Transannular Ozonides of 9-Alkoxyanthracenes

Article abstract of DOI:10.1021/jo00223a012

Ozonation of 9-alkoxyanthracenes in methanol at -78 deg C leads to transannular ozonides 7, most of which can be isolated in crystalline form.On warming in CH2Cl2, ozonides 7 undergo around -30 deg C a decomposition with O2 release leading mainly to 10-alkoxy-9-anthrones 8.The radical character of this decomposition is established, in the case of 9-methoxy-10-methylanthracene ozonide (7e), by adding H donors such as 2,4,6-tri-tert-butylphenol or hydroquinone, which direct the process toward formation of 10-hydroperxy-10-methyl-9-anthrone (2a).