A method of the preparation of N-hydroxy aspartic acid derivate
申请人:HOECHST CELANESE CORPORATION
公开号:EP0452094A2
公开(公告)日:1991-10-16
The present invention pertains to a method of preparing substituted and unsubstituted N-hydroxy-2-aminobutane diacid derivatives which can be dehydrated to 2-aminobut-2-ene dioic acid derivatives, which can be subsequently converted to pyridine and quinoline derivatives.
Conversion of pyridine-2,3-dicarboxylic acid esters to their cyclic anhydrides
申请人:HOECHST CELANESE CORPORATION
公开号:EP0564083A1
公开(公告)日:1993-10-06
In one embodiment this invention provides a process for converting a pyridine-2,3-dicarboxylic acid diester to the corresponding cyclic anhydride directly, without any recovery and purification of the pyridine-2,3-dicarboxylic acid intermediate.
An important aspect of the invention process is the utility of pure pyridine-2,3-dicarboxylic acid diester starting matter. A procedure for providing pure diester starting material is demonstrated.