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991.
Jean-Ulrich Mullot Sara Karolak Anne Fontova Bruno Huart Yves Levi 《Analytical and bioanalytical chemistry》2009,394(8):2203-2212
Pollution of the environment by pharmaceuticals is a subject of growing scientific and societal concern. However, few quantitative
data have been reported concerning hospital wastewater contamination. Among the different molecules used at hospital, antineoplastic
drugs appear to be of special interest, and 5-fluorouracil (5-FU) can be considered as a key compound of this therapeutic
class. To monitor this pharmaceutical in hospital wastewater, a highly specific and selective method was developed using gas
chromatography tandem mass spectrometry after solid-phase extraction. This sensitive method (limit of quantification = 40 ng L−1) was then applied to assess sewage contamination of a middle-size hospital with oncology service located in Paris, France.
Native 5-FU was detectable in 12 of the 14 analysed samples. In positive samples, concentration range was measured from 0.09
to 4.0 μg L−1. Finally, a predicting model for the hospital wastewater concentrations is presented, and results of this model are discussed. 相似文献
992.
The reactivity of different Co(2)(CO)(6)-acetylene complexes in the Pauson-Khand reaction is strongly dependent on the nature of the olefin. Theoretical calculations at both the DFT and ONIOM levels are concordant with experimental observations and suggest how the olefin-cobalt interactions in the complex could have a major effect on the relative reactivity of the olefins. This study rationalizes for the first time the experimentally observed reactivity differences of cyclohexene, cyclopentene, and norbornene. 相似文献
993.
John M. Beierle W. Seth Horne Dr. Jan H. van Maarseveen Prof. Dr. Beatrice Waser Jean Claude Reubi Prof. Dr. M. Reza Ghadiri Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(26):4725-4729
A would‐be amide : A 1,4‐disubstituted 1,2,3‐triazole was used as a surrogate for a trans amide bond to create a library of 16 diastereomeric pseudotetrapeptides as β‐turn mimetics. High‐resolution structural analysis indicated that these scaffolds adopt distinct, rigid, conformationally homogeneous β‐turn‐like structures (see example), some of which bind somatostatin receptor subtypes selectively, and some of which show broad‐spectrum activity.
994.
Anaïs Geny Dr. Nicolas Agenet Dr. Laura Iannazzo Max Malacria Prof. Dr. Corinne Aubert Dr. Vincent Gandon Dr. 《Angewandte Chemie (International ed. in English)》2009,48(10):1810-1813
Cobalt cyclopentadienyl complexes incorporating a fumarate and a CO ligand (see picture) efficiently catalyze inter‐ and intramolecular [2+2+2] cycloadditions of alkynes, nitriles, and/or alkenes to give benzenes, pyridines, or 1,3‐cyclohexadienes. Unlike catalysts such as [CpCo(CO)2] or [CpCo(C2H4)2] (Cp=C5H5), they are air‐stable, easy to handle, compatible with microwave conditions, and do not necessarily require irradiation to be active.
995.
Liuqing Yang Marco Hill Dr. Meitian Wang Dr. Santosh Panjikar Dr. Joachim Stöckigt Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(28):5211-5213
Cutting carbons : The three‐dimensional structure of polyneuridine aldehyde esterase (PNAE) gives insight into the enzymatic mechanism of the biosynthesis of C9‐ from C10‐monoterpenoid indole alkaloids (see scheme). PNAE is a very substrate‐specific serine esterase. It harbors the catalytic triad S87‐D216‐H244, and is a new member of the α/β‐fold hydrolase superfamily. Its novel function leads to the diversification of alkaloid structures.
996.
Katharina Landfester Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(25):4488-4507
The miniemulsion process allows the formation of complex polymer nanoparticles and the encapsulation of widely varying materials into a polymer shell (see examples). Functionalization of the nanoparticles can be easily carried out, and polymerization to form polymer nanoparticles can be performed in environmentally friendly solvents, such as water.
997.
David Coquière Dr. Jeffrey Bos Joris Beld Gerard Roelfes Dr. 《Angewandte Chemie (International ed. in English)》2009,48(28):5159-5162
Site creation : Enantioselective artificial metalloenzymes have been created by grafting a new active site onto bovine pancreatic polypeptide through the introduction of an amino acid capable of coordinating a copper(II) ion. This hybrid catalyst gave good enantioselectivities in the Diels–Alder and Michael addition reactions in water (see scheme) and displayed a very high substrate selectivity.
998.
Yasushi Yokoyama Prof. Dr. Tatsuya Shiozawa Yutaka Tani Dr. Takashi Ubukata Dr. 《Angewandte Chemie (International ed. in English)》2009,48(25):4521-4523
Into my arms : Photochemical cyclization of diarylethenes that have two chiral side arms showed up to 100 % de (see scheme). Introduction of these chiral side arms onto the carbon atoms where ring closure occurs is a general strategy for the highly diastereoselective cyclization of diarylethenes.
999.
Yoshihito Kayaki Dr. Masafumi Yamamoto Takao Ikariya Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(23):4194-4197
Getting a fix : N‐heterocyclic carbenes (NHCs) and NHC–CO2 adducts serve as potent organocatalysts for carbonate synthesis by the addition of a CO2 unit to propargylic alcohols or epoxides under mild and solvent‐free reaction conditions (see scheme). The enhanced Lewis basicity of imidazol‐2‐ylidenes bearing electron‐donating alkyl groups on the nitrogen atoms leads to utilizing CO2 as a nucleophilic fragment in the chemical fixation processes.
1000.
Israel Fernández Dr. Gernot Frenking Prof. Dr. Einar Uggerud Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(9):2166-2175
Myths of steric hindrance : In contrast with current opinion, energy decomposition analysis shows that the presence of bulky substituents at carbon leads to the release of steric repulsion in the transition state shown in the graphic. It is rather the weakening of the electrostatic attraction, and in particular the loss of attractive orbital interactions, that are responsible for the activation barrier.