کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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67684 | 48491 | 2008 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Microwave-assisted solvent free synthesis of hydroxy derivatives of 4-methyl coumarin using nano-crystalline sulfated-zirconia catalyst Microwave-assisted solvent free synthesis of hydroxy derivatives of 4-methyl coumarin using nano-crystalline sulfated-zirconia catalyst](/preview/png/67684.png)
Nano-crystalline sulfated-zirconia solid acid catalyst has been studied for microwave-assisted solvent free synthesis of hydroxy derivatives of 4-methyl coumarin by Pechmann reaction. The catalyst showed good activity for activated m-hydroxy phenol substrates, viz., phloroglucinol and pyrrogallol with ethyl acetoacetate for the synthesis of 5,7-dihydroxy 4-methyl coumarin and 7,8-dihydroxy 4-methyl coumarin, respectively, showing significant yields ranging from 78 to 85% within 5–20 min at 130 °C. However, the less activated phenol and m-methyl phenol was observed to be inactive for the synthesis of 4-methyl coumarin and 4,7-dimethyl coumarin, respectively, under the studied experimental conditions.
Nano-crystalline sulfated-zirconia catalysts showed good catalytic activity for microwave-assisted solvent free synthesis of hydroxy derivatives of 4-methyl coumarin by Pechmann reaction using activated m-hydroxy phenol substrates and ethyl acetoacetate. Less activated phenolic substrates were observed to be inactive under the experimental conditions studied.Figure optionsDownload as PowerPoint slide
Journal: Journal of Molecular Catalysis A: Chemical - Volume 286, Issues 1–2, 1 May 2008, Pages 41–46