1963-03-7Relevant articles and documents
Microbial transformation of dehydroepiandrosterone (DHEA) by some fungi
Yildirim, Kudret,Kuru, Ali,Y?lmazer Keskin, Semra,Ergin, Sinan
, p. 465 - 474 (2020/11/12)
In this work, biotransformations of dehydroepiandrosterone (DHEA) 1 by Ulocladium chartarum MRC 72584, Cladosporium sphaerospermum MRC 70266 and Cladosporium cladosporioides MRC 70282 have been reported. U. chartarum MRC 72584 mainly hydroxylated 1 at C-7α and C-7β, accompanied by a minor hydroxylation at C-4β, a minor epoxidation from the β-face and a minor oxidation at C-7 subsequent to its hydroxylations. 3β,7β-Dihydroxy-5β,6β-epoxyandrostan-17-one 6, 3β,4β,7α-trihydroxyandrost-5-en-17-one 7 and 3β,4β,7β-trihydroxyandrost-5-en-17-one 8 from this incubation were identified as new metabolites. C. sphaerospermum MRC 70266 converted some of 1 into a 3-keto-4-ene steroid and then hydroxylated at C-6α, C-6β and C-7α, accompanied a minor 5α-reduction and a minor oxidation at C-6 following its hydroxylations. C. sphaerospermum MRC 70266 also hydroxylated some of 1 at C-7α and C-7β. C. cladosporioides MRC 70282 converted almost half of 1 into a 3-keto-4-ene steroid and then hydroxylated at C-6α and C-6β. C. cladosporioides MRC 70282 also reduced some of 1 at C-17.
Sensitized Aliphatic Fluorination Directed by Terpenoidal Enones: A "visible Light" Approach
Bume, Desta Doro,Harry, Stefan Andrew,Pitts, Cody Ross,Lectka, Thomas
, p. 1565 - 1575 (2018/02/09)
In our continued effort to address the challenges of selective sp3 C-H fluorination on complex molecules, we report a sensitized aliphatic fluorination directed by terpenoidal enones using catalytic benzil and visible light (white LEDs). This sensitized approach is mild, simple to set up, and an economical alternative to our previous protocol based on direct excitation using UV light in a specialized apparatus. Additionally, the amenability of this protocol to photochemical flow conditions and preliminary evidence for electron-transfer processes are highlighted.
Regio- and stereoselective reduction of 17-oxosteroids to 17β-hydroxysteroids by a yeast strain Zygowilliopsis sp. WY7905
Liu, Yuanyuan,Wang, Yu,Chen, Xi,Wu, Qiaqing,Wang, Min,Zhu, Dunming,Ma, Yanhe
, p. 17 - 24 (2016/12/22)
The reduction of 17-oxosteroids to 17β-hydroxysteroids is one of the important transformations for the preparation of many steroidal drugs and intermediates. The strain Zygowilliopsis sp. WY7905 was found to catalyze the reduction of C-17 carbonyl group of androst-4-ene-3,17-dione (AD) to give testosterone (TS) as the sole product by the constitutive 17β-hydroxysteroid dehydrogenase (17β-HSD). The optimal conditions for the reduction were pH 8.0 and 30 °C with supplementing 10 g/l glucose and 1% Tween 80 (w/v). Under the optimized transformation conditions, 0.75 g/l AD was reduced to a single product TS with >90% yield and >99% diastereomeric excess (de) within 24 h. This strain also reduced other 17-oxosteroids such as estrone, 3β-hydroxyandrost-5-en-17-one and norandrostenedione, to give the corresponding 17β-hydroxysteroids, while the C-3 and C-20 carbonyl groups were intact. The absence of by-products in this microbial 17β-reduction would facilitate the product purification. As such, the strain might serve as a useful biocatalyst for this important transformation.
