Isolation and structure elucidation of two new compounds from artemisia Ordosica Krasch

Abstract

Two new compounds, namely arteordoyn A (1) and arteordoyn B (2), together with four known compounds, were isolated from the petroleum ether extract of Artemisia ordosica Krasch. The structures elucidation of 1 and 2 were carried out by 1D-NMR (¹H and ¹³C NMR), 2D-NMR (COSY, HSQC, HMBC and NOESY) and HR-ESI-MS spectral analysis.     

Synthesis and structure elucidation of new cytotoxic azathioxanthones

A series of new cytotoxic azathioxanthones 7a-h was synthesized and characterized by their spectral data.     

Isolation and structure elucidation of three metabolites from verticillium intertextum: sorbicillin, dihydrosorbicillin and bisvertinoquinol

From the culture medium of Verticillium inlertexlum three metabolitcs have been isolated, namely the hexaketidcs sorbicillin (1) and 2'3'-dihydrosorbicillin (2), and the dimeric hexaketide bisvertinoquinol (3). 1 has previously been isolated from Penicillium chrysogenum and also synthesised. Hydrogenation of 1 yielded tetrahydrosorbicillin (8), 2'5'-dihydrosorbicillin (9) and 2',3'-dihydrosorbicillin (2). 2 was also obtained by a BF₃-catalysed condensation of 2,4-dimethyl-resorcinol (5) with (4R^*, 5S^*)-4,5-dibromo-hexanoic acid (6), followed by debromination with zinc and acetic acid. The structure of the dimeric hexaketide 3 (without absolute configuration) was obtained by X-ray structure analysis. It may be considered to be a Diels-Alder adduct of the quinols 11 and 12, the latter being related to 1 and 2, respectively, by simple hydroxylation at C(5). The ¹H and ¹³C NMR signals of 3 and its mono-methyl ether 10 are interpreted and compared with the corresponding properties of 1, 2, vertinolide (4), 3-methoxy-2-methyl-2-cyclohexenone (14), and 2-[(E,E)-2,4-hexadienoyl)]-cyclohexanone (13). The latter was prepared by acylation of the lithium enolate of cyclohexanone with sorbyl chloride. From the spectra of the hexaketides from V. intertextum several patterns have been extracted which are characteristic for some common and some distinguishing substructures in these natural products.     

红树林植物角果木内生真菌次级代谢产物的分离鉴定

研究红树林植物角果木根部内生真菌Fusarium sp.JG13次级代谢产物。用硅胶柱层析、制备薄层层析和重结晶等方法,从该菌发酵液的乙酸乙酯萃取相中分离获得4个单体化合物,以及一对顺反异构体。运用现代波谱技术以及文献数据对照,鉴定其结构分别为physcion(1)、trans physcion bianthrone(2)、cis physcion bianthrone(3)、asperflavin(4)、neoechinulin A(5)和isodihydroauroglaucin(6)。所有化合物均为首次从角果木根内生真菌Fusarium sp.JG13发酵分离得到。     

Isolation and structure elucidation of ovalicin

The structure of ovalicin, a metabolite of the fungus Pseudeurotium ovalis with immunosuppressive activity, has been determined to be 11 .     

Isolation, structure elucidation, and biological activity of a new alkaloid from Zanthoxylum rhetsa

Several biologically active alkaloids (1-4, 6), including a new quinazoline-6-carboxylic acid (1), were isolated from the medicinal plant Zanthoxylum rhetsa, an evergreen tree, native to subtropical areas. Whereas the pharmacological properties of the plant extract and single constituents have been widely tested, we now show that all of the metabolites have antialgal activities, all but 6 are antibacterial, and 6 and the reduction product 5 (derived from 4) are also antifungal.     

Isolation and structure elucidation of 11-desacetoxywortmannin

The structure of 11-desacetoxy-wortmannin ( 3 ), a new antiinflammatory metabolite of the fungus Penicillium funiculosum THOM, has been elucidated by physico-chemical methods and chemical correlation with wortmannin ( 1 ).     

Isolation and structure elucidation of ishwarol B

Ishwarol B was isolated from the bark oil of Cedrelopsis grevei and its structure elucidated by 1D and 2D NMR spectroscopy.     

Isolation, structure elucidation, and total synthesis of two new Chimonanthus alkaloids, chimonamidine and chimonanthidine

Two new tryptamine-related alkaloids, chimonamidine and chimonanthidine, were isolated from the seeds of Chimonanthus praecox Link. and their structures including absolute configuration were elucidated by spectroscopic analysis and biomimetic total synthesis from tryptamine.     

Isolation and structure elucidation of new sesquiterpenes of protoilludane origin from the fungus Clavicorona divaricata

Four novel sesquiterpenes of protoilludane origin, divaricatines A 3a and B 3b, 7-epitsugicoline H 4a and tsugicoline M 5a have been isolated from agar cultures of the fungus Clavicorona divaricata (Basidiomycetes). Their structures were elucidated by means of NMR studies and chemical correlations. All the metabolites are weakly active on bacteria but inhibited the germination of the water cress Lepidium sativum. A possible mechanism of their formation from the protoilludane tsugicoline A 1 is suggested. A fifth metabolite, the norsesquiterpene tsugicoline L 2b, was also isolated from the same fungus together with the known tsugicoline I 2a.     

Isolation and structure elucidation of a new prenylcoumarin from Murraya paniculata var. omphalocarpa (Rutaceae)

A new C-8 prenylated 5,7-dimethoxycoumarin named omphamurrayin was isolated from the leaves of Murraya paniculata var. omphalocarpa, and its structure was established as 5,7-dimethoxy-8-(1-oxo-2-senecioyl-3-methyl-3-butenyl)-2H-1-benzopyran-2-one on the basis of the spectroscopic evidence. The taxonomic status of M. paniculata var. omphalocarpa is briefly discussed, along with its synonymity to M. paniculata from the chemosystematic viewpoint.     

Isolation and elucidation of the structure of homocryptolepinone

The structure of a new indolobenzazepine alkaloid, homocryptolepinone, isolated from extracts of the roots of the indigenous Ghanaian medicinal plant Cryptolepis sanguinolenta, is reported. The structure was determined using mass spectrometric, one-dimensional nOe difference nmr, and inverse-detected two-dimensional nmr experiments which included HMQC, IDR-(Inverted Direct Response)-HMQC-TOCSY, and HMBC experiments. The structure of homocryptolepinone is significant in that it may provide insight into the biogenesis of the benzpyrrolizinobenzazepine portion of the structure of the complex spiro nona-cyclic alkaloid cryptospirolepine previously isolated in these laboratories from C. sanguinolenta, and which has no precedent in alkaloid chemistry.     

Isolation and structure elucidation of a new compound from the fungus Aspergillus flavipes PJ03-11

A new diphenyl ether 3-methylpentyl-2, 4-dichloroasterrate (2), along with a known diphenyl ether butyl 2, 4-dichloroasterrate (1) were isolated from the metabolites of a wetland fungus Aspergillus flavipes. PJ03-11. The structures of 1 and 2 were determined by extensive NMR and HR–ESI–MS experiments. Compounds 1 and 2 showed weak cytotoxic activity, but both of them showed no antimicrobial activity.     

Isolation and structure elucidation of a new amphidinol with a truncated polyhydroxyl chain from Amphidinium klebsii

A new member of amphidinols (AM7) possessing a polyene-polyhydroxyl structure with the shortest carbon backbone and sulfate ester was isolated from the cultured dinoflagellate, Amphidinium klebsii. AM7 showed hemolytic and antifungal activities. The structure was elucidated on the basis of 2D NMR data in combination with CID MS/MS experiments.     

Isolation,structural determination and cytotoxic activity of two new ceramides from the root of Isatis indigotica

Two new ceramides were isolated from the 95% EtOH extract of traditional Chinese medicinal plant Isatis indigotica. Their structures were elucidated as 1-O-β-D-glucopyranosyl-(2S, 3R)-N-(2'-hydroxypentacosanoyl)-octadeca-11E-sphingenine (1) and 1-O-β-D-glucopyranosyl-(2S,3R)-N-(2'-hydroxyhe xacosanoyl)-octadeca-11E-sphingenine (2) on the basis of spectroscopic data. Their cytotoxic effects were evaluated by using MTT method.     

Biomimetic synthesis and structure elucidation of rubicordifolin, a cytotoxic natural product from Rubia cordifolia

The biomimetic synthesis and full structural elucidation of rubicordifolin, a cytotoxic natural product isolated from Rubia cordifolia, is described.     

Isolation,purification and identification of two new alkaloids metabolites from marine-derived Verrucosispora sp. FIM06025

Chemical investigation of a marine-derived actinomycete strain Verrucosispora sp. FIM06025 isolated from a marine sponge sample collected from the East China Sea, resulted in the discovery of two new alkaloids, (2-(hydroxymethyl)-3-(2-(hydroxymethyl)-3-methylaziridin-1-yl) (2-hydroxyphenyl) methanone (1) and 2-(1-hydroxyethyl)-3,4-dihydrobenzo [f] [1,4]oxazepin-5(2H)-one (2). The structures of compounds 1 and 2 were determined by the detailed analysis of 1D, 2D NMR and HR-TOF-MS data, along with literature data analysis. The bioefficacy investigations revealed that compound 1 exhibited a broad spectrum of antimicrobial activity with MIC (minimum inhibitory concentration) values ranging from 3.4 to 200?μg·mL^?1 against H. pylori, P. aeroginosa, A. baumanniiin, E. coli and K. pneumonia, S. aureus, C. albicans and E. faecium, however, compound 2, up to 200?μg/mL, displayed no antibacterial activity against these bacteria.