Mechanistic aspects of rearrangement of 16alpha-hydroxy-17-keto steroids to the 17beta-hydroxy-16-keto isomers

The mechanistic aspects of the alkali-catalyzed rearrangement of 16alpha-hydroxy-17-keto steroid 1 to 17beta-hydroxy-16-keto steroid 2 are elucidated by use of (18)O- and deuterium-labeling experiments. The (18)O-labeling experiments refute the gem-hydration-quasi-diaxial dehydration mechanism for the rearrangement previously proposed and support the conventional enolization mechanism. Moreover, equilibrium by gem-hydration-dehydration occurs at the C-17 carbonyl more efficiently than at the C-16 carbonyl. Enolization rate of a carbonyl group at C-16 of 17beta-ketol 2 toward the C-17 position (k(16,17)) was about 8-10 times higher than those of 16alpha-ketol 1 toward the C-16 position (k(17,16)) and ketol 2 toward the C-15 position (k(16,15)). The marked deuterium-isotope effect on each enolization was observed with k(H)/k(D) ranging between 5.4 and 8.8. The present findings reveal that the initial hydration-dehydration equilibration at the C-17 carbonyl of ketol 1 followed by enolization of the carbonyl gives the ene-diol intermediate that isomerizes quantitatively to the 16-keto isomer of which the 16-carbonyl moiety enolizes preferentially toward the C-17 position rather than the C-15 position, yielding the ene-diol. Computational calculations of ground state energies of ketols 1-M and 2-M, trans-cyclohexane/cyclopentane structures, and their activation energies in the rearrangement support the dynamic aspects of the rearrangement as well as the kinetics data of the enolization.     

梨头霉11α—羟基化制备16β—甲基—11α,17α21—三烃基孕甾—1, …

选育到一株对１６β－甲基－１７α,２１－二羟基孕甾－１,４＝－二烯－３,２０－二酮（Ⅱａ）１１α－羟基化活性强的梨头霉Ａ２８菌株,并发现底物２１－乙酰化（Ⅱｂ）可明显提高１１α－羟工 能力。在适宜的转化条件下,１１ｂ投料浓度０．５％,产物１６β－基１１α,１７α,２１－三羟基孕甾－１,４－二烯－３,２０－二酮（Ⅲ）收率为７３％,结构经波谱分析确认。     

Synthesis of 16 alpha,19-dihydroxy-4-androstene-3,17-dione and 3 beta,16 alpha,19-trihydroxy-5-androsten-17-one and their 17 beta-hydroxy-16-keto isomers

3 beta,16 alpha,19-Trihydroxy-5-androsten-17-one and 16 alpha,17-dihydroxy-4-androstene-3,17-dione were synthesized from the 5 alpha-bromo-6 beta,19-epoxy-17-ketone derivative 1, using the bromination at C-16 alpha of the 17-ketone 1 and the controlled alkaline hydrolysis of the 16 alpha-bromo-17-ketones 2 and 11 as key reactions. Zinc dust reductive cleavage of the 6 beta,19-epoxy-16 alpha-hydroxy-17-ketones 4 and 12, produced by controlled hydrolysis, gave the corresponding 19-alcohol derivatives 6 and 14, which were rearranged to the 17 beta-hydroxy-16-ketones 7 and 15 when treated with sodium hydroxide. The 3 beta,16 alpha,17 beta,19-tetrol 8 was obtained from the 16 alpha-ketol 6 by reaction with sodium borohydride.     

A simple radioimmunoassay for plasma cortisol and 11-deoxycortisol (17, 21-dihydroxy-4-pregnene-3, 20-dione).

A simple procedure for the measurement of cortisol and 11-deoxycortisol in plasma or serum is described. One-half ml. of plasma is extracted with methylene chloride. Separation of cortisol and deoxycortisol is achieved by a Sephadex LH-20 mini-column. The assay itself is achieved by the use of a commercially available cortisol kit employing rabbit anti-cortisol coated tubes. This antibody exhibits a 20% crossreactivity with 11-deoxycortisol. This procedure is extremely useful in the assessment of a pituitary-adrenal reserve in the Metyrapone test.     

Synthesis of 5,17-dihydroxy-5 alpha, 17 alpha,-19-norpregn-20-yn-3-one, a major photodegradation product of norethindrone

A convenient synthesis of 5,17-dihydroxy-5 alpha,17 alpha-19-norpregn-20-yn-3-one in multigram quantities from norethindrone is reported. Confirmation of the structural assignment of this major photodegradation product of norethindrone is thus made.     

Structure determination of 3 beta, 17-dihydroxy-17 alpha-pregn-5-ene-20-one

The title compound was synthesized as part of an effort to determine the identity of an abnormal steroid metabolite present in the urine of a patient exhibiting pronounced gynecomastia. The X-ray investigation of the synthesized compound showed that the 20-carbonyl of the 17 alpha oriented side chain lies under the D ring, and does not participate in hydrogen bonding in the crystal lattice. This conformation appears to be stable and sufficiently shielded that it is unlikely to make a major contribution to possible protein interactions.     

Highly efficient synthesis of steroid-17-spiro-5'-oxazolidine-2',4'-diones from 17-keto steroids

Spiro[androst-4-en-17 alpha,5'-oxazolidine]-2',3,4'-trione 8a and spiro[androst-4-en-17 alpha,5'-oxazolidine]-2',3,4',11-tetraone 8b, two potentially bioactive spiranes, were prepared from the parent 17-ketones in four steps (64% and 49.5% yield, respectively). The key intermediates were the hydroxyimidates 5a and 5b, which easily underwent cyclization to the corresponding spirooxazolinone 4'-enol ethers when treated with alkylchlorocarbonates. The respective N-amyl derivatives of the spiranes 8a and 8b were obtained with n-pentyl bromide in the presence of KF. A new method for the synthesis of steroid 17 alpha-hydroxy-17-carboxyesters and 17 alpha-hydroxy-17-carboxamides is described. Attempts to synthesize the title compounds from these products were unsuccessful.     

Reduction of 17-keto steroids by anaerobic microorganisms isolated from human fecal flora

The 17-keto function of phenolic steroids is reduced by the following intestinal bacteria: Eubacterium lentum, Clostridium paraputrificum, Clostridium J-1 and Clostridium innocuum. The 17-keto group of androstenedione is reduced solely by Bacteroides fragilis.     

Isolation of 20 alpha and 20 beta 5 beta-pregnane-3 alpha,17 alpha,20,21-tetrol (hexahydro-Reichstein's compound-S) in a case of congenital adrenal hyperplasia

5β-Pregnane-3α, 17α, 20α, 21-tetrol (l) and 5β-pregnane-3α, 17α 20β, 21-tetrol (II) have been isolated and identified from the urine of a girl with congenital adrenal hyperplasia. The total 5β-pregnane-3α, 17α, 20(α+β),21-tetrol consisted of 60% of I and 40% of II. The final identity of the compounds was established by gas chromatography — mass spectrometry. The mass spectra of the two trimethylsilyl isomers were closely related to each other in contrast to the spectra of five other pairs of C₂₁-C-20(α and β)-hydroxy steroid-trimethylsilyl-ethers. The mass spectra of free I and II also exhibited many common features, but were less similar to each other than their trimethylsilyl derivatives.