Microbial hydroxylation of benzoxazoles containing fluorine atoms in the aromatic ring -: tracing of the products by 19F NMR

2-Cyclopentyl- and 2-cyclohexyl-6-fluorobenzoxazole were prepared and microbially hydroxylated employing Cunninghamella blakesleeana DSM 1906 and Bacillus megaterium CCM 2037. The conversions mimic those previously observed with benzoxazoles not containing fluorine atoms. The fluorinated substrates have the advantage that the course of hydroxylation and in addition any side reactions, can be investigated by F-19 NMR spectroscopy. F-19 NMR spectra could be measured directly from the fermentation samples which had neither been extracted nor chromatographed, consequently minimising the loss of any material. (C) 1998 Elsevier Science B.V. All rights reserved.