نتایج جستجو برای: perkin
تعداد نتایج: 861 فیلتر نتایج به سال:
Experimental Section Solvents and reagents were purchased from Merck and used as received. 1,6,7,12Tetrachloroperylene-3,4:9,10-tetracarboxylic acid bisanhydride was obtained from BASF. N,N'-Didodecylperylene-3,4:9,10-tetracarboxylic acid bisimide 2 was synthesized according to the literature. NMR spectra were recorded on a Bruker DRX 400 spectrometer using the proton signal of TMS as internal ...
The practical synthesis of important natural polyphenolic stilbenes, including resveratrol, piceatannol and oxyresveratrol, through Perkin methodology is described. Starting from 3,5-dihydoxyacetophenone (1), the common intermediate 3,5-dimethoxyphenylacetic acid (3) can be obtained via methylation and Willgerodt-Kindler reaction. Perkin condensations between (3) and substituted phenylaldehydes...
General H NMR and C NMR spectra were recorded with a JEOL JNM-Alice 400 spectrometer (400 MHz and 100 MHz, respectively). Chemical shifts are given in parts per million (δ) downfield from internal tetramethylsilane. Infrared spectra were obtained with a Perkin-Elmer FT-IR (Model 1600). Both conventional and high resolution mass spectra were recorded with a JEOL JMS-DX303HF spectrometer. GC Mass...
The aphorism that those who do not remember the past are condemned to live it again is an often quoted warning from the writings of George Santayana. This paper will attempt to illustrate this adage with two examples, one having historical and the other having contemporary significance. We will examine the rise and very rapid decline of the British synthetic dyestuffs industry as the historical...
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