- Sequential photo-addition of glycine methyl-ester to [60]fullerene
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While direct photo-addition of glycine-methyl-esters (GME) to [60]fullerene (C60) can yield a complex product mixture, only a fulleropyrrolidine (FP) mono-adduct has been characterized and the mechanism remains to be ascertained. We show here that visible light irradiation of a mixture of C 60 and GME in the presence of oxygen is a direct route to synthesize sequentially higher FP poly-adducts through an unprecedented cyclization-deamination mechanism. Each step of this mechanism leads to a FP adduct involving the correlated addition of two GME radicals and the departure of an ammonia molecule.
- Skanji, Rym,Ben Messaouda, Mhamed,Zhang, Yongmin,Abderrabba, Manef,Szwarc, Henri,Moussa, Fathi
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Read Online
- Unusual course of “enolate-imine” condensation in approach to β-lactams
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In reaction of methyl (Е)-3-(methoxycarbonyl)methylimino-2,2-dimethylpropanoate with enolate of ethyl 3-hydroxybutanoate an abnormal reaction product was isolated, 2-methyl 4-ethyl-(2S*,3S*,4S*,5S*)-3-methyl-5-(2-methyl-1-methoxy-1-oxopropan-2-yl)pyrrolidine-2,4-dicarboxylate.
- Valiullina,Gimalova,Spirikhin,Miftakhov
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Read Online
- Participation of C-H Protons in the Dissociation of a Proton Deficient Dipeptide
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The dissociation of anionic dipeptides Phe*Gly and GlyPhe*, where Phe* refers to sulfonated phenyl alanine, has been investigated by using ion trap mass spectrometry. The dipeptides undergo collision-induced dissociation (CID) to give the same products, indicating that they rearrange to a common structure before dissociation. The rearrangement does not occur with the dipeptide methyl esters. The structures of the b2 ions were investigated to determine the effect that having a remote, anionic site has on product formation. Comparison with the CID spectra for authentic structures shows that the b2 ion obtained from GlyPhe* has predominantly a diketopiperazine structure. The CID spectra for the Phe*Gly b2 ion and the authentic oxazolone are similar, but differences in intensity suggest a two-component mixture. Isotopic labeling studies are consistent with the formation of two products, with one resulting from loss of a non-mobile proton on the Gly α-carbon. The results are attributed to the formation of an oxazole and oxazolone enol product. Electronic structure calculations predict that the enol structure of the Phe*Gly b2 ion is lower in energy than the keto version due to intramolecular hydrogen bonding with the sulfonate group. [Figure not available: see fulltext.].
- Koirala, Damodar,Mistry, Sabyasachy,Wenthold, Paul G.
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Read Online
- Studying Histone Deacetylase Inhibition and Apoptosis Induction of Psammaplin A Monomers with Modified Thiol Group
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Psammaplin A (PsA) is a bromotyrosine disulfide dimer with histone deacetylase (HDAC) inhibition and acts through reduced monomer PsA-SH. We studied the connection of HDAC inhibition, cell growth inhibition, and apoptosis induction of PsA-SH by modifying the -SH group with deletion (6a) or replacement with hydroxamic acid (10b) or benzamide (12g). PsA-SH inhibits HDAC1/2/3 and 6a loses the HDAC inhibition ability. 10b inhibits HDAC1/2/3/6 while 12g shows selective inhibition of HDAC3. PsA-SH and 10b, but neither 6a nor 12g, induce apoptosis in human leukemia HL-60 cells associated with increased acetylation of Histone H3. PsA-SH and 10b inhibit growth of several solid tumor cell lines in vitro and Lewis lung cancer cell growth in vivo. PsA-SH is a simple scaffold for developing selective HDAC inhibitors and induces apoptosis through inhibiting HDAC1/2.
- Bao, Yu,Xu, Qihao,Wang, Lin,Wei, Yunfei,Hu, Baichun,Wang, Jian,Liu, Dan,Zhao, Linxiang,Jing, Yongkui
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- Single Electron Transfer-Induced Selective α-Oxygenation of Glycine Derivatives
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Modification of amino acids is an important strategy in organic and bioorganic chemistry. In contrast to common side-chain functionalization, backbone modification is much less explored. Especially glycine units seem to be attractive and versatile since a wide range of functionality can be potentially introduced. We report here oxidative modification of glycinates that are stable and enable further functionalization. Selective glycinate enolate oxidation by TEMPO or a FeCp2PF6/TEMPO reagent combination provides stable alkoxyamines in good to excellent yields. The methodology is expanded to glycine-containing dipeptides demonstrating selective oxygenation at the glycine unit. The orthogonal reactivity potential of oxygenated glycines for transformation to other amino acid derivatives is explored.
- Císa?ová, Ivana,Jahn, Ullrich,K?nig, Burkhard,Moser, Johannes,Venugopal, Navyasree,Vojtí?ková, Margaréta
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supporting information
(2021/11/03)
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- Synthesis and evaluation of antitumor activities of 4-selenopyrimidine derivatives
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Pyrimidine antimetabolic agents are the essential drugs in treatment of various tumors. Novel synthesis and biological evaluation of the pyrimidine derivatives incorporating selenium element and amino acid carrier as potential antitumor agents have not been tried and studied. Based on the biological significance of pyrimidine structure, these two additional elemental fragments maybe enhance the antitumor effect and reduce toxic side effects of pyrimidine agents. The aim of this paper is to synthesis a series of 4-selenopyrimidine derivatives in order to find more potent lead compounds against cancer. In this study, 12 new 4-selenopyrimidine derivatives that are unstable in acidic solutions but very stable in alkaline and neutral solutions avoiding light were synthesized, and the antitumor activities on HepG2 cell lines of these compounds were evaluated by MTT assay. The results have shown that these compounds could reduce the proliferation of HepG2 cells in a dose-dependent fashion, and the inhibitory activity of compounds a6 was greater than that of positive control 5-fluorouracil (5-FU), the IC50 for a6 was 3.63 μM. In the comprehensive analysis of the structure–activity relationship, we could draw the antitumor effect of selenouracil derivatives is stronger than those of selenothymine derivatives. These results suggest that the substituent groups of selenium element and amino acid on the pyrimidine derivatives are vital for their antitumor activities on HepG2 cells.
- Shi, Mingxing,Wang, Libo,Zhang, Long,Wang, Kexin,Zhang, Hualin,Wang, Yajing,Li, Chang,Han, Weina
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- PSA derivatives with HDAC3 inhibitory activity and application thereof
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The invention belongs to the technical field of medicines. The invention relates to a series of PSA derivatives with antitumor activity. The invention specifically relates to compounds containing (E)-3-bromo-4-hydroxyphenyl-2-oximido fragments and pharmaceutically acceptable salts and hydrates of the compounds, and pharmaceutical compositions containing the compounds and the pharmaceutically acceptable salts and hydrates thereof as active ingredients, and uses of the compounds and the pharmaceutically acceptable salts and hydrates thereof and the pharmaceutical compositions in preparation of histone deacetylase inhibitors and drugs for treatment and/or prevention of cancers. The compounds, and the pharmaceutically acceptable salts and hydrates thereof are represented by a formula I. In theformula I, R and n are described in the claims and the specification.
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Paragraph 0079; 0082-0084
(2020/08/27)
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- Discovery of 3-Quinazolin-4(3 H)-on-3-yl-2, N-dimethylpropanamides as Orally Active and Selective PI3Kα Inhibitors
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Phosphoinositide 3-kinases (PI3Ks) mediate a series of events related to cell growth, proliferation, survival, and differentiation. Overexpression of PI3Ks can lead to the dysregulation of cell homeostasis and cause tumorigenesis. In this study, rationally designed compounds were investigated as PI3Kα-selective inhibitors. Our efforts culminated in the discovery of a series of quinazolin-4(3H)-one derivatives with 2-substituted-N-methylpropanamide substitutions as PI3Kα-selective inhibitors. The best compound, 10, has PI3Kα enzymatic and cellular IC50 values of 1.8 and 12.1 nM, respectively. It exhibits biochemical selectivities for PI3Kα over PI3Kβ/δ/γof 150/7.72/7.67-fold and cellular selectivities of 115/15.1/>826-fold, respectively. Compound 10 is 59% orally bioavailable with a dose-normalized AUC of 3090 nM. These effects translated into in vivo conditions, as 10 significantly time- and dose-dependently inhibited phosphorylation of Akt in BT-474 subcutaneous xenograft mice and inhibited tumor growth.
- Dong, Jiaqiang,Huang, Jingjie,Zhou, Ji,Tan, Ye,Jin, Jing,Tan, Xi,Wang, Bei,Yu, Tao,Wu, Chengde,Chen, Shuhui,Wang, Tie-Lin
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supporting information
p. 1463 - 1469
(2020/08/14)
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- Novel carboxylated pyrroline-2-one derivatives bearing a phenylhydrazine moiety: Design, synthesis, antifungal evaluation and 3D-QSAR analysis
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Aiming to discover novel high-efficient antifungal leads that possess an innovative action mechanism, twenty-three carboxylated pyrroline-2-one derivatives, bearing a phenylhydrazine moiety, were rationally designed and firstly prepared in this letter. The in vitro bioassays showed that most of the compounds possessed excellent antifungal effects with the EC50 values of less than 1 μg/mL against the phytopathogenic fungi Fusarium graminearum (Fg), Botrytis cinerea (Bc), Rhizoctonia solani (Rs) and Colletotrichum capsici (Cc). The further bioassays showed that the compound 6u showed the comparable in vivo control effect with carbendazim against fusarium head blight and rice sheath blight. The 3D-QSAR model revealed the pivotal effects of a bulky electron-donating group at the 1-position of pyrrole ring, a bulky electron-withdrawing group at the 4-position of phenyl ring and a small alkyl at the carbonate group on the anti-Rs activities of target compounds. The abnormal mycelial morphology and delayed spore germination were observed in the treatments of compound 6u. Given the excellent and broad-spectrum antifungal effects the target compounds have, we unfeignedly anticipated that the above finding could motivate the discovery of high-efficient antifungal leads, which might possess an innovative action mechanism against phytopathogenic fungi.
- Chen, Min,Zhang, Lizhi,Lu, Aimin,Wang, Xiaobin,Si, Weijie,Yan, Jinghua,Yang, Chunlong
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- Optimized synthesis process of anticancer drug dacarbazine
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The invention provides an optimized synthesis process of an anticancer drug dacarbazine. The optimized synthesis process of the anticancer drug dacarbazine comprises the following steps: synthesis ofglycine methyl ester, synthesis of N-formylglycine methyl ester, synthesis of alpha-methyl isocyanoacetate, synthesis of alpha-isocyanoacetamide, synthesis of 5-amino-4-imidazolecarboxamide and synthesis of dacarbazine. Synthesis of the glycine methyl ester comprises the following steps: weighing 7.5 g of glycine and adding the glycine into a 500 mL round-bottom flask, taking 200 mL of redistilledmethanol as a solvent and cooling with stirring in an ice bath for 15 min; weighing 22 mL of thionyl chloride by a syringe and slowly dropwise adding the thionyl chloride into the reaction flask to react overnight at room temperature; and removing excess thionyl chloride and methanol by rotary evaporation at the room temperature, dissolving the residues by using as little hot methanol as possible, quickly adding a large amount of cold diethyl ether, and cooling in the reaction bottle in an ice bath. By improving the synthesis process of the anticancer drug dacarbazine, the optimized synthesisprocess of the anticancer drug dacarbazine has the advantages of reasonable synthesis circuit, cheap raw materials, mild reaction conditions and high total yield, thereby effectively solving the problems and defects in the prior art.
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Paragraph 0024; 0025
(2019/10/17)
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- In situ formation of AuNPs using fatty N-acylamino hydrazide organogelators as templates
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This work reports, for the first time, the synthesis of new fatty N-acylamino hydrazides and demonstrates the activity of these compounds as low-molecular-weight organic gelators and templates for preparation of gold nanoparticles (AuNPs). Initially, we evaluated the gelation properties of fatty N-acylamino hydrazides in various nonpolar and polar solvents (n-hexane, toluene, benzene, cyclohexane, and ethanol). Fatty N-acylamino hydrazide derived of the glycine and stearic acid (C18:0) did not form gels in any of the tested solvents. All other hydrazides did form gels in at least two of the organic solvents tested. The morphology of each gel was observed via scanning electron microscopy. The organogels derived from alanine, valine, and phenylalanine had translucid properties, while the serine organogels were opaque. Afterwards, the synthesis of AuNPs in the presence of the organogelator using microwave irradiation was realized. Organogelator agents reduced HAuCl4 showing plasmon band peaks between 530 and 543 nm. In addition, the method does not require a reducing agent, which is typically a potential source of contamination and toxicity. Therefore, this work confirms the importance of the hydrazide group of the new fatty N-acylamino hydrazides in gel formation and as organogelator agents for preparation of AuNPs.
- Ongaratto, Renata,Conte, Naiane,Montes D'Oca, Caroline R.,Brinkerhoff, Rafael C.,Ruas, Caroline Pires,Gelesky, Marcos Alexandre,Montes D'Oca, Marcelo G.
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p. 295 - 303
(2019/01/04)
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- Cleavable Amide Bond: Mechanistic Insight into Cleavable 4-Aminopyrazolyloxy Acetamide at Low pH
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The cleavage of amide bonds under mild acidic conditions is a rare chemical event. N-Acetamide bond of peptides is extremely stable even under the strongest organic acid trifluoromethanesulfonic acid. This report mechanistically describes a new cleavable amide bond in 4-aminopyrazolyloxy acetamide peptide analogues under mild acidic conditions such as trifluoroacetic acid (10-20%) or HCl (0.1-4.0 N) at room temperature, and the formation of unusual lactam from 4-aminopyrazolyloxy acetic acid after evaporation of solvent. This is a rare chemical event in peptide bond, which could be explored as acid-sensitive protecting group of free amines.
- Bollu, Amarnath,Sharma, Nagendra K.
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supporting information
(2019/05/08)
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- Design, synthesis, and molecular docking studies of N-(9,10-anthraquinone-2-carbonyl)amino acid derivatives as xanthine oxidase inhibitors
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A series of N-(9,10-anthraquinone-2-carbonyl)amino acid derivatives (1a–j) was designed and synthesized as novel xanthine oxidase inhibitors. Among them, the L/D-phenylalanine derivatives (1d and 1i) and the L/D-tryptophan derivatives (1e and 1j) were effective with micromolar level potency. In particular, the L-phenylalanine derivative 1d (IC50?=?3.0?μm) and the D-phenylalanine derivative 1i (IC50?=?2.9?μm) presented the highest potency and were both more potent than the positive control allopurinol (IC50?=?8.1?μm). Preliminary SAR analysis pointed that an aromatic amino acid fragment, for example, phenylalanine or tryptophan, was essential for the inhibition; the D-amino acid derivative presented equal or greater potency compared to its L-enantiomer; and the 9,10-anthraquinone moiety was welcome for the inhibition. Molecular simulations provided rational binding models for compounds 1d and 1i in the xanthine oxidase active pocket. As a result, compounds 1d and 1i could be promising lead compounds for further investigation.
- Zhang, Ting-Jian,Li, Song-Ye,Yuan, Wei-Yan,Zhang, Yi,Meng, Fan-Hao
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p. 893 - 901
(2018/03/21)
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- Structure-Guided Design and Development of Potent and Selective Dual Bromodomain 4 (BRD4)/Polo-like Kinase 1 (PLK1) Inhibitors
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The simultaneous inhibition of polo-like kinase 1 (PLK1) and BRD4 bromodomain by a single molecule could lead to the development of an effective therapeutic strategy for a variety of diseases in which PLK1 and BRD4 are implicated. Compound 23 has been found to be a potent dual kinase-bromodomain inhibitor (BRD4-BD1 IC50 = 28 nM, PLK1 IC50 = 40 nM). Compound 6 was found to be the most selective PLK1 inhibitor over BRD4 in our series (BRD4-BD1 IC50 = 2579 nM, PLK1 IC50 = 9.9 nM). Molecular docking studies with 23 and BRD4-BD1/PLK1 as well as with 6 corroborate the biochemical assay results.
- Liu, Shuai,Yosief, Hailemichael O.,Dai, Lingling,Huang, He,Dhawan, Gagan,Zhang, Xiaofeng,Muthengi, Alex M.,Roberts, Justin,Buckley, Dennis L.,Perry, Jennifer A.,Wu, Lei,Bradner, James E.,Qi, Jun,Zhang, Wei
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p. 7785 - 7795
(2018/09/13)
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- Synthesis of amphiphilic meso -tetrasubstituted porphyrin-L-amino acid and -heterocyclic conjugates based on m -THPP
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Two series of amphiphilic meso-tetrasubstituted porphyrin conjugates based on 5,10,15,20-tetrakis(3-hydroxyphenyl)porphyrin (m-THPP) covalently linked to L-amino acids and heterocycles were synthesized efficiently in the context of a program targeting new photosensitizers for PDT. 5,10,15-Tris(3-hydroxyphenyl)-20-(3-oxyacetic acid)phenyl]porphyrin and the respective trihexyl ether derivatives were conjugated with polar and non-polar natural L-amino acids such as glycine, L-proline, and L-tyrosine via an amide bond linker using N,N,N′,N′-tetramethyl-O-(1H-benzotriazol-1-yl)uroniumhexafluorophosphate in diisopropylethylamine (HBTU/DIPEA). m-THPP was also conjugated with heterocyclic systems such as indole 3-acetic acid, 4-methylthiazole-5-carboxylic acid, and thiophene-2-carboxylic acid via ester linker using N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride in N-hydroxysuccinamide or 1-hydroxybenzotriazole (EDCI, NHS or HOBt). The members of the two series were obtained in good yields and characterized by UV-vis, HRMS MALDI-TOF, 1H NMR and 13C NMR spectroscopy.
- Sweed, Ayman M. K.,Senge, Mathias O.,Atta, Sanaa M. Sh.,Farrag, Dalia S.,Abdel-Rahman, Abdel-Rahman H.,Shaker, Yasser M.
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p. 997 - 1009
(2018/09/12)
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- A class of α-amino acids-derived multifunctional amidophosphane precatalysts: application to the highly enantio- and diastereoselective silver(I)-catalyzed 1,3-dipolar cycloaddition reaction
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A class of multifunctional amidophosphanes derived from chiral α-amino acids have been developed with two amide bonds, a tertiary amine and a phosphine. In combination with Ag(I) salts, these amidophosphanes have been demonstrated as highly efficient multifunctional catalysts in the asymmetric 1,3-dipolar cycloaddition of azomethine ylides as well as the three-component reaction of the α-iminoesters in situ generated. Under optimal conditions, highly functionalized endo-8 pyrrolidines were obtained with good to excellent yields (up to 99% yield) and enantioselectivities (up to 98% ee).
- Hou, Yihui,Zhou, Zhipeng,Liu, Pingle,Wang, Jiankang,Hou, Qinglin,Wen, Pushan,Wang, Haifei
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p. 930 - 938
(2017/07/11)
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- Imines derived from 4-methyl-4-diphenylphosphorylpentan-2-one and potassium salts of aminocarboxylic acids
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An effective procedure for the preparation of imines based on 4-methyl-4-diphenylphosphorylpentan-2-one, aminoacetic, aminopropionic, and aminobutyric acids with yields of 90–95% was developed. Reaction of dimephosphone (4-methyl-4-dimethoxyphosphorilpent
- Dimukhametov,Mironov,Tatarinov
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p. 882 - 884
(2017/05/29)
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- Copper(I)-Mediated Denitrogenative Macrocyclization for the Synthesis of Cyclic α3β-Tetrapeptide Analogues
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A copper(I)-mediated denitrogenative reaction has been successfully developed for the preparation of cyclic tetrapeptides. The key reactive intermediate, ketenimine, triggers intramolecular cyclization through attack of the terminal amine group to generate an internal β-amino acid with an amidine linkage. The chemistry developed herein provides a new synthetic route for the preparation of cyclic α3β-tetrapeptide analogues that contain important biological properties and results in rich structural information being obtained for conformational studies. With the success of this copper(I)-catalyzed macrocyclization, two histone deacetylase inhibitor analogues consisting of the cyclic α3β-tetrapeptide framework have been successfully synthesized.
- Chen, Chun-Chi,Wang, Sheng-Fu,Su, Yung-Yu,Lin, Yuya A.,Lin, Po-Chiao
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p. 1326 - 1337
(2017/06/23)
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- POLYMER AND CONTRAST AGENT FOR PHOTOACOUSTIC IMAGING INCLUDING THE POLYMER
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To provide a polymer having a high ratio of the amount thereof present in a tumor to the amount thereof present in blood (hereinafter, sometimes abbreviated as a tumor/blood ratio). The polymer has phosphorylcholine (derivative) as a side chain and has a dye (near-infrared dye) having absorption in the near-infrared wavelength region bound to the polymer.
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Page/Page column 36
(2016/05/24)
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- Synthesis and biological evaluation of novel lipoamino acid derivatives
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Seven novel lipoamino acid conjugates were synthesized from methyl oleate and amino acids. Methyl oleate was grafted to different amino acids using thioglycolic acid as a spacer group. Seven derivatives (3a-g) were prepared and characterized by spectral data (NMR, IR and MS spectral studies). All the derivatives were studied for their antimicrobial, anti-biofilm and anticancer activities. Among all the derivatives, it was found that compound 3b was the most potent antibacterial compound which showed good activity against four Gram positive bacterial strains and also exhibited excellent antifungal activity against a fungal strain. In the anti-biofilm assay, compound 3b showed promising activity with IC50 value of 2.8 μM against Bacillus subtilis MTCC 121. All the compounds showed anticancer activities with 3c showing promising anticancer activity (IC50 = 15.3-22.4 μM) against the four cell lines tested.
- Kaki, Shiva Shanker,Arukali, Sammaiah,Korlipara, Padmaja V.,Prasad,Yedla, Poornachandra,Ganesh Kumar
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supporting information
p. 209 - 212
(2015/12/20)
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- Identification of a diverse indole-2-carboxamides as a potent antileishmanial chemotypes
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A novel series of highly diverse indole-2-carboxamides was synthesized utilizing the isocyanide based multicomponent reaction (IMCR)-post modification approach and were identified as potential antileishmanial chemotype. Among the synthesized 18 analogues, 12 analogues exhibited better antileishmanial activity against intracellular amastigotes form of Leishmania donovani (IC50values of 0.6-7.5 μM) as compared to standard drugs miltefosine and sodium stibogluconate. The compounds were also non-toxic towards Vero cells. Compounds 2b, 2m and 2p with significant in vitro activity were then evaluated for their in vivo efficacy following intraperitoneal route. These three compounds at a concentration of 50 mg/kg/day for 5 consecutive days showed 70.0, 63.5 and 63.4% inhibition of Leishmania amastigotes, respectively at day 7 post treatment in hamster model of visceral leishmaniasis.
- Pandey, Shashi,Chauhan, Shikha S.,Shivahare, Rahul,Sharma, Abhisheak,Jaiswal, Swati,Gupta, Suman,Lal, Jawahar,Chauhan, Prem M.S.
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p. 237 - 245
(2016/07/06)
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- Synthesis, biological activity screening and molecular modeling study of acylaminoacetamide derivatives
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In this study, non-rigid analogs of thalidomide have been designed in order to develop potentially active, more effective and safer lead molecules for disorders caused or contributed by inflammation. Five different series of acylaminoacetamide compounds were synthesized, and the biological inhibitory potency of the title compounds has been determined by evaluating their effects on COX-2 isoenzyme expression and PGE2 production in A549 (human lung adenocarcinoma) cell lines. Among the studied series, N-[2-(isopropylamino)-2-oxoethyl]isonicotinamide is the most active inhibitory compound on COX-2 isoenzyme expression, and N-[2-oxo-2-(pyrolydine-1-yl)etyl]isonicotinamide is the most active inhibitory compound on the biosynthesis of PGE2. Molecular docking studies and molecular dynamics simulations were also applied to investigate non-covalent interactions of the most active compounds inside the active side of the crystal structure of murine cyclooxygenase 2 (mCOX-2) isoenzyme.
- Coban, Gunes,Kose, Fadime Aydin,Kirmizibayrak, Petek Ballar,Pabuccuoglu, Varol
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p. 3710 - 3729
(2015/09/07)
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- Instability of Amide Bond Comprising the 2-Aminotropone Moiety: Cleavable under Mild Acidic Conditions
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An unusual hydrolysis/solvolysis of the classical acyclic amide bond, derived from N-troponylaminoethylglycine (Traeg) and α-amino acids, is described under mild acidic conditions. The reactivity of this amide bond is possibly owed to the protonation of the troponyl carbonyl functional group. The results suggest that the Traeg amino acid is a potential candidate for protecting and caging of the amine functional group of bioactive molecules via a cleavable amide bond.
- Balachandra, Chenikkayala,Sharma, Nagendra K.
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p. 3948 - 3951
(2015/09/01)
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- AMINOQUINAZOLINE DERIVATIVES AND THEIR SALTS AND METHODS OF USE
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The present invention relates to the field of medicine. Provided herein are aminoquinazoline derivatives, their salts and pharmaceutical formulations useful in modulating the protein tyrosine kinase activity, and in modulating inter- and/or intra-cellular signaling. Also provided herein are pharmaceutically acceptable compositions comprising the aminoquinazoline compounds and methods of using the compositions in the treatment of hyperproliferative disorders in mammals, especially humans.
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Paragraph 0299-0300
(2014/08/19)
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- Efficacious anticancer drug delivery mediated by a pH-sensitive self-assembly of a conserved tripeptide derived from tyrosine kinase NGF receptor
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We present herein a short tripeptide sequence (Lys-Phe-Gly or KFG) that is situated in the juxtamembrane region of the tyrosine kinase nerve growth factor (Trk NGF) receptors. KFG self-assembles in water and shows a reversible and concentration-dependent switching of nanostructures from nanospheres (vesicles) to nanotubes, as evidenced by dynamic light scattering, transmission electron microscopy, and atomic force microscopy. The morphology change was associated with a transition in the secondary structure. The tripeptide vesicles have inner aqueous compartments and are stable at pH 7.4 but rupture rapidly at pH≈6. The pH-sensitive response of the vesicles was exploited for the delivery of a chemotherapeutic anticancer drug, doxorubicin, which resulted in enhanced cytotoxicity for both drug-sensitive and drug-resistant cells. Efficient intracellular release of the drug was confirmed by fluorescence-activated cell sorting analysis, fluorescence microscopy, and confocal microscopy. Package for special delivery: A biologically active tripeptide self-assembles to produce nanovesicles at lower concentrations and nanotubes at higher concentrations (see scheme). The nanovesicles rupture at pH≈6 and are highly efficient in doxorubicin delivery to both drug-sensitive and drug-resistant cancer cells. This system is highly promising as a stimulus-responsive biocompatible nanovehicle. Copyright
- Moitra, Parikshit,Kumar, Krishan,Kondaiah, Paturu,Bhattacharya, Santanu
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supporting information
p. 1113 - 1117
(2014/03/21)
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- Lipodiscamides A-C, new cytotoxic lipopeptides from discodermia kiiensis
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Lipodiscamides A-C, three new lipodepsipeptides, were characterized from the marine sponge Discodermia kiiensis. These structurally rare cyclic lipodepsipeptides were found to possess an unprecedented dilactone macrocycle and, thus, represent a new family of lipopeptides. They are the only lipopeptides bearing 4S-hydroxy-trans-2-enoate, and noncanonical amino acids, l-3-ureidoalanine (Uda), E-dehydronorvaline (Denor), and d-citrulline (Cit). MTT assays against P388 and HeLa cells revealed the moderate cytotoxicity of all three compounds.
- Tan, Karen Co,Wakimoto, Toshiyuki,Abe, Ikuro
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supporting information
p. 3256 - 3259
(2014/07/08)
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- Syntheses and evaluation of drug-like properties of CO-releasing molecules containing ruthenium and group 6 metal
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In this paper, drug-like properties of two series of carbonyl metal CO-releasing molecules, Ru(CO)3ClnL (n = 1, L = amino acid or its derivatives 1-7, L = acetylacetone 8 or 2,2′-bipyridyl 9; n = 2, L = aminopyridine derivatives 10-13; n = 0, L = salicylaldehyde Schiff base 14-15) and M(CO)5L(M = Cr, Mo, W; L = glycine methyl ester 16-18; L = N-methyl imidazole 19-21), were preliminarily evaluated from four aspects involving in cytotoxicity, in vivo toxicity, bio-distribution and metabolism. Cytotoxic effects of all complexes were assayed by MTT. IC50 values of complexes 1-15 were 39.55-240.16 mg/l, and those of complexes 16 and 18 were 21.36-22.21 mg/l. Toxicity tests of mice used oral acute toxic class method and got LD50 values of some complexes; among them, LD50 of complex 1 was in 800-1000 mg/kg, complex 7 in 1100-1500 mg/kg and complex 18 in 75-125 mg/kg. After several consecutive administrations, tested complexes severely damaged liver and kidney in both functional and morphological aspects. And by metal ions measurements using ICP-AES, we found that the tested complexes were unevenly distributed in tissues and organs. In vivo, RuII in complexes was oxidized to RuIII by P450 enzymes, and for Mo 0 and W0 in complexes, part of them transformed into higher oxidation state, the others kept original state.
- Wang, Pengpeng,Liu, Huapeng,Zhao, Quanyi,Chen, Yonglin,Liu, Bin,Zhang, Baoping,Zheng, Qian
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p. 199 - 215
(2014/02/14)
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- Hydroxylamine as an oxygen nucleophile: Substitution of sulfonamide by a hydroxyl group in benzothiazole-2-sulfonamides
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Benzothiazole-2-sulfonamides react with an excess of hydroxylamine in aqueous solutions to form 2-hydroxybenzothiazole, sulfur dioxide, and the corresponding amine. Mechanistic studies that employ a combination of structure-reactivity relationships, oxygen labeling experiments, and (in)direct detection of intermediates and products reveal that the reaction proceeds via oxygen attack, and that oxygen incorporated in the 2-hydroxybenzothiazole product derives from hydroxylamine. The reaction, which is performed under mild conditions, can be used as a deprotection method for cleavage of benzothiazole-2-sulfonyl-protected amino acids.
- Kamps, Jos J. A. G.,Belle, Roman,Mecinovi?, Jasmin
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supporting information
p. 1103 - 1108
(2013/03/28)
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- AMINOQUINAZOLINE DERIVATIVES AND THEIR SALTS AND METHODS OF USE
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The present invention relates to the field of medicine. Provided herein are aminoquinazoline derivatives, their salts and pharmaceutical formulations useful in modulating the protein tyrosine kinase activity, and in modulating inter-and/or intra-cellular signaling. Also provided herein are pharmaceutically acceptable compositions comprising the aminoquinazoline compounds and methods of using the compositions in the treatment of hyperproliferative disorders in mammals, especially humans.
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Paragraph 00210
(2013/06/05)
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- In situ deprotection and incorporation of unnatural amino acids during cell-free protein synthesis
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The S30 extract from E. coli BL21 Star (DE3) used for cell-free protein synthesis removes a wide range of α-amino acid protecting groups by cleaving α-carboxyl hydrazides; methyl, benzyl, tert-butyl, and adamantyl esters; tert-butyl and adamantyl carboxamides; α-amino form-, acet-, trifluoroacet-, and benzamides and sidechain hydrazides and esters. The free amino acids are produced and incorporated into a protein under standard conditions. This approach allows the deprotection of amino acids to be carried out in situ to avoid separate processing steps. The advantages of this approach are demonstrated by the efficient incorporation of the chemically intractable (S)-4-fluoroleucine, (S)-4,5- dehydroleucine, and (2S,3R)-4-chlorovaline into a protein through the direct use of their respective precursors, namely, (S)-4-fluoroleucine hydrazide, (S)-4,5-dehydroleucine hydrazide, and (2S,3R)-4-chlorovaline methyl ester. These results also show that the fluoroand dehydroleucine and the chlorovaline are incorporated into a protein by the normal biosynthetic machinery as substitutes for leucine and isoleucine, respectively. Copyright
- Arthur, Isaac N.,Hennessy, James E.,Padmakshan, Dharshana,Stigers, Dannon J.,Lesturgez, Stéphanie,Fraser, Samuel A.,Liutkus, Mantas,Otting, Gottfried,Oakeshott, John G.,Easton, Christopher J.
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supporting information
p. 6824 - 6830
(2013/06/26)
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- Synthesis of peptides employing protected-amino acid halides mediated by commercial anion exchange resin
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Coupling of protected-amino acid halides (chloride, fluoride) mediated by commercial anion exchange resin for the solution phase synthesis of peptides is described. The reaction was carried out in an organic medium, circumventing the use of an organic base or an inorganic base. The coupling is fast, clean and racemization free. The anion exchange resin functions as a solid-phase basic scavenger, soaking up the HCl produced and allowing the amine to react. The method is extended for the coupling of sterically hindered α,α,- dialkylamino acids. Graphical Abstract: [Figure not available: see fulltext.]
- Bhaskara Redddy,Kumari, Y. Bharathi,Ananda, Kuppanna
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p. 225 - 229
(2013/12/04)
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- Chiral iminoesters derived from d-glyceraldehyde in [3+2] cycloaddition reactions. Asymmetric synthesis of a key intermediate in the synthesis of neuramidinase inhibitors
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Silver-catalyzed endo-selective and copper-catalyzed exo-selective asymmetric [3 + 2] cycloadditions of acrylates to chiral iminoesters derived from d-glyceraldehyde have been investigated. The reaction diastereoselectively provides highly functionalized pyrrolidines. This approach was used to develop the first asymmetric synthesis of a key intermediate in the synthesis of pyrrolidine influenza neuramidinase inhibitors.
- Galvez, Jose A.,Diaz-De-Villegas, Maria D.,Alias, Miriam,Badorrey, Ramon
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p. 11404 - 11413
(2013/12/04)
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- Antineoplastic agents. 548. Synthesis of iodo- and diiodocombstatin phosphate prodrugs
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Toward the objective of designing a structurally modified analogue of the combretastatin A-4 phosphate prodrug (1b) with the potential for increased specificity toward thyroid carcinoma, synthesis of a series of iodocombstatin phosphate (11a-h) and diiodocombstatin phosphate prodrugs (12a-h) has been accomplished. The diiodo series was obtained via 8a and 9c from condensation of 4 and 6, and the iodo sequence involved a parallel pathway. Both series of iodocombstatins were found to display significant to powerful inhibition of the growth of a panel of human cancer cell lines and of the murine P388 lymphocytic leukemia cell line. Of the diiodo series, 12a was also found to markedly inhibit growth of pediatric neuroblastoma, and monoiodocombstatin 9a strongly inhibited HUVEC growth. Overall, the strongest activity was found against the breast, CNS, leukemia, lung, and prostate cancer cell lines and the least activity against the pancreas and colon lines. Parallel biological investigations of tubulin interaction, antiangiogenesis, and antimicrobial effects were also conducted.
- Pettit, George R.,Rosenberg, Heidi J.,Dixon, Rachel,Knight, John C.,Hamel, Ernest,Chapuis, Jean-Charles,Pettit, Robin K.,Hogan, Fiona,Sumner, Brandy,Ain, Kenneth B.,Trickey-Platt, Brindi
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experimental part
p. 385 - 393
(2012/06/29)
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- Poly(vinyl)chloride supported palladium nanoparticles: Catalyst for rapid hydrogenation reactions
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Palladium nanoparticles supported over poly(vinyl)chloride matrix (PVC-Pd0) are prepared through an efficient and inexpensive protocol. The catalyst has been characterized by XRD, SEM and TEM and its utility for the reduction of a range of functional groups as well as for the removal of some common protecting groups employed in peptide chemistry is demonstrated.
- Hemantha, Hosahalli P.,Sureshbabu, Vommina V.
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experimental part
p. 2597 - 2601
(2011/05/12)
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- Comparison of liquid chromatography-isotope ratio mass spectrometry (LC/IRMS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) for the determination of collagen amino acid δ13C values for palaeodietary and palaeoecological reconstruction
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Results are presented of a comparison of the amino acid (AA) δ13C values obtained by gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) and liquid chromatography-isotope ratio mass spectrometry (LC/IRMS). Although the primary focus was the compound-specific stable carbon isotope analysis of bone collagen AAs, because of its growing application for palaeodietary and palaeoecological reconstruction, the results are relevant to any field where AA δ13C values are required. We compare LC/IRMS with the most up-to-date GC/C/IRMS method using N-acetyl methyl ester (NACME) AA derivatives. This comparison involves the analysis of standard AAs and hydrolysates of archaeological human bone collagen, which have been previously investigated as N-trifluoroacetyl isopropyl esters (TFA/IP). It was observed that, although GC/C/IRMS analyses required less sample, LC/IRMS permitted the analysis of a wider range of AAs, particularly those not amenable to GC analysis (e.g. arginine). Accordingly, reconstructed bulk δ13C values based on LC/IRMS-derived δ13C values were closer to the EA/IRMS-derived δ13C values than those based on GC/C/IRMS values. The analytical errors for LC/IRMS AA δ13C values were lower than GC/C/IRMS determinations. Inconsistencies in the δ13C values of the TFA/IP derivatives compared with the NACME- and LC/IRMS-derived δ13C values suggest inherent problems with the use of TFA/IP derivatives, resulting from: (i) inefficient sample combustion, and/or (ii) differences in the intra-molecular distribution of δ13C values between AAs, which are manifested by incomplete combustion. Close similarities between the NACME AA δ13C values and the LC/IRMS-derived δ13C values suggest that the TFA/IP derivatives should be abandoned for the natural abundance determinations of AA δ13C values.
- Dunn, Philip J. H.,Honch, Noah V.,Evershed, Richard P.
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experimental part
p. 2995 - 3011
(2012/05/20)
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- The design of α/β-peptides: Study on three-residue turn motifs and the influence of achiral glycine on helix and turn
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Novel three-residue helix-turn secondary structures, nucleated by a helix at the N terminus, were generated in peptides that have 'β-Caa-L-Ala-L-Ala, ' 'β-Caa-L-Ala-γ-Caa,' and 'β-Caa-L-Ala-γ-Caa' (in which β-Caa is C-linked carbo-β-amino acid, γ-Caa is C-linked carbo-γ-amino acid, and γ-Caa is C-linked carbo-γ-amino acid) at the C terminus. These turn structures are stabilized by 12-, 14-, and 15-membered (mr) hydrogen bonding between NH(i)/CO(i+2) (i+2 is the last residue in the peptide) along with a 7-mr hydrogen bond between CO(i)/NH(i+2). In addition, a series of α/β-peptides were designed and synthesized with alternating glycine (Gly) and (S)-β-Caa to study the influence of an achiral α-residue on the helix and helix-turn structures. In contrast to previous results, the three 'β-α-β' residues at the C terminus (α-residue being Gly) are stabilized by only a 13-mr forward hydrogen bond, which resembles an α-turn. Extensive NMR spectroscopic and molecular dynamics (MD) studies were performed to support these observations. The influence of chirality and side chain is also discussed. A turn for the better: α/β-Peptides with novel turns (12/7-, 14/7-, and 15/7-) at the C terminus were prepared. Similarly, the design with glycine gave an opportunity to study the influence of achiral α-residues on helix formation and stability. This study also resulted in a new 13-membered 'turn' in the forward direction, which resembles the α-turn (see picture). Copyright
- Sharma, Gangavaram V. M.,Chandramouli, Nagula,Basha, Shaik Jeelani,Nagendar, Pendem,Ramakrishna, Kallaganti V. S.,Sarma, Akella V. S.
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experimental part
p. 84 - 97
(2011/10/08)
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- Supported p-toluenesulfonic acid as a highly robust and eco-friendly isocyanide scavenger
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We document here the use of polymer-supported p-toluenesulfonic acid as a highly effective, robust, economical and eco-friendly isocyanide scavenger. The herein described strategy circumvent the intense and repulsive odor of volatile isocyanides, enabling simplified and odorless workup and purifications. The usefulness of the new scavengers has been validated in a set of diverse isocyanide-based organic transformations and this approach is also amenable to parallel synthesis techniques.
- Azuaje, Jhonny,Coelho, Alberto,Maatougui, Abdelaziz El,Blanco, Jose Manuel,Sotelo, Eddy
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experimental part
p. 89 - 95
(2011/04/15)
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- A class of novel Schiff's bases: Synthesis, therapeutic action for chronic pain, anti-inflammation and 3D QSAR analysis
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To discover analgesics for treating chronic pain 17 novel Schiff's bases, N,N′-(Z-allylidene-1,3-diyl)bisamino acid methyl esters were prepared from 1,1,3,3,-tetramethoxypropane and amino acid methyl esters. On tail-flick mouse model 20 μmol/kg of these Schiff's bases were orally administered, the analgesic action started 30 min after administration, reached the maximum 120 min after administration, and at 180 min this action was still observed. On a xylene-induced ear edema mouse model 20 μmol/kg of these Schiff's bases exhibited desirable anti-inflammation. Thus the present Schiff's bases are able to treat chronic pain from inflammation. The effect of the side chains of the amino acid residues of these Schiff's bases on the analgesic activity was explained with 3D QSAR.
- Zhou, Yinjian,Zhao, Ming,Wu, Yingting,Li, Chunyu,Wu, Jianhui,Zheng, Meiqing,Peng, Li,Peng, Shiqi
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experimental part
p. 2165 - 2172
(2010/05/18)
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- A highly efficient flow reactor process for the synthesis of N-Boc-3,4-dehydro-l-proline methyl ester
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The multi-step preparation of N-Boc-3,4-dehydro-l-proline methyl ester using a modular flow reactor is reported. The use of immobilised reagents and scavengers in pre-packed glass tubes allows us to obtain the pure product in 87% overall yield, 97% purity, and >98% enantiomeric excess without any additional purification step. Our flow-based protocol enables the rapid multi-gram synthesis (about 9 g/12 h) of the desired product.
- Tamborini, Lucia,Conti, Paola,Pinto, Andrea,Micheli, Carlo De
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experimental part
p. 222 - 225
(2010/05/02)
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- PROCESS FOR THE COVALENT COUPLING OF TWO MOLECULES BY MEANS OF A DIELS-ALDER REACTION WITH INVERSE ELECTRON REQUIREMENT
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The present invention relates to a process for linking two molecules by means of a Diels Alder reaction with inverse electron requirement (DARinv), comprising the following steps: reaction of a (a) triazine or tetrazine with one or more electron-attracting substituents on the ring as a diene component, the electron-attracting substituents being selected from: COORC(O)NR2 CX3 (X=halogen)halogenCNSO2—R or SO3—RPR2 wherein R═H, alkyl, aryl, heterocycle, which in turn may be substituted, where appropriate, with alkyl, OH, SH, halogen, aryl, heterocycle, nitro, carboxyamido or amine group. —heterocyclic rings having 1, 2 or 3 N, O or S atoms with a ring size of 5 or 6 ring members, which are substituted with at least one carboxyl, sulfonic acid or phosphone group with (b) an isolated double bond or triple bond in a (hetero)carbocyclic ring or an isolated olefinic double bond or triple bond in a linear or branched hydrocarbon chain which may also contain heteroatoms, where appropriate, as a dienophile component.
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Page/Page column 49
(2010/02/17)
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- Supramolecular gelation of alcohol and water by synthetic amphiphilic gallic acid derivatives
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The supramolecular organogelation of alcohols was observed in relatively hydrophobic amphiphiles with a short oligo(ethylene glycol) unit and three long alkyl chains at room temperature, while the hydrogelation occurred in more hydrophilic gelators with a longer poly(ethylene glycol) unit and two long alkyl chains at various temperatures. When a hot aqueous solution of some of the synthetic hydrogelators was cooled down, the supramolecular hydrogel was formed at room temperature. In some other amphiphiles with less intermolecular interactivity in water at room temperature, a reverse phase transition of sol to gel was observed by elevating the temperature of their aqueous systems, especially below a physiological temperature, 37 °C. The supramolecular hydrogelation at a low or high temperature was dependent on a slight molecular modification of the synthetic amphiphiles.
- Tamiaki, Hitoshi,Ogawa, Keishiro,Enomoto, Keisuke,Taki, Kazutaka,Hotta, Atsushi,Toma, Kazunori
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supporting information; experimental part
p. 1661 - 1666
(2010/04/24)
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- Polyketide synthase thioesterases catalyze rapid hydrolysis of peptidyl thioesters
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Polyketide synthase (PKS) thioesterases (TEs) catalyze the macrocyclization of linear acyl chains into macrolactones. Herein we show that peptide based substrates are processed by PKS TEs with greater catalytic efficiency than more native like acyl substrates. This result strengths the link between PKS and non-ribosomal peptide synthetase systems and provides a new tool for studying PKS TEs.
- Wang, Meng,Opare, Peter,Boddy, Christopher N.
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supporting information; experimental part
p. 1413 - 1415
(2009/10/15)
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- Synthesis and molecular recognition of novel multiimidazole cyclophanes
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(Chemical Equation Presented) Cyclophanes based on 2,2′-biimidazole and 2,2′-bibenzimidazole were synthesized as receptors. UV spectroscopic titration in chloroform at 25°C showed 1:1 complexes between the cyclophanes and the guests, and the binding constants (K) and Gibbs free energy changes (-ΔG0) were calculated according to the modified Benesi-Hildebrand equation.
- Xu, Xiao-Wei,Wang, Xin-Long,Wu, Ai-Ming,Zheng, Zhi-Ming,Yi, Mei-Gui,Xiao, Rong
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experimental part
p. 1137 - 1141
(2010/03/01)
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- Diversity-oriented synthesis of a cytisine-inspired pyridone library leading to the discovery of novel inhibitors of Bcl-2
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Four enantiopure cytisine-inspired scaffolds can be accessed via a versatile pyrrolidine template derived from a stereocontrolled [3+2] azomethine ylide-alkene cycloaddition. Differential ester protection allows for the selective formation of either a bridged bicyclic or tricyclic scaffold via pyridone cyclization. Solid-phase diversification of the pyridone scaffolds yielded a diverse library of 15,000 compounds enabling the discovery of a novel class of Bcl-2 inhibitors.
- Marcaurelle, Lisa A.,Johannes, Charles,Yohannes, Daniel,Tillotson, Bonnie P.,Mann, David
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supporting information; experimental part
p. 2500 - 2503
(2009/12/31)
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- Design and synthesis of N-methylmaleimide indolocarbazole bearing modified 2-acetamino acid moieties as Topoisomerase I inhibitors
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A novel series of N-methylmaleimide indolocarbazole derivatives bearing modified 2-acetamino acid moieties are first reported. The cytotoxic effects of these compounds were tested in five human tumor cell lines. The potent compounds 9a, 9b, 9d, and 9e have been further evaluated for their effect on Topoisomerase I (TOPO I) and cancer cell cycle. It is concluded that the indolocarbazoles with alkyl piperazine or morpholine substituent groups instead of esters or glycosyl residues would have better activities against tumors.
- Li, Zhiyu,Zhai, Fuming,Zhao, Li,Guo, Qinglong,You, Qidong
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scheme or table
p. 406 - 409
(2011/02/26)
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- Phosphorylthioureas and phosphorylureas containing amino acid fragments
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A series of (dialkoxyphosphoryl)thioureas and their 1,3,2-oxazaphosphinane analogs containing fragments of glycine, alanine, ss-alanine, L-aspartic and L-glutamic acids, as well as phosphorylureas derived from glycine and ss-alanine were synthesized in the search for potential biologically active compounds (including possible inhibitors of aspartate trans-carbamoylase).
- Shipov,Genkina,Petrovskii
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p. 2512 - 2516
(2014/05/06)
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- Biomimetic synthesis of esters of natural amino acids
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A method for the synthesis of Gly, Ala, Phe, and Thr esters is proposed and considered as being a stage of possible biomimetic synthesis of peptides. The methyl esters of the said amino acids are obtained via intervention of 2-hydroxypropyl phosphonate. The resulting aminoacyl phosphonates reacts with methanol to produce the amino acid methyl esters, with the release of phosphoric acid. The reaction is carried out at room temperature in water.
- Devedjiev, Ivan T.,Bairyamov, Stanislav G.,Videva, Vladimira S.
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p. 252 - 255
(2008/09/19)
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- On the mechanism of the thermal retrocycloaddition of pyrrolidinofullerenes (retro-prato reaction)
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In contrast to N-methyl or N-unsubstituted pyrrolidinofullerenes, which efficiently undergo the retrocycloaddition reaction to quantitatively afford pristine fullerene, N-benzoyl derivatives do not give this reaction under the same experimental conditions. To unravel the mechanism of the retrocycloaddition process, trapping experiments of the in-situ thermally generated azomethine ylides, with an efficient dipolarophile were conducted. These experiments afforded the respective cycloadducts as an endolexo iso-meric mixture. Theoretical calculations carried out at the DFT level and by using the two-layered ONIOM (our own n-layered integrated molecular orbital and molecular mechanics) approach underpin the experimental findings and predict that the presence of the dienophile is not a basic requirement for the azomethine ylide to be able to leave the fullerene surface under thermal conditions. Once the 1,3-dipole is generated in the reaction medium, it is efficiently trapped by the dipolarophile (maleic anhydride or N-phenylmaleimide). However, for N-unsubstituted pyrrolidinofullerenes, the participation of the dipolarophile in assisting the 1,3-dipole to leave the fullerene surface throughout the whole reaction pathway is also a plausible mechanism that cannot be ruled out.
- Filippone, Salvatore,Barroso, Marta Izquierdo,Martin-Domenech, Angel,Osuna, Silvia,Sola, Miquel,Martin, Nazario
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supporting information; experimental part
p. 5198 - 5206
(2009/05/27)
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- Ceric ammonium nitrate (CAN) mediated esterification of N-Boc amino acids allows either retention or removal of the N-Boc group
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Reaction of N-Boc amino acids with ceric ammonium nitrate in an alcohol as the solvent at room temperature resulted in the esterification of N-Boc amino acids with Boc group retention. When the reaction was conducted at reflux temperature, esterification was accompanied with simultaneous removal of the Boc group. Both reactions gave the desired products in good yields.
- Kuttan, Ashani,Nowshudin, Shiek,Rao
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p. 2663 - 2665
(2007/10/03)
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