20820-77-3Relevant articles and documents
PROCESS FOR THE PREPARATION OF DIALKYL 3-OXOGLUTARATES
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Page 20-26, (2010/02/09)
This invention relates to a process for the preparation of 3-oxoglutarates of general formula (I), wherein R stands for methyl or ethyl. Said process comprises reacting citric acid of the formula (II) or the monohydrate thereof with chlorosulphonic acid in a lower chlorinated aliphatic hydrocarbon and reacting the intermediate thus obtained with methanol or ethanol by applying a ratio of lower chlorinated aliphatic hydrocarbon to chlorosulphonic acid in the range of 0,1:1 to 1:1 by volume and carrying out the addition of citric acid to the mixture of chlorosulphonic acid and lower aliphatic hydrocarbon at a rate of 1 - 2 kg/minute. The dialkyl 3-oxoglutarates are valuable pharmaceutical intermediates.