THE PREPARATION OF ALPHA,ALPHA-DISUBSTITUTED GLYCOLIC ACIDS

Several methods for the synthesis of glycolic acids of the type RR'C(OH)CO2H, in which R and R' are aryl, alkyl, or cycloalkyl groups (equal or different), were investigated to find a practicable route not requiring use of Grignard reagents. Benzilic acid, 9-fluorenol-9 -carboxylic acid, a...

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Bibliographic Details
Main Authors: Proper, Reuben, hoffmann, Friedrich W
Format: Report
Language:English
Subjects:
ACETIC ACID
ALCOHOLS
ALKYNES
AMINES
AROMATIC COMPOUNDS
CARBOXYLIC ACIDS
GLYCOLIC ACIDS
KETONES
Organic Chemistry
POTASSIUM COMPOUNDS
SUBSTITUTION REACTIONS
SYNTHESIS(CHEMISTRY)
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Summary:Several methods for the synthesis of glycolic acids of the type RR'C(OH)CO2H, in which R and R' are aryl, alkyl, or cycloalkyl groups (equal or different), were investigated to find a practicable route not requiring use of Grignard reagents. Benzilic acid, 9-fluorenol-9 -carboxylic acid, and potassium 4,4'-di-(dimethylamino) benzilate were obtained in yields of 82.5%, 93.4%, and 45.5%, respectively, by the carbonation in dioxane of benzophenone disodioketyl, fluorenone disodioketyl, and dipotassioketyl of 4,4'di-(dimethylamino) benzophenone(Michler's ketone). The conversion of 1,1-di-(parachlorophenyl)-1, 2,2,2-tetrachloroethane to 4,4'dichlorobenzil in a 98.5% yield was effected by the action of sulfuric acid at from 65 degrees to 75 degrees C. A :(% yield of 4,4'-dichlorobenzilic acid was obtained by the benzilic acid rearrangement of 4, 4'-dichlorobenzil. Cyclopentylphenylglycolic acid in 30% yield resulted from oxidation of 1-cyclopentyl-1-phenyl-2-propyn-1-o1. This method is unsatisfactory, however, because of poor yield and hazards encountered in the preparation of the propynol from acetylene and ketone. With desired-product yield only 18%, the synthesis of a mixed acyloin (as a glycolic acid precursor) was unsatisfactory when aqueous potassium cyanide acted on an equimolar mixture of an acyloin and a benzoil.