Three water-soluble copper(II) N-heterocyclic carbene complexes: toward copper-catalyzed ketone reduction under sustainable conditions.

A series of tridentate copper(II) N-heterocyclic carbene (NHC) complexes with imidazole, benzimidazole, and 5,6-dimethylbenzimidazole azole rings were synthesized and comprehensively characterized via X-ray crystallography, ESI-MS, cyclic voltammetry, and UV-Vis and EPR spectroscopic studies. These complexes were then utilized for the optimization of ketone reduction under sustainable conditions using 2-acetylpyridine and phenylsilane. The relationships between product formation, temperature, reaction time, and catalyst loading for the hydrogenation reactions are covered in detail. Reduction of eighteen different aliphatic, cyclic, and aromatic ketones were demonstrated, which were compatible to produce the corresponding products in moderate to good yields. These systems were used to develop related DNA-hybrid catalytic systems, but only supported weak enantioselectivity. Further thermodynamic experiments showed Cu-NHC complexes did not demonstrate specific binding to DNA, which is consistent with their limited selectivity.

Copper(II) NHC Catalyst for the Formation of Phenol from Arylboronic Acid.

Arylboronic acids are commonly used in modern organic chemistry to form new C-C and C-heteroatom bonds. These activated organic synthons show reactivity with heteroatoms in a range of substrates under ambient oxidative conditions. This broad reactivity has limited their use in protic, renewable solvents like water, ethanol, and methanol. Here, we report our efforts to study and optimize the activation of arylboronic acids by a copper(II) N-heterocyclic carbene (NHC) complex in aqueous solution and in a range of alcohols to generate phenol and aryl ethers, respectively. The optimized reactivity showcases the ability to make targeted C-O bonds, but also identifies conditions where water and alcohol activation could be limiting for C-C and C-heteroatom bond-forming reactions. This copper(II) complex shows strong reactivity toward arylboronic acid activation in aqueous medium at ambient temperature. The relationship between product formation and temperature and catalyst loading are described. Additionally, the effects of buffer, pH, base, and co-solvent are explored with respect to phenol and ether generation reactions. Characterization of the new copper(II) NCN-pincer complex by X-ray crystallography, HR-MS, cyclic voltammetry, FT-IR and UV-Vis spectral studies is reported.

Adherence to Exercise Prescription and Improvements in the Clinical and Vascular Health of African Americans.

Improvements in indices of vascular health and endothelial function have been inversely associated with hypertension, a risk factor for cardiovascular disease (e.g., myocardial infarction, stroke, and heart failure), renal failure, and mortality. Aerobic exercise training (AEXT) has been positively associated with improvements in clinical health values, as well as vascular health biomarkers, and endothelial function. The purpose of this study was to evaluate whether measures of exercise adherence were related to clinical outcome measures and indices of vascular health subsequent to a 6-month AEXT intervention in a middle-to-older aged African American cohort. Following dietary stabilization, sedentary, apparently healthy, African American adults (40 - 71 y/o) underwent baseline testing including blood pressure, flow-mediated dilation (FMD) studies, fasting blood sampling, and graded exercise testing. Upon completion of a supervised 6-month AEXT intervention, participants repeated all baseline tests. Exercise adherence was measured three ways: exercise percentage, exercise volume, and exercise score. There were no significant correlations between the changes in the vascular health biomarkers of the participants and any of the adherence measures. In addition, there were no significant correlations between any of the adherence measures and the clinical values of the participants that had been significantly changed pre-post-AEXT. Participants improved their clinical and vascular health and decreased risk factors for hypertension and cardiovascular disease regardless of their level of adherence to AEXT. Future studies should continue to accurately quantify adherence in order to assess the exercise dose for improvements in vascular and clinical health.

A standardized exercise intervention differentially affects premenopausal and postmenopausal African-American women.

OBJECTIVE: African-American women represent an understudied population in menopause research yet face greater postmenopausal challenges associated with mortality than their white peers. We investigated the effects of a mild-intensity aerobic exercise training program on markers of mortality risk in both premenopausal and postmenopausal African-American women. METHODS: Sixteen premenopausal women and 19 postmenopausal women underwent 6 months of mild-intensity aerobic exercise training. Measurements included markers of blood lipid and glucose profile, inflammation, kidney function, vascular health, and aerobic fitness before and after the exercise intervention. RESULTS: Before the exercise intervention, the premenopausal and postmenopausal groups only differed in age, low-density lipoprotein, and total cholesterol levels, with the latter two being higher in the postmenopausal group. Both triglycerides and markers of early-stage endothelial dysfunction (CD62E endothelial microparticles) improved in both groups with aerobic exercise training. Aerobic fitness, glomerular filtration rate, body mass index, plasma glucose levels, and markers of late-stage endothelial dysfunction (CD31/CD42b endothelial microparticles) only improved in the premenopausal group. CONCLUSIONS: Mild-intensity aerobic exercise training succeeds in improving some markers of cardiovascular disease and mortality in postmenopausal women. Higher levels of exercise intensity or perhaps additional interventions may need to be considered to further decrease mortality risk in this population.

Endothelial activation microparticles and inflammation status improve with exercise training in african americans.

African Americans have the highest prevalence of hypertension in the world which may emanate from their predisposition to heightened endothelial inflammation. The purpose of this study was to determine the effects of a 6-month aerobic exercise training (AEXT) intervention on the inflammatory biomarkers interleukin-10 (IL-10), interleukin-6 (IL-6), and endothelial microparticle (EMP) CD62E+ and endothelial function assessed by flow-mediated dilation (FMD) in African Americans. A secondary purpose was to evaluate whether changes in IL-10, IL-6, or CD62E+ EMPs predicted the change in FMD following the 6-month AEXT intervention. A pre-post design was employed with baseline evaluation including office blood pressure, FMD, fasting blood sampling, and graded exercise testing. Participants engaged in 6 months of AEXT. Following the AEXT intervention, all baseline tests were repeated. FMD significantly increased, CD62E+ EMPs and IL-6 significantly decreased, and IL-10 increased but not significantly following AEXT. Changes in inflammatory biomarkers did not significantly predict the change in FMD. The change in VO2 max significantly predicted the change in IL-10. Based on these results, AEXT may be a viable, nonpharmacological method to improve inflammation status and endothelial function and thereby contribute to risk reduction for cardiovascular disease in African Americans.