A revised structure for (-)-dihydropertusaric acid, a gamma-butyrolactone acid from the lichen punctelia microsticta
The gamma-butyrolactone acid (1) and two known compounds, (-)-isomuronic acid and the tridepside gyrophoric acid, have been isolated from the lichen Punctelia microsticta. The structure and stereochemistry of compound 1 were determined on the basis of spectroscopic evidence and molecular modeling. Spectroscopic and physical data of 1 and (-)-dihydropertusaric acid, previously isolated from the lichen Pertusaria albescens, showed that both are the same compound, although for the latter the epimeric structure 2 has been proposed.
Maier
MS
Departamento de Quimica Organica and Departamento de Ciencias Biologicas, Facultad de Ciencias Exactas y Naturales, Pabellon 2, Ciudad Universitaria, 1428 Buenos Aires, Argentina.
Gonzalez Marimon DI
Stortz
CA
Adler
MT