40222-70-6Relevant academic research and scientific papers
IMPROVED PROCESS FOR PREPARING SUBSTITUTED CARBOXYLIC ANHYDRIDES
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Page/Page column 6; 7-8, (2008/12/06)
An improved process for preparing anhydrides of the general formula (I) in which X and Y may be the same or different and are each C, N, O or P, where X and Y, depending on their definition, may be mono- to trisubstituted by a radical from the group of H, a C1-C20-alkyl radical optionally mono- or polysubstituted by groups which are inert under the reaction conditions, or a C5-C10-aryl, C3-C6-heteroaryl or heterocycle radical optionally mono- or polysubstituted by groups which are inert under the reaction conditions, and may optionally be connected by a C1-C5-alkyl chain which may optionally be mono- or polysubstituted by substituents which are inert under the reaction conditions to form a ring system, in which dicarboxylic acids of the formula (II) in which X and Y are each as defined above in a high-boiling organic solvent which forms an azeotrope with water in the presence of an organic or inorganic acid in an amount of from 0.000001 to 50 mol%, based on the dicarboxylic acid, are heated to reflux temperature and water is separated out as an azeotrope, then the reaction mixture is cooled and the desired product is isolated.
Process for producing optically active hemiesters
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, (2008/06/13)
There is disclosed a process for producing an optically active hemiester of formula (1): 1wherein R1, R2 and R5 represent the same meanings as described below, which comprises reacting a cyclic acid anhydride of formula (2): 2wherein R1 and R2 are different and independently represent a hydrogen atom, a halogen atom, an alkyl group optionally substituted with an alkoxy group or a halogen atom, and the like, with a hydroxy compound of formula (3): R3OH ??(3) wherein R3 represents an alkyl group optionally substituted with an alkoxy group, a phenoxy group, a dialkylamino group or a halogen atom and the like, in the presence of an asymmetric catalyst.
