Synthesis and mass spectrometry of some methoxylated PCB
摘要:
The syntheses of 46 methoxy-polychlorobiphenyls (MeO-CBs), containing 3 to 7 chlorine atoms, are described. The MeO-CBs were synthesized via the Cadogan diaryl coupling reaction of the appropriate polychloroaniline and polychloroanisole, or via the Ullmann coupling of a polychloroiodobenzene and 4-iodoanisole with subsequent chlorination of the isolated 4-MeO-CB product. The synthesized MeO-CBs were characterized by electron ionization (EI) mass spectrometry (MS) on an ion trap MS instrument and by EI and negative ion chemical ionization (NICI) on a quadrupole mass spectrometer.Both instruments gave similar EI spectra but the fragments were in general more abundant relative to the molecular ion, in the spectra obtained from the ion trap instrument. Characteristic fragmentation patterns were obtained by EI for ortho-, meta- and para-MeO-CBs, respectively, depending on the position of the MeO-group, with the exception of three meta-substituted MeO-heptaCBs, with a 3-MeO-2,4,6-trichloro-substitution pattern, that gave an abundant [M-15](+)-fragment, similar to para-substituted MeO-CBs. MS(NICI) of ortho-, meta- and para-MeO-CBs did not give any characteristic fragmentation patterns depending on the position of the MeO-group, except for ortho-substituted MeO-CBs that showed abundant fragments at [M-36]. The MS(NICI) gave approximately 10-50 times higher response for MeO-tetraCBs - MeO-heptaCBs than the MS(EI). The ion trap instrument (ITS40) has a somewhat lower detection-limit than the quadrupole MS when operated in the EI-mode.
Hydroxylated polychlorinatedbiphenyls (PCBs) have been identified in wildlife and human samples. Most of these compounds are highly chlorinated (penta-hepatachloro) and contain a single meta- or para-hydroxyl group. Using the Cadogan coupling procedure, the following hydroxy-PCBs congeners were synthesized: 2,3,3',4',5-pentachloro-4-biphenylol, 2,3',4,4',5-pentachloro-3-biphenylol, 2',3,3',4',5-p
METHODS FOR TREATING TRANSTHYRETIN AMYLOID DISEASES
申请人:Kelly Jeffery W.
公开号:US20100120919A1
公开(公告)日:2010-05-13
Kinetic stabilization of the native state of transthyretin is an effective mechanism for preventing protein misfolding. Because transthyretin misfolding plays an important role in transthyretin amyloid diseases, inhibiting such misfolding can be used as an effective treatment or prophylaxis for such diseases. Treatment methods are disclosed.