Unusual chlorinated pregnanes from the eastern Pacific octocoral Carijoa multiflora

Phytoconstituents from Turraea obtusifolia and their antiplasmodial activity

Three new steroids, turranin M, N and O (1-3), together with four known limonoids, nymania 1 (4), rubralin B (5), aphapolynin C (6) and Trichillia substance Tr B (7), were isolated from the leaves of Turraea obtusifolia. Their chemical structures were elucidated using NMR and MS. Rubralin B (5) displayed good activity against the asexual parasites from the drug sensitive Plasmodium falciparum NF54 strain with an IC50 value of 3.47 µg/mL (4.57 µM), nymania 1 (4) showed a weak activity (IC50 13.36 µg/mL (19.40 µM)) and the rest of compounds had IC50 > 20 µg/mL.

Biological Activity and Structural Diversity of Steroids Containing Aromatic Rings, Phosphate Groups, or Halogen Atoms

This review delves into the investigation of the biological activity and structural diversity of steroids and related isoprenoid lipids. The study encompasses various natural compounds, such as steroids with aromatic ring(s), steroid phosphate esters derived from marine invertebrates, and steroids incorporating halogen atoms (I, Br, or Cl). These compounds are either produced by fungi or fungal endophytes or found in extracts of plants, algae, or marine invertebrates. To assess the biological activity of these natural compounds, an extensive examination of referenced literature sources was conducted. The evaluation encompassed in vivo and in vitro studies, as well as the utilization of the QSAR method. Numerous compounds exhibited notable properties such as strong anti-inflammatory, anti-neoplastic, anti-proliferative, anti-hypercholesterolemic, anti-Parkinsonian, diuretic, anti-eczematic, anti-psoriatic, and various other activities. Throughout the review, 3D graphs illustrating the activity of individual steroids are presented alongside images of selected terrestrial or marine organisms. Additionally, the review provides explanations for specific types of biological activity associated with these compounds. The data presented in this review hold scientific interest for academic science as well as practical implications in the fields of pharmacology and practical medicine. The analysis of the biological activity and structural diversity of steroids and related isoprenoid lipids provides valuable insights that can contribute to advancements in both theoretical understanding and applied research.

Two-Stage Syntheses of Clionastatins A and B

A concise and divergent synthesis of the polychlorinated marine steroids clionastatin A and B from inexpensive testosterone has been achieved through a unique two-stage chlorination-oxidation strategy. Key features of the two-stage synthesis include (1) conformationally controlled, highly stereoselective dichlorination at C1 and C2 and C4-OH-directed C19 oxygenation followed by a challenging neopentyl chlorination to install three chlorine atoms; (2) desaturation through one-pot photochemical dibromination-reductive debromination and anti-Markovnikov olefin oxidation by photoredox-metal dual catalysis to enhance the oxidation level of the backbone; and (3) Wharton transposition to furnish the D-ring enone. This synthesis proved that the introduction of the C19 chloride in the early stage of the synthesis secured the stability of the backbone against susceptibility to aromatization during the oxidation stage.

A Temperature-Controlled Switch between Fürst-Plattner Rule and Anti-Fürst-Plattner Rule Ring Opening of 2,3-Epoxy-steroids with Various Halide Sources in the Presence of Imidazolium Ionic Liquids

The ring opening of 2α,3α- and 2β,3β-epoxy-5α-androstan-17-one with halide reagents (AlCl₃, TMSCl, LiCl, and LiBr) was investigated using imidazolium ionic liquids in the dual role of solvent and catalyst. The application of the ionic liquid was shown to result in an increase in the amount of the unusual diequatorial halohydrins especially at temperatures above 100 °C. With a careful choice of reaction conditions, the latter derivatives could be produced with 43-96% selectivity depending on the nature of the halide ion. Moreover, the usual diaxial products could also be isolated in 70-85% yields by a proper change in the reaction conditions. The reusability of the ionic liquid was demonstrated in both types of reactions. The structures of the products were proved unequivocally by nuclear magnetic resonance (NMR) measurements including two-dimensional (2D) techniques as well as high-resolution mass spectrometry (HRMS). Based on quantum chemical calculations, the effect of the ionic liquid could be explained by the stabilization of the transition state leading to the diequatorial product.

Chemical Diversity of Soft Coral Steroids and Their Pharmacological Activities

The review is devoted to the chemical diversity of steroids produced by soft corals and their determined and potential activities. There are about 200 steroids that belong to different types of steroids such as secosteroids, spirosteroids, epoxy- and peroxy-steroids, steroid glycosides, halogenated steroids, polyoxygenated steroids and steroids containing sulfur or nitrogen heteroatoms. Of greatest interest is the pharmacological activity of these steroids. More than 40 steroids exhibit antitumor and related activity with a confidence level of over 90 percent. A group of 32 steroids shows anti-hypercholesterolemic activity with over 90 percent confidence. Ten steroids exhibit anti-inflammatory activity and 20 steroids can be classified as respiratory analeptic drugs. Several steroids exhibit rather rare and very specific activities. Steroids exhibit anti-osteoporotic properties and can be used to treat osteoporosis, as well as have strong anti-eczemic and anti-psoriatic properties and antispasmodic properties. Thus, this review is probably the first and exclusive to present the known as well as the potential pharmacological activities of 200 marine steroids.

Oxysterols from an octocoral of the genus Gorgonia from the eastern Pacific of Panama

Eighteen new oxysterols were isolated from a previously undescribed octocoral of the genusGorgonia. Antimicrobial and antileishmanial properties of these compounds have been evaluated.

Total synthesis of steroids and heterosteroids from BISTRO

Due to their high profile biological activity, the steroids are among the most important secondary metabolites. A review of literature on the total synthesis of steroids starting from BISTRO (1,8-bis(trimethylsilyl)-2,6-octadiene) is presented.

Efficient synthesis of 17-acetyl-13-(p-bromophenyl)-3-methoxy-11,11-bis(methoxycarbonyl)gona-1,3,5(10)-trienes

We described an efficient synthesis of (8β,9β,14β)-17β-acetyl-13β-p-bromophenyl-11,11-di(methoxycarbonyl)-3-methoxygona-1,3,5(10)-triene, (8β,9α,14β)-17β-acetyl-13β-p-bromophenyl-11,11-di(methoxycarbonyl)-3-methoxygona-1,3,5(10)-triene, (8β,9β,14β)-13 β-p-bromophenyl-11,11-di(methoxycarbonyl)-17β-(2-hydroxyethyl)-3-methoxygona-1,3,5(10)-triene, and (8β,9β,14β)-13β-p-bromophenyl-11,11-di(methoxycarbonyl)-17β-(2-oxoxyethyl)-3-methoxygona-1,3,5(10)-triene in five or six steps from 1-iodo-4-methoxybenzocyclobutene and readily available materials.

Carijodienone from the octocoral Carijoa multiflora. A spiropregnane-based steroid

Two new steroids (1 and 2) and the known pregna-1,4,20-trien-3-one (3) have been isolated from the Pacific octocoral Carijoa multiflora. Compound 1 possesses a novel spiropregnane-based steroidal skeleton. The photochemical transformation of 3 into 1 allowed the assignment of the absolute configuration at C-10 of 1. The antibacterial activities of compounds 1 and 3 were evaluated against a panel of bacterial strains.

Carijoside A, a bioactive sterol glycoside from an octocoral Carijoa sp. (Clavulariidae)

A new bioactive sterol glycoside, 3β-O-(3′,4′-di-O-acetyl-β-d-arabinopyranosyl) -25ξ-cholestane-3β,5α,6β,26-tetrol-26-acetate) (carijoside A, 1), was isolated from an octocoral identified as Carijoa sp. The structure of glycoside 1 was established by spectroscopic methods and by comparison with spectral data for the other known glycosides. Carijoside A (1) displayed significant inhibitory effects on superoxide anion generation and elastase release by human neutrophils and this compound exhibited moderate cytotoxicity toward DLD-1, P388D1, HL-60, and CCRF-CEM tumor cells.

6β-Chloro-5α-hydr-oxy-20-oxopregnan-3β-yl acetate

The title steroid, C₂₃H₃₅ClO₄, is a pregnane derivative prepared by ring opening of the corresponding 5α,6α-ep­oxy steroid with BiCl₃. There are two symmetry-independent mol­ecules in the asymmetric unit that show no significant differences concerning bond lengths and angles. The conformation of the six-membered rings in both mol­ecules is close to a chair form, while the five-membered ring adopts an envelope conformation. All rings in both mol­ecules are trans-fused. The mol­ecules are held together by an extensive O—H⋯O hydrogen-bonding network.

New pregnane steroids from Turraea pubescens

Three new pregnane steroids, 2beta,3beta,5beta-trihydroxy-pregn-20-en-6-one (1), 3beta-hydroxy-5alpha-pregn-7,20-dien-6-one (2), and 3beta-acetoxy-5alpha-pregn-7,20-dien-6-one (3) were isolated from the twigs and leaves of Turraea pubescens, and were structurally elucidated on the basis of spectroscopic data and chemical method.

Marine natural products

This review covers the literature published in 2004 for marine natural products, with 693 citations (491 for the period January to December 2004) referring to compounds isolated from marine microorganisms and phytoplankton, green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates and echinoderms. The emphasis is on new compounds (716 for 2004), together with their relevant biological activities, source organisms and country of origin. Biosynthetic studies (8), and syntheses (80), including those that lead to the revision of structures or stereochemistries, have been included.