The free acid I1 was characterized through the crystalline methyl and ethyl esters 111 and IV. The structure of the product was proved by saponification of the methyl ester, followed by decarboxylation with copper chromite in boiling quinoline to 5-methylbenzpyrene, which was shown to be identical with an authentic sample, 6 prepared by reduction of the 5- aldehyde6 by the modified'Wolff-Kishner procedure. Irradiation of thioglycolic acid and ...
