Alkoxyallene‐Based LANCA Three‐Component Synthesis of 1,2‐Diketones, Quinoxalines, and Unique Isoindenone Dimers and a Computational Study of the Isoindenone Dimerization

A series of β‐alkoxy‐β‐ketoenamides was prepared by the well‐established LANCA three‐component reaction of lithiated 1‐(2‐trimethylsilylethoxy)‐substituted allenes, nitriles, and α,β‐unsaturated carboxylic acids. The α‐tert‐butyl‐substituted compounds were smoothly converted into the expected 1,2‐diketones by treatment with trifluoroacetic acid. A subsequent condensation of the 1,2‐diketones with o‐phenylenediamine provided the desired highly substituted quinoxalines in good overall yield. Surprisingly, the α‐phenyl‐substituted β‐alkoxy‐β‐ketoenamides investigated afford not only the expected 1,2‐diketones, but also pentacyclic compounds with an anti‐tricyclo[4.2.1.12,5]deca‐3,7‐diene‐9,10‐dione core. These interesting products are very likely the result of an isoindenone dimerization which was mechanistically studied with the support of DFT calculations. Under the strongly acidic reaction conditions, a stepwise reaction is likely leading to a protonated isoindenone as reactive intermediate. It may first form a van der Waals complex with a neutral isoindenone before the two regio‐ and diastereoselective ring forming steps occur. Interestingly, two neutral or two protonated isoindenones are also predicted to dimerize giving the observed pentacyclic product

Managing Water Supply in Turbulent Times

2008 S.C. Water Resources Conference - Addressing Water Challenges Facing the State and Regio

High-sensitivity tool for studying phonon related mechanical losses in low loss materials

Fundamental mechanical loss mechanisms exist even in very pure materials, for instance, due to the interactions of excited acoustic waves with thermal phonons. A reduction of these losses in a certain frequency range is desired in high precision instruments like gravitational wave detectors. Systematic analyses of the mechanical losses in those low loss materials are essential for this aim, performed in a highly sensitive experimental set-up. Our novel method of mechanical spectroscopy, cryogenic resonant acoustic spectroscopy of bulk materials (CRA spectroscopy), is well suited to systematically determine losses at the resonant frequencies of the samples of less than 10^(-9) in the wide temperature range from 5 to 300 K. A high precision set-up in a specially built cryostat allows contactless excitation and readout of the oscillations of the sample. The experimental set-up and measuring procedure are described. Limitations to our experiment due to external loss mechanisms are analysed. The influence of the suspension system as well as the sample preparation is explained.Comment: 4 pages, 3 figures, proceedings of PHONONS07, submitted to Journal of Physics: Conference Serie

Influence of a six month endurance exercise program on the immune function of prostate cancer patients undergoing Antiandrogen or Chemotherapy: design and rationale of the ProImmun study

Background: Exercise seems to minimize prostate cancer specific mortality risk and treatment related side effects like fatigue and incontinence. However the influence of physical activity on the immunological level remains uncertain. Even prostate cancer patients undergoing palliative treatment often have a relatively long life span compared to other cancer entities. To optimize exercise programs and their outcomes it is essential to investigate the underlying mechanisms. Further, it is important to discriminate between different exercise protocols and therapy regimes. Methods/Design: The ProImmun study is a prospective multicenter patient preference randomized controlled trial investigating the influence of a 24 week endurance exercise program in 80–100 prostate cancer patients by comparing patients undergoing Antiandrogen therapy combined with exercise (AE), Antiandrogen therapy without exercise (A), Chemotherapy with exercise(CE) or Chemotherapy without exercise (C). The primary outcome of the study is a change in prostate cancer relevant cytokines and hormones (IL-6, MIF, IGF-1, Testosterone). Secondary endpoints are immune cell ratios, oxidative stress and antioxidative capacity levels, VO2 peak, fatigue and quality of life. Patients of the intervention group exercise five times per week, while two sessions are supervised. During the supervised sessions patients (AE and CE) exercise for 33 minutes on a bicycle ergometer at 70-75% of their VO2 peak. To assess long term effects and sustainability of the intervention two follow-up assessments are arranged 12 and 18 month after the intervention. Discussion: The ProImmun study is the first trial which primarily investigates immunological effects of a six month endurance exercise program in prostate cancer patients during palliative care. Separating patients treated with Antiandrogen therapy from those who are additionally treated with Chemotherapy might allow a more specific view on the influence of endurance training interventions and the impact of different therapy protocols on the immune function. Trial registration: German Clinical Trials Register: DRKS0000473