846-46-8Relevant articles and documents
Miescher,Wettstein
, p. 112,116 (1939)
Kinetic analysis of androstenedione 5α-reductase in epithelium and stroma of human prostate
Weisser, Heike,Krieg, Michael
, p. 589 - 594 (1997)
In the human prostate, various androgen-metabolizing enzymes are present. Among these enzymes, testosterone 5α-reductase seems to be dominant. However androstenedione is also a potential substrate of the prostatic 5α-reductase. To address the question of to what extent the reduction of androstenedione to androstanedione occurs, the present study describes in detail the kinetic characteristics (K(m) and V(max)) and possible age-dependent alterations of this enzymatic step in epithelium and stroma of the human prostate. In normal prostate (NPR), the mean K(m) (nM) and V(max) (pmol/mg protein · h) were about twofold higher in stroma (K(m) 211; V(max), 130) than in epithelium (K(m), 120; V(max), 56), whereas in the benign prostatic hyperplasia (BPH), the mean K(m) (nM; mean ± SEM) and V(max) (pmol/mg protein · h: mean ± SEM) were about sixfold higher in stroma (K(m), 688 ± 121; V(max), 415 ± 73) than in epithelium (K(m), 120 ± 10; V(max), 73 ± 8). In BPH, those differences between epithelium and stroma were highly significant (p 0.001). However, the efficiency ratios (V(max)/K(m)) of neither BPH nor NPR showed any significant differences between epithelium (NPR, 0.47; BPH, 0.62 ± 0.06) and stroma (NPR, 0.70; BPH. 0.63 ± 0.05). With respect to age-related changes, only stroma showed a significant increase of K(m) (P 0.01) and V(max) (p 0.05) with age. In summary, in both epithelium and stroma of the human prostate, a 5α-reductase converts in measurable amounts androstenedione to androstanedione. The kinetic data were, in part, different between epithelium and stroma; the reason for this difference remains unclear. In comparison to other metabolic conversions, such as testosterone to dihydrotestosterone and androstenedione to testosterone, it is unlikely that, in the human prostate, the adrenal androgen androstenedione contributes significantly to the formation of testosterone and, further, of dihydrotestosterone.
A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for aerobic oxidation of alcohols
Zhu, Xianjin,Liu, Can,Liu, Yong,Yang, Haijun,Fu, Hua
, p. 12443 - 12446 (2020/10/30)
A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for the aerobic oxidation of alcohols has been developed for the first time, and the photoredox aerobic oxidation of secondary and primary alcohols provided the corresponding ketones and carboxylic acids, respectively, in high to excellent yields.
Catalytic Acceptorless Dehydrogenation of Aliphatic Alcohols
Fuse, Hiromu,Mitsunuma, Harunobu,Kanai, Motomu
supporting information, p. 4493 - 4499 (2020/03/05)
We developed the first acceptorless dehydrogenation of aliphatic secondary alcohols to ketones under visible light irradiation at room temperature by devising a ternary hybrid catalyst system comprising a photoredox catalyst, a thiophosphate organocatalyst, and a nickel catalyst. The reaction proceeded through three main steps: hydrogen atom transfer from the α-C-H bond of an alcohol substrate to the thiyl radical of the photo-oxidized organocatalyst, interception of the generated carbon-centered radical with a nickel catalyst, and β-hydride elimination. The reaction proceeded in high yield under mild conditions without producing side products (except H2 gas) from various alcohols, including sterically hindered alcohols, a steroid, and a pharmaceutical derivative. This catalyst system also promoted acceptorless cross-dehydrogenative esterification from aldehydes and alcohols through hemiacetal intermediates.
Unified Total Synthesis of Five Bufadienolides
Hagiwara, Koichi,Inoue, Masayuki,Itoh, Hiroaki,Shimizu, Shinsuke
supporting information, (2020/11/13)
We report a unified total synthesis of five bufadienolides: bufalin (1), bufogenin B (2), bufotalin (3), vulgarobufotoxin (4), and 3-(N-succinyl argininyl) bufotalin (5). After the steroidal ABCD ring 8 was produced, the D ring was cross-coupled with a 2-pyrone moiety and stereoselectively epoxidized to generate 6. TMSOTf promoted a stereospecific 1,2-hydride shift from 6 to establish the β-oriented 2-pyrone of 19. Functional group manipulations from 19 furnished 1-5, which potently inhibited cancer cell growth.
