Metachromins R--T, new sesquiterpenoids from marine sponge Spongia sp

Three new sesquiterpenoids, metachromins R--T (1--3), have been isolated from an Okinawan marine sponge Spongia sp. The structures and stereochemistry of 1--3 were elucidated on the basis of the spectroscopic data. Metachromins S (2) and T (3) showed modest cytotoxicity.     

New sesquiterpenoids from the New Zealand liverwort Chiloscyphus subporosus

A new aromadendrane-type sesquiterpenoid, 4(15)-aromadendren-12,5alpha-olide and an aromadendrane-guaianolide dimer have been isolated from the New Zealand liverwort Chiloscyphus subporosus. Their structures were established by extensive NMR techniques and X-ray crystallographic analysis.     

New cadinane sesquiterpenoids from Mikania micrantha

Abstract

Chemical investigation of the aerial parts of Mikania micrantha led to the isolation of eight sesquiterpenoids and ten diterpenoids, including five cadinane sesquiterpenoids (1?5), three bisabolene sesquiterpenoids (6???8), nine ent-kaurane diterpenoids (9–17), and an abietane diterpenoid (18). Among them, 1???3 are new and feature a rare lactone or furan ring derived from C-6 isopropyl group side chain. Compound 18 was isolated from genus Mikania for the first time, and was also the first example of abietane-type diterpenoids from this plant. Their structures were elucidated on the basis of extensive spectroscopic analyses (1D and 2D NMR, HRESIMS, and ECD). All compounds were examined for their inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophage cells, and compound 18 exhibited pronounced inhibition on NO production (IC₅₀ = 11.04?µM), being comparable to the positive control, quercetin (IC₅₀ = 11.15?µM).     

New sesquiterpenoids from the oleoresin of Abies alba

The structures of four new sesquiterpenoids from the oleoresin ofAbies alba have been studied. On the basis of various spectral characteristics, the structures of (10S, 11S)-himachala-2,4-diene, (10S, 11S)-himachala-3(12), 4-diene, humula-4,9-dien-8-ol, and (4S, 5S, 10S)-selina-6-en-4-ol have been proposed for the compounds isolated. The stereochemistry of the asymmetric centers was determined by the conversion of these compounds into known sesquiterpenes and also by analysis of PMR spectra with a shift reagent.Novosibirsk Institute of Organic Chemistry, Siberian Branch, USSR Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 712–718, September–October, 1988.     

Isolation and structure of axisonitrile-2 : A new sesquiterpenoid isonitrile from the sponge Axinella cannabina

On the basis of chemical and physico-chemical evidence, structure 3 has been assigned to axisonitrile-2, a new sesquiterpenoid isonitrile from the marine sponge Axinella cannabina.     

Halichonadins A-D, new sesquiterpenoids from a sponge Halichondria sp.

A new dimeric sesquiterpenoid with two eudesmane skeletons through a urea linkage, halichonadin A (1), as well as three new eudesmane sesquiterpenoids having a carbamate, an isonitrile, or an amino functionality, halichonadins B (2), C (3), and D (4), respectively, have been isolated from a marine sponge Halichondria sp., and the gross structures and relative stereochemistry of 1-4 were elucidated on the basis of spectral data and chemical means.     

Halichonadins K and L, new dimeric sesquiterpenoids from a sponge Halichondria sp

Two new structurally unique dimeric sesquiterpenoids, halichonadins K (1) and L (2), were isolated from an Okinawan marine sponge Halichondria sp. The structures of 1 and 2 were elucidated on the basis of spectroscopic analysis including a single crystal X-ray diffraction analysis and chemical conversion. Halichonadins K (1) and L (2) are homodimers of the eudesmane sesquiterpene linked with a piperidine ring through amide bonds. Halichonadin K (1) showed moderate cytotoxicity against KB cells.     

Halichonadins G-J, new sesquiterpenoids from a sponge Halichondria sp.

Three new dimeric sesquiterpenoids, halichonadins G-I (1-3), and one new eudesmane sesquiterpenoid possessing a 1-phenethyl urea moiety, halichonadin J (4), were isolated from a marine sponge Halichondria sp. Halichonadins G (1) and H (2) are homo-dimers of eudesmane sesquiterpenoid, linked through a methyl 2-{1-(2-amino-2-oxoethyl)ureido}acetate fragment and a 2-hydroxymalonamide fragment, respectively, while halichonadin I (3) is a new hetero-dimer of eudesmane sesquiterpenoid linked through a urea fragment. The structures of 1-4 were elucidated on the basis of spectroscopic data.     

Bazzanane sesquiterpenoids from the New Zealand liverwort Frullania falciloba

Two new bazzanane-type sesquiterpenoids have been isolated from the New Zealand liverwort Frullania falciloba. Their structures were confirmed by NMR and CD spectroscopy and chemical reactivity.     

Novel bisabolene-type sesquiterpenoids with a conjugated diene isolated from the okinawan sea sponge theonella cf. swinhoei

Three Novel sesquiterpenoids have been isolated from the Okinawan see sponge $\text{Theonella}$ cf. $\text{swinhoei}$ and the structures have been determined on the basis of the spectral data and chemical reactions.     

Isolation of sesquiterpenoids from sponge Dysidea avara and chemical modification of avarol as potential antitumor agents

The marine sponge Dysidea avara contained avarol (1) and avarone (2). Avarol on acylation yielded 2',5'-O-dibenzoylavarol (3); 2,5'-O-(4-chlorobenzoyl)avarol (4); 2,5'-O-dicinnamoylavarol (5); 2,5'-O-(4-bromobenzoyl)avarol(6); 2',5'-O-dioctanoylavarol (7); 2',5'-O-(4-fluorobenzoyl)avarol (8) and diacetylavarol (9). The structural elucidation of all the compounds 1-9 have been done by spectral analysis. The cytotoxicity of these compounds were also determined and evaluated. Compounds 6 and 9 showed selective cytotoxicity against Hepa (human hepatoma) and KB cell lines respectively.     

New tetrahydropyrans from a marine sponge

Two new tetrahydropyrans have been isolated from the sponge Haliclona sp. From chemical and spectroscopic evidence they are shown to be (1′$\text{R}$, 2$\text{S}$, 2″$\text{E}$, 5$\text{R}$, 6$\text{R}$)-2-(1′-bromethyl)-2,5-dimethyl-6-(penta-2″,4″-dienyl)-tetrahydropyran and (1′$\text{R}$, 2$\text{S}$, 5$\text{R}$, 6$\text{R}$)-2-(1′-bromoethyl)-2,5-dimethyl-6-(pent-4″-enyl)-tetrahydropyran.     

New diterpenes from the Caribbean sponge Epipolasis reiswigi

Two diterpenes, epipolone (1) and epipolol (3), produced by terpenoid pathways leading to a tricarbocyclic structure with an irregular "head to tail" isoprene configuration, have been isolated from the Caribbean marine sponge Epipolasis reiswigi collected in Puerto Rico. The structures of 1 and 3 were elucidated largely by 1D and 2D NMR methods and chemical conversion.     

New diterpene isocyanides from a sponge

Six new diterpene isocyanides have been isolated from a sponge ($\text{Adocia}$ sp.). Their structures support the biosynthetic suggestion for the formation of diisocyanoadociane reported from the same sponge.     

New antimicrobial diterpenes from the sponge spongia officinalis

The methanol extract of the sponge Spongia officinalis from Pt. Guimar, Tenerife (Canary Islands) contained new diterpenoids which inhibited the growth of microbes. The structures of the new diterpenes isolated were determined as; 11β-hydroxyspongi-12-en-16-one ($\text{2}$), 11β-acetoxyspongi-12-en-16-one ($\text{3}$), 7β,11β-dihydroxy8pongi-12-en-16-one ($\text{5}$), and 7β,11α-dihydroxy-spongi-12-en-16-one ($\text{6}$), by spectral and chemical degradation studies. The previously reported diterpenes isoagatholactone ($\text{1}$) and aplysillin ($\text{4}$) were also found in the extract.     

New meroterpenoids from the marine sponge Aka coralliphaga

Three new sulfated meroterpenoids containing sesquiterpene and hydroquinone moieties, namely siphonodictyal A sulfate (1), akadisulfate A (2) and akadisulfate B (3), along with the known siphonodictyal B3 and bis(sulfato)-cyclosiphonodictyol A were isolated from the sponge Aka coralliphaga. Their structures were elucidated on the basis of spectroscopic data. Akadisulfate B and siphonodictyal B3 showed a radical-scavenging activity comparable with that of the known lipophylic antioxidant BHT.     

Eudesmane sesquiterpenoids from the Asteraceae family

This review covers the structures and biological activities of eudesmane-type sesquiterpenoids from the plants of the Asteraceae family. Biosynthetic studies or chemical syntheses leading to the revision of structures or stereochemistries have also been included, and 593 references are cited.     

Paniceins,unusual aromatic sesquiterpenoids linked to a quinol or quinone system from the marine sponge Halichondria panicea

Five new substances, panicein-A, -B₁, -B₂, -B₃ and C, containing an aromatic sesquiterpenoid moiety linked to a quinol or a quinone system, have been isolated from the sponge Halichondria panicea. The structures of these compounds were elucidated from their chemical and spectral properties.