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1.
Chemical and physical analyses of malt, the main ingredient of beer, have been used to predict the concentration of certain volatile compounds in the finished beer.The prediction was done by means of the partial least squares regression (PLS2) in SIMCA. The total data set as well as individual malt clusters were submitted to PLS analysis. Best prediction was obtained by separating the total object matrix in classes according to similarity found by fuzzy pattern recognition (FCV). FCV was also used to separate the beer variables in classes and to select the subset of variables to be predicted.A joint approach of fuzzy pattern recognition to identify groups of samples and SIMCA-PLS2 to predict several dependent variables is suggested as a powerful tool in process-analytical chemistry. 相似文献
2.
Straightforward α‐Amino Nitrile Synthesis Through Mo(CO)6‐Catalyzed Reductive Functionalization of Carboxamides 下载免费PDF全文
Dr. Paz Trillo Dr. Tove Slagbrand Prof. Dr. Hans Adolfsson 《Angewandte Chemie (International ed. in English)》2018,57(38):12347-12351
The selective reduction of amides into an intermediate hemiaminal catalyzed by Mo(CO)6 together with the inexpensive and easy to handle TMDS (1,1,3,3‐tetramethyldisiloxane) as reducing agent, followed by subsequent trapping of the hemiaminal with a cyanide source, allows for the straightforward synthesis of α‐amino nitriles. The methodology presented here, displays high levels of chemoselectivity allowing for the reduction of amides in the presence of functional groups such as ketones, imines, aldehydes, and acids, which affords a simple route for the synthesis of α‐amino nitriles with a broad scope of functionalities in high yields. Furthermore, the applicability of this methodology is demonstrated by scale up experiments and by derivatization of the target compounds into synthetically interesting products. The selective cyanation is successfully applied in late stage functionalizations of amide containing drugs and prolinol derivatives. 相似文献
3.
Nilsen LT Hannevik M Aalerud TN Johnsen B Friberg EG Veierød MB 《Photochemistry and photobiology》2008,84(5):1100-1108
Abstract Indoor tanning increases skin cancer risk, but the importance of different parts of the UV spectrum is unclear. We assessed irradiance of tanning devices in Norway for the period 1983-2005. Since 1983, all tanning models needed approval before being sold or used. UV Type 3 limits were valid from late 1992 (<0.15 W m(-2) for CIE-weighted, i.e. erythemally weighted, short and long wave irradiances). We analyzed data from 90% of the approved tanning models (n = 446 models) and two large inspection surveys in 1998/1999 and 2003 (n = 1341 tanning devices). Mean CIE-weighted short wave irradiance of approved models increased from 0.050 W m(-2) (95% confidence interval [CI] 0.045-0.055) in 1983-1992 to 0.101 W m(-2) (95% CI 0.098-0.105) in 1993-2005, and mean long wave from 0.091 W m(-2) (95% CI 0.088-0.095) to 0.112 W m(-2) (95% CI 0.109-0.115), respectively. Inspection surveys revealed short wave irradiances much higher than that approved. In 1998-1999, only 28% (293/1034) of the devices were equipped with correct sunlamps and only 1 out of 130 inspected establishments fulfilled all requirements. In 2003, corresponding numbers were 59% (180/307) of devices and 2 out of 52 establishments. Mean short and long wave irradiances of the inspected tanning devices in 2003 were 1.5 and 3.5 times, respectively, higher than the irradiance of natural summer sun in Oslo. In conclusion, the short wave irradiance has increased in indoor tanning devices in Norway over the last 20 years. Due to the high long wave irradiance throughout this period, the percentage of short wave irradiance was much lower than for natural sun. 相似文献
4.
Johansson T Weidolf L Jurva U 《Rapid communications in mass spectrometry : RCM》2007,21(14):2323-2331
The extent to which electrochemical oxidation, electrochemically assisted Fenton chemistry and synthetic metalloporphines can be used to mimic cytochrome P450 catalyzed oxidations has been investigated for a large range of metabolic reactions. Most relevant metabolic oxidations can be mimicked by at least one of the three investigated systems. The EC oxidation system successfully mimics benzylic hydroxylation, hydroxylation of aromatic rings containing electron-donating groups, N-dealkylation, S-oxidation, dehydrogenation and less efficiently N-oxidation and O-dealkylation. The EC-Fenton system is able to mimic aliphatic hydroxylation, benzylic hydroxylation, aromatic hydroxylation, N-dealkylation, N-oxidation, O-dealkylation, S-oxidation and dehydrogenation. The porphine system mimics all types of reactions although the yields are low for some reactions. In conclusion, these three complementary systems can be used during the drug discovery and development of new drugs to elucidate the structure of metabolites that are difficult to characterize in biological matrices. Moreover, such techniques can replace the classical chemistry strategy, especially when synthesis is complicated or too time-consuming in order to access metabolites for further testing. 相似文献
5.
Early experiences in establishing a regional quantitative imaging network for PET/CT clinical trials
Robert K. Doot Tove Thompson Benjamin E. Greer Keith C. Allberg Hannah M. Linden David A. Mankoff Paul E. Kinahan 《Magnetic resonance imaging》2012
The Seattle Cancer Care Alliance (SCCA) is a Pacific Northwest regional network that enables patients from community cancer centers to participate in multicenter oncology clinical trials where patients can receive some trial-related procedures at their local center. Results of positron emission tomography (PET) scans performed at community cancer centers are not currently used in SCCA Network trials since clinical trials customarily accept results from only trial-accredited PET imaging centers located at academic and large hospitals. Oncologists would prefer the option of using standard clinical PET scans from Network sites in multicenter clinical trials to increase accrual of patients for whom additional travel requirements for imaging are a barrier to recruitment. In an effort to increase accrual of rural and other underserved populations to Network trials, researchers and clinicians at the University of Washington, SCCA and its Network are assessing the feasibility of using PET scans from all Network sites in their oncology clinical trials. A feasibility study is required because the reproducibility of multicenter PET measurements ranges from approximately 3% to 40% at national academic centers. Early experiences from both national and local PET phantom imaging trials are discussed, and next steps are proposed for including patient PET scans from the emerging regional quantitative imaging network in clinical trials. There are feasible methods to determine and characterize PET quantitation errors and improve data quality by either prospective scanner calibration or retrospective post hoc corrections. These methods should be developed and implemented in multicenter clinical trials employing quantitative PET imaging of patients. 相似文献
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Anders Lennartson Tove Wiklund Mikael Hkansson 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(12):m550-m552
The title compound, [CuCl2(C6H7NO)2], was synthesized during a study of conformationally chiral square‐planar coordination compounds. The coordination geometry deviates from the square‐planar geometry generally adopted by copper(II) chloride complexes with pyridine ligands towards a tetrahedral arrangement of ligands. The complex is conformationally chiral but crystallizes in a centrosymmetric space group with both enantiomers present in the unit cell. 相似文献
8.
Novel glutathione conjugates of phenyl isocyanate identified by ultra‐performance liquid chromatography/electrospray ionization mass spectrometry and nuclear magnetic resonance 下载免费PDF全文
Tove Johansson Mali'n Sandra Lindberg Crister Åstot 《Journal of mass spectrometry : JMS》2014,49(1):68-79
Phenyl isocyanate is a highly reactive compound that is used as a reagent in organic synthesis and in the production of polyurethanes. The potential for extensive occupational exposure to this compound makes it important to elucidate its reactivity towards different nucleophiles and potential targets in the body. In vitro reactions between glutathione and phenyl isocyanate were studied. Three adducts of glutathione with phenyl isocyanate were identified using ultra‐performance liquid chromatography/electrospray ionization mass spectrometry and nuclear magnetic resonance (NMR). Mass spectrometric data for these adducts have not previously been reported. Nucleophilic attack on phenyl isocyanate occurred via either the cysteinyl thiol group or the glutamic acid α‐amino group of glutathione. In addition, a double adduct was formed by the reaction of both these moieties. NMR analysis confirmed the proposed structure of the double adduct, which has not previously been described. These results suggest that phenyl isocyanate may react with free cysteines, the α‐amino group and also with lysine residues whose side chain contains a primary amine. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
9.
Chemoselective Reduction of Tertiary Amides under Thermal Control: Formation of either Aldehydes or Amines 下载免费PDF全文
Dr. Fredrik Tinnis Alexey Volkov Tove Slagbrand Prof. Dr. Hans Adolfsson 《Angewandte Chemie (International ed. in English)》2016,55(14):4562-4566
The chemoselective reduction of amides in the presence of other more reactive reducible functional groups is a highly challenging transformation, and successful examples thereof are most valuable in synthetic organic chemistry. Only a limited number of systems have demonstrated the chemoselective reduction of amides over ketones. Until now, the aldehyde functionality has not been shown to be compatible in any catalytic reduction protocol. Described herein is a [Mo(CO)6]‐catalyzed protocol with an unprecedented chemoselectivity and allows for the reduction of amides in the presence of aldehydes and imines. Furthermore, the system proved to be tunable by variation of the temperature, which enabled for either C?O or C?N bond cleavage that ultimately led to the isolation of both amines and aldehydes, respectively, in high chemical yields. 相似文献
10.
Tove Johansson Mali'n Lars Weidolf Neal Castagnoli Jr. Ulrik Jurva 《Rapid communications in mass spectrometry : RCM》2010,24(9):1231-1240
The metabolites formed via the major metabolic pathways of haloperidol in liver microsomes, N‐dealkylation and ring oxidation to the pyridinium species, were produced by electrochemical oxidation and characterized by ultra‐performance liquid chromatography/electrospray ionization mass spectrometry (UPLC/ESI‐MS). Liver microsomal incubations and electrochemical oxidation in the presence of potassium cyanide (KCN) resulted in two diastereomeric cyano adducts, proposed to be generated from trapping of the endocyclic iminium species of haloperidol. Electrochemical oxidation of haloperidol in the presence of KCN gave a third isomeric cyano adduct, resulting from trapping of the exocyclic iminium species of haloperidol. In the electrochemical experiments, addition of KCN almost completely blocked the formation of the major oxidation products, namely the N‐dealkylated products, the pyridinium species and a putative lactam. This major shift in product formation by electrochemical oxidation was not observed for the liver microsomal incubations where the N‐dealkylation and the pyridinium species were the major metabolites also in the presence of KCN. The previously not observed dihydropyridinium species of haloperidol was detected in the samples, both from electrochemical oxidation and the liver microsomal incubations, in the presence of KCN. The presence of the dihydropyridinium species and the absence of the corresponding cyano adduct lead to the speculation that an unstable cyano adduct was formed, but that cyanide was eliminated to regenerate the stable conjugated system. The formation of the exocyclic cyano adduct in the electrochemical experiments but not in the liver microsomal incubations suggests that the exocyclic iminium intermediate, obligatory in the electrochemically mediated N‐dealkylation, may not be formed in the P450‐catalyzed reaction. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献