80141-07-7Relevant articles and documents
The Structure and Synthesis of the Novel Orchid Pigments Dengibsin and Dengibsinin
Sargent, Melvyn V.
, p. 2553 - 2564 (2007/10/02)
The structures of the orchid pigments dengibsin and dengibsinin have been revised to 2,5-dihydroxy-4-methoxy-9H-fluoren-9-one (4) and 3,5-dihydroxy-2,4-dimethoxy-9H-fluoren-9-one (5).The synthesis of these compounds is described.It has been found that 2'-methoxybiphenyl-2-carboxylic acids, on treatment with trifluoroacetic anhydride or oxalyl chloride, undergo cyclization giving 6H-dibenzopyran-6-ones.