Selective microbial hydroxylation and biological rearrangement of taxoids

Conversion of 7‐deoxy‐10‐deacetylbaccatin‐III into 6‐α‐hydroxy‐7‐deoxy‐10‐deacetylbaccatin‐III byNocardioides luteus

“…Hydroxylation of taxadienes by filamentous fungi at the 6‐position and other positions has been reported by Hu and co‐workers [36–42]; however, fungal hydroxylation of taxanes having an oxetane ring was not reported. Hydroxylation of paclitaxel by a Streptomyces sp.…”

Regio‐ and stereoselective hydroxylation of taxoids by filamentous fungi

“…Among these cultures, A. coerula appears to be the most efficient strain based on TLC and HPLC analysis. 6 Under the standard incubation conditions, when taxoid 1 was used as the substrate it was readily converted by A. coerula to 1b-hydroxylated metabolite 1 in good yield (58%) and 9a-hydroxylated derivative 1b in modest yield (8%) (Scheme 1). The 9b-hydroxylated products were not detected from the reaction mixture.…”

“…Our previous results also confirmed that microbial transformation of taxoid 5 regio-and stereoselectively produced 1b-hydroxylated metabolites in modest yield. 6 In order to compare Scheme 1.…”

“…In contrast, 5-acetoxy taxoid 5 is a good substrate and can be readily converted to the 1b-hydroxylated product in modest yield (12%) and two other products. 6 In addition, unreacted substrate was largely recovered from the supernatant and the mycelia. Furthermore, we have shown that taxoids 2 and 6 are not substrates for this microorganism (Fig.…”

“…Taxoids 3À6 were prepared as previously described. 6,7 Growth Conditions and General Biotransformation Procedure…”