Anthracenes 9-anthracenecarboxylic acid

There are several reports wherein head-head dimers were not formed preferentially in micellar solutions. For example, the syn head-tail simers, 61, the same ones obtained in solution formed when a number of 7-al-koxycoumarins (60) (alkoxy group chain length was varied between methoxy to octadecyloxy) were irradiated in SDS and HDTC1 micelles [194,195], The same head-tail dimers, obtained in solution, were formed when 9-methyl-anthracene and 9-anthracenecarboxylic acid were irradiated in CTAB and... 

To our knowledge, only one report exists in which the formation of carboxylic acid by radical carboxylation with carbon dioxide has been documented. Curran and co-workers observed the formation of 9-anthracenecarboxylic acid in 10% yield, together with 71% yield of anthracene, when the radical reduction of 9-io-doanthracene with the ethylene-spaced fluorous tin hydride was run using supercritical CO2 (90°C, 280 atm) as the reaction media (Scheme 4-41) [69], As demonstrated in this example, the CO2 trapping reaction by radicals is not an efficient process and therefore is of limited synthetic utility. The rate constant for the addition is yet to be determined, but kinetic studies to date indicate that generally the decarboxylation of acyloxyl radicals is a rapid process [70]. 

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