An efficient method for the synthesis of methyl 11α-amino-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate

The synthesis of methyl 11α-azido-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate, methyl 11β-azido-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate and methyl 11α-amino-3α,7α-diacetoxy-12-oxo-5β-cholan-24-oate have been achieved. Mechanistic aspects for the decomposition of steroidal azidoketones to its enamines are discussed.     

Synthesis of a Key Intermediate for the Synthesis of Pyranocoumarins. Contrasting Reactivity in the 1,2-and 1,4-Reduction of an Unsaturated Carbonyl System

[2,2-dimethyl-4-(t-butyldimethylsiloxy)-3,4-dihydro-2H-pyran-6-yl] methanal (1) was synthesized from commercially available butopyronoxyl (2). The selectivity of reducing agents such as DIBAL-H and LiAlH₄ towards butopyronoxyl was studied. Solvent effects were found to influence 1,2 versus 1,4 reduction.     

The structural elucidation of two new artificial steroidal saponins

Two novel steroidal saponins(timosaponin BⅢ-a,timosaponin BⅢ-b) together with a known steroidal saponin(timosaponin BⅡ-b) were prepared by the dilute acid hydrolysis of timosaponin BⅢ.Their structures were elucidated by means of 1D,2D NMR and TOF-MS spectral analysis.     

Separation and purification of steroidal saponins from Paris polyphylla by microwave‐assisted extraction coupled with countercurrent chromatography using evaporative light scattering detection

A method of microwave‐assisted extraction coupled with countercurrent chromatography using evaporative light scattering detection was successfully developed for the separation and purification of steroidal saponins from Paris polyphylla. The main extraction conditions including microwave power, liquid/solid ratio, irradiation time, and extraction temperature were optimized using an orthogonal array design method. A suitable two‐phase solvent system consisting of n‐heptane/n‐butanol/acetonitrile/water (10:19:6:20, v/v/v/v) was employed in the separation and purification of the extracts of P. polyphylla. A total of 7.1 mg polyphyllin VII, 4.3 mg gracillin, 9.2 mg dioscin, and 10.2 mg polyphyllin I were obtained from 1.5 g P. polyphylla in less than 300 min, the purities of which determined by HPLC were 96.7, 97.3, 98.7, and 98.6%, respectively. The identification and characterization of these compounds were performed by LC–ESI‐MS and ¹H NMR spectroscopy. The results demonstrated that the proposed method is feasible, economical and efficient for the extraction, separation and purification of effective compounds from natural products.     

Steroidal cyclobutanones

Cycloaddition of dichloroketene and 3-, 7-, 17-, and 20-methylene steroids affords the corresponding cyclobutaneones in yields reflecting the steric crowding around the reacting olefinic double bond.

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Steroid-Cyclobutaneone (Kurz Mitteilung)

Zusammenfassung Cycloaddition von Dichlorketen an 3-, 7-, 17- und 20-Methylen-Steroide ergab die jeweiligen Cyclobutanonderivate in Ausbeuten, die den sterischen Gegebenheiten rund um die reagierenden olefinischen Doppelbindungen entsprechen.

     

Visual authentication of steroidal saponins in Allium macrostemon Bge. and Allium chinense G. Don using MALDI-TOF imaging mass spectrometry and their structure activity relationship

Allium macrostemon Bge. (AMB) and Allium chinense G. Don (ACGD), both named Allii Macrostemonis Bulbus or Xiebai in Chinese, belong to the same genus. They are both used as edible vegetables and medicinal herbs for the treatment of atherosclerosis. So far, comparative analysis of the spatial metabolomes and platelet aggregation function of steroidal saponins has rarely been performed. In this study, high mass resolution matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF MSI) were performed on the fresh bulbs of these two herbs for the spatial distribution of steroidal saponins, and ultra-high-performance liquid chromatography tandem triple quadrupole mass spectrometry (UHPLC/TQD-MS) was used to quantify their content levels. Platelet inhibitory activity induced by arachidonic acid, adenosine diphosphate and collagen were fully investigated. A total of 53 differential variables with compounds were identified or tentatively characterized between AMB and ACGD samples by UHPLC/TQD-MS. Furthermore, these steroidal saponins were almost distributed in tunic and outer scale regions of AMB, while they were rich in tunic and whole leaf scale, and rarely in developing flower bud of ACGD bulbs. Quantitative results demonstrated several saponins were the unique components for AMB (macrostemonoside I, timosaponin B-II, macrostemonoside F, etc.) and ACGD (chinenoside I, chinenoside II, chinenoside IV, etc.). Moreover, spirostanol saponins exhibited stronger inhibitory platelet activity than furostanol saponins, and the structure activity relationship was further summarized. In conclusion, high-mass resolution MALDI full-scan MSI provides abundant spatial distribution information of steroidal saponins in AMB and ACGD. And we finished the discussion of their activity characteristics. These findings would benefit the understanding of safety and effectiveness for their edible and medicinal use.     

Ionic hydrogenation-directed stereoselective construction of C-20(H) stereogenic center in steroid side chains: Scope and limitations

Stereoselective synthesis of steroidal C-20 tertiary alcohols with n-butyl, vinyl, furyl, thienyl, thiazolyl, aryl and pyridyl side chains via Grignard reaction or organolithium reagents have been realized starting from readily available 16-dehydropregnenolone acetate. The ionic hydrogenation of steroidal C-20 tertiary alcohols having furyl, methylfuryl, thienyl, phenyl and 4-methoxyphenyl side chains, resulted into the deoxygenated product with C-20 natural configuration in excellent yields. However, the alkyl, thiazolyl and pyridyl incorporated steroidal C-20 tertiary alcohols were failed under the same reaction condition. The scope of ionic hydrogenation is further highlighted through the stereoselective reduction of steroidal C-20,21-ene compounds with furyl, thienyl and 4-methoxyphenyl side chains gave the saturated compounds with C-20 natural configuration.     

Polyhydroxypregnane Glycosides from the Roots of Cynanchum otophyllum

Six new polyhydroxypregnane glycosides, namely cynotophyllosides A–F ( 1 – 6 ), together with five known steroids, were isolated from the roots of Cynanchum otophyllum. Their structures were elucidated by extensive spectroscopic methods (especially 2D‐NMR techniques) and acid‐catalyzed hydrolysis. Furthermore, high field 1D‐ and 2D‐NMR experiments were employed to elucidate the structure of 8 previously deduced only on the basis of LC/MS data.     

Separation by capillary zone electrophoresis of the active anthraquinone components of the Chinese herbPolygonum multiflorum Thunb

Summary An optimization strategy was applied to explore the capability of hybrid micellar eluents of sodium dodecyl sulphate (SDS), using acetonitrile or pentanol as modifiers, to resolve mixtures of eleven steroids showing a wide range of hydrophobicity (clostebol acetate, dehydrotestosterone, dydrogesterone, medroxyprogesterone, medroxyprogesterone acetate, methandienone, methyltestosterone, progesterone, testosterone, testosterone enanthate and testosterone propionate). The accurate prediction of the retention behaviour of the steroids, with relative errors in the 0.8–1.7% and 0.4–2.9% ranges for SDS-acetonitrile and SDS-pentanol eluents, respectively, demonstrated the reliability of the methodology. Acetonitrile and pentanol had a complementary effect in these analyses. The elution strength of acetonitrile was weaker, but allowed higher efficiencies. A 0.094 M SDS-16% acetonitrile eluent separated seven steroids (dehydrotestosterone, dydrogesterone, medroxyprogesterone, medroxyprogesterone acetate, methandienone, methyltestosterone and testosterone) in 27 min, while the most hydrophobic steroids were strongly retained. In contrast, a 0.125 M SDS-5.8% pentanol eluent permitted the elution of a mixture of eight steroids (dehydrotestosterone, dydrogesterone, medroxyprogesterone acetate, methandienone, methyltestosterone, progesterone, testosterone enanthate and testosterone propionate) of diverse hydrophobicity in 14 min. With this eluent, however, the peaks of dehydrotestosterone-medroxyprogesterone and methandienone-testosterone were highly overlapping.