Importance of oxygen functions in the biological hydroxylation of flavonoids by Absidia blackesleeana

1. The synthesis and microbiological transformation of 2-phenyl-1-tetralone (compound 3, 1-deoxyisoflavanone), 3-phenyl-l-tetralone (compound 4, 1-deoxyflavanone), 2-phenylchroman (compound 7, 4-deoxyflavanone), 3-phenylchroman (compound 8, 4-deoxyisoflavanone) and 1,2-dihydro-3-phenylnaphthalene (compound 10, 1,4-dideoxy-dehydroflavanone) by Absidia blackesleeana are described.2. Compounds 3, 4, 7 and 8 were hydroxylated at the 4′-position while compound 10 was not utilized as a substrate. The two phenylchroman analgoues 7 and 8 gave approximately the same yield (22% and 26%, respectively) of the 4′-hydroxylation products, while the phenyltetralone analogues 3 and 4 showed significant differences in 4′-hydroxylation (2% and 47%, respectively).