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1.
Acyclic nucleoside 2-amino-6-(4-methoxyphenylthio)-9-[2-(phosphonomethoxy)ethyl]purine bis(2,2,2-trifluoroethyl) ester (ABE, 1) is a new hepatitis B virus (HBV) specific antiviral reagent and shows high anti-HBV activity. Carbon-11 labeled ABE may serve as a novel reporter probe for positron emission tomography (PET) to image HBV and herpes simplex virus thymidine kinase (HSV-tk) in cancers. The radiolabeling precursors 2-amino-6-(4-hydroxyphenylthio)-9-[2-(phosphonomethoxy)ethyl]purine bis(2,2,2-trifluoroethyl) ester (10) and 2-N-Boc protected analogue 2-N-bis(Boc)amino-6-(4-hydroxyphenylthio)-9-[2-(phosphonomethoxy)ethyl]purine bis(2,2,2-trifluoroethyl) ester (12), and the reference standard ABE were synthesized from bis(trifluoroethyl) (2-iodoethoxy)methylphosphonate (5), guanine (6), and 2-amino-6-chloropurine (8). The target radiotracer 2-amino-6-(4-[11C]methoxyphenylthio)-9-[2-(phosphonomethoxy)ethyl]purine bis(2,2,2-trifluoroethyl) ester ([11C]ABE, [11C]1) was prepared by O-[11C]methylation of the unprotected HO-precursor 10, or 2-N-Boc protected HO-precursor 12 with [11C]methyl triflate followed by a quick deprotection reaction, and isolated by solid-phase extraction (SPE) purification in 40-55% radiochemical yields.  相似文献   

2.
Robert H. White 《Chirality》1996,8(4):332-340
The configuration at the C-9 of methanopterin (MPT) has been determined by comparing the circular dichroism (CD) spectra of MPT and its hydrolytic fragment, 1-[4-[[1-(2-amino-7-methyl-4-hydroxy-6-pteridinyl)-ethyl]amino]phenyl]-1-deoxy-D -ribitol (HP-1), with the CD spectra of a series of model compounds of known stereochemistry. These compounds included (S)-6-[1-(4-carboxymethylanilino)ethyl]pterin, (S-6(1-hydroxyethyl)-7-methylpterin, (S-6-(1-hydroxyethyl)pterin, (R)-6-(1-phenoxyethyl)pterin, D (+)-neopterin, and L -biopterin. From this comparison it was concluded that MPT has the R configuration at C-9 and is thus configurationally related to D (+)-neopterin, which has the S configuration at C-1. From previous work establishing the relative stereochemistry at C-6, C-7, and C-9 of N5-N10-methenyl-5,6,7,8-tetrahydromethanopterin (N5-N10-methenyl-H4MPT) as R, S, and R, respectively, it is clear that the remaining asymmetric carbons at C-6 and C-7 of H4MPT have the S and S configuration, respectively. Comparison of these latter two positions to the equivalent carbons in 5,6,7,8-tetrahydrofolate (H4folate) show that the steps involved in the biological reduction of MPT to H4MPT occur with the same stereochemical outcome as those involved in the biological reduction of folate to H4folate. © 1996 Wiley-Liss, Inc.  相似文献   

3.
为研究柯拉斯那(Aquilaria crassna Pierre ex Lecomte)沉香的化学成分。实验采用多种柱色谱方法从该沉香中分离得到9个2-(2-苯乙基)色酮类化合物,通过现代波谱学技术分别鉴定为6-甲氧基-2-[2-(3′-羟基-4′-甲氧基苯基)乙基]色酮(1)、5-羟基-6-甲氧基-2-[2-(3′-羟基-4′-甲氧基苯基)乙基]色酮(2)、tetrahydrochromone F(3)、6-甲氧基-2-[2-(3′-甲氧基-4′-羟基苯基)乙基]色酮(4)、6-甲氧基-7-羟基-2-[2-(4′-甲氧基苯基)乙基]色酮(5)、6,7-二甲氧基-2-[2-(3′-羟基-4′-甲氧基苯基)乙基]色酮(6)、6,7-二甲氧基-2-[2-(4′-甲氧基苯基)乙基]色酮(7)、6-羟基-2-[2-(4′-羟基苯基)乙基]色酮(8)、5-羟基-2-[2-(2′-羟基苯基)乙基]色酮(9)。化合物2、3和5~9均为首次从柯拉斯那所得沉香中分离得到。采用MTT法对单体化合物的细胞毒活性进行测试,测试结果表明,化合物1,2和4具有微弱的细胞毒活性。  相似文献   

4.
The synthesis and antimalarial properties of twelve new chlorinated 9H-xanthones, carrying a [2-(diethylamino)ethyl]amino group in position 1, are reported. All compounds were found to be active towards the chloroquine-susceptible and chloroquine-resistant strains 3D7 and Dd2, resp., of the protozoa parasite Plasmodium falciparum. Especially one compound, 6-chloro-1-{[2-(diethylamino)ethyl]amino}-9H-xanthen-9-one (1k), was found to exhibit significant in vitro activity (IC50 = 3.9 microM) towards the resistant Dd2 strain.  相似文献   

5.
The in vivo effects of nociceptin (N/OFQ(1–13)NH2) and its structural analogues ([Dab9]N/OFQ(1–13)NH2, [Dap9]N/OFQ(1–13)NH2 and [Cav9]N/OFQ(1–13)NH2) on the levels of lipid peroxidation and cell antioxidants (enzyme and non‐enzyme) in brain of control and kainic acid (KA)‐treated rats were studied. In control animals, [Dab9]N/OFQ(1–13)NH2 and [Dap9]N/OFQ(1–13)NH2, unlike N/OFQ(1–13)NH2 and [Cav9]N/OFQ(1–13)NH2, slightly increased the brain lipid peroxidation; the rest of the parameters were unchanged by all neuropeptides tested. KA (0.25 µg in 0.5 µl, i.c.v) increased the lipid peroxidation (4 and 24 h after KA‐injection) and decreased the glutathione level (1 h after KA‐administration). One hour after KA‐administration, the neuropeptides (2 µg in 0.5 µl, injected 30 min before KA) showed the following effects: a slight decrease in the KA‐induced lipid peroxidation by all nociceptin analogues and an enhancement of the KA‐decreased GSH level, but by [Cav9]N/OFQ(1–13)NH2 only. The brain antioxidant enzyme activities were unchanged in all used experimental groups. In addition, the nociceptin analogues, especially [Can9]N/OFQ(1–13)NH2, showed a good antioxidant capacity in chemical systems, generating reactive oxygen species. In conclusion, the substitution of lysin (Lys) in N/OFQ(1–13)NH2 molecule with other amino acids might contribute to changes in its antioxidant properties. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

6.
Ni2+ affinity columns are widely used for protein purification, but they carry the risk that Ni2+ ions may bind to the protein, either adventitiously or at a physiologically important site. Dialysis against ethylenediaminetetraacetic acid (EDTA) is normally used to remove metal ions bound adventitiously to proteins; however, this approach does not always work. Here we report that a bacterial endonuclease, the DNase domain of colicin E9, binds Ni2+ acquired from Ni2+ affinity columns, and appears to bind [Ni(EDTA)(H2O)n]2- at low ionic strength. NMR was used to detect the presence of both Ni2+ coordinated to amino acid side chains and [Ni(EDTA)(H2O)N]2-. Dialysis against > or =0.2 M NaCl was required to remove the [Ni(EDTA)(H2O)n]2-. The NMR procedure we have used to characterize the presence of Ni2+ and [Ni(EDTA)(H2O)n]2- should be applicable to other proteins where there is the possibility of binding paramagnetic metal ions that are present to expedite protein purification. In the present case, the binding of Ni2+ seems likely to be physiologically relevant, and the NMR data complement recent X-ray crystallographic evidence concerning the number of histidine ligands to bound Ni2+.  相似文献   

7.
For 22 days after monocrotaline injection two groups of rats received either of the monocarbonyl curcumin analogs (2E,6E)‐2,6‐bis(2‐bromobenzylidene)cycloxehanone (B2BrBC) and (2E,6E)‐2,6‐bis([2‐tri?uoromethyl]benzylidene)cyclohexanone (C66), and their right ventricle parameters were compared to those from the control and the monocrotaline injected animals. B2BrBC and C66 treatments did not prevent the monocrotaline‐induced right ventricular hypertrophy but attenuated the changes in antioxidant enzyme activities and reduced inflammation. The level of thiol‐based nonenzymatic antioxidants did not change in the function of monocrotaline or curcumin analogs treatment. However, due to its stronger antioxidant properties, only B2BrBC treatment was effective in the reduction of monocrotaline‐associated lipid peroxidation. The obtained results suggest that increasing the levels of antioxidant enzymes may not be sufficient to reduce oxidative stress and chronic inflammation optimally and our current study supports the potential of compounds with more than one beneficial biological activity as a promising treatment against the progression of cardiac hypertrophy.  相似文献   

8.
Serotonin stimulated adenylate cyclase in Aplysia neurons with a Kact of 0.7 microM. Under the same conditions, 1-[2-(4-aminophenyl)ethyl]4-(3-trifluoromethylphenyl)piperazine stimulated adenylate cyclase with a Kact of 20 microM. The azido derivative of this compound, 1-[2-(4-azidophenyl)ethyl]4-(3-trifluoromethylphenyl)piperazine, or of serotonin, (4-amino, 3-nitrophenylazido-serotonin), also stimulated the cyclase in the dark, but with lower efficiency (Kact greater than 10(-4) M). Irradiation of the membranes in the presence of 100 microM 1-[2-(4-azidophenyl)ethyl]4-(3-trifluoromethylphenyl)piperazine abolished 75% of the cyclase activity stimulated by 5 microM serotonin. Under the same conditions, 100 microM 4-amino, 3-nitrophenylazido-serotonin did not inhibit serotonin-stimulated adenylate cyclase activity. When [3H]1-[2-(4-azidophenyl)ethyl]4-(3-trifluoromethylphenyl)piperazine (20 microM) was irradiated with membranes for 5 min at 4 degrees C, a dozen peptides were labeled, as revealed by a fluorogram of sodium dodecyl sulfate-polyacrylamide gels. Among them, the labeling of five polypeptides (molecular weights of 45,000, 55,000, 63,000, 80,000, and 94,000) was protected by the presence of 0.2 mM serotonin during photolysis. These peptides may be related to serotonin receptors.  相似文献   

9.
A series of novel bis(L-amino acid) ester prodrugs of 9-[2-(phosphonomethoxy)ethyl] adenine (PMEA) was synthesized and their anti-HBV activity was evaluated in HepG 2 2.2.15 cells. Compounds 11, 12, 21, 22, 26, and 27 demonstrated more potent anti-HBV activity and higher selective index (SI) than adefovir dipivoxil, which was used as a positive control. Compound 11, which was found to be the most potent one, was five times more potent than adefovir dipivoxil with EC50 value of 0.095 microM and CC50 value of 6636 microM. The SI value (>69,000) of compound 11 was 60 times and 24 times higher than those of adefovir dipivoxil and lamivudine, respectively. In vitro stability studies showed that compound 11 was relatively more stable than adefovir dipivoxil with t1/2 of 270 min. These findings suggested that compound 11 could be considered as a promising candidate for further in vivo studies.  相似文献   

10.
Rahman MM  Gray AI 《Phytochemistry》2005,66(13):1601-1606
A benzoisofuranone derivative, 3xi-(1xi-hydroxyethyl)-7-hydroxy-1-isobenzofuranone, and a dimeric carbazole alkaloid, 3,3'-[oxybis(methylene)]bis(9-methoxy-9H-carbazole), along with six known carbazole alkaloids and three known steroids were isolated from the stem bark of Murraya koenigii. The structures of these compounds were established unambiguously by UV, IR, MS and a series of 1D and 2D NMR analyses. The minimum inhibitory concentrations (MIC) of these compounds were found to be in the range 3.13-100 microg/ml.  相似文献   

11.
In a previous study, it was demonstrated that N-(phenethyl)succinamic acid (PESA) derivatives form a new category of root-promoting substances which do not exhibit auxin-like activities, such as stem elongation and leaf epinasty (Soejima et al., 2000 [Plant Cell Physiol. 41s: 197]). In this study, N-[2-(3-indolyl)ethyl]succinamic acid (IESA) and N-[2-(1-naphthyl)ethyl]succinamic acid (NESA) were synthesized, and their biological activities were evaluated. In an adzuki root-promoting assay, IESA and NESA exhibited root-promoting activity equivalent to PESA. In adzuki stem elongation assays, elongation activity was not observed in the stem segments soaked in either an IESA or NESA aqueous solution, whereas the stem segments immersed in Indole-3-acetic acid (IAA) or 1-naphthylacetic acid (NAA) aqueous solution were clearly elongated. In an epinastic bending study, IAA and NAA exhibited leaf epinasty, whereas IESA and NESA did not, suggesting that the IESA and NESA derivatives belong to the same category of root-promoting substances as PESA derivatives and are different from auxin-like substances. In addition, eleven kinds of IESA derivatives and nineteen kinds of NESA derivatives were synthesized, and their root-promoting activities were measured. The activities of methyl ester derivatives were approximately three times higher than that of the acid compounds, with exceptions for some compounds. The partition coefficient (P) between 1-octanol and water for each IESA, NESA, and PESA derivative was measured in order to evaluate the hydrophobicity of their molecules and to determine their structure–activity relationship. The results indicate that the root-promoting activity of the acid compounds was significantly correlated with their hydrophobicity, whereas that of ester derivatives was not correlated.  相似文献   

12.
该文采用ODS、硅胶、Sephadex LH-20等柱色谱技术,对柬埔寨野生柯拉斯那沉香(Aquilaria crassna)进行了研究。结果表明:从柬埔寨柯拉斯那所产沉香的乙醇提取物中进行分离共得到了10个化合物,包括一对对映异构体(9a/9b)。经波谱解析分别鉴定为6-甲氧基-2-[2-(3-羟基-4-甲氧基苯)乙基]色酮(1)、6-甲氧基-2-[2-(3-甲氧基-4-羟基苯)乙基]色酮(2)、6,7-二甲氧基-2-(2-苯乙基)色酮(3)、6-羟基-2-(2-苯乙基)色酮(4)、6-羟基-2-[2-(4-甲氧基苯)乙基]色酮(5)、8-氯-6-羟基-2-[2-(3-羟基-4-甲氧基苯)乙基]色酮(6)、8-氯-6-羟基-2-[2-(4-甲氧基苯)乙基]色酮(7)、oxidoagarochromone B(8)、4'-demethoxyaqusisnenone D(9)。其中,化合物6、7和9均为首次从柯拉斯那沉香中分离得到。活性测试结果显示,化合物1和2对乙酰胆碱脂酶具有一定的抑制活性,化合物2对人慢性髓原白血病细胞K562具有较弱的抑制作用。  相似文献   

13.
Condensation of 1,3‐dihydro‐2,3‐dioxo‐2H‐indoles (1a–c) with galactaric acid bis hydrazide (2) gave the corresponding galactaric acid bis[2‐(1,2‐dihydro‐2‐oxo‐3H‐indol‐3‐ylidene)hydrazides] (3a–c). Acetylation of the latter compounds with acetic anhydride in the presence of pyridine at ambient temperature gave the 2,3,4,5‐tetra‐O‐acetylgalactaric acid bis[2‐(1,2‐dihydro‐2‐oxo‐1‐substituted‐3H‐indol‐3‐ylidene)hydrazides] (4b–d). Heterocyclization of the tetra‐O‐acetates 4b–d by heating with thionyl chloride afforded the double headed acyclo C‐nucleosides: 1,2,3,4‐tetra‐O‐acetyl‐1,4‐bis{9‐substituted‐1,3,4‐oxadiazino[6,5‐b]indol‐2‐yl‐1‐ium}‐galacto‐tetritol dichlorides (5b–d). Structures of the prepared compounds were elucidated from their spectral properties.  相似文献   

14.
Five compounds having a striking effect on the color of Marsh seedless grapefruit are reported. The compounds, namely [β-(diethylamino)-ethoxy]-benzene, [γ-(diethylamino)-propoxy]-benzene, [δ-(diethylamino)-butoxy]-benzene, 4-[β-(diethylamino)-ethoxy]-benzaldehyde, and diethylaminoethyl anisolate caused a 5- to 12-fold increase in the carotene content. Lycopene, not normally accumulated, became the major pigment. The mode of action appears to be similar to that of CPTA.  相似文献   

15.
A series of new arctigenin and 9-deoxy-arctigenin derivatives bearing different ester and ether side chains at the phenolic hydroxyl positions are designed, synthesized, and evaluated for activating AMPK potency in L6 myoblasts. Initial biological evaluation indicates that some alkyl ester and phenethyl ether arctigenin derivatives display potential activities in AMPK phosphorylation improvement. Further structure–activity relationship analysis shows that arctigenin ester derivatives 3a, 3h and 9-deoxy-arctigenin phenethyl ether derivatives 6a, 6c, 6d activate AMPK more potently than arctigenin. Moreover, the 2-(3,4-dimethoxyphenyl)ethyl ether moiety of 6c has been demonstrated as a potential functional group to improve the effect of AMPK phosphorylation. The structural optimization of arctigenin leads to the identification of 6c as a promising lead compound that exhibits excellent activity in AMPK activation.  相似文献   

16.
Two new isoprenoid compounds, 6, 10-dimethylspiro [4,5] dec-6-ene-2, 8-dione and 2-(1′, 2′-dihydroxy-1′-methylethyl)-6, 10- dimethyl-9-hydroxyspiro [4,5] dec-6-en-8-one, have been isolated from potato tubers infected with Phoma exigua var. foveata.  相似文献   

17.
 The stability constants of the 1 : 1 complexes formed between Mg2+ and the anions of the N1, N3, and N7 deaza derivatives of 9-[2-(phosphonomethoxy)ethyl]adenine (PA2–), i.e., of Mg(H;PA)+ and Mg(PA), were determined by potentiometric pH titration in aqueous solution (25  °C; I=0.1 M, NaNO3) and compared with previous results [Sigel H, et al. (1992) Helv Chim Acta 75 : 2634–2656], obtained under the same conditions, for the corresponding complexes of 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA2–) and (phosphonomethoxy)ethane (PME2–). Based on the analysis of a microconstant scheme it is concluded that in the monoprotonated complexes, Mg(H;PA)+, Mg2+ is coordinated to a significant part at the nucleobase, H+ being at the phosphonate group. By making use of log K Mg Mg(R-PO3) versus pK H H(R-PO3) straight-line plots (also obtained previously; see above) for simple phosphonates and phosphate monoesters, it is shown that all the Mg(PA) complexes, including those with PMEA2– and PME2–, are more stable than expected on the basis of the basicity of the ―PO2– 3 group. This proves that, to some extent, five-membered chelates, Mg(PA)cl/O, involving the ether oxygen of the ―CH2―O―CH2―PO2– 3 chain are formed; their formation degree amounts to about 30–40% in equilibrium with the isomer having only a phosphonate-Mg2+ coordination. In the case of Mg(1-deaza-PMEA), probably a further isomer occurs in which also N3 of the nucleobase participates. The different properties between the Mg(PA) species and the Mg(AMP) complex are discussed. Received: 26 January 1998 / Accepted: 19 May 1998  相似文献   

18.
Rat hippocampal 5-hydroxytryptamine1A (5-HT1A) binding sites were solubilized with a yield of 34% using 3-[3-(cholamidopropyl)dimethylammonio]-1-propane sulfonate (CHAPS, 10 mM) as detergent. Kinetic analyses of [3H]8-hydroxy-2-(di-n-propylamino)tetralin ([3H]8-OH-DPAT) binding indicated that the 5-HT1A sites exhibit the same properties in the soluble form as in the membrane-bound form. Furthermore, a positive correlation (r = 0.988) was found between the respective pIC50 values of a series of agonists and antagonists to inhibit [3H]8-OH-DPAT binding to either soluble or membrane-bound 5-HT1A sites. Gel filtration through Sephacryl S-400 as well as chromatography on wheat germ agglutinin (WGA)-agarose did not affect the modulation by guanine nucleotides (5'-guanylylimidodiphosphate) of [3H]8-OH-DPAT binding which suggests that the 5-HT1A binding subunit is a glycoprotein tightly attached to a G protein even in its soluble form. The [3H]8-OH-DPAT binding material eluted from Sephacryl S-400 had an apparent molecular mass of 155 kilodaltons, as expected from a heterodimer with one binding subunit (approximately 60 kilodaltons) and one G protein (approximately 80 kilodaltons). Marked enrichment in 5-HT1A binding sites relative to other soluble proteins was found in the peak fractions eluted from Sephacryl S-400 (by sixfold) and WGA-agarose (by 26-fold) columns, suggesting that these chromatographic steps might be of interest for the purification of central 5-HT1A receptors.  相似文献   

19.
The effect of chronic nicotine treatment on the release of endogenous glutamate (GLU), aspartate (ASP) and GABA evoked in vitro by KCl, 4-aminopyridine (4AP) and nicotinic agonists in synaptosomes of rat hippocampus was investigated. Rats were chronically administered with nicotine bitartrate or saline vehicle each for 14 days using osmotic mini-pumps. Hippocampal synaptosomes were stimulated with KCl, 4AP, nicotine or with choline (Ch) and 5-iodo-A-85380 dihydrochloride (5IA85380). The GLU and ASP overflow evoked by Ch, nicotine, KCl and 4AP were increased in treated animals while the nicotine-evoked GABA overflow was reduced and that evoked by Ch, KCl and 4AP was unaffected. The 5IA85380-evoked overflow of the three aminoacids (AAs) was always reduced. The increase of ASP and GLU overflow evoked by KCl, 4AP or Ch was blocked by dl-threo-β-benzyloxyaspartic acid (dl-TBOA), a carrier transporter inhibitor, and by inhibitors of the Na(+)/Ca(2+) exchangers 2-[[4-[(4-nitrophenyl)methoxy]phenyl]methyl]-4-thiazolidinecarboxylic acid ethyl ester (SN-6) and 2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea mesylate (KB-R7943). In conclusion long-term nicotine treatment may selectively increase GLU and ASP overflow elicited by KCl, 4AP and Ch through the activation of a carrier-mediated release mechanism and completely abolished the stimulatory effects of α4β2 nAChRs which modulate the release of all the three AA.  相似文献   

20.
Abstract

A series of 20?N-substituted derivatives of 1-arylimidazolidyn-2-ylideneurea and products of their cyclization was designed as compounds having double antinociceptive and serotoninergic activity. Ethyl {[(1-arylimidazolidin-2-ylidene)carbamoyl]amino}acetates were prepared from 1-aryl-4,5-dihydro-1H-imidazol-2-amines and ethyl isocyanatoacetate, and then converted with ammonia solution to 2-{[(1-phenylimidazolidin-2-ylidene)carbamoyl]amino}acetamides. Both series of N-substituted derivatives of 1-arylimidazolidyn-2-ylideneureas were subjected to cyclization to respective imidazo[1,2-a][1,3,5]triazines. Chain and cyclic compounds bearing ester moiety affected spontaneous locomotor activity, body temperature of mice as well as showed antinociceptive and serotoninergic activity. Interestingly, their antinociceptive activity was not reversed by naloxone, thus it is not mediated through the opioid system. Chain and cyclic compounds bearing amide moiety were devoid of central nervous system (CNS) activity which may be attributed to unfavorably low lipophilicity (connected with too high polar surface area and too small molecular volume) and poor blood–brain barrier permeation properties.  相似文献   

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