Acylation by carbonyl chlorides

Boiling chloroacetyl chloride with pyrocatechol and phosphoryl chloride in benzene gives co-chloro-3,4-dihydroxyacetophenone in 85% yield.526 para-Acylation of acetanilide in 79-83% yield has been effected by chloroacetyl chloride and aluminum chloride in carbon disulfide.548 

Diketones can be obtained by use of dicarbonyl dichlorides, e.g., 1,6-di-phenyl- 1,6-hexanedione in 81% yield from adipoyl dichloride.549 For the use of oxalyl bromide see page 980. 

Ester chlorides of dicarboxylic acids, e.g., ethoxalyl chloride afford aryl-glyoxalic esters 550,551 

Kindler, W. Metzendorf, and Dschi-yin-Kwok, Ber. Deut. Chem. Ges., 76, 308 (1943). 

Because it appears as a neutral product, the methyl ester chloride of phthalic acid has various advantages over the anhydride for preparation of aroylbenzoic acids and esters 552 reaction times are shorter, the required temperatures are lower, yields are good, and the products are more easily isolated. 

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