The 13 NMR singles for some 4‐substituted phenacylchlorides and iodides were assigned. The carbonyl carbons exhibit upfield shifts compared with those of the corresponding 4‐substituted acetophenones; in the chlorinated derivatives a downfield shift is observed for the α‐methylene carbons, while a reverse effect occurs in the iodinated compounds. The chemical shifts of the aromatic ring carbons are
Prostaglandin endoperoxide H synthase biosynthesis inhibitors
申请人:Black Lawrence A.
公开号:US20090042888A1
公开(公告)日:2009-02-12
The present invention describes pyridazinone compounds of formula I
which are cyclooxygenase (COX) inhibitors, and in particular, are selective inhibitors of cyclooxygenase-2 (COX-2). COX-2 is the inducible isoform associated with inflammation, as opposed to the constitutive isoform, cyclooxygenase-1 (COX-1) which is an important “housekeeping” enzyme in many tissues, including the gastrointestinal (GI) tract and the kidneys. The selectivity of these compounds for COX-2 minimizes the unwanted GI and renal side-effects seen with currently marketed non-steroidal anti-inflammatory drugs (NSAIDs).
A practical method for the asymmetric transferhydrogenation of α‐substituted ketones was developed utilizing oxo‐tethered N‐sulfonyldiamine‐ruthenium complexes. Reduction by HCO2H and HCO2K in a mixed solvent of EtOAc/H2O allowed for the selective synthesis of halohydrins from 2‐bromoacetophenone (98%) and 2‐chloroacetophenone (>99%), leading to suppressed undesired side reactions stemming from formylation