Tetramethyl 1,3 cyclobutanedione, reaction with aluminum chloride

Tetramethyl-1,3-cyclobutanedione, reaction with aluminum chloride, 48,72... 

The isomerization is usually complete in 5 hours and can easily be followed by vapor-phase chromatography. Heating periods up to 20 hours are not detrimental. The only failure among numerous preparations occurred when tetramethyl-1,3-cyclobutanedione contaminated with 4% of isobutyric acid was used. In case of partial conversion after 5 hours, additional increments (0.5 g.) of aluminum chloride should be added to complete the reaction. 

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See also in sourсe #XX -- [ , ]

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