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Silica Gel Supported gamma-Picolonium Chloromate ; A New and Efficient Reagent for Selective Conversion of Alcohols and Oximes into Carbonyl Compounds under Mild and Non-Aqueous Conditions

100%

Salehi P. , Khodaei M. M. , Yazdanipoor A.

2003

tom Vol. 77 / nr 10

1281-1286

The preparation of silica gel supported _-picolinium chlorochromate and its application as an efficient reagent for selective oxidation of oximes and alcohols into carbonyl compounds is reported. The trimethylsilyloxy and ester groups survived under the reaction conditions.

Wpływ oksymów 2-hydroksy-5-alkilobenzofenonu na strukturę, wielkość cząstek oraz morfologię powierzchni strącanych krzemionek

75%

Błaszczak J. , Jesionowski T.

tom Nr 5

11-12

Przeprowadzono badania nad modyfikacją krzemionek strącanych. Modyfikację realizowano z zastosowaniem oksymów 2-hy-droksy-5-alkilobenzofenonu. Zmodyfikowane substancje poddano ocenie fizykochemicznej, badano stopień modyfikacji, wielkość cząstek i morfologię powierzchni. Najbardziej jednorodną krzemionkę uzyskano przy zastosowaniu do modyfikacji 3 cz.wag. 2-hydroksy-5—nonylobenzofenonu.

The studies on formation and modification of precipitated silicas were evaluated. The surface modification was conducted using 2-hydroxy-5-alkilbenzophenone oximes. Moreover, tests of physicochemical properties, as well as, degree of modification, particle size and surface morphology were performed. The most monodisperse silicas were obtained for 3 weight parts of 2-hydroxy-5-nonylbenzophenone oxime per 100 weight parts of SiOa in modification.

A new approach to the determination of the number of oxo groups in carbonyl compounds using the chloramine-T oxidative method

63%

Umesha K. B. , Rai K. M. L. , Kumar K. A. , Prasad K. R. , Shashikanth S.

tom Vol. 46, No. 2

269-274

A simple titrimetric method for the determination of the number of the oxo groups in car-bonyl compounds via their oximes is described. The method involves the oxidative dehydrogenation of the oximes by chloramine-T in water, followed by the iodometric determination of the unreacted chloramine-T.

Opisano prostą metodę oznaczania liczby grup C=O w związkach karbonylowych na drodze tworzenia oksymów. Metoda polega na utleniającym odwodnieniu oksymów w wodzie za pomocą chloraminy T, a następnie na jodometrycznym oznaczeniu nie-przereagowanej chloraminy T.

Synteza i redukcja prochiralnych imin

63%

Berniak T. A.

2016

tom [Z] 70, 5-6

353--368

Natural chemical compounds and their derivatives could be used for designing new classes of anticancer, antifungal or antiviral drugs. One of those compounds is gossypol, isolated from grains of wool. Gossypol’s derivatives can freely penetrate the blood-brain barrier (BBB). This basic review considers synthesis and reduction of prochiral imines. Gossypol derivatives belong to imines. Imines as unstable compounds, hydrolyze in contact with a small amount of water. There are substrates for preparation of oximes and its derivatives. In this article three methods of imines production are presented. There are: (a) reaction of aldehyde or ketones with primary amine, (b) addition of Grignard reagents to nitriles and (c) pyrolysis of alkyl azide. The first one is discussed in details with specific description of the mechanism of both steps: first stage - addition to form a hemiaminal, second one – dehydration with formation of imine. Many conditions such as acid power, value of pH reaction and environment (preferably anhydrous) have influence on the formation rate of imines and determine each of two stages, i.e. addition and dehydration. Furthermore, the imines-enamines tautomeric and stereochemical aspects with possible attack of nucleophile molecules to the carbon atom of the C=N bond from the Si or Re side of prochiral imines as well as potential ways of imines reductions to amines by using commonly used reducers (NaCNBH3) are discussed. Moreover, two new methods of reduction are presented: the first – with using trichlor acids catalyzed chiral Lewis’s bases and the second one – asymmetric hydrogenation of imines.

Synteza nitronów

51%

Socha J. , Jabłońska M. , Głąb K. , Mikulska M. , Jasiński R. , Barański A.

2012

tom R. 109, z. 2-Ch

183--207

W artykule przeprowadzono krytyczną analizę danych literaturowych dotyczących syntezy nitronów.

The paper is a critical review of available literature data that are connected with synthesis of nitrones.