共查询到20条相似文献,搜索用时 15 毫秒
1.
Xiao Zhou Hongbo Huang Jie Li Yongxiang Song Renwang Jiang Jing Liu Si Zhang Yan Hua Jianhua Ju 《Tetrahedron》2014
Six cycloheptadepsipeptides, marformycins A–F (1–6), featuring a unique N-terminally formylated side chain and five non-proteinogenic amino acid residues, were isolated from the deep Sea-derived Streptomyces drozdowiczii SCSIO 10141. The previously unsolved absolute stereochemistry of 3 and 4 was determined and the structures of other four new congeners were elucidated by extensive spectroscopic, chiral-phase HPLC, and single-crystal X-ray diffraction analyses. Compounds 1–5 bear no cytotoxicity against a number of human tumor cell lines but show selective anti-infective activity against Micrococcus luteus. 相似文献
2.
Michelle Farrugia Nicholas Trotter Soumini Vijayasarathy Angela A. Salim Zeinab G. Khalil Ernest Lacey Robert J. Capon 《Tetrahedron letters》2014
Chemical fractionation of the southern Australian marine sponge Phoriospongia sp. (CMB-03107) yielded phorioadenine A (1) as a nematocidal agent and the first reported example of a 6-N-acyladenine natural product. The structure of 1 was confirmed by spectroscopic analysis and the chemical synthesis of racemic (1a) and enantiomeric (1b) analogues. HPLC–ESIMS analysis of the crude sponge extract with comparisons to the synthetic 6-N-acyladenosine 2a provided evidence that the biosynthetically related adenosine, phorioadenosine A (2), was present as a trace co-metabolite. The rare starfish metabolite asterubine (3) was also isolated as a co-metabolite, and its structure confirmed by spectroscopic analysis and chemical synthesis. Biological investigations confirmed that natural products 1–3 and synthetic analogues 1a–e and 2a were not cytotoxic to multiple mammalian cancer cell lines, or Gram-positive or -negative bacteria. Nematocidal activity (inhibition of larval development of Haemonchus contortus) detected in the Phoriospongia sp. extract was attributed to 1 (LD99 31 μg/mL), with preliminary structure–activity relationship investigations confirming the importance of the N-acyl side chain. 相似文献
3.
Two new Lycopodium alkaloids, lycopladines F (1) and G (2), have been isolated from the club moss Lycopodium complanatum, and the structures and relative stereochemistries of 1 and 2 were elucidated on the basis of spectroscopic data. Lycopladine F (1) is a rare C16N2-type Lycopodium alkaloid possessing an amino acid residue (C4N). 相似文献
4.
Kiyotake Suenaga Tsuyoshi Mutou Takashi Itoh Noboru Takada Masaki Takagi Hideo Kigoshi Kiyoyuki Yamada 《Tetrahedron》2004,60(38):8509-8527
The bioassay-guided fractionation of the cytotoxic constituents of the Japanese sea hare Dollabella auricularia led to the isolation of aurilide (1), a 26-membered cyclodepsipeptide. The gross structure of 1 was established by spectroscopic analysis including 2D NMR techniques. The absolute stereostructure was determined by chiral HPLC analysis of acid hydrolysates of 1 and by the enantioselective synthesis of a degradation product arising from a dihydroxylated fatty acid portion. The enantioselective synthesis of 1 was achieved in 12% overall yield (16 steps) and confirmed the absolute stereostructure of 1. The cytotoxicity of 1 was evaluated using a synthetic sample, which was found to exhibit potent cytotoxicity against HeLa S3 cells with an IC50 of 0.011 μg/mL. Further biological and pharmacological studies of 1 have been carried out by using synthetic 1. 相似文献
5.
N,N,N′,N′-Tetramethylmethanediamine (1a), N,N,N′,N′-tetramethylethanediamine (1b), N,N,N′,N′-tetramethyl-1,3-propanediamine (1c), and N,N,N′,N′-tetramethyl-1,6-hexanediamine (1d) were reacted at 25 °C with 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (2a), 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedione (2b), 2-thenoyltrifluoroacetone (2c), and 4,4,4-trifluoro-1-(2-furyl)-1,3-butanedione (2d) to form the ionic adducts 3-18. 1,4,7,10-Tetraazacyclododecane (1e) reacted at 25 °C with β-diketones (2a-d) and 1,1,1-trifluoro-2,4-pentanedione (2e) to give ionic solids 19-23 in good yields. Some of the products are liquid at 25 °C and are thermally stable over long liquid ranges as determined by thermal gravimetric analyses. Single-crystal X-ray structure determinations show that compounds 9 and 21 crystallize in the monoclinic space groups P2(1)/c and P2(1)/n, respectively. All the new compounds were characterized by 1H, 19F and 13C NMR, electrospray MS and/or elemental analyses. 相似文献
6.
Satomi Nakatani Masaaki Sato Hiroshi Hirota Masami Ishibashi 《Tetrahedron letters》2005,46(2):267-271
Melleumin A (1), a novel peptide lactone, has been isolated from the laboratory-cultured plasmodium of myxomycete Physarum melleum, and its structure was elucidated by spectral data. Melleumin A (1) consisted of four residues (p-methoxybenzoic acid, l-threonine, glycine, and an unusual amino acid, a tyrosine-attached acetic acid). 相似文献
7.
The reaction of the Baylis-Hillman adducts 1b-f derived from o-nitrobenzaldehydes in trifluoroacetic acid in the presence of triflic acid (0.2 equiv.) afforded 3-substituted-4-hydroxyquinoline N-oxides 2b-e and 2a in good to moderate yields. The reaction mechanism was evidenced by the experiment with 1f, the Baylis-Hillman adduct of 2-nitrobenzaldehyde N-tosylimine, as the one involving N-hydroxyisoxazoline as the key intermediate. 相似文献
8.
The nucleophilic conjugate addition of chiral formaldehyde N,N-dialkylhydrazones 1 to doubly activated cyclic alkenes 2-8 proceeds smoothly to afford the corresponding Michael adducts 14, 16, 18, 20, 22, 24, and 25 in variable yields and selectivities. The reactions take place either spontaneously or in the presence of MgI2 as a mild Lewis acid depending on the type of substrate. Release of the chiral auxiliary was achieved by transformation of the hydrazone moiety into acetals, dithioacetals or nitriles. 相似文献
9.
Vered Reshef 《Tetrahedron》2006,62(31):7361-7369
Three new microviridins namely, SD1684 (1), SD1634 (2), and SD1652 (3), were isolated from the hydrophilic extract of Microcystis aeruginosa. The planar structures of compounds 1-3 were determined by homonuclear and inverse-heteronuclear 2D-NMR techniques as well as by high-resolution mass spectrometry. The absolute configuration of the asymmetric centers was studied using Marfey's method for HPLC. Compounds 1-3 contain l-threo-β-hydroxy aspartic acid as a building block of the peptide chain. This is the first example where microviridins contain non-proteinogenic amino acid in their structure. Compound 2 is a mild serine protease inhibitor. 相似文献
10.
Maria Daoudi Abdelali Kerbal Jean-Pierre Launay Taibi Ben Hadda Pierre H. Dixneuf 《Tetrahedron》2006,62(13):3123-3127
A series of tridentate ligands N,N-bis-[(di-substituted-1-pyrazolyl)methyl]arylamines 2-3a,b and benzylamine 4a,b, tetradentate N,N′-bis-[(di-substituted-1-pyrazolyl)methyl]para-phenylenediamines 7a,b and hexadentate N,N,N′,N′-tetra-[(di-substituted-1-pyrazolyl)methyl]para-phenylenediamines 8a,b has been prepared in good yield by condensation of arylamines, benzylamine or para-phenylenediamine with N-hydroxymethyl disubstituted pyrazoles 1a,b. The synthesis and characterisation of these various polydentate ligands are described. 相似文献
11.
Deyi Zhang 《Tetrahedron letters》2008,49(13):2052-2055
Under near neutral and mildly basic conditions, primary N4-(α-aminoacyl)cytidines (4a-g) undergo a facile rearrangement to form N-(4-cytidinyl)amino acid amides (5a-g). Secondary aminoacyl derivatives rearrange with other competing pathways. Tertiary aminoacyl derivatives do not rearrange. 相似文献
12.
Santosh Kurhade Vandana Rajopadhyay Satheesh Veerappa Avaragolla Summon Koul Parimi Atchuta Ramaiah Debnath Bhuniya 《Tetrahedron letters》2014
l-(N-Cbz)-7-azaisotryptophan, l-(N-Cbz)-1a, a new isostere of tryptophan, was synthesized by reacting Li2-(N-Boc)-2-amino-3-picoline, Li2-(N-Boc)-2a, with appropriately protected l-aspartic acid followed by simple functional group manipulation. This synthetic success led us to access a set of analogs of azaisotryptophan (4a–c; 6a–c) as well as a new class of chiral amines (7a–c; 8a–c) for future application in asymmetric synthesis and design of homochiral ligands. Further, we have generalized the method substantiating a variety of new azaindol-2-yl derivatives (10aa–10lc) with functionalized substituents. In a preliminary luminescence characterization, l-(N-Cbz)-1a has exhibited about 30 nm bathochromic shifted fluorescence emission compared to tryptophan and (N-Cbz)-tryptophan. 相似文献
13.
M. Letizia Ciavatta Emiliano Manzo Guido Villani Margherita Gavagnin 《Tetrahedron》2010,66(38):7533-1979
Five new unsaturated 2-amino-3-alcohols, crucigasterins A-E (2-6), were isolated together with known related compound 7 from the Mediterranean ascidian Pseudodistoma crucigaster and characterised as diacetyl derivatives (2a-6a) by spectroscopic methods. The threo-relative configuration of the amino alcohol portion was inferred by NOE analysis of the oxazolidinone derivative of crucigasterin A (2) as well as by 13C NMR comparison with synthetic threo and erythro model compounds. The co-occurring metabolites were assumed to have the same relative configuration as 2 by comparison of the diagnostic carbon value of C-1. The absolute stereochemistry of compound 7 that had not been previously reported was determined by applying the modified Mosher’s method on the corresponding N-acetyl derivative. The same absolute configuration was suggested for the other co-occurring crucigasterins by biogenetic considerations. Antibacterial and antifungal activities of selected crucigasterins were also evaluated. 相似文献
14.
Two novel pyrroloquinoline ribosides, N-1-β-D-ribofuranosyldamirone C (1), and N-1-β-D-ribofuranosylmakaluvamine I (2) were isolated from a new species of South African latrunculid sponge, Strongylodesma aliwaliensis. Standard spectroscopic techniques were used to determine the structures of 1 and 2. Molecular modeling studies and NOESY data of 1 and 2, in combination with chiral GC analysis of their derivatized acid hydrolysis products, established the β-D-configuration of the ribofuranose moieties. 相似文献
15.
Three new prenylated butylphloroglucinol derivatives, takaneones A-C (1-3), were isolated from the MeOH extracts of the aerial parts of Hypericum sikokumontanum together with two new prenylated phloroglucinol derivatives, takaneols A and B (4 and 5). The structures of the isolated compounds were elucidated by exhaustive spectroscopic analysis. The cytotoxicities of the isolated compounds against human cancer cell lines were evaluated. Compounds 2-4 showed cytotoxicities against K562/Adr multi-drug resistant (MDR) cancer cells with IC50 values ranging from 4.7 to 10.0 μg/mL, which were slightly more potent than doxorubicin. Their potency of cytotoxicities against MDR cancer cell lines (KB-C2 and K562/Adr) were similar to those against sensitive cell lines (KB and K562). 相似文献
16.
Kenichi Miyata Ryuji Tamamushi Haruhiko Taguchi Kohji Seio Mitsuo Sekine 《Tetrahedron letters》2004,45(51):9365-9368
Modified oligodeoxynucleotides incorporating 4-N-(N-arylcarbamoyl)-dC derivatives 1a-c were synthesized. The 1H NMR spectra of 1a-c suggest that the carbamoyl group forms an intramolecular hydrogen bond with the cytosine ring nitrogen atom so that formation of a Watson-Crick base pair with the complementary guanine base is inhibited. The hybridization properties of oligodeoxynucleotides containing 1a-c were investigated by use of Tm analysis. The hybridization properties of 4-N-(N-phenylcarbamoyl)-dC (1a) were similar to those of 4-N-(N-alkylcarbamoyl)-dC derivatives reported previously. In sharp contrast to 1a, it turned out that 4-N-(N-napht-1-yl) and (N-quionol-5-yl)-dC (1b,c) have a unique property as a universal base. 相似文献
17.
A new 3-amino-6-hydroxy-2-piperidone (Ahp) containing peptolide, pompanopeptin A (1), and a novel N-methyl-2-amino-6-(4′-hydroxyphenyl)hexanoic acid (N-Me-Ahpha) containing cyclic pentapeptide connected with a sixth amino acid residue via a rare ureido linkage, pompanopeptin B (2), were isolated from the marine cyanobacterium Lyngbya confervoides collected from the southeastern coast of Florida. Their planar structures were determined by a combination of NMR spectroscopic analysis and mass spectrometry. The absolute configurations were established using advanced Marfey's method and chiral HPLC analysis of the chemical degradation products. Compound 1 selectively inhibited trypsin over elastase and chymotrypsin, with an IC50 value of 2.4 μM; selectivity is conferred by an arginine residue in the cyclic core. 相似文献
18.
Douglas Onyancha Vincent Nyamori Christopher Imrie Thomas I.A. Gerber 《Journal of organometallic chemistry》2009,694(2):207-1132
The efficient and simple routes for the synthesis of various ferrocenyl derivatives from ferrocenylcarbinols and N,N′-thiocarbonyldiimidazole (TCDI) are described. It involves grinding the two substrates in a Pyrex tube with a glass rod at room temperature. The reaction of ferrocenylmethanol (1a) provided S,S-bis(ferrocenylmethyl)dithiocarbonate (1b), whose crystal structure and a plausible mechanism for its formation are also reported. The reaction of 1-ferrocenyl-1-phenylmethanol (2a) and 1-ferrocenylbutanol (2b) gave the products 2c and 2d, respectively. The reaction of ω-ferrocenyl alcohols 4-ferrocenylphenol (3a) and 6-ferrocenylhexan-1-ol (3b) yielded the products 3c and 3d, respectively. Reaction of 1,1′-ferrocenedimethanol (3e) afforded 3f in moderate yield, and by contrast, it was not similar to 1b. Reaction of [4-(trifluoromethyl)phenyl]methanol (4a) provided the thiocarbonate 4b in good yield. 相似文献
19.
Shreyans K. Jain Samdarshi Meena Asif K. Qazi Aashiq Hussain Sunil K. Bhola Rajendra Kshirsagar Koteppa Pari Anamika Khajuria Abid Hamid R. Uma Shaanker Sandip B. Bharate Ram A. Vishwakarma 《Tetrahedron letters》2013
The chromone alkaloid dysoline (1), a new regioisomer of rohitukine (2) along with rohitukine and rohitukine-N-oxide (3) were isolated from the stem barks of Dysoxylum binectariferum. The structure of dysoline (1) was determined by extensive 2D-NMR studies and the absolute configuration was established by NOESY and CD spectra. Dysoline (1) consisted of a 5,7-dihydroxy-2-methylchromone nucleus substituted with a 2′-hydroxylated N-Me piperidine ring at the C-6 position. Dysoline differs from rohitukine by the position of the piperidine ring on the chromone nucleus. Dysoline displayed promising cytotoxicity in HT1080 fibrosarcoma cells with an IC50 of 0.21 μM, and also displayed significant inhibition of proinflammatory cytokines TNF-α and IL-6. 相似文献
20.
Akira Yogi Jae-Hwan Oh Takanori Nishioka Rika Tanaka Eiji Asato Isamu Kinoshita Satoshi Takara 《Polyhedron》2010
The syntheses and characterization of novel ruthenium(II) complexes containing bis(3,5-dimethylpyrazol-1-yl)acetato (bdmpza), a new class of scorpionate ligands, are reported herein. [RuCl(bdmpza)(η4-1,5-cyclooctadiene)] (1) was found to be a versatile precursor to synthesize a wide range of new ruthenium(II) complexes with the bdmpza ligand. The treatment of 1 with pyridine (py), diphenylphosphinoethane (dppe), 2,2′-bipyridyl (bpy), 1,10-phenanethroline (phen), or bispicolylamine (Hbpica) in refluxing N,N-dimethylformamide resulted in displacement of the 1,5-cyclooctadiene ligand to afford [RuCl(bdmpza)(py)2] (2), [RuCl(bdmpza)(dppe)] (3), [RuCl(bdmpza)(bpy)] (4), [RuCl(bdmpza)(phen)] (5), and [Ru(bdmpza)(Hbpica)]Cl (6Cl) in good yields, respectively. The structures of 1–4, and 6 were determined by X-ray structure analyses. 相似文献