
%0 Journal Article
%A Armarego, WLF 
%T The Synthesis of 5,7-Dichlorocoumaran-3-one and Related Problems
%J Australian Journal of Chemistry
%D 1960/03/01
%V 13
%N 1
%P 95-102
%K 
%R https://doi.org/10.1071/CH9600095
%U https://www.publish.csiro.au/paper/CH9600095 
%X 5,7-Dichlorocoumaran-3-one has been prepared from methyl 2-hydroxy-3,5-dichlorobenzoate by a three stage synthesis.   It could not be prepared by (i) intramolecular cyclization of 2,4-dichlorophenoxy- acetic acid or 2,4-dichlorophenoxyacetyl chloride or (ii) by the reaction of &#969;-bromo-2-hydroxy-3,5-dichloroacetophenone with bases.   The reaction of 2,4-dichlorophenoxyacetic acid with phosphorus pentoxide in benzene gave 2,4-dichlorophenol, 2',4'-dichlorophenyl 2,4-dichlorophenoxyacetate, and diphenylmethane. By the use of 14C-labelled acids the methylene carbon atom of the diphenylmethane was shown to be derived from the methylene carbon atom of 2,4-dichlorophenoxyacetic acid. A possible mechanism is proposed for this reaction. 
