Studies on the Steroids of Marine Sponge(Ⅳ)──Steroids from the Marine Spo

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Two Phaeophytin Type Analogues from Marine Sponge Dysidea sp.

A new compound named 13b (S)-hydroxy-17c-ethoxypheaophorbide a (2) together with a known compound 17c-ethoxypheaophorbide a (1) were isolated from marine sponge Dysidea spcollected in South China sea. The structures were elucidated by spectroscopic analysis as well as comparison with those reported in literatures.     

Two furano-sesquiterpenes from the South China Sea Sponge Dysidea fragilis

A new sesquiterpene, ent-furodysin (1), has been isolated from the South China Sea Sponge Dysidea fragilis, along with a known sesqui-terpene, ent-furodysinin (2). The structure and relative stereochemistry of 1 and 2 were established by spectral analysis.     

Stereoselective Synthesis of 3(R) and 3(S)-Hydroxyeicos-4(E)-en-1-yne, a Component of the Marine Sponge Cribrochalina Vasculum

Recently,aseriesofacetylenicalc0hols'possessingacharacteristic4-en-l-yn-3-olskeletonwasis0latedfromthemarinesp0ngeCribrochalinavasculum(Figure1)andshowedirnmnosuPpresiveandantitumoractivitiesinvitr0.1Toourknowledge,stereoselectivesynthesishasnotbeencarriedoutonthesecomPounds.WedescribehereinthestereoselectivesynthesisoftW0enantiomersof3-hydroxy-4(E)-en-l-yne(A)fromD-gluconolactoneandD-xyloserespectivelyusingacetylenictechnology.Bythepublishedmethod',theacetylenicalcohollwaspreparedfromD-gl…     

Nitrile Oxide Approach to the Synthesis of Δ23-22-Oxo Steroids

^{2 3}-22-Oxo steroids were synthesized via 1,3-dipolar cycloaddition of steroidal nitrile oxides to low-molecular dipolarophiles. Cycloaddition of 2-propynyl bromide to 20-carbonitrile oxide, followed by hydrogenation of the isoxazole derivative thus formed gave 22-enamino-24-keto steroid. The latter was then converted into the target enones via several pathways. Compounds with unnatural configuration of the C^{2 0} atom can also be obtained. ^{2 3}-22-Oxo steroids were also synthesized through isoxazole derivatives.     

A Study on the Engineering Geological Properties of Fine-grained Marine Sediments

Through studies on the engineering geological properties of fine marine sediments, this article fully verified that the sedimentary environment is an important factor which determines the engineering geological properties of fine marine sediments. Meanwhile, these properties are controlled and affected by factors such as composition, physico-chemical nature, micro-textures, etc. of fine soils.     

LC–MS/MS Method for the Simultaneous Determination of Free Urinary Steroids

Cortisol homeostasis is implicated in hypertension and metabolic syndrome. Two enzymes modulate cortisol availability; 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) preferentially converts inactive cortisone to cortisol, whereas 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) converts cortisol to cortisone. In contrast, 5α and 5β reductases inactivate cortisol by conversion to its tetrahydrometabolites: tetrahydrocortisol, allo-tetrahydrocortisol and tetrahydrocortisone. A subtle local increase in cortisol can be detected by measuring 24-h urine metabolites, LC–MS/MS being the reference method. The 11β-HSD2 activity is assessed based on the cortisol/cortisone ratio, and the 11β-HSD1 activity on the (tetrahydrocortisol + allo-tetrahydrocortisol)/tetrahydrocortisone ratio. To better understand hypertension and/or metabolic syndrome pathogenesis a method for simultaneous determination of cortisol, cortisone, tetrahydrocortisol, allo-tetrahydrocortisol and tetrahydrocortisone was developed and validated in an LC coupled with the new detector AB Sciex QTrap^® 4500 tandem mass spectrometer. The steroids were extracted from 1 mL urine, using cortisol-D4 as internal standard. The quantification range was 0.1–120 ng/mL for cortisol and cortisone, and 1–120 ng/mL for tetrahydrometabolites, with >89 % recovery for all analytes. The coefficient of variation and accuracy was <10 %, and 85–105 %, respectively. Our LC–MS/MS method is accurate and reproducible in accordance with Food and Drug Administration guidelines, showing good sensitivity and recovery. This method allows the assessment of 11β-HSD2 and 11β-HSD1 activities in a single analytical run providing an innovative tool to explain etiology of misclassified essential hypertension and/or metabolic syndrome.     

Phyllofenone A, a New Scalarane Sesterterpene from the Sponge Phyllospongia Foliascens(Pallas)

The present paper covers the structure of a new sesterterpene, phyllofenone A(1) , isolated from the South China Sea sponge Phyllospongia foliascens. Phyllofenone A is a member of the scalarane class of sesterterpenes with a (C-20, C-24)-bishomo-(C-25)-nortetra-cyclic skeleton. The structure charcterization was based on one- and two-dimensional NMR and mass spectroscopy with the assistance of molecular modeling. Phyllofenone A shows weak antifungal activity against Candida pseudotropicalis.     

Nanjiols D and E, Two New Uncommon Steroids from the Chinese Soft Coral Nephthea bayed

Two new steroids, nanjiols D and E, were isolated from the soft coral Nephthea bayeri. Their structures were characterized by spectroscopic methods and comparison with known compounds.     

Synthesis of 5α-Iodo-6-one Steroids

Abstract: The synthesis of 5-iodo-5α-cholestan-6-one (6), its 3β-acetoxy-(7) and 3β-chloro-(8) analogues, 3β-acetoxy-5-iodo-5α-stigmastan-6-one (9) and its 3β-chloro-(10) analogue by the reacion of silver chromate-iodine and pyridine with the corresponding steroidal olefins (1-5) is described. The structures of these products have been established on the basis of their elemental, analytical and spectral data.     

A Novel Approach for Determining the Orientation of 3-Hydroxyl Group of Some Steroids by CIMS

Stereochemicalanalysisisanimportantsubjectinorganicstructureelucidation,andmassspectrometryprovestobeapromisingtoolforthisproposeduetoitshighsensitivity(thelimitofdetectionisabout10-14mole),rapidity,etcl.Inourpreviouswork,aseriesofstudiesonthestereochemicaleffectsinmassspectrometryhavebeendiscussed2-6.Inthiscommunicationwereportanovelapproachfordeterminationtheeoraorientationof3hydroxylgroupofsomesteroidsdirectlybychemicalionizationmassspectrometryusingtrimethylchlorosilaneasastereoselectivere…     

Nanjiols D and E, Two New Uncommon Steroids from the Chinese Soft Coral Nephthea bayeri

Marine organisms have been found to be a storehouse of steroids, particularly in term ofunique side-chain structures and unusual functionalization. Marine steroids are oftenfound in highly oxygenated forms and possessing various biological activities1.Previously, we reported the isolation and structural elucidation of three new marinesteroids, nanjiols A-C, which showed cytotoxicity against HL-60 and BEL 7402 celllines, from a soft coral Nephthea bayeri in East China Sea2. In continuation …     

Two New C21 Steroids from Marsdenia tenacissima

Two new C21 steroids were isolated from the CHCI3 extract of the stem of Marsdenia tenacissima. On the basis of spectroscopic analysis and chemical methods, their structures were elucidated as 1713-tenacigenin B (2) and 3-O-6-deoxy-3-O-methyl-β-D-allopyranosyl-(l→4)-β-D-oleandropyranosyl-tenacigenin C (3). The structure of the known aglycon tenacigenin C was revised as 5ct, 9ct, 1713-pregnane-313, 813, llct, 1213, 14β-pentanol-20-one. Compound 3 is the firstreported glycoside of tenacigenin C.     

A New Isomalabaricane Triterpenoid from Sponge Jaspis sp.

From the marine sponge Jaspis sp., a new isomalabaricane triterpenoid 22, 23-dihydrostellettin D (1) was isolated, and its structure was established on the basis of IR, MS and extensive 2D NMR spectroscopic analysis. It is a unique skeleton compound rarely obtained from Chinese marine organisms.     

Zur papierchromatographischen Trennung von Triterpenoid- und Steroids?uren

Ohne Zusammenfassung     

Where is the Oxygen? Structural Analysis of α‐Humulene Oxidation Products by the Crystalline Sponge Method

Crystal structures of α‐humulene, a cyclic sesquiterpene, and its oxidized subproducts, were analyzed by the crystalline sponge method. Regio‐ and stereochemistry, including absolute configuration when a chiral oxidant was applied, and the stable conformations of all the scaffold‐related compounds were successfully determined for samples on a 5–50 μg scale.     

Where is the Oxygen? Structural Analysis of α‐Humulene Oxidation Products by the Crystalline Sponge Method

Crystal structures of α‐humulene, a cyclic sesquiterpene, and its oxidized subproducts, were analyzed by the crystalline sponge method. Regio‐ and stereochemistry, including absolute configuration when a chiral oxidant was applied, and the stable conformations of all the scaffold‐related compounds were successfully determined for samples on a 5–50 μg scale.     

Formation of Amphiphilic Molecules from the Most Common Marine Polysaccharides,toward a Sustainable Alternative?

Marine polysaccharides are part of the huge seaweeds resources and present many applications for several industries. In order to widen their potential as additives or bioactive compounds, some structural modifications have been studied. Among them, simple hydrophobization reactions have been developed in order to yield to grafted polysaccharides bearing acyl-, aryl-, alkyl-, and alkenyl-groups or fatty acid chains. The resulting polymers are able to present modified physicochemical and/or biological properties of interest in the current pharmaceutical, cosmetics, or food fields. This review covers the chemical structures of the main marine polysaccharides, and then focuses on their structural modifications, and especially on hydrophobization reactions mainly esterification, acylation, alkylation, amidation, or even cross-linking reaction on native hydroxyl-, amine, or carboxylic acid functions. Finally, the question of the necessary requirement for more sustainable processes around these structural modulations of marine polysaccharides is addressed, considering the development of greener technologies applied to traditional polysaccharides.