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1.
The syntheses of the proposed structures of hachijodine B 1, ikimine B 2 and niphatesine D 3 from S-citronellol are described. Our results suggest that the gross structures of hachijodine B and niphatesine D are correct, but that ikimine B was incorrectly assigned. We have also established that the previous absolute stereochemical assignment for niphatesine D is unreliable. 相似文献
2.
Y. Huang L. Chen B. He S.Y. Liu D.Q. Zeng Y.H. Wang L.W. Du W.W. Tang 《Arabian Journal of Chemistry》2021,14(7):103228
There are many nutrients and active substances in the residue of traditional Chinese medicine, which can be processed into organic fertilizer and returned to the field to improve the soil fertility. In this study, we found that Brucea javanica (L.) Merr. residue has herbicidal activity and can be used for weed control in the field, this prompted us to investigate the active constituents in it. The herbicidal activities of extracts of B. javanica residue were evaluated by conducting bioassays against gramineous weed, Eleusine indica (L.) Gaertn. and broad-leaved weed, Bidens pilosa L., respectively. It confirmed that ethyl acetate and n-butanol extracts possessed potent biological activities on seed germination and seedling growth of E. indica at 5 mg/mL. This prompted us to investigate the active constituents in the seeds residue. By the activity-guided fractionation, eight known compounds were isolated, which were bruceines D?F (1–3), pityriacitrin (4), 4-(9H-β-carbolin-1-yl)-4-oxobut-2-enoic acid methyl ester (5), protocatechuic acid (6), vanillic acid (7) and carisphthalate (8). Then, three quassinoids (1–3) were evaluated for their potential herbicidal effects in bioassay. Results showed that bruceines D?F have potential herbicidal activity against the test weeds. In the range of experimental concentration, bruceine D had obvious herbicidal effect on the two tested weeds. At the concentration of 31.25 μg/mL, bruceine D could completely inhibit the root growth of E. indica; at the concentration of 125 μg/mL, bruceine D can inhibit the seed germination and shoot elongation of E. indica and the shoot growth of B. pilosa, with the inhibition reached 100%. In addition, at the same concentration (250 μg/mL), bruceines D?F could completely affected shoot elongation of B. pilosa. These results showed that B. javanica residue is a potential source of botanical herbicide development, which has great agricultural economic value, at the same time, the reuse of B. javanica residue realizes the transformation of waste into treasure, rational utilization of resources and sustainable development. 相似文献
3.
Takeshi Yamada Takashi Kikuchi Reiko Tanaka Atsushi Numata 《Tetrahedron letters》2012,53(23):2842-2846
Halichoblelide B (1) and C (2), novel macrolides with potent cytotoxicity against tumor cells in culture, have been isolated from a strain of Streptomyces hygroscopicus originally derived from the marine fish Halichoeres bleekeri, and their absolute stereostructures have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques and chemical transformations. These compounds exhibited significant cytotoxicity against human cancer cell lines. 相似文献
4.
Naonobu Tanaka Yuyu Jia Kanji Niwa Kiyoshi Imabayashi Yutaka Tatano Hideki Yagi Yoshiki Kashiwada 《Tetrahedron》2018,74(1):117-123
Seven new phloroglucinol derivatives, myrtucommunins A–D (1–4), 6-methylisomyrtucommulone B (5), 4-methylmyrtucommulone B (6), and 2-isobutyryl-4-methylphloroglucinol 1-O-β-d-glucopyranoside (7), and one new chromone derivative, undulatoside A 6′-O-gallate (8), were isolated from the leaves of Myrtus communis (Myrtaceae). Myrtucommunins A–D (1–4) were conjugates of polymethylated acylphloroglucinol and flavonol rhamnoside. The absolute configurations of the rhamnosyl moieties for 1–4 were confirmed to be l in each case by HPLC analyses, while those of the aglycones were assigned by comparisons of the experimental and TDDFT calculated ECD spectra. 6-Methylisomyrtucommulone B (5) and 4-methylmyrtucommulone B (6) were assigned as 6/6/6 tricyclic acylphloroglucinol derivatives with a racemic nature. Antimicrobial activities of 1–8 and related known compounds were evaluated. 相似文献
5.
Jyh-Horng Sheu Chih-Hua Chao Kuang-Chih Hung M.Y. Chiang Chin-Chung Wu 《Tetrahedron letters》2004,45(34):6413-6416
The first A-nor-hippuristanol, A-nor-22-epi-hippurin-2α-carboxylic acid (1), and two 4,5-secosuberosane sesquiterpenoids, isishippuric acids A and B (2 and 3), have been isolated from the gorgonian coral Isis hippuris. Those structures were deduced by extensive 1D and 2D NMR studies. The structure of 1 was further supported by a single crystal X-ray diffraction analysis. Isishippuric acid B has been shown to exhibit potent cytotoxicity toward a limited panel of cancer cells. 相似文献
6.
Xu-Jie Qin Hui Liu Qian Yu Huan Yan Jin-Feng Tang Lin-Kun An Afsar Khan Qi-Run Chen Xiao-Jiang Hao Hai-Yang Liu 《Tetrahedron》2017,73(14):1803-1811
Three new acylphloroglucinol derivatives, callisalignones A–C (1–3), six new meroterpenoids, callisalignenes A–F (4–9), along with 18 known analogues (10–27) were isolated from the twigs and leaves of Callistemon salignus. Their structures and absolute configurations were established by comprehensive spectroscopic evidences (NMR, MS, amd electronic circular dichroism calculations). The absolute configurations of callistenones B (13) and H (14) were determined by comparison of their ECD spectra with that of callisalignone B (2). Callisalignones B and C are new adducts of β-triketone and acylphloroglucinol, whereas callisalignenes A–D are new meroterpenoids of acylphloroglucinol and α-phellandrene with different coupling models via hetero-Diels-Alder reaction, respectively. Myrtucommulone D (15) showed significant antibacterial activity against Staphylococcus aureus and three drug resistant S. aureus strains with MIC values of 1.953 and 0.975 μg/mL, respectively. Isomyrtucommulone B (17) displayed remarkable antibacterial activity against Escherichia coli with an MIC value of 0.122 μg/mL. Cytotoxic assay revealed that isomyrtucommulone B (17) was the most active against HCT116 with an IC50 value of 2.09 ± 0.10 μM. 相似文献
7.
Oleamide is an interesting compound, which shows various pharmacological activities including the inhibitory effect of gap junction formation. Recently, the studies of the gap junction have been some of the hot topics in biology and its inhibitors have become more useful tools [Cravatt, B. F.; Garcia, O. P.; Siuzdak, G.; Gilula, N. B.; Henriksen, S. J.; Boger, D. L.; Lerner, R. A. Science1995, 268, 1506-1509; Cravatt, B. F.; Lerner, R. A.; Boger, D. L. J. Am. Chem. Soc.1996, 118, 580-590; Guan, X; Cravatt, B. F.; Ehring, G. R.; Hall, J. E.; Boger, D. L.; Lerner, R. A.; Gilula, N. B. J. Cell Biol.1997, 139, 1785-1792; Boger, D. L.; Patterson, J. E.; Guan, X.; Cravatt, B. F.; Lerner, R. A.; Gilula, N. B. Proc. Natl. Acad. Sci. U.S.A.1998, 95, 4810-4815; Ito, A.; Morita, N.; Miura, D.; Koma, Y.; Kataoka, T. R.; Yamasaki, H.; Kitamura, Y.; Kita, Y.; Nojima, H. Carcinogenesis2004, 25, 2015-2022]. However, many reports suggest that the functionalizations of oleamide to retain its biological activity were difficult [Boger, D. L.; Patterson, J. E.; Guan, X.; Cravatt, B. F.; Lerner, R. A.; Gilula, N. B. Proc. Natl. Acad. Sci. U.S.A.1998, 95, 4810-4815; Ito, A.; Morita, N.; Miura, D.; Koma, Y.; Kataoka, T. R.; Yamasaki, H.; Kitamura, Y.; Kita, Y.; Nojima, H. Carcinogenesis2004, 25, 2015-2022]. The synthesis of the functionalized oleamide derivatives, whose biological activity is not blocked, has become attractive in both the biological and chemical fields.Herein, by linking the fluorophore to the oleamide by alkyl chains, we synthesized the fluorescently tagged oleamide whose biological feature is similar to that of oleamide. Moreover, we also synthesized other bioactive derivatives tagged by other groups such as the sugars and biotin via alkyl chain linkers. 相似文献
8.
Delphine BryBernard Banaigs Christophe LongNataly Bontemps 《Tetrahedron letters》2011,52(23):3041-3044
Two new pyridoacridine alkaloids, 13-didemethylaminocycloshermilamine D (1) and demethyldeoxyamphimedine (2), were isolated from the purple chromotype of the Western Mediterranean ascidian Cystodytes dellechiajei. This morph also contained the known shermilamine B (3), kuanoniamine D (4), N-deacetylshermilamine B (5), N-deacetylkuanoniamine D (6), styelsamines C (7), and D (8). The structures of new compounds were elucidated on the basis of spectroscopic data. A hypothetic biosynthetic pathway from the tetracyclic styelsamine D (8) was proposed for both compounds 1 and 2 and their antimicrobial potential was evaluated. 相似文献
9.
Fleurdeliz Maglangit Ming Him Tong Marcel Jaspars Kwaku Kyeremeh Hai Deng 《Tetrahedron letters》2019,60(1):75-79
Two new siderophores belonging to the hydroxamate class, Legonoxamine A (1) and B (2) have been isolated from the soil bacterium, Streptomyces sp. MA37, together with one known compound, desferrioxamine B (3). Their structures were elucidated based on spectroscopic methods including 1D, 2D NMR, MS, as well as by comparison with the relevant literatures. To our knowledge, this is the first report describing a siderophore containing the N-hydroxyl phenylacetyl cadaverine (HPAC) moiety in the structure. Based on bioinformatics analysis and previous knowledge of the biosynthesis of the hydroxamate-type siderophore, the biosynthetic gene cluster (lgo) responsible for the production of 1–3 was identified in the annotated genome of the producing strain. The supplementation of phenylacetate and benzoate analogues with meta substitution into the cultures of Streptomyces sp. MA37 resulted in the production of new legonoxamine A derivatives as observed in LC-HR-ESIMS, suggesting that the legonoxamine biosynthetic pathway has a good degree of natural flexibility of accepting unnatural precursors with different functional groups. 相似文献
10.
Hua-Yong Lou Lian Jin Tao Huang Dao-Ping Wang Guang-Yi Liang Wei-Dong Pan 《Tetrahedron letters》2017,58(5):401-404
Three new diterpenoids, vulgarisins B–D (1–3), have been isolated from a medicinal plant Prunella vulgaris Linn. These diterpenoids contain a rare 5/6/4/5 fused tetracyclic ring skeleton. Their structures were determined through the analysis of spectroscopic data, and the absolute configuration were further confirmed by single crystal X-ray diffraction as well as CD analysis. All the compounds were evaluated for their cytotoxicity activity, vulgarisins B (1) and C (2) demonstrated modest cytotoxicity activity against human lung carcinoma A549 cell line. 相似文献
11.
Dehai Li Shengxin Cai Tianjiao Zhu Fengping Wang Xiang Xiao Qianqun Gu 《Tetrahedron》2010,66(27-28):5101-5106
Eighteen sorbicillonoids, including three new sorbicillin trimers, trisorbicillinones B (2), C (3), and D (4), were isolated from a deep ocean sediment derived fungus, Phialocephala sp. FL30r. Their structures were determined by IR, MS, CD, and NMR spectral data. The cytotoxic activities of the new trisorbicillinones B (2), C (3), and D (4) were tested against both P388 and K562 cell lines. 相似文献
12.
Wei-Guang Wang Xiao-Nian Li Xue Du Ke Dong Wei Zhao Hai-Yan Wu Ling-Mei Kong Yan Li Jian-Xin Pu Han-Dong Sun 《Tetrahedron letters》2012,53(22):2777-2781
Two novel caged ent-kauranoids, neolaxiflorins D (1) and E (2), along with three other new ent-kauranoids, neolaxiflorins F–H (3–5), and a known one, eriocalyxin B (6), were obtained from Isodon eriocalyx var. laxiflora. Neolaxiflorin D (1) is the first 15,16-seco-16,17-dinor-ent-kaurane diterpenoid, and neolaxiflorin E (2) is the first 15,16-seco-17-homo-ent-kauranoid. The absolute configurations of ent-kauranoids 1 and 2 were determined by single-crystal X-ray diffraction analyses. Structural analysis of intermediate compounds 3–5 indicated that eriocalyxin B (6) is a biogenetic precursor of caged ent-kauranoids 1 and 2 as illustrated. The cytotoxic activity of the new compounds was evaluated by an MTT assay. 相似文献
13.
Yuji TanakaTakeshi Yamada Yasuko InOsamu Muraoka Tetsuya KajimotoReiko Tanaka 《Tetrahedron》2011,67(4):782-792
A new gedunin, three new mexicanolides and three new phragmalin-type limonoids named Andirolides A (1), B (2), C (3), D (4), E (5), F (6), and G (7) were isolated from oil of the flower of Carapa guianensis Aublet (Meliaceae). Their absolute stereostructures were determined by 2D NMR and CD spectra, and single-crystal X-ray analysis, and all compounds were confirmed to have the C-17βH configuration. Considering the similarity in CD spectra between Andirolide G (7) and the xyloccensins reported by Wu, we concluded that the structures of xyloccensins should be revised so as to have the absolute configuration of 17R. 相似文献
14.
A new dimer of C16N2 type alkaloid, complanadine B (1), and two new C16N type alkaloids, obscurumines A (2) and B (3), have been isolated from the club moss Lycopodium complanatum and L. obscurum, respectively. The structures and stereochemistry of 1-3 were elucidated by combination of 2D NMR spectra and chemical transformation. Complanadine A (4) isolated together with 1 induced secretion of neurotrophic factors from human astrocytoma cells. 相似文献
15.
《Tetrahedron》2019,75(16):2379-2384
Seven new vibsane-type diterpenoids, 6-O-methyl-6,7-dihydroxyvibsanin B (1), 4-hydroxyvibsanin A (2), 14(R*),15-epoxyneovibsanin B (3), 14(S*),15-epoxyneovibsanin B (4), (8Z)-neovibsanin B (5), 18-O-methylvibsanin C (6), and (8Z)-vibsanin E (7), have been isolated from the leaves of Viburnum awabuki. Their structures have been elucidated by molecular mechanics 2 (MM2) calculations and comparison of the spectroscopic data, including 13C NMR data, with those of previously known compounds. Moreover, neovibsane-type diterpenoids 3, 4, and 5 enhanced the neurite outgrowth of NGF-mediated PC12 cells at a concentration of 40 μM. 相似文献
16.
Five new fawcettimine-type alkaloids (1–5) and three new natural products (6–8), along with four known analogues, fawcettimine (9), fewcettidine (10), lycopoclavamine B (11), and lycopladine B (12), were isolated from the whole plant of Lycopodium complanatum var. glaucum Ching. The structures of lycogladines A-H (1–8) were determined based on HRESIMS, 1D and 2D NMR spectroscopic analysis, as well as single-crystal X-ray diffraction. Compound 1 possesses a new ring system that is formed through the linkage of C-13-OC-2, which is rarely present in Lycopodium alkaloids (LAs). Compounds 1–8 were tested for their β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) and acetylcholinesterase (AChE) inhibitory activities. 相似文献
17.
O-Benzyl-N-benzyloxymalimide 12 has been synthesized as a useful variant of the chiral building blocks 9. The advantage of the malimide 12 over 9 was demonstrated by mild and high-yielding reductive N-deprotection of N-benzyloxylactams 18a–i to give a series of (4R,5S)-5-alkyl-4-hydroxy-pyrrolidin-2-ones, which are key intermediates for the asymmetric synthesis of pyrrolidines, pyrrolizidines, and indolizidines, as well as β-hydroxy γ-amino acids. Lactam ent-11a has been applied to the synthesis of the mixed imide 25, a key intermediate for the total synthesis of microcolin B, which also demonstrated that lactam ent-11a or 11a can serve as a latent form of the 5-methyl-3-pyrrolin-2-one substructure of majusculamide D 4, deoxymajusculamide D, and the jamaicamides A–C. 相似文献
18.
13C NMR studies reveal that the polyen chain of neo-zeaxanthin A (2) and that of neo-capsorubin A (5) have 13-cis configuration, while those of neo-zeaxanthin B (3) and neo-capsorubin B (6) have 9-cis geometrical configuration. 13C NMR data on the corresponding all-trans carotenoids (1 and 4) are also reported. 相似文献
19.
Wei Jiang Yao Fei Xiao-Lang Du Ze-Jing Mu Bo Li Shou-Wen Zhang Guo-Yue Zhong 《Tetrahedron letters》2017,58(36):3541-3544
Two novel cucurbitane triterpenoid glycosides, named saxifraganoids A (1) and B (2), were isolated from Saxifraga umbellulata var. pectinata. Their structures including absolute configurations were elucidated based on the analysis of spectroscopic data (1D, 2D NMR and HRMS), and single-crystal X-ray diffraction. Compound 1 represents the first example of cucurbitane triterpenoid with a Δ17(20), and compound 2 contained an unusual N-acetylglucosamine at C-16. The protective effects against liver injury induced by carbon tetrachloride (CCl4) in the human embryonic-liver L-02 cells of these two compounds were evaluated. 相似文献
20.
Two unusual euphane triterpenoids, named euphatexols A (1) and B (2), were isolated from the latex of Euphorbia resinifera. Their structures were elucidated based on the extensive analysis of spectroscopic data (HRMS, 1D and 2D NMR). Compound 1 possesses a rare tetrahydrofuran ring formed via C-1 and C-11, which is firstly reported in euphane triterpenoids. Compound 2 represents an unusual 27-nor-euphane triterpenoid. Moreover, compounds 1 and 2 showed significant cytotoxic activities against HepG2 cells with 87.0% and 87.4% inhibition rate at 1 μM, respectively. 相似文献