Single-molecule-force spectroscopy study of the mechanism of interactions between TSP-1 and CD47

The 4N1K peptide,which is derived from the C-terminal domain of thrombospondin-1(TSP-1),is usually used as a functional mimic peptide for TSP-1.Knowledge about the interaction force of 4N1K/CD47 is important in explaining how TSP-1 affects the biological effect of CD47.Here we used a single-molecule force spectroscopy(SMFS)technique to explore the interaction of 4N1K/CD47 on both normal and oxidative human red blood cells(h RBCs)at single-molecule level.There was no interaction force between 4N1K and CD47 on normal h RBCs;however,we did find 4N1K-bound CD47 on oxidative h RBCs.We also detected interaction forces for 4N1K/CD47ex(extracellular domain of human CD47),and 4N1K/oxidative CD47ex.The interaction forces of 4N1K/CD47ex were almost consistent with those of 4N1K/oxidative CD47ex at the same loading rate.These results suggest that the conformational change of CD47 is critical for 4N1K-CD47 interaction on oxidative h RBCs.     

The preparation of N- and C-halogen derivatives of 1, 2, 4-triazole

The action of halogens in an alkaline medium on 1, 2, 4-triazoles has given their N-chloro, N-bromo, and N-iodo derivatives. The formation of C-halogen derivatives of some 1, 2, 4-triazoles from their N-halogen derivatives has been studied, and also the action of halogens on 1, 2, 4-triazoles at elevated temperatures. It has been shown that N-bromo-1, 2, 4-triazoles very readily form 1, 2, 4-triazole and 3, 5-dibromo-1, 2, 4-triazole in approximately equimolar proportions. N-Chloro-1, 2, 4-triazole is more stable to the action of heat and forms 3-chloro-1, 2, 4-triazole with a yield of 40%. It was impossible to convert N-iodo-1, 2, 4-triazole into C-derivatives.     

顺1,4及反1,4聚丁二烯共混及共聚物结晶形态结构研究

本文用电镜、电子衍射及DSC等研究了顺1,4PB及反1,4PB的共混及共聚物的形态结构。观察了室温下两相结构分布随组分变化的规律及反1,4PB含量对顺1,4PB低温结晶、片层厚度和球晶大小的影响。进一步讨论了这两种不能形成类质同象结构物质结晶的相互影响。     

Spectroscopic studies of inclusion complexes of 1-naphthol-4-sulfonate with beta-cyclodextrin in aqueous solution

The photophysical properties of 1-naphthol-4-sulfonate (1N4S) in some solvents and in aqueous beta-cyclodextrin solution have been investigated. The effect of beta-cyclodextrin on the fluorescence quantum yield and on the proton transfer is examined. Fluorescence measurements show 1:1 inclusion of 1N4S in the beta-cyclodextrin cavity with an association constant of 108M(-1). NMR studies are used to study the inclusion phenomena and to provide information on the geometry of 1N4S inside the cavity of beta-cyclodextrin.     

Reactions of 4-acyl-1-alkoxyaryl-5-aryl-3-hydroxy-2,5-dihydro-1H-pyrrol-2-ones with nucleophilic reagents

4-Acetyl-1-alkoxyaryl-5-aryl-3-hydroxy-2,5-dihydro-1H-pyrrol-2-ones reacted with amines to give 1-alkoxyaryl-5-aryl-4-(1-R-aminoethylidene)pyrrolidine-2,3-diones. Reactions of amines with 4-benzoyl-substituted analogs involve nucleophilic attack on the C³ atom in the heteroring to produce the corresponding 3-R-amino-1-alkoxyaryl-5-aryl-4-benzoyl-2,5-dihydro-1H-pyrrol-2-ones. Reactions of the title compounds with hydrazine hydrate, regardless on the substituent on C₄, afforded 4-aryl-3-methyl(phenyl)-5-[2(4)-methoxyphenyl]-4,6-dihydropyrrolo[3,4-c]pyrazol-6-ones.     

A fragmentation study of podophyllotoxin and its 4'-demethyl-4beta-substituted derivatives by electrospray ionization ion-trap time-of-flight tandem mass spectrometry

High-resolution electrospray ionization multistage tandem mass spectrometry (MS(1-9)) was used to determine the accurate masses and the fragmentation pathways of protonated podophyllotoxin (1) and its corresponding 4'-demethyl-4beta-substituted derivatives (2-4). The protonated molecules, [M + H](+), of all the four compounds were observed in the conventional single-stage mass spectra. Two fragmentation pathways, that appear to be characteristic of the four compounds, are proposed on the basis of their multistage tandem mass spectrometric data. The characteristic elimination, from the precursor protonated ions, of the neutral groups 4-R(1)H, 1-ArH, CO, CH(2)O and C(4)H(4)O(2), in which R is located on C-4, is the common elimination, and the product ions at m/z 267, 239, 229, 181, 173, 153, 143 and 115 are the common diagnostic masses. The elimination of the R(1) group substituent located on the C-4 position of compounds 1-4 has a significant influence on the fragmentation pathway obtained in the conventional single-stage mass spectra. A large R(1) group would be unfavorable for this elimination, unless the collision energy is raised. Apart from the common fragmentations obtained for the protonated molecules 1-4, significant additional product ions were detected in the various multistage tandem mass spectrometric analyses, particularly in the case of the product ions derived initially from the phenolic hydroxyl group of 2-4, which are different from those of 1. Based on these additional formed product ions, several additional fragmentation pathways for 1 or 2-4 are also presented.     

铂和铜电极上4-硝基吡啶-1-氧化物还原过程研究

4-氨基吡啶是一种重要的精细化工产品, 为探讨其电化学合成过程的反应机理, 采用循环伏安法、库仑电解等方法对强酸性条件下4-硝基吡啶-1-氧化物的电化学行为进行了研究. 结果表明: 4-硝基吡啶-1-氧化物在铂电极上主要经历电化学-化学-电化学(ECE)还原历程, 并生成4-羟胺吡啶-1-氧化物; 对铜电极而言, 当电位高于－0.65 V时主要经历ECE还原历程, 并生成4-羟胺吡啶-1-氧化物; 当电位低于－0.85 V时经历ECE还原历程生成的4-羟胺吡啶-1-氧化物, 可发生进一步4e^－还原, 并生成4-氨基吡啶.     

Investigations on 2,3'-Biquinolyls. 15. Regioselectivity of the Addition of Nitromethane Anion to 1'-Alkyl-3'-(2-quinolyl)quinolinium Halides

1'-R-3'-(2-Quinolyl)quinolinium halides react with nitromethane forming products of addition at the position 4', the 1'-R-4'-nitromethyl-1',4'-dihydro-2,3'-biquinolyls. A method has been developed for the synthesis of 1'-phenacyl-1',4'-dihydro-2,3'-biquinolyls based on the alkylation of 1',4'-dihydro-2,3'-biquinolyl with halogen derivatives in DMF.     

4-Lithio-1-tritylimidazole as a synthetic intermediate. Synthesis of imidazole-4-carboxaldehyde

Reaction of 4-iodo-1-tritylimidazole with n-butyllithium at –79°, followed by rapid quenching of the reaction mixture with DMF, gives good yields of 1-tritylimidazole-4(5)-carboxaldehyde, the isolation of which demonstrates the intermediacy of 4-lithio-1-tritylimidazole. This species should be destabilized by repulsive interaction of the negative charge on C-4 with the adjacent lone pair electrons on N-3 (the ALP effect). The isolation of 1-tritylimidazole-4(5)-carboxaldehyde in good yield and the versatility of the aldehyde functionality make 4-lithio-1-tritylimidazole a useful synthetic intermediate.     

Growth of sputter-deposited gold nanoparticles in ionic liquids

The growth of gold nanoparticles (NPs) synthesized by sputter deposition on an ionic liquid surface is studied in situ in the bulk phase of the ionic liquids (ILs) 1-butyl-3-methylimidazolium dicyanamide [C(1)C(4)Im][N(CN)(2)], 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide [C(1)C(4)Im][Tf(2)N], 1-butyl-3-methylimidazolium tetrafluoroborate [C(1)C(4)Im][BF(4)], 1-butyl-3-methylimidazolium hexafluorophosphate [C(1)C(4)Im][PF(6)] and 1-butyl-3-methylimidazolium triflate [C(1)C(4)Im][TfO]. It is found that primary nanoparticles with a diameter smaller than 2.5 nm are present in the sample immediately after sputtering. Growth of these primary particles proceeds after the end of the sputtering process and stops when the nanoparticles reach a certain size. Depending on the viscosity of the ionic liquid this growth process can proceed several hours to several days. The growth speed is fastest for the least viscous ionic liquid and follows the trend [C(1)C(4)Im][N(CN)(2)] > [C(1)C(4)Im][Tf(2)N] > [C(1)C(4)Im][TfO] > [C(1)C(4)Im][BF(4)] > [C(1)C(4)Im][PF(6)]. It is also found that a higher concentration of sputtered gold results in faster growth of the gold nanoparticles. A discussion on the growth mechanism of sputtered gold NPs is included.     

Metal ion-controlled self-assembly using pyrimidine hydrazone molecular strands with terminal hydroxymethyl groups: a comparison of Pb(II) and Zn(II) complexes

Metal complexation studies were performed with the ditopic pyrimidine-hydrazone (pym-hyz) strand 6-hydroxymethylpyridine-2-carboxaldehyde (2-methyl-pyrimidine-4,6-diyl)bis(1-methylhydrazone) (1) and Pb(ClO(4))(2)·3H(2)O, Pb(SO(3)CF(3))(2)·H(2)O, Zn(SO(3)CF(3))(2), and Zn(BF(4))(2) to examine the ability of 1 to form various supramolecular architectures. X-ray crystallographic and NMR studies showed that coordination of the Pb(II) salts with 1 on a 2:1 metal/ligand ratio in CH(3)CN and CH(3)NO(2) resulted in the linear complexes [Pb(2)1(ClO(4))(4)] (2), [Pb(2)1(ClO(4))(3)(H(2)O)]ClO(4) (3), and [Pb(2)1(SO(3)CF(3))(3)(H(2)O)]SO(3)CF(3) (4). Two unusually distorted [2 × 2] grid complexes, [Pb1(ClO(4))](4)(ClO(4))(4) (5) and [Pb1(ClO(4))](4)(ClO(4))(4)·4CH(3)NO(2) (6), were formed by reacting Pb(ClO(4))(2)·6H(2)O and 1 on a 1:1 metal/ligand ratio in CH(3)CN and CH(3)NO(2). These grids formed despite coordination of the hydroxymethyl arms due to the large, flexible coordination sphere of the Pb(II) ions. A [2 × 2] grid complex was formed in solution by reacting Pb(SO(3)CF(3))(2)·H(2)O and 1 on a 1:1 metal/ligand ratio in CH(3)CN as shown by (1)H NMR, microanalysis, and ESMS. Reacting the Zn(II) salts with 1 on a 2:1 metal/ligand ratio gave the linear complexes [Zn(2)1(H(2)O)(4)](SO(3)CF(3))(4)·C(2)H(5)O (7) and [Zn(2)1(BF(4))(H(2)O)(2)(CH(3)CN)](BF(4))(3)·H(2)O (8). (1)H NMR studies showed the Zn(II) and Pb(II) ions in these linear complexes were labile undergoing metal ion exchange. All of the complexes exhibited pym-hyz linkages in their cisoid conformation and binding between the hydroxymethyl arms and the metal ions. No complexes were isolated from reacting either of the Zn(II) salts with 1 on a 1:1 metal/ligand ratio, due to the smaller size of the Zn(II) coordination sphere as compared to the much larger Pb(II) ions.     

枸杞子糖缀合物LbGp4糖链的结构及其免疫活性的研究

枸杞子糖缀合物LbGp4经β--消除、柱层析分离后得到一条分子量高达180800的分支多糖化合物LbGp4-OL.LbGp4-OL糖基组成为n(Rha):n(Ara):n(Gal)=0.05:1.33:1.根据甲基化、部分酸水解及¹HNMR、¹³CNMR分析,确定了其主要的结构,并对LbGp4和LbGp4-OL的免疫活性进行了研究.     

Synthesis of 5-amino-1-(aminothioformyl)-1, 2, 4-triazoles

By the reaction of 5-amino-1, 2, 4-triazoles with benzoyl isothiocyanate we have synthesized 5-amino-1-(benzoylaminothioformyl)-1, 2, 4-triazoles, which form 5-amino-1-(aminothioformyl)-1, 2, 4-triazoles on alkaline hydrolysis.     

New phenolic glycosides from the seeds of Cucurbita moschata

Five new phenolic glycosides, cucurbitosides A-E (1-5), were isolated from the seeds of Cucurbita moschata. Their structures were elucidated as 2-(4-hydroxy)phenylethanol 4-O-(5-O-benzoyl)-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (1), 2-(4-hydroxyphenyl)ethanol 4-O-[5-O-(4-hydroxy)benzoyl]-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (2), 4-hydroxybenzyl alcohol 4-O-(5-O-benzoyl)-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (3), 4-hydroxybenzyl alcohol 4-O-[5-O-(4-hydroxy)benzoyl]-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (4) and 4-hydroxyphenyl 5-O-benzoyl-beta-D-apiofuranosyl(1-->2)-beta-D-glucopyranoside (5) on the basis of spectroscopic analysis and chemical evidence.     

The investigation in 2,3'-biquinoline series 26.* Regioselective nitration of 1'-alkyl-1',4'-dihydro-2,3'-biquinolin-4'-ones and 1'-alkyl-1',2'-dihydro-2,3'-biquinolin-2'-ones

The nitration of 1'-alkyl-1',4'-dihydro-2,3'-biquinolin-4'-ones and 1'-alkyl-1',2'-dihydro-2,3'-biquinolin-2'-ones has been investigated. It was shown that the regioselectivity of nitration of the first depends on the acidity of the medium and the order of adding reactants. In strongly acidic medium 1'-alkyl-5,6'-dinitro-1',4'-dihydro-2,3'-biquinolin-4'-ones or mixtures of them with 1'-alkyl-5-nitro-1',4'-dihydro-2,3'-biquinolin-4'-ones are formed. In less acidic media 1'-alkyl-6'-nitro-1',4'-dihydro-2,3'-biquinolin-4'-ones and then 1'-alkyl-6,6'-dinitro-1',4'-dihydro-2,3'-biquinolin-4'-ones are formed. Nitration of 1'-alkyl-1',2'-dihydro-2,3'-biquinolin-2'-ones leads to 1'-alkyl-6'-nitro-1',2'-dihydro-2,3'-biquinolin-2'-one and then 1'-alkyl-6,6',8'-trinitro-1',2'-dihydro-2,3'-biquinolin-2'-one. *For Communication 25 see [1]. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 578-585, April, 2009.     

1-(1-Carboxy-2-R-4-methylcyclohex-4-enyl)carbonyl- and 1-(2-R-4-Methylcyclohex-4-enyl)carbonyl-3,5-dimethyl(diphenyl)pyrazoles

1-(1-Carboxy-2-R-4-methylcyclohex-4-enyl)carbonyl- and 1-(2-R-4-methylcyclohex-4-enyl)carbonyl-3,5-dimethyl(diphenyl)pyrazoles have been obtained from the reaction of monohydrazides of 2-R-methyl-4-cyclohexen-1,1-dicarboxylic acids and hydrazides of 2-R-4-methyl-4-cyclohexen-1-monocarboxylic acids with acetylacetone and dibenzoylmethane. The conditions for the formation of the pyrazoles depend on the nature of the substituents in the hydrazide starting materials and the structure of the 1,3-diketone used.     

Enolate structure and electron affinity

Photodetachment cross sections for a series of cyclic enolates were measured using a continuous wave (CW) ion cyclotron resonance instrument to generate and detect the ions. We report electron affinities for the radicals corresponding to the removal of the extra electron from the following anions: 2-methylcyclopent-1-enolate, 3-methylcyclopent-1-enolate, 4-methylcyclopent-1-enolate, 5-methylcyclopent-1-enolate, 2-methylcyclohex-1-enolate, 3-methylcyclohex-1-enolate, 4-methylcyclohex-1-enolate, 4-ethylcyclohex-1-enolate, 5-methylcyclohex-1-enolate, and 6-methylcyclohex-1-enolate. Some of these anions are mixed with their tautomers, derived from deprotonation of the parent ketone; the consequences of this are analyzed. The effect of alkylation on the electron affinities is discussed. The effect of vibrational modes on the lifetimes of the dipole-bound states of 4-methylcyclohex-1-enolate and 4-ethylcyclohex-1-enolate is discussed.     

Synthesis,characterization and antimicrobial activity of novel sulphapiperazine containing arylazopyrazoles

Mannich reaction of benzotriazole (1), ethyl-4-amino benzoate (2) and formaldehyde in ethanol afforded 4-(1H)-benzotriazoyl methyl amino benzoate (3), which on treatment with hydrazine hydrate results in the 4-(1H)-benzotriazoyl methyl amino benzoyl hydrazide (4). This compound on condensation with pre-prepared various ethyl-2-substituted phenyl hydrazono-3-oxobutyrates (6a–h), furnished 1-(4-((1H-benzo[d][1,2,3]triazol-1-yl) methyl amino) benzoyl)-3-methyl-4-(2-(4-(4-alkylpiperazin-1-ylsulfonyl) phenyl) hydrazono)-1H-pyrazol-5(4H)-ones (7a–h). All these compounds (7a–h) were characterized by spectral studies. The compounds showed significant antimicrobial activity against various bacteria and fungi.     

Serum concentrations of soluble 4-1BB and 4-1BB ligand correlated with the disease severity in rheumatoid arthritis

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease whose etiopathogenesis is not well understood. Although soluble (s) forms of 4-1BB (s4-1BB) and 4-1BB legand (s4-1BBL) have been detected in the sera of RA patients, their significance is not known. We compared the serum levels of s4-1BB and s4-1BBL in RA patients with those in systemic lupus erythematosus (SLE) and Behcet's disease (BD) patients. Serum levels of s4-1BB and s4-1BBL were significantly higher in RA patients compared with healthy controls, SLE or BD patients, and the abundance was correlated with disease severity in patients with RA. The serum levels of s4-1BB in RA patients were inversely corroborated with 4-1BB expression levels on activated T lymphocytes. In addition, there was a correlation between serum levels of s4-1BB and s4-1BBL. The augmented secretion of s4-1BB and s4-1BBL levels into the serum may reflect the clinical symptoms of RA and levels of s4-1BB and s4-1BBL in sera at the time of diagnosis may be indicative of the severity and outcome of RA.     

New pregnane glycosides from Cynanchum ascyrifolium

Two new pregnane glycosides, cynascyrosides D and E, were isolated from the roots of Cynanchum ascyrifolium. The structures of these compounds were determined on the basis of spectroscopic and chemical evidence as cynajapogenin A 3-O-alpha-L-cymaropyranosyl-(1-->4)-beta-D-digitoxopyranosyl-(1-->4)-beta-L-cymaropyranoside and cynajapogenin A 3-O-beta-D-glucopyranosyl-(1-->4)-alpha-L-diginopyranosyl-(1-->4)-beta-L-cymaropyranosyl-(1-->4)-beta-D-digitoxopyranoside.