Ketones In Presence Research Articles

A Remote 'Imidazole'-Based Ruthenium(II) Para-Cymene Pre-catalyst for the Selective Oxidation Reaction of Alkyl Arenes and Alcohols.

Herein we disclosed the use of a remote 'imidazole'-based precatalyst [(para-cymene)RuII (L)Cl]+ , C-1 where L=2-(4-substituted-phenyl)-1H-imidazo[4,5-f][1,10] phenanthroline) for the selective oxidation of a variety of alkyl arenes/heteroarenes and alcohols to their corresponding aldehydes or ketones in presence of tert-butyl hydroperoxide (TBHP). The remote 'imidazole' moiety present in the complex facilitates the activation of oxidant and subsequent generation of active species via the release of para-cymene from C-1, which in-turn was less effective without the 'imidazole' moiety. The mechanistic features of C-1 promoted oxidation of alkyl arenes were also assessed from spectroscopic, kinetic, and few control experiments. The substrate scope for C-1 promoted oxidation reaction was assessed based on the selective oxidation of 27-different alkyl arenes/heteroarenes and 25 different alcohols to their corresponding aldehydes/ketones in moderate to good yields.

Application of Raman spectroscopy to diagnose the metabolic state of volleyball and soccer players through the identification of urine components

Raman spectroscopy is a rapid technique that allows the simultaneous determination of several components of urine to assess the metabolic status. In this study, the urine composition was evaluated in volleyball and soccer athletes using Raman spectroscopy to identify biomarkers of sports performance. Urine samples were collected from 20 athletes before and after exercise to be analyzed with a Raman microscope with excitation at 532 nm and a laser power of 67 mW. The analyses were compared with a group of 10 non-sports subjects. Raman analyses show peaks associated with the presence of urea, uric acid, creatinine, and ketone compounds with different intensity before and after exercise. The concentrations of urea, creatinine, and ketones were determined by commercial kits and were compared with the Raman analyses. The excretion of urea in urine increased after exercise in most volleyball athletes, while in some soccer players it decreased. The creatinine concentration increased significantly with exercise. The presence of ketones was observed in all of the spectra after exercise. The excretion of these metabolites is the result of the intensity and physical activity performed. Through this technique, we can evaluate athletes under training to establish their metabolic conditions and make nutritional adjustments to improve their athletic performance.

A chemoselective photolabile protecting group for aldehydes

A new and high-efficiency photolabile protecting group (PLPG) for aldehydes is described. The PLPG was introduced to aldehydes by using a Lewis acid. Results showed that the PLPG can be released rapidly and smoothly under ultraviolet (UV) irradiation with high efficiency and low cost. This PLPG can easily synthesized and also be selectively protect aldehydes in the presence of ketones.

Dipyrazolodioxadiazocines as shelf-stable "ready-to-use" precursors for an in situ generation of enolate-iminium 1,4-dipoles: a straightforward atom-economical approach to pyrazolo[5,1-d][1,3,5]dioxazines.

An original, facile and highly efficient method for the in situ generation of cyclic enolate-iminium 1,4-dipoles via unique thermal decomposition of easily available dipyrazolodioxadiazocines has been developed. Various substituted pyrazolo[5,1-d][1,3,5]dioxazines have been prepared in high yields via unusual cycloconversion of dipyrazolodioxadiazocines in the presence of ketones. Furthermore, the developed method is 100% atom economical and proceeds under metal-, catalyst- and solvent-free conditions.

Comparison of methodologies for the extraction of snakes’ (Reptilia: Serpentes) skin secretions and preliminary results on the presence of pheromones

During this preliminary study, 26 specimens from 8 different snake species were examined. Three methodologies for extraction of skin secretions by immersion of skin in n-hexane were used: immersing the whole body of live individuals for approximately 1 min in the field (n = 13), immersing the whole body of dead specimens (found freshly killed on road) for 24 h (n = 4), and soaking a shed skin for 24 h (n = 9). immersing the whole body of live individuals for approximately 1 min in the field (n = 13), immersing the whole body of dead specimens (found freshly killed on road) for 24 h (n = 4), and soaking a shed skin for 24 h (n = 9). We did not immerse the head and tail to avoid contamination of the samples. All samples were collected during snakes’ active period (February – first half of June) and were analyzed by gas chromatography-mass spectrometry (GC/qMS). Based on the prevalence in the fraction of long-chained hydrocarbons, lipids or lipids with ketones we can separate the samples in three categories. The lipid fractions were present mainly in the shed skin samples, while the long-chained hydrocarbons dominated in the live specimens. According to the literature, ketones are the main component of the snakes’ pheromone communication. We found ketones in five samples, three live and two dead specimens, from five different species (Vipera ammodytes (Linnaeus, 1758), V. berus (Linnaeus, 1758), Dolichophis caspius (Gmelin, 1789), Natrix natrix (Linnaeus, 1758), and Platyceps najadum (Eichwald, 1831)). No ketones were found in the shed skin extracts. Ketones were found only in adults, both males and females. Presence of ketones was observed only for the period from the end of May to the beginning of June. Based on the preliminary results, we can suggest that secretion extraction from live specimens in the field could prove a valuable method in studies on snake pheromones in addition to the already developed methodologies. We speculate that the pheromones are present only in the reproductive and probably post-reproductive period. However, further research with larger sample size is required.

Glucose Metabolism in Cardiac Hypertrophy and Heart Failure.

Glucose Metabolism in Cardiac Hypertrophy and Heart Failure.

Convergent Total Synthesis of Principinol D, a Rearranged Kaurane Diterpenoid.

The total synthesis of principinol D, a rearranged kaurane diterpenoid, is reported. This grayanane natural product is constructed via a convergent fragment coupling approach, wherein the central seven-membered ring is synthesized at a late stage. The bicyclo[3.2.1]octane fragment is accessed by a Ni-catalyzed α-vinylation reaction. Strategic reductions include a diastereoselective SmI2-mediated ketone reduction with PhSH and a new protocol for selective ester reduction in the presence of ketones. The convergent strategy reported herein may be an entry point to the larger class of kaurane diterpenoids.

Review article: Accelerated starvation of childhood: Have I judged ketones?

Acute ketosis is an important physiological mechanism to prevent irreversible neurological damage from hypoglycaemia during starvation, and represents a significant metabolic stress. A cohort of children adapt to relatively short periods of reduced caloric intake by generating large quantities of ketone bodies. When excessive, the gastrointestinal symptoms of starvation ketosis such as nausea and pain may create a vicious cycle that delays spontaneous resolution. The presence of ketones can be dismissed as a normal feature of childhood metabolism, sometimes even when extreme. A broader understanding of this process under the banner of 'accelerated starvation of childhood' is helpful for clinicians managing acute illness in children. We advocate that children less than 7 years of age with a history suggestive of accelerated starvation of childhood should be screened by emergency clinicians for ketosis using a simple and cheap bedside capillary test, even if glucose levels are greater than 2.6 mmol/L. Identification and appropriate management of ketosis may alleviate the distressing gastrointestinal symptoms associated with many minor illnesses, and potentially prevent hypoglycaemia in some children. Appropriate advice to carers may be helpful to prevent further episodes. Illustrative case examples from our own practice are provided.

A New Entry of Highly Selective and Nucleophilic BrH2C‐ and ClH2C‐Titanium Complexes for Carbonyl Coupling

The direct coupling of various aldehydes and ketones with CH2Br2 or CH2Cl2 promoted by TiCl4‐Mg bimetallic complex provides an extremely simple, practical, and efficient approach for the construction of bromomethyl or chloromethyl carbinols. The high chemoselectivity of this chemistry is illustrated by the TiCl4‐Mg‐promoted selective coupling of CH2Br2 or CH2Cl2 with an aldehyde in the presence of ketone and selective transfer of CH2Br or CH2Cl to saturated carbonyl moiety. This protocol is also suitable for sterically hindered and enolizable carbonyl compounds.

Chemoselective reduction of aldehydes via a combination of NaBH4 and acetylacetone

A bench-stable combination of NaBH4–acetylacetone was developed for the efficient chemoselective reduction of aldehydes in the presence of ketones.

Photolysis of Tp'Rh(CNneopentyl)(PhNCNneopentyl) in the presence of ketones and esters: kinetic and thermodynamic selectivity for activation of different aliphatic C-H bonds.

The active fragment [Tp'Rh(CNneopentyl)], generated from the precursor Tp'Rh(CNneopentyl)(PhN[double bond, length as m-dash]CNneopentyl), underwent oxidative addition of substituted ketones and esters resulting in Tp'Rh(CNneopentyl)(R)(H) complexes (Tp' = tris-(3,5-dimethylpyrazolyl)borate). These C-H activated complexes underwent reductive elimination at varying temperatures (24-70 °C) in C6D6 or C6D12. Using previously established kinetic techniques, the relative Rh-C bond strengths were calculated. Analysis of the relative Rh-C bond strengths vs. C-H bond strengths shows a linear correlation with slope RM-C/C-H = 1.22 (12). In general, α-substituents increase the relative Rh-C bond strengths compared to the C-H bond that is broken.

Relationship with pineapple consume the presence of ketones in the urine

Relationship with pineapple consume the presence of ketones in the urine

Green Approach for the Domino Reduction/Reductive Amination of Nitroarenes and Chemoselective Reduction of Aldehydes Using Fe/aq. Citric Acid/Montmorillonite K10

AbstractWe have developed a new and mild method for the direct one‐pot reduction/reductive amination of nitroarenes with arylaldehydes using Fe/aq citric acid/montmorillonite K10 catalytic system under ambient conditions. This catalyst has excellent functional group compatibility and the reaction provides rapid access to a diverse range of secondary amines. Under the conditions, aromatic aldehydes are selectively reduced to benzyl alcohols in the presence of ketones. A concise and efficient approach to the synthesis of diverse range of 1,2‐disubstituted benzimidazoles has also been accomplished for the first time from 1,2‐dinitrobenzene and aromatic aldehydes using the above catalytic system. The method involves the domino nitro reduction/cyclization/reduction cascade.

Access to 3‐(2‐Oxoalkyl)‐azaspiro[4.5]trienones via Acid‐Triggered Oxidative Cascade Reaction through Alkenyl Peroxide Radical Intermediate

AbstractAzaspiro[4.5]trienones bearing ketone side chains at the 3‐position are prepared from N‐alkyl‐arylpropiolamides and ketones via oxidative 1,2‐difunctionalization of alkynes. The cascade sequence starts with the generation of alkenyl peroxide intermediates, which are obtained by addition of tert‐butyl hydroperoxide to ketones in presence of a catalytic amount of a strong acid. Then, the ketone radical adds to alkynes, followed by spirocyclization and dearomatization process. This method represents a new example of difunctionalization of alkynes with simultaneous formation of two carbon−carbon single bonds and one carbon−oxygen double bond in one step.magnified image

Empagliflozin Increases Cardiac Energy Production in Diabetes: Novel Translational Insights Into the Heart Failure Benefits of SGLT2 Inhibitors

SGLT2 inhibitors have profound benefits on reducing heart failure and cardiovascular mortality in individuals with type 2 diabetes, although the mechanism(s) of this benefit remain poorly understood. Because changes in cardiac bioenergetics play a critical role in the pathophysiology of heart failure, the authors evaluated cardiac energy production and substrate use in diabetic mice treated with the SGTL2 inhibitor, empagliflozin. Empagliflozin treatment of diabetic db/db mice prevented the development of cardiac failure. Glycolysis, and the oxidation of glucose, fatty acids and ketones weremeasured in the isolated working heart perfused with 5 mmol/l glucose, 0.8 mmol/l palmitate, 0.5 mmol/l ß-hydroxybutyrate (ßOHB), and 500 μU/ml insulin. In vehicle-treated db/db mice, cardiac glucose oxidation rates were decreased by 61%, compared with control mice, but only by 43% in empagliflozin-treated diabetic mice. Interestingly, cardiac ketone oxidation rates in db/db mice decreased to 45% of the rates seen in control mice, whereas a similar decrease (43%) was seen in empagliflozin-treated db/db mice. Overall cardiac adenosine triphosphate (ATP) production rates decreased by 36% in db/db vehicle-treated hearts compared with control mice, with fatty acid oxidation providing 42%, glucose oxidation 26%, ketone oxidation 10%, and glycolysis 22% of ATP production in db/db mouse hearts. In empagliflozin-treated db/db mice, cardiac ATP production rates increased by 31% compared with db/db vehicle-treated mice, primarily due to a 61% increase in the contribution of glucose oxidation to energy production. Cardiac efficiency (cardiac work/O2 consumed) decreased by 28% in db/db vehicle-treated hearts, compared with control hearts, and empagliflozin did not increase cardiac efficiency per se. Because ketone oxidation was impaired in db/db mouse hearts, the authors determined whether this contributed to the decrease in cardiac efficiency seen in the db/db mouse hearts.Addition of 600 μmol/l ßOHB to db/db mouse hearts perfused with5mmol/l glucose, 0.8 mmol/l palmitate, and100 μU/ml insulin increased ketone oxidation rates, butdidnotdecrease either glucose oxidation or fatty acid oxidation rates. The presence of ketones did not increase cardiac efficiency, but did increase ATP production rates, due tothe additional contribution ofketoneoxidation to energy production. The authors conclude that empagliflozin treatment is associatedwithanincrease in ATP production, resulting in an enhanced energy status of the heart.

A Domino Approach for the Synthesis of α,β‐Epoxy Ketones from Carbonyl Compounds under Neat Conditions at Ambient Temperature

AbstractAn efficient method has been developed for the synthesis of α,β‐epoxy ketones from one pot reaction between aldehydes and ketones in presence of cesium carbonate and tert‐butyl hydrogen peroxide (TBHP) under neat conditions. In this methodology we have used the one pot domino type reaction with aldehydes and ketones to get α,β‐epoxy ketones without presynthesized chalcone precursors. A library of α,β‐epoxy ketones having a variety of substituents has been synthesized. Clean reaction, mild reaction conditions, ease of product isolation/purification, easily accessible reactants, wide substrates scope and metal and solvent‐free and environmental friendly reaction conditions are the notable advantages of the present method. The present methodology is applicable to gram scale synthesis.

Mild and selective reduction of aldehydes utilising sodium dithionite under flow conditions.

We recently reported a novel hybrid batch–flow synthesis of the antipsychotic drug clozapine in which the reduction of a nitroaryl group is described under flow conditions using sodium dithionite. We now report the expansion of this method to include the reduction of aldehydes. The method developed affords yields which are comparable to those under batch conditions, has a reduced reaction time and improved space-time productivity. Furthermore, the approach allows the selective reduction of aldehydes in the presence of ketones and has been demonstrated as a continuous process.

Ketones to Success—Does NICH Involvement Influence DKA Discharge Presentation?

Objective: Youth struggling with diabetes management are at increased risk of DKA. Novel Interventions in Children’s Healthcare (NICH) is designed for youth with T1D who are experiencing or are at high risk of experiencing DKA. Previous findings from smaller samples indicate that youth in NICH are less likely to experience a DKA event and typically experience a shorter average hospital stay. However, counter to physician anecdotes, DKA-related lab values at admission for NICH patients do not differ from labs prior to program involvement. This study aims to determine whether patients in NICH are being discharged when less stable. Methods: Retrospective chart reviews were conducted on 52 youth enrolled and treated with NICH. Data included presence and number of DKA episodes in the year prior to and the year following NICH enrollment, as well as associated lab values at discharge—ketones, blood glucose level, bicarb, and pH. The mean youth age was 14.7 years (SD=3.5); 55.8% were female; and 92.3% were caucasian. Eighteen youth had lab values associated with DKA discharge available both prior to and during NICH. Results: Youth were less likely (p=.001) to experience DKA during NICH (35.3%) than prior to NICH (69.2%) and experienced fewer DKA events (t(51)=3.53; p=.001) during NICH (M=1.0; SD=1.8) than prior (M=1.8; SD=2.1). Regarding discharge presentation, only the presence of ketones indicated a significant difference (t(17)=2.11; p=0.5), with patients in NICH being discharged with trace to small ketones on average while in the program, as opposed to negative to trace ketones prior to program involvement. Conclusions: Youth in NICH experience fewer DKA events and are less likely to experience a DKA during program involvement. In addition, youth are discharged, on average, with a stronger presence of ketones during NICH than prior to program involvement. This may reflect increased medical provider confidence that ketones and associated youth health can be managed at home when NICH providers are involved. Disclosure D.V. Wagner: None. R. Chuong: None. N.C. Koskela: None. H. Luzod: None. E. Beeson: None. I. Guttmann-Bauman: None. M.A. Harris: Consultant; Self; Eli Lilly and Company.

Chemoselective reduction of aldehydes and ketones by potassium diisobutyl-t-butoxy aluminum hydride (PDBBA)

t-Butoxy derivatives of DIBALH [lithium diisobutyl-t-butoxyaluminum hydride (LDBBA), sodium diisobutyl-t-butoxyaluminum hydride (SDBBA), and potassium diisobutyl-t-butoxyaluminum hydride (PDBBA)] were examined as chemoselective reducing agents of carbonyl compounds. Among them, PDBBA was found to be the most efficient for the reduction of aldehydes and ketones to the corresponding alcohols in the presence of ester, amide, and nitrile substituents at ambient temperature. In addition, the optimal conditions gave higher chemoselectivity for aldehydes in the presence of ketones.

Interaction of gabaergic ketones with model membranes: A molecular dynamics and experimental approach

γ-Aminobutyric-acid receptor (GABAA-R), a membrane intrinsic protein, is activated by GABA and modulated by a wide variety of recognized drugs. GABAA-R is also target for several insecticides which act by recognition of a non-competitive blocking site. Mentha oil is rich in several ketones with established activity against various insects/pests. Considering that mint ketones are highly lipophilic, their action mechanism could involve, at least in part, a non-specific receptor modulation by interacting with the surrounding lipids. In the present work, we studied in detail the effect on membranes of five cyclic ketones present in mint plants, with demonstrated insecticide and gabaergic activity. Particularly, we have explored their effect on the organization and dynamics of the membrane, by using Molecular Dynamics (MD) Simulation studies in a bilayer model of DPPC. We performed free diffusion MD and obtained spatially resolved free energy profiles of ketones partition into bilayers based on umbrella sampling. The most favored location of ketones in the membrane corresponded to the lower region of the carbonyl groups. Both hydrocarbon chains were slightly affected by the presence of ketones, presenting an ordering effect for the methylene groups closer to the carbonyl. MD simulations results were also contrasted with experimental data from fluorescence anisotropy studies which evaluate changes in membrane fluidity. In agreement, these assays indicated that the presence of ketones between lipid molecules induced an enhancement of the intermolecular interaction, increasing the molecular order throughout the bilayer thickness.