Synthesis of enantiomerically pure amino-substituted fused bicyclic rings
申请人:——
公开号:US20030114679A1
公开(公告)日:2003-06-19
This invention describes various processes for synthesis and resolution of racemic amino-substituted fused bicyclic ring systems. One process utilizes selective hydrogenation of an amino-substituted fused bicyclic aromatic ring system. An alternative process prepares the racemic amino-substituted fused bicyclic ring system via nitrosation. In addition, the present invention describes the enzymatic resolution of a racemic mixture to produce the (R)- and (S)-forms of amino-substituted fused bicyclic rings as well as a racemization process to recycle the unpreferred enantioner. Further provided by this invention is an asymmetric synthesis of the (R)- or (S)-enantiomer of primary amino-substituted fused bicyclic ring systems.
Substituted pyridines from isoxazoles: scope and mechanism
作者:Seokjoo Lee、Rashmi Jena、Aaron L. Odom
DOI:10.1039/d2ob00779g
日期:——
Treatment of isoxazoles with enamines leads to an inverse electron-demand hetero-Diels–Alder reaction that produces substitutedpyridines in the presence of TiCl4(THF)2 and titanium powder. The reaction is highly regioselective with only a single isomer of the product observed by GC/MS and tolerant of many common functional groups. The transformation was examined computationally, and it was found that
Synthesis of 6-substituted 2-(N-acetylamino)pyridines and 2-aminopyridines by cyclization of 5-oximinoalkanenitriles
作者:Robert J. Vijn、Henricus J. Arts、Peter J. Maas、Anna M. Castelijns
DOI:10.1021/jo00056a021
日期:1993.2
Oxime derivatives of 5-oxoalkanenitriles (C6 chain or longer) were cyclized in most cases with a combination of AcCl and Ac2O, or Ac2O and HCl to 6-substituted 2-(N-acetylamino)pyridines. hydrolysis gave the corresponding 2-aminopyridines in overall yields of 40-65 %, with the exception of pyridine 3e. Oxime derivatives of 5-oxopentanenitriles did not cyclize but gave glutaronitriles instead. In some experiments with 5-oximinohexanenitrile(1a),2,4-dimethyl-5-(2-cyanoethyl)oxazole (9)was detected in addition to the main product, 2-(N-acetylamino)-6-methylpyridine(2a). Formation of these compounds can be explained on the basis of a common intermediate 7 formed through rearrangement of the O-acetylated 5-oximinohexanenitrile (4).
EP1487795A4
申请人:——
公开号:EP1487795A4
公开(公告)日:2005-02-09
SYNTHESIS OF ENANTIOMERICALLY PURE AMINO-SUBSTITUTED FUSED BICYCLIC RINGS