نتایج جستجو برای: alpha hydroxy ketones

تعداد نتایج: 238507  

Journal: :The Journal of Biophysical and Biochemical Cytology 1958
Russell J. Barrnett Arnold M. Seligman

A method has been developed to demonstrate the alpha-acylamido carboxyl groups of protein, taking advantage of the fact that acylamido carboxyl groups are converted to ketonic carbonyls by the action of acetic anhydride and absolute pyridine. The method utilizes deparaffinized sections of tissues fixed in a variety of fixatives. Following the conversion of carboxyls to the methyl ketones, the l...

Journal: :Organic & biomolecular chemistry 2006
David J Fox Daniel Sejer Pedersen Stuart Warren

alpha-Diphenylphosphinoyl ketones are selectively and sequentially alkylated at the alpha-position. Double lithiation and selective alkylation occurs at the less stabilised gamma-position. Dephosphinoylation of the alkylation products gives ketones. Mono-alkylation is selective, highly crystalline intermediates are formed and a one-pot strategy is possible. The method is ideally suited for the ...

Journal: :Journal of agricultural and food chemistry 2000
L Pripis-Nicolau G de Revel A Bertrand A Maujean

This work describe products of reactions between four alpha-dicarbonyl compounds (diacetyl, pentan-2,3-dione, glyoxal, and methylglyoxal) or two alpha-hydroxy ketones, (acetoine and acetol) and amino acids present in wines. The results shows the formation of odorous products or strong-smelling additives resulting from the Maillard and Strecker reaction in a primarily aqueous medium, at low temp...

Journal: :Chemical communications 2013
Robert Westphal Simon Waltzer Ursula Mackfeld Michael Widmann Jürgen Pleiss Maryam Beigi Michael Müller Dörte Rother Martina Pohl

We report the first rationally designed (S)-selective MenD from E. coli for the synthesis of functionalized α-hydroxy ketones. By mutation of two amino acids in the active site stereoselectivity of the (R)-selective EcMenD (ee > 93%) was inverted giving access to (S)-5-hydroxy-4-oxo-5-phenylpentanoate derivatives with stereoselectivities up to 97% ee.

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2007
G K Surya Prakash Thomas Mathew Chiradeep Panja Steevens Alconcel Habiba Vaghoo Clement Do George A Olah

The synthesis of alpha-aminonitriles and their fluorinated analogs has been carried out in high yield and purity by the Strecker reaction from the corresponding ketones and amines with trimethylsilyl cyanide using gallium triflate in dichloromethane. Monofluoro-, difluro-, or trifluoromethyl groups can be incorporated into the alpha-aminonitrile product by varying the nature of the fluorinated ...

Journal: :Organic & biomolecular chemistry 2015
Yogesh Siddaraju Kandikere Ramaiah Prabhu

Tetrabutyl ammonium iodide (TBAI) catalyzed α-aminoxylation of ketones using aq. TBHP as an oxidant has been accomplished. We have shown that the CDC (cross dehydrogenative coupling) reactions of ketones with N-hydroxyimidates such as N-hydroxysuccinimide (NHSI), N-hydroxyphthalimide (NHPI), N-hydroxybenzotriazole (HOBt) and 1-hydroxy-7-azabenzotriazole (HOAt) lead to the corresponding oxygenat...

Journal: :Journal of the American Chemical Society 2013
Kevin Chung Steven M Banik Antonio G De Crisci David M Pearson Timothy R Blake Johan V Olsson Andrew J Ingram Richard N Zare Robert M Waymouth

The regio- and chemoselective oxidation of unprotected vicinal polyols with [(neocuproine)Pd(OAc)]2(OTf)2 (1) (neocuproine = 2,9-dimethyl-1,10-phenanthroline) occurs readily under mild reaction conditions to generate α-hydroxy ketones. The oxidation of vicinal diols is both faster and more selective than the oxidation of primary and secondary alcohols; vicinal 1,2-diols are oxidized selectively...

Journal: :Molecules 2013
Tingting Yan Xiaoyan Wang Hongbao Sun Jie Liu Yongmei Xie

An efficient approach for the synthesis of 3-substituted-3-hydroxy-2-oxindoles has been achieved via an aldol reaction of α,β-unsaturated ketones and isatins using arginine as an organocatalyst. A range of 3-substituted-3-hydroxy-2-oxindoles were obtained in moderate to high (up to 99%) yields. These 3-substituted-3-hydroxy-2-oxindoles with an additional enone moiety provide an opportunity for ...

Journal: :Chemical communications 2011
Sun Ah Lee Se Hun Kwak Kee-In Lee

We achieved highly enantioselective synthesis of cyclic 1,2-sulfamidates and -sulfamides via rhodium-catalyzed transfer hydrogenation, and also revealed one-pot preparation of cyclic N-sulfonylimines from α-hydroxy ketones.

Journal: :Chemical communications 2013
Matthew Lenze Eike B Bauer

A mild, iron-based catalyst system is presented that selectively oxidizes secondary alcohols to the corresponding hydroxy ketones in the presence of primary alcohols within 15 minutes at room temperature, utilizing H2O2 as the oxidant.

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