Synthesis and Attempted 2H Labeling of 2,4-Positions of 1,3, 8- Trihydroxynapthalene, An Intermediate of Fungal Melanin Biosynthesis

Abstract

1, 3, 8 - Trihydroxynaehthalene (T3HN), an intermediate of fungal melanin biosynthesis was successfully synthesized using 3,5- dimethoxybanzoic acid as the starting material. 2-and 4- positions ofT3HN was attempted to label with deuterium as it is expected to be important to study the stereochemistry of the reduction of 1,3- dihydroxy ring ofT3HN. The study showed that similar to H-2 and H-4 protons of 1, 3, 6, 8 - tetrahydroxynapthalene (another intermediate offungal melanin biosynthesis) those of T3HN also rapidly exchange with the protons in the medium and T3HN does exist as an equilibrium mixture or tautomeric forms in pH 7 buffered aqueous solution. Hence stereochemical study of reduction of T3HN using 2-and 4-deuteratcd T3HN was impossible.