Zobrazeno 1 - 10
of 62
pro vyhledávání: '"Dirk Courtheyn"'
Autor:
Dirk Courtheyn, Bruno Le Bizec, Bert Matthijs, Geert Janssens, Sven Mangelinckx, Norbert De Kimpe
Publikováno v:
Journal of Agricultural and Food Chemistry. 63:7574-7581
The administration of synthetic homologues of naturally occurring steroids can be demonstrated by measuring (13)C/(12)C isotopic ratios of their urinary metabolites. Gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-
Autor:
Geert Janssens, Sven Mangelinckx, Geert De Poorter, Fabrice Monteau, Bruno Le Bizec, Norbert De Kimpe, Emmanuelle Bichon, Dirk Courtheyn, Stéphanie Prévost
Publikováno v:
Analytica Chimica Acta. 772:1-15
Although substantial technical advances have been achieved during the past decades to extend and facilitate the analysis of growth promoters in cattle, the detection of abuse of synthetic analogs of naturally occurring hormones has remained a challen
Autor:
Bruno Le Bizec, Dirk Courtheyn, Sven Mangelinckx, Bert Matthijs, Norbert De Kimpe, Geert Janssens
Publikováno v:
Journal of chromatography. A. 1449
Currently, no analytical method is available to demonstrate progesterone administration in biological samples collected in rearing animals, and therefore, tracking the abuse of this popular growth promoter is arduous. In this study, a method is prese
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 89:441-458
A method is described for the synthesis of α,α-dichloroaldehydes, free from monochloroaldehyde, by chlorination of aldehydes or alcohols in dimethylformamide at 40–90°C. Results are reported for: (yield %) propanal (90), butanal (78), pentanal (
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 86:55-63
Reaction of dimethyl 2-bromo-2-methylpropylidene malonate with various nucleophiles mainly afforded dimethyl cyclopropane 1,1-dicarboxylates while treatment with amines gave substitution products.
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 89:1043-1059
Selective chlorination methods were elaborated for the conversion of cyclopentanone into 2, 2, 5, 5-tetrachloro-, 2, 2, 3, 5, 5-pentachloro- and 2, 2, 3, 3, 5, 5-hexachlorocyclopentanone. Dimethylformamide-hydrogen chloride mixtures served as catalys
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 87:215-222
Heating of dialkyl 2-bromoalkylidenemalonates in boiling xylene resulted in lactonization with formation of 2-alkoxycarbonyl-2-buten-4-olides. Bromination of dimethyl 2-phenylpropylidenemalonate with NBS in CCI4 gave the corresponding butenolide. How
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 90:837-846
Efficient procedures for the synthesis of 3,3,5-trimethyl-1,2,4-cyclopentanetrione are described starting from the commercially available ketones 2,2,4-trimethylcyclopentanone, 2,4,4-trimethylcyclopentanone and 3,3,5-trimethylcyclohexanone. The metho
Publikováno v:
Bulletin des Sociétés Chimiques Belges. 92:371-396
Reactions of allylic halides bearing two electron-withdrawing groups in γ-position with various nucleophiles (alkoxides, phenoxide, thiolates and cyanide) gave rise to substituted electrophilic cyclopropanes or ring-opening products, depending upon
Autor:
Dirk Courtheyn, W. Gillis, K. Verheyden, Herlinde Noppe, H.F. De Brabander, P. Vanthemsche, Virginie Mortier, M Vandewiele, B. Le Bizec
Publikováno v:
Analytica Chimica Acta. 586:57-72
Regularly new anabolic steroids appear on the black market. In most cases these substances are marketed on websites or are confiscated during inspections. 1,(5alpha)-Androstene-17beta-ol-3-one, also known as 1-testosterone, is one of these substances