Detail of "823-96-1"

Reference

Detection of inhaled clenbuterol in horse urine by GC/MS/MS

Detection of inhaled clenbuterol in horse urine by GC/MS/MS. Van Eenoo, P.; Delbeke, F. T.; Deprez, P. (Doping Control Unit, Department of Pharmacology, Pharmacy and Toxicology, Ghent University, Merelbeke B-9820, Belg.). 21898-19-1 and 823-96-1 are also occured in this study. Biomedical Chromatography, 16(7), 475-481 (English) 2002 John Wiley & Sons Ltd. CODEN: BICHE2. ISSN: 0269-3879. DOCUMENT TYPE: Journal CA Section: 4 (Toxicology) Section cross-reference(s): 1 Clenbuterol, a b-adrenergic agonist, is used in the treatment of recurrent airway obstruction in horses. It is prohibited by horse racing authorities, because of its stimulating and growth-promoting properties. However, information on detection times of clenbuterol after administration by nebulization is lacking. In this study, a fast, sensitive quant. GC/MS/MS method for the detection of clenbuterol in urine was developed. Alk. liq.-liq. extn. was followed by derivatization to a cyclic Me boronate deriv. and anal. on a Finnigan MAT GCQ instrument. Method validation showed good linearity in the range 0.1-2.0 ng/mL, excellent repeatability and specificity. The limit of quant. detection of the method was 0.1 ng/mL. Different instrumental parameters of the ion trap mass spectrometer were changed to increase the no. of diagnostic ions for the cyclic Me boronate deriv. of clenbuterol. The influence of these changes and their applicability within the requirements and the criteria for mass spectrometry set by the responsible regulatory bodies are discussed. Clenbuterol was administered via nebulization to five standardbred mares (0.4 mg/kg body wt.). Anal. of the urine samples resulted in the detection of clenbuterol, as early as 2 h post administration and for up to 36 h post treatment. Generally, max. urinary concns. of 1.2 ng/mL were reached after 6-9 h. .

Development of 4,4'-substituted-XylBINAP ligands for highly enantioselective hydrogenation of ketones

Development of 4,4'-substituted-XylBINAP ligands for highly enantioselective hydrogenation of ketones.Some chemicals with cas registry numbers like 823-96-1 are also used. Ngo, Helen L.; Lin, Wenbin (Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA). Journal of Organic Chemistry, 70(4), 1177-1187 (English) 2005 American Chemical Society. CODEN: JOCEAH.Chemical with cas number 823-96-1 also plays role. ISSN: 0022-3263. DOCUMENT TYPE: Journal CA Section: 25 (Benzene, Its Derivatives, and Condensed Benzenoid Compounds) Section cross-reference(s): 75, 78 A family of 4,4'-substituted-xylBINAPs was synthesized in multistep sequences and characterized by NMR spectroscopy and mass spectrometry. Ru(diphosphine)(diamine)Cl2 complexes based on these 4,4'-substituted-xylBINAPs and chiral diamines (DPEN and DAIPEN) were synthesized by treatment of [(benzene)RuCl2]2 with 4,4'-substituted-xylBINAP followed by chiral diamine, and characterized by 1H and 31P NMR spectroscopy and mass spectrometry. These Ru complexes were used for asym. hydrogenation of arom. ketones in a highly enantioselective manner with complete conversion. With very low catalyst loading, complete conversion and excellent enantioselectivity obtained for most of the arom. ketones examd. A single-crystal X-ray diffraction study of Ru[(R)-L4][(R,R)-DPEN]Cl2 indicated that the 4-Me group of the naphthyl ring and the Me groups of the two xylyl moieties form a fence on the opposite side of the DPEN ligand of the Ru center. These three Me groups will have significant repulsive interactions with the bulky aryl ring of the hydrogen-bonded arom. ketone in the disfavored transition state. These results supported the hypothesis of combining dual modes of enantiocontrol (i.e., the substituents on 4,4'-positions of the binaphthyl framework and the Me groups on the bis(xylyl)phosphino moieties) to achieve higher stereoselectivity in the hydrogenation of arom. ketones. ..