نتایج جستجو برای: spirooxindole derivatives

تعداد نتایج: 104963  

پایان نامه :دانشگاه بین المللی امام خمینی (ره) - قزوین - دانشکده علوم پایه 1390

چکیده : * در یک واکنش تک ظرفی و با استفاده از واکنش آلدهید های آروماتیک و 3- متیل 1- فنیل پیرازولین-5- ان با نسبت مولی 1:1، ساختارهای هتروسیکل پیرازول سنتز شد. از مزایای آن، انجام واکنش در دمای اتاق، عدم نیاز به کاتالیزور، بازده بالای واکنش، استفاده از آب بعنوان حلال سبز و بی خطر به جای حلال های آلی وسمی می باشد . * توانستیم با استفاده از ملدرام اسید ومشتقات 2- هیدروکسی بنزآلدهید، ترکی...

2003
Luc Florack Remco Duits

Gaussian scale space permits one to compute image derivatives. The limitation to some finite order is not inherent in the paradigm itself (Gaussian blurred functions are always smooth), but is caused by the interplay of (at least) two external factors. One is the ratio of the Gaussian scale parameter versus the atomic scale that limits physically or perceptually meaningful sizes (e.g. pixel siz...

Journal: :Journal of dairy science 2008
B N Janicek P J Kononoff A M Gehman P H Doane

Two studies were performed to evaluate the effects of dried distillers grains with solubles (DDGS) on the lactational performance of dairy cows. The intent of experiment 1 was to evaluate the effects of feeding increasing concentrations of DDGS on the feed intake and production of Holstein dairy cows. Twenty multiparous Holstein cows averaging 76 +/- 24 d in milk and 638 +/- 68 kg of body weigh...

2014
Moritz Schubert Dieter Schollmeyer Siegfried R. Waldvogel

The title compound, C17H27O8P, was prepared by Michaelis-Arbuzov reaction of ethyl 2-bromo-2-(2,3,4-tri-meth-oxy-phen-yl)acetate and triethyl phosphite. Such compounds rarely crystallize, but single crystals were recovered after the initial oil was left for approximately 10 years. The bond angle of the sp (3)-hybridized C atom connecting the benzene derivative with the phospho unit is widened m...

Journal: :The Journal of organic chemistry 2001
J Li H Jiang M Chen

Many metals or their complexes can catalyze the cyclotrimerization of alkynes to give benzene derivatives.1-9 Among these catalysts, palladium chloride10 and its bis(benzonitrile) complex11 are the most convenient. In these reactions, the yields of benzene derivatives generally depend on the substituents of alkynes. In the past 50 years, the regioand chemoselectivity for the cyclotrimerization ...

Journal: :Symmetry 2011
Fliur Macaev Natalia Sucman Felix Shepeli Marina Zveaghintseva Vsevolod Pogrebnoi

The paper presents an application of the asymmetry approach to spirooxindoles via Brevicolline, Cinchonidine or Cinchonine catalyzed one-pot multicomponent synthesis. Brevicolline, in comparison with Cinchonidine or Cinchonine, catalyzes the reaction of isatins, acetylacetone/ethyl 3-oxobutanoate and malononitrile, with the formation of spiro[oxindole-3,4'-4'H-pirane] derivatives in an opticall...

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