Chemical process

3-Isochromanone is prepared by partially chlorinating o-tolylacetic acid with sulphuryl chloride or chlorine gas in an inert organic solvent in the presence of a free radical initiator. The 2-chloromethylphenylacetic acid first obtained is converted to 3-isochromanone by treatment with a base and se...

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Bibliographische Detailangaben
Hauptverfasser: BENNIE COLIN J, JONES RAYMOND V.H, WHITTON ALAN J, BUGNON PASCAL, RITCHIE DAVID J
Format: Patent
Sprache:eng
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Beschreibung
Zusammenfassung:3-Isochromanone is prepared by partially chlorinating o-tolylacetic acid with sulphuryl chloride or chlorine gas in an inert organic solvent in the presence of a free radical initiator. The 2-chloromethylphenylacetic acid first obtained is converted to 3-isochromanone by treatment with a base and separated from unreacted o-tolylacetic acid, which is in the form of a salt, by a phase separation technique. The separated o-tolylacetic acid salt is converted to o-tolylacetic acid by controlled acidification and the o-tolylacetic acid is extracted for re-use. The invention reduces the formation of unwanted, over-chlorinated by-products and leads to a more efficient process.