共查询到20条相似文献,搜索用时 31 毫秒
1.
Kosaku Hirota Yasunari Monguchi Hironao Sajiki Chizuko Yatome Akio Hiraoka Yukio Kitade 《Nucleosides, nucleotides & nucleic acids》2013,32(8):1333-1345
Abstract In expectation of discovering their antiviral activity, acyclic adenosine derivatives 7, 11, 12, and 16 were designed as analogs of neplanocin A (NPA) and L-eritadenine which are strong inhibitors of S-adenosyl-L-homocysteine hydrolase. The 1′,5′-seco-analog of 4′-deoxymethyl-NPA (DHCA) 7 was synthesized by dideoxygenation of 9-(2,3-O-isopropylidene-D-ribityl)adenine (2). Acyclic DHCA analogs 11 and 16 were obtained by Wittig reaction of the aldehyde 3 with Ph3P=CHCO2Et and Ph3P=CHCN, respectively. Hydrolysis of the ester 11 afforded a vinylog of L-eritadenine 12. The synthesized acyclic nucleosides 7, 10, and 11 were evaluated for antiviral activity, however, none of them showed any significant antiviral activity. 相似文献
2.
《Nucleosides, nucleotides & nucleic acids》2013,32(3):161-172
A useful route is described for obtaining Z and E unsaturated alkylating agents 3 and 4. Coupling 6-azauracils 5 and 6 with unsaturated alkylating agent followed by the deprotection with H+ resin gave acyclonucleosides 11–14 in good overall yields. Unsaturated acyclonucleosides phosphonates 19 and 20 were prepared using potassium carbonate as base and 4-bromobut-2-enyl diethyl phosphonate 16 as the alkylating agent. The introduction of a propargyl group at the N-3 position of acyclonucleosides 7, 8, 17, 18, 19, and 20 was achieved using potassium carbonate in DMF. 相似文献
3.
Amalraj Ambrose Jiri Zemlicka Earl R. Kern John C. Drach Elizabeth Gullen Yung-Chi Cheng 《Nucleosides, nucleotides & nucleic acids》2013,32(10-12):1763-1774
The Z- and E-thymine and cytosine pronucleotides 3d, 4d, 3e, and 4e of methylenecyclopropane nucleosides analogues were synthesized, evaluated for their antiviral activity against human cytomegalovirus (HCMV), herpes simplex virus 1 and 2 (HSV-1 and HSV-2), varicella zoster virus (VZV), Epstein-Barr virus (EBV), human immunodeficiency virus type 1 (HSV-1), and hepatitis B virus (HBV) and their potency was compared with the parent compounds 1d, 2d, 1e, and 2e. Prodrugs 3d and 4d were obtained by phosphorylation of parent analogues 1d or 2d with reagent 8. A similar phosphorylation of N4-benzoylcytosine methylenecyclopropanes 9a and 9b gave intermediates 11a and 11b. Deprotection with hydrazine in pyridine–acetic acid gave pronucleotides 3e and 4e. The Z-cytosine analogue 3e was active against HCMV and EBV. The cytosine E-isomer 4e was moderately effective against EBV. 相似文献
4.
Zhang L Liu HL Yang GH Huang XR Li Y Sun YB Sun CC 《Journal of molecular modeling》2011,17(12):3173-3181
A detailed doublet potential energy surface for the reaction of CH with CH3CCH is investigated at the B3LYP/6-311G(d,p) and G3B3 (single-point) levels. Various possible reaction pathways are probed.
It is shown that the reaction is initiated by the addition of CH to the terminal C atom of CH3CCH, forming CH3CCHCH 1 (1a,1b). Starting from 1 (1a,1b), the most feasible pathway is the ring closure of 1a to CH3–cCCHCH 2 followed by dissociation to P
3
(CH3–cCCCH+H), or a 2,3 H shift in 1a to form CH3CHCCH 3 followed by C–H bond cleavage to form P
5
(CH2CHCCH+H), or a 1,2 H-shift in 1 (1a, 1b) to form CH3CCCH2
4 followed by C–H bond fission to form P
6
(CH2CCCH2+H). Much less competitively, 1 (1a,1b) can undergo 3,4 H shift to form CH2CHCHCH 5. Subsequently, 5 can undergo either C–H bond cleavage to form P
5
(CH2CHCCH+H) or C–C bond cleavage to generate P
7
(C2H2+C2H3). Our calculated results may represent the first mechanistic study of the CH + CH3CCH reaction, and may thus lead to a deeper understanding of the title reaction. 相似文献
5.
Akira Tanaka Hirotoshi Kamata Kyohei Yamashita 《Bioscience, biotechnology, and biochemistry》2013,77(8):2043-2048
A novel synthesis of the enone 12 starting from (+)-dihydrocarvone (3) and its transformation into (+)-7-hydroxycostal (1) are described. The ketone 10, obtained from 4 through a four-step sequence was converted to 12 by acid-catalyzed elimination and subsequent regioselective hydrogenation. Alternatively, the methoxyhydroperoxide 13 generated by the ozonolysis of 4 was subjected to the Criegee rearrangement, providing a mixture of 10 and 14, which on acid treatment, gave 11. Transformation of 12 into 19 was accomplished via a five-step reaction sequence. The reaction of 19 with the lithium alkoxide of 2-lithio-2-propenol afforded (+)-7-hydroxycostol (2), whose oxidation with manganese dioxide gave rise to (+)-7-hydroxycostal (1). 相似文献
6.
Michael Kessler Ana Laura Moguel Velázquez Michael Sundue Paulo H. Labiak 《Brittonia》2011,63(2):233-244
Alansmia, a new genus of grammitid ferns is described and combinations are made for the 26 species known to belong to it. Alansmia is supported by five morphological synapomorphies: setae present on the rhizomes, cells of the rhizome scales turgid, both
surfaces of the rhizome scales ciliate, laminae membranaceous, and sporangial capsules setose. Other diagnostic characters
include pendent fronds with indeterminate growth, concolorous, orange to castaneous rhizome scales with ciliate or sometimes
glandular margins, hydathodes often cretaceous, and setae simple, paired or stellate. The group also exhibits the uncommon
characteristic of producing both trilete and apparently monolete spores, sometimes on the same plant. New combinations are
made for Alansmia alfaroi, A. bradeana, A. canescens, A. concinna, A. contacta, A. cultrata, A. dependens, A. diaphana, A. elastica, A. glandulifera, A. heteromorpha, A. immixta, A. kirkii, A. lanigera, A. laxa, A. longa, A. monosora, A. reclinata, A. semilunaris, A. senilis, A. smithii, A. spathulata, A. stella var. stella, A. stella var. flava, A. turrialbae, A. variabilis, A. xanthotrichia. Lectotypifications are made for Alansmia concina, A. variabilis, Polypodium ciliare, P. flexile, and P. ovalescens. The genus is named in honor of pteridologist Alan R. Smith. 相似文献
7.
Synthesis of 2,2,3-tris(hydroxymethyl)methylenecyclopropane analogues 16a, 16b, 17a, and 17b is described. Diethyl ester of Feist's acid 18b was hydroxymethylated via carbanion formation using formaldehyde under simultaneous isomerization to cis diester to give intermediate 19. Reduction followed by acetylation gave triacetate 22. Addition of bromine afforded reagent 23, which was used for alkylation-elimination of adenine and 2-amino-6-chloropurine to provide Z,E-isomeric mixtures of 24a and 24b. Deacetylation and separation furnished the Z-isomers 16a, 16c and E-isomers 17a, 17c. Hydrolytic dechlorination of 16c and 17c gave guanine analogues 16b and 17b. None of the analogues exhibited a significant antiviral activity. Adenosine deaminase is refractory toward adenine analogues 16a and 17a. 相似文献
8.
《Journal of enzyme inhibition and medicinal chemistry》2013,28(3):440-444
Conferin (1), a new isoflavone, has been isolated from the ethyl acetate soluble fraction of Caragana conferta Benth. along with seven known compounds, namely biochanin A (2), p-hydroxybenzoic acid (3), 3,5- dimethoxybenzoic acid (4), ursolic acid (5), erythrodiol (6), pinoresinol (7), and syringresinol (8), reported for the first time from this species. The structure of the new isoflavone was deduced on the basis of spectroscopic studies. Compounds 1 and 2 were investigated for biological activities and showed significant anti-inflammatory activity in carrageenan induced paw edema of rats. Evaluation of antioxidant activity by the radical scavenging method indicated that compound 1 is a potent antioxidant while 2 is moderately active. It was also shown that the reducing capability of compound 2 was remarkably increased in a concentration dependent manner as compared to 1. Compound 1 showed moderate inhibitory activity against the enzyme lipoxygenase, while 2 showed weak activity. 相似文献
9.
《Bioscience, biotechnology, and biochemistry》2013,77(8):1896-1901
Rubralactone (1), rubralides A, B and C (2–4), rubramin (5), and 2-formyl-3,5-dihydroxy-4-methylbenzoic acid (6), were isolated from Penicillium rubrum, and their structures established by spectroscopic methods including 2D NMR. The effects on plant growth of 1–6 were examined using the lettuce seedling bioassay. Compound 1 promoted root growth. Compounds 2, 3 and 5 inhibited the growth of lettuce seedlings, but 4 and 6 did not have any inhibitory effect on their growth. 相似文献
10.
Véronique Faivre-Buet Annie Grouiller Gérard Descotes 《Nucleosides, nucleotides & nucleic acids》2013,32(7):1411-1424
Abstract Various routes to the targets 1, 2, 3, 1-deoxy-psicofuranosyl nucleoside analogues related to anti-HIV agents, are reported. Two routes afforded their 6′-benzylated derivatives 9, 10 and 15. Only the epoxide 12 and deoxynucleosides 19 and 22 were able to be deprotected leading in the first case to 16 and its ring opening derivative 17 and in the second case to 20 and to the target 3. 相似文献
11.
《Journal of receptor and signal transduction research》2013,33(1-4):421-430
ABSTRACTThe coat colour in mammals is determined by the relative amounts of eumelanin (black/brown) and phaeomelanin (red/yellow), produced in melanocytes, which are controlled by melanocyte stimulating hormone receptor (MSH-R). Melanocyte stimulating hormone receptor is activated by α-melanocyte-stimulating hormone (α-MSH). Stimulated MSH-R activates adenylyl cyclase (AC), thereby increasing the amount of cyclic AMP in the cell, which activates the enzyme tyrosinase resulting in eumelanin synthesis. In this study the complete coding sequences of five alleles of the MSH-R gene found in Holstein, Red Holstein, Simmental, and Brown Swiss cattle were cloned into a mammalian expression vector and transfected into human embryonic kidney (HEK) 293 cells. The expressed receptors were analyzed for their ability to increase intracellular cAMP in response to stimulation by α-MSH. The recessive red allele (e) found in Red Holstein and Simmental and the dominant black allele (ED) found in Holstein were unresponsive to a wide range of α-MSH concentrations. Two alleles from Brown Swiss (Ed1, Ed2) and one allele found in the Simmental breed (ef) responded to stimulation by α-MSH in a dose-dependent manner. When compared to Ed1 and Ed2, the cells transfected with the ef MSH-R allele, however, reached the corresponding intracellular cAMP concentrations at a 10-fold higher concentration of α-MSH. In conjunction with the mode of inheritance of coat colour, the results indicate that the e MSH-R allele is a non-functional receptor, ED is constitutively activated receptor, and Ed1 and Ed2 are hormonally activated receptors. The delay in ef MSH-R response may explain the similarity between the e and ef phenotypes. 相似文献
12.
《Bioscience, biotechnology, and biochemistry》2013,77(5):1220-1229
The constituents of cape aloe were investigated after a preliminary screening of the growth-inhibiting effect on Ehrlich ascites tumor cells (EATC) of several extracts of this plant. Ten compounds were isolated from the dichloromethane (CH2Cl2) extract that showed the strongest activity, and their structures were elucidated as aloe-emodin (1), p-hydroxybenzaldehyde (2), p-hydroxyacetophenone (3), pyrocatechol (4), 10-oxooctadecanoic acid (5), 10-hydroxyoctadecanoic acid (6), methyl 10-hydroxyoctadecanoate (7), 7-hydroxy-2,5-dimethylchromone (8), furoaloesone (9), and 2-acetonyl-8-(2-furoylmethyl)-7-hydroxy-5-methylchromone (10) based on MS and various NMR spectroscopic techniques. Compounds 2–7 were isolated for the first time from cape aloe. Compounds 4–7 and 10 showed a significant growth-inhibiting effect, and compound 1 exhibited a remarkable synergistic effect on compounds 8–10, which was not observed with the treatment by each compound alone on EATC. These results suggest that the strong growth-inhibiting effect of the CH2Cl2 extract was dependent not on one compound alone, but on the synergistic effect from the combination of compound 1 and the other compounds. 相似文献
13.
Hyoung Jae Lee Bunta Watanabe Masaru Nakayasu Michio Onjo Yukihiro Sugimoto 《Bioscience, biotechnology, and biochemistry》2017,81(12):2253-2260
Fifteen steroidal saponins 1–15, which include 4 furostanol glycosides 1–3 and 15, and 11 spirostanol glycosides 4–14, were isolated from the tubers and leaves of lesser yam (Dioscorea esculenta, Togedokoro). Their structures were identified by nuclear magnetic resonance and liquid chromatography mass spectroscopy. Four steroidal saponins 9, 11, 14, and 15 were found to be novel compounds. 相似文献
14.
Antonov AS Kalinovsky AI Dmitrenok PS Kalinin VI Stonik VA Mollo E Cimino G 《Carbohydrate research》2011,346(14):2182-2192
Seven new triterpene glycosides, erylosides R1 (1), T1 (3), T2 (4), T3 (5), T4 (6), T5 (7), and T6 (8) along with the known formoside (2) were isolated from the sponge Erylus formosus collected along the Caribbean coast of Mexico. Glycoside 1 was determined as a trisaccharide, glycoside 2 as a tetrasaccharide while glycosides 3–8 were hexasaccharide. Their carbohydrate chains were unprecedented and have never been found in oligosaccharides from other biological sources, except Erylus spp. Three carbohydrate chains in the glycosides 3 and 6, 4 and 7, 5 and 8 correspondingly are new. The glycosides 1–5 have penasterol as aglycone while glycosides 6–8 proved to be glycoconjugates of 24-methylene-14-carboxy-lanost-8(9)-en-3β-ol. 相似文献
15.
Morais M Raposinho PD Oliveira MC Correia JD Santos I 《Journal of biological inorganic chemistry》2012,17(4):491-505
Abstract
Aiming to apply the multivalency concept to melanoma imaging, we have assessed the in vivo melanocortin type 1 receptor (MC1R)-targeting properties of 99mTc(I)-labeled homobivalent peptide conjugates which contain copies of the α-melanocyte-stimulating hormone (α-MSH) analog [Ac-Nle4, Asp5, d-Phe7, Lys11]α-MSH4–11 separated by linkers of different length (L 2 nine atoms and L 3 14 atoms). The MC1R-binding affinity of L 2 and L 3 is significantly higher than that of the monovalent conjugate L 1 . Metallation of these conjugates yielded the complexes fac-[M(CO)3(k3-L)]+ (M is 99mTc/Re; 1/1a, L is L 1 ; 2/2a, L is L 2 ; 3/3a, L is L 3 ), with IC50 values in the subnanomolar and nanomolar range. The MC1R-mediated internalization of 2 and 3 is higher than that of 1 in B16F1 melanoma cells. Biodistribution studies in melanoma-bearing mice have shown low nonspecific accumulation with a tumor uptake that correlates with IC50 values. However, no correlation between tumor uptake and valency was found. Nevertheless, 2 displayed the highest tumor retention, and the best tumor to nontarget organ ratios. 相似文献16.
为了解苦槛蓝(Myoporum bontioides)的化学成分,采用色谱分离法从叶中分离得到11个化合物,分别鉴定为:5,7,3’-三羟基-4’-甲氧基黄酮(1)、3,5,7,4’-四羟基-3’-甲氧基黄酮(2)、5,7,4’-三羟基-3’,5’-二甲氧基黄酮(3)、木犀草素(4)、山奈酚(5)、鼠李黄素(6)、5,7-二羟基二氢黄酮(7)、7,4’-二羟基二氢黄酮(8)、5,7,3’,4’-四羟基二氢黄酮(9)、5-O-乙酰基-3,7,3’,4’-四羟基二氢黄酮(10)和7-甲氧基香橙素(11)。除化合物4、7、11之外,其他化合物均为首次从苦槛蓝叶中分离得到。菌丝生长速率法测试表明化合物4、7~9和11对荔枝霜疫霉菌具有较好的抑菌活性。 相似文献
17.
Ahmed H. Moustafa Hassan A. El-Sayed Abd El-Fattah Z. Haikal El Sayed H. El Ashry 《Nucleosides, nucleotides & nucleic acids》2013,32(5):340-352
Reaction of pyridin-2(1H)-one 1 with 4-bromobutylacetate (2), (2-acetoxyethoxy)methyl bromide (3) gave the corresponding nicotinonitrile O-acyclonucleosides, 4 and 5, respectively. Deacetylation of 4 and 5 gave the corresponding deprotected acyclonucleosides 6 and 7, respectively. Treatment of pyridin-2(1H)-one 1 with 1,3-dichloropropan-2-ol (8), epichlorohydrin (10) and allyl bromide (12) gave the corresponding nicotinonitrile O-acyclonucleosides 9, 11, and 13, respectively. Furthermore, reaction of pyridin-2(1H)-one 1 with the propargyl bromide (14) gave the corresponding 2-O-propargyl derivative 15, which was reacted via [3+2] cycloaddition with 4-azidobutyl acetate (16) and [(2-acetoxyethoxy)methyl]azide (17) to give the corresponding 1,2,3-triazole derivatives 18 and 19, respectively. The structures of the new synthesized compounds were characterized by using IR, 1H, 13C NMR spectra, and microanalysis. Selected members of these compounds were screened for antibacterial activity. 相似文献
18.
Karim Christina Scopinho Furquim Gervásio Henrique Bechara Maria Izabel Camargo Mathias 《Experimental & applied acarology》2010,50(1):59-70
This study describes the changes undergone by cells of the salivary glands of unfed and feeding (at day two and four post-attachment)
Rhipicephalus sanguineus males, as well as new cell types. In unfed males, types I and II acini are observed with cells “undifferentiated”, undefined
1 and 2 (the latter, with atypical granules), a, c1 and c3; type III is composed of cells d and e; and type IV present cells g. In males at day two post-attachment, type I acini exhibit the same morphology of unfed individuals. An increase in size
is observed in types II, III, and IV, as cells are filled with secretion granules. Some granules are still undergoing maturation.
In type II acinus, cells a, b and c1–c8 are observed. Cells c7 and c8 are described for the first time. Cells c7 are termed as such due to the addition of polysaccharides in the composition of the secretion granules (in unfed individuals,
they are termed undefined
1). Type III acini exhibit cells d and e completely filled with granules, and in type IV, cells g contain granules in several stages of maturation. In males at day four post-attachment, type I acini do not exhibit changes.
Granular acini exhibit cells with fewer secretion granules, which are already mature. In type II acini, cells a, b, c1–c5 are present, type III exhibit cells d and e, and type IV contain cells g with little or no secretion. This study shows that in the salivary glands of R.
sanguineus males, cells a, c1, and c3 of type II acinus, and cells d and e of type III do not exhibit changes in granular content, remaining continuously active during the entire feeding period. This
indicates that during the intervals among feeding stages, gland cells reacquire the same characteristics found in unfed individuals,
suggesting that they undergo reprogramming to be active in the next cycle. 相似文献
19.
The sorptive behavior of bacteria—iron oxide composites was investigated in batch metal sorption assays using ferrihydrite in isolation (0.13 and 0.14 g/L ferrihydrite in cadmium and lead systems, respectively) as well as in combination with Bacillus subtilis (0.25 g/L adsorbent mixture) and Escherichia coli (0.27 g/L adsorbent mixture). A pH range from 3.0 to 6.5 was studied using total metal concentrations of 1.0 × 10 ? 4.0 and 3.2 × 10 ? 5 M with adsorbent mixtures proportioned on a 1:1 mass/volume basis. The log of the apparent surface complex formation constants (log K S M ) and sorption capacity (S max ) values were determined by fitting the experimental data to one-site Langmuir sorption isotherms. The one-site model effectively described the sorption data (r 2 > 0.9), where Cd 2 + exhibited somewhat lower sorption affinities (log K S M = ?3 for ferrihydrite, ?1.7 for B. subtilis–ferrihydrite, and ?1.1 for E. coli–ferrihydrite) than Pb 2 + (log K S M = ?0.9 for ferrihydrite, ? 0.2 forB. subtilis–ferrihydrite, and –0.1 for E. coli–ferrihydrite). The corresponding S max values for Cd 2 + and Pb 2 + on ferrihydrite were 0.78 mmole/g and 1.34 mmole/g, respectively. For the B. subtilis–ferrihydrite composites, Cd 2 + and Pb 2 + S max values were lower at 0.29 mmole/g and 0.5 mmole/g, respectively. Similar values were determined for the E. coli–ferrihydrite composites (0.15 mmole/g and 0.68 mmole/g for Cd 2 + and Pb 2 + , respectively). The sorption of Cd 2 + and Pb 2 + by each of the sorbent systems exhibited a strong dependence on pH with sorption edges in the range of pH 4.0 to 7.3. The observed S max of the composites were lower than values predicted upon available site additivity (Cd 2 + B. subtilis ?ferrihydrite : 0.29 mmole/g (observed) < 0.57 mmole/g (calculated); Cd 2 + E. coli ?ferrihydrite : 0.15 mmole/g (observed) < 0.44 mmole/ g (calculated); Pb 2 + B. subtilis ?ferrihydrite : 0.5 mmole/g (observed) < 0.805 mmole/g (calculated); Pb 2 + E. coli –ferrihydrite : 0.68 mmole/g (observed) < 0.775 mmole/g (calculated)), implying that a masking of reactive surface sites by attachment had occurred between the bacteria and ferrihydrite. Electrophoretic mobility analysis indicated that the ferrihydrite surface properties dominate the net surface charge for each composite system with lesser contributions from the bacteria. 相似文献
20.
Ramirededy Nageswara Reddy Ravichandra Reddy Mutyala Polamarasetty Aparoy Pallu Reddanna Mutyala Rami Reddy 《Journal of molecular modeling》2010,16(2):203-209
Since the human body for many reasons can adapt and become resistant to drugs, it is important to develop and validate computer
aided drug design (CADD) methods that could help predict binding affinity changes that can result from these resistant enzymes.
The free energy perturbation (FEP) methodology is the most accurate means of estimating relative binding affinities between
inhibitors and protein variants. In this paper, we describe the role played by hydrophobic residues lining the active site
region, particularly
79
Ile and
176
Phe, in the binding of methotrexate to the Escherichia coli (E. coli) thymidylate synthase (TS) enzyme, using the thermodynamic cycle perturbation (TCP) approach. The computed binding free energy
differences on the binding of methotrexate to the native and some mutant E. coli TS structures have been compared with experimental results. Computationally, four different ‘mutations’ have been simulated
on the TS enzyme with methotrexate (MTX):
79
Ile →
79
Val;
79
Ile →
79
Ala;
79
Ile →
79
Leu; and
176
Phe →
176
Ile. The calculated results indicate that in each of these cases, the native residues (
79
Ile and
176
Phe) interact more favorably with methotrexate than the mutant residues and these results are corroborated by experimental measurements.
Binding preference to wild type residues can be rationalized in terms of their better hydrophobic contacts with the phenyl
ring of methotrexate. 相似文献