نتایج جستجو برای: preparation of ketones
تعداد نتایج: 21170795 فیلتر نتایج به سال:
The synthesis of unsymmetrical diaryl ketones via the Fukuyama coupling of thioesters and organozinc reagents is described. Typically, the synthesis of diaryl ketones using this methodology provides low yields. The simple complex, Pd(dba)(2), was found to convert a variety of aryl thioesters to diaryl ketones in good yields.
Polycyclic ’cage’ ketones, such as pentacyclo[5.4.0.02,6.03,10.05,9]undecan-8-one (10), pentacyclo[5.4.0.02,6.03,10.05,9]undecane8,11-dione (11), and adamantan-2-one (16) were treated with the nucleophilic dimethoxycarbene (DMC; 1), which was generated thermally from 2,5-dihydro-2,2-dimethoxy-5,5-dimethyl-1,3,4-oxadiazole (4a) in boiling toluene. In this ’one-pot’ procedure, the ahydroxycarboxy...
Dietary protocols that increase serum levels of ketones, such as calorie restriction and the ketogenic diet, offer robust protection against a multitude of acute and chronic neurological diseases. The underlying mechanisms, however, remain unclear. Previous studies have suggested that the ketogenic diet may reduce free radical levels in the brain. Thus, one possibility is that ketones may media...
Bentourkia M, Tremblay S, Pifferi F, Rousseau J, Lecomte R, Cunnane S. PET study of C-acetoacetate kinetics in rat brain during dietary treatments affecting ketosis. Am J Physiol Endocrinol Metab 296: E796 –E801, 2009. First published January 27, 2009; doi:10.1152/ajpendo.90644.2008.—Normally, the brain’s fuel is glucose, but during fasting it increasingly relies on ketones ( -hydroxybutyrate, ...
[reaction: see text] Organocatalytic asymmetric Mannich reaction of protected amino ketones with imines in the presence of an L-proline-derived tetrazole catalyst afforded diamines with excellent yields and enantioselectivities of up to 99%. The amino ketone protecting group controlled the regioselectivity of the reaction providing access to chiral 1,2-diamines from azido ketones and 1,4-diamin...
a novel potentiometric ion-selective pvc membrane sensor for analysis of atorvastatin (at) in pharmaceutical preparations based on atorvastatin-(tetraphenyl borate), (at-(tpb)2) as sensing element, tetraphenyl borate as additive and tris-2-ethyl-hexyl phosphate (top) as plasticizer solvent was prepared. the electrode shows a good nernestian response over the concentration range of 0.09–5586 µg ...
Reaction of various ketones with [hydroxy(tosyloxy)iodo]benzene (HTIB) followed by treatment of the α-tosyloxy ketones thus generated in situ with NaN3 offers a one-pot procedure for the synthesis of α-azido ketones. The HTIB used in this conversion may also be generated in situ by using iodosobenzene in combination with p-toluenesulphonic acid.
PURPOSE To investigate whether it is better to use blood beta-hydroxybutyrate (BHB) or urinary ketones to monitor ketogenic diet (KD). METHOD In 33 patients on KD we measured ketosis in two different ways. At the 3-monthly visits to the clinic we measured BHB in capillary blood obtained by finger-prick and the level of ketones in the urine using a urine dipstick. If the patient was able to co...
In the course of the preparation of a series of ferrocenyl derivatives of diethylstilbestrol (DES), in which one of the 4-hydroxyphenyl moieties was replaced by a ferrocenyl group, the McMurry reaction of chloropropionylferrocene with a number of mono-aryl ketones unexpectedly yielded the hydroxylated ferrocenyl DES derivatives, 5a-c, in poor yields (10%-16%). These compounds showed high activi...
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 ...
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