These reactions were dependent on catalyst quality, solvent and ultrasonic amplitude and, in comparison to their silent reactions, proceeded much faster and afforded higher yields. (c) 2005 Elsevier Ltd. All rights reserved.
Chemoselective reduction of nitroarenes to azo and azoxy compounds was easily achieved using zinc powder and ammonium chloride in DMF or DMF-water (95:5) under high intensity ultrasound (US) or microwave (MW) irradiation, separately or combined. When carried out under conventional heating the reaction required much higher temperatures and gave lower yields. The addition of a small amount of water caused a dramatic increase in the reactivity, permitting the reduction of hindered nitroarenes at the expense of selectivity. A novel reactor for combined US/MW irradiation was employed which demonstrated additional beneficial effects.
High intensity ultrasound-assisted reduction of sterically demanding nitroaromatics
作者:Georgios A. Heropoulos、Spyros Georgakopoulos、Barry R. Steele
DOI:10.1016/j.tetlet.2005.02.038
日期:2005.4
Sterically demanding nitroaromatic compounds have been prepared and reduced to their corresponding amines with high intensity ultrasound using hydrazine in the presence of a Raney nickel catalyst. These reactions were dependent on catalyst quality, solvent and ultrasonic amplitude and, in comparison to their silent reactions, proceeded much faster and afforded higher yields. (c) 2005 Elsevier Ltd. All rights reserved.