K. Ichinose et al., Mechanistic studies on the biomimetic reduction of tetrahydroxynaphthalene, a key intermediate in melanin biosynthesis, CHEM PHARM, 49(2), 2001, pp. 192-196
1,3,6,8-Tetrahydroxynaphthalene (T4HN) is an aromatic polyketide, serving a
s a general precursor of fungal melanin. Melanin biosynthesis involves two
consecutive deoxygenations of T4HN, consisting of the reduction of a phenol
ic carbon followed by dehydration. The first reduction to produce scytalone
was studied in a biomimetic reduction with sodium borohydride. The reducti
on required a strong alkaline condition, leading to the tautomerization of
T4HN to a reactive species whose structure was clarified bit NMR spectrosco
py.