Synthesis of haemofluorone B trimethyl ether

Abstract

The revision of the structure of haemofluorone B to 5,8,9-trihydroxy- 3H-naphtho[2,1,8-mna]xanthen-3-one is confirmed by the synthesis of its trimethyl ether by photochemical oxidative cyclization of 9-(3,4- dimethoxyphenyl)-4-hydroxy-2-methoxy-1H-phenalen-1-one. The conventional process for conjugate arylation of phenalenones has been improved by the use of aryllithium reagents.