- Temperatures and enthalpies of solid-solid and melting transitions of the odd-numbered n-alkanes C21, C23, C25, C27, and C29
-
Very high purity samples of normal pentacosane and heptacosane are made by synthesis: the procedures for the C25 and C27 synthesis and the original conditions of their purification, particularly using the extraction by supercritical carbon dioxide, are described. Measurements of temperatures and enthalpies of the solid-solid transitions and of the melting transition were carried out by differential scanning calorimetry on the C25 and C27 synthetic samples and the odd-numbered homologous n-alkanes (from C21 to C29). The results show the importance of the effect of the impurities, particularly for the δ and γ crystal-crystal transition temperatures of C25 and C27. Several current data of the literature are also shown concerning the temperatures and the enthalpies of solid-solid and melting transitions of these five n-alkanes.
- Chevallier, Virginie,Bouroukba, Mohammed,Petitjean, Dominique,Barth, Danielle,Dupuis, Paul,Dirand, Michel
-
-
Read Online
- Aziridine-2-carboxylic acid derivatives and its open-ring isomers as a novel PDIA1 inhibitors
-
[Figure not available: see fulltext.] Acyl derivatives of aziridine-2-carboxylic acid have been synthesized and tested as PDIA1 inhibitors. Calculations of charge value and distribution in aziridine ring system and some alkylating agents were performed. For the first time was found that acyl derivatives of aziridine-2-carboxylic acid are weak to moderately active PDIA1 inhibitors.
- Leite, Irena,Andrianov, Victor,Zelencova-Gopejenko, Diana,Loza, Einars,Kazhoka-Lapsa, Iveta,Domracheva, Ilona,Stoyak, Marta,Chlopicki, Stefan,Kalvins, Ivars
-
p. 1086 - 1106
(2022/01/12)
-
- Synthesis of 1-Palmitoyl-2-((E)-9- and (E)-10-nitrooleoyl)- sn -glycero-3-phosphatidylcholines
-
Extensive investigation of nitrated phospholipids in connection with various biologically important processes requires reliable access to suitable material. A selective chemical synthesis introducing a defined nitrofatty acid at the sn -2 position of a 2-lyso sn -glycero-3-phosphatidylcholine was developed. Given that the nitroalkene moiety of both reactant nitrofatty acid derivative and the product esters is characterised by particular sensitivity to nucleophile addition and, depending on the intermediate, subsequent olefin isomerisation and retro-Henry-type reaction, a reliable two-step ester formation was introduced. The activation of the nitrofatty acid succeeded after reaction with trichlorobenzoyl chloride, and the mixed anhydride could be isolated via extractive work-up. Subsequent reaction with 1-palmitoyl-2-lyso- sn -glycero-3-phosphatidylcholine enabled the sn -2 esterification to be achieved with high yield by using a minimum of reagents, avoiding the formation of side products and facilitating final isolation and purification.
- Dietz, Ulrich,Frank, Andrea,Lehr, Alexander,Münch, Winfried,Nubbemeyer, Udo
-
supporting information
p. 3295 - 3304
(2019/08/28)
-
- Small-Molecule Activators of Glucose-6-phosphate Dehydrogenase (G6PD) Bridging the Dimer Interface
-
We recently identified AG1, a small-molecule activator that functions by promoting oligomerization of glucose-6-phosphate dehydrogenase (G6PD) to the catalytically competent forms. Biochemical experiments indicate that the activation of G6PD by the original hit molecule (AG1) is noncovalent and that one C2-symmetric region of the G6PD homodimer is important for ligand function. Consequently, the disulfide in AG1 is not required for activation of G6PD, and a number of analogues were prepared without this reactive moiety. Our study supports a mechanism of action whereby AG1 bridges the dimer interface at the structural nicotinamide adenine dinucleotide phosphate (NADP+) binding sites of two interacting G6PD monomers. Small molecules that promote G6PD oligomerization have the potential to provide a first-in-class treatment for G6PD deficiency. This general strategy could be applied to other enzyme deficiencies in which control of oligomerization can enhance enzymatic activity and/or stability.
- Raub, Andrew G.,Hwang, Sunhee,Horikoshi, Naoki,Cunningham, Anna D.,Rahighi, Simin,Wakatsuki, Soichi,Mochly-Rosen, Daria
-
supporting information
p. 1321 - 1324
(2019/07/04)
-
- Azelanitrile preparation method
-
The invention relates to an azelanitrile preparation method, which comprises: (1) dissolving glutaraldehyde in a solvent, adding a condensation catalyst and an optional cocatalyst, adding cyanoaceticacid in batches to maintain the temperature of the reaction solution of not more than 40 DEG C, and carrying out a condensation reaction, wherein a molar ratio of the glutaraldehyde to the cyanoaceticacid is 1:2; and (2) further adding a palladium carbon catalyst (Pd/C) to the condensation reaction liquid obtained in the step (1), introducing hydrogen gas, maintaining the pressure, heating, and carrying out a decarboxylation and hydrogenation reaction to obtain azelanitrile, wherein the hydrogen pressure is 3.0-4.0 MPa. According to the present invention, the method can perform the reaction by using the one-step method so as to eliminate the separation and purification process of the intermediate product, such that the reaction process is simple, and the cost is low.
- -
-
Paragraph 0068-0071
(2019/10/01)
-
- Thermotropic liquid crystalline polyesters derived from 2-chloro hydroquinone
-
Abstract: Synthesis of thermotropic liquid crystalline polyesters derived from bis[4-hydroxy benzoyloxy]-2-chloro-1,4-benzene (BHBOCB) and aliphatic dicarboxylic acid chlorides by interfacial polycondensation methodology is presented. Synthesised polyesters consist of bis[4-hydroxy benzoyloxy]-2-chloro-1,4-benzene as a mesogen and aliphatic diacid chloride as flexible spacer. The length of oligomethylene units in the polymer was varied from the trimethylene to the dodecamethylene groups. Synthesized polyesters were characterized by differential scanning calorimetry and optical microscopy. The transition temperatures and thermodynamic properties were studied for all these polymers. These polyesters exhibited thermotropic liquid crystalline behavior and showed nematic texture except decamethylene spacer. Decamethylene spacer based polyester showed marble texture of smectic C. Mesophase stability of these polyesters was higher than 123 °C (except first heating cycle of PE-1). Graphical Abstract:: SYNOPSIS The present study deals with the synthesis of thermotropic liquid crystalline polyesters derived from bis[4-hydroxy benzoyloxy]-2-chloro-1,4-benzene (BHBOCB) and aliphatic dicarboxylic acid chlorides by interfacial polycondensation methodology. [Figure not available: see fulltext.].
- Manurkar, Nagesh,More, Sayaji,Mulani, Khudbudin,Ganjave, Nitin,Chavan, Nayaku
-
p. 1461 - 1468
(2017/09/27)
-
- Towards New Oligomesogenic Phosphonic Acids as Stabilizers of Nanoparticles Colloids in Nematic Liquid Crystals
-
Several synthetic strategies for the construction of linear and branched oligomesogenic phosphonic acids are examined, which differ in the method of building the key bimesogen unit. An efficient synthetic approach to the most promising compounds employs regioselective Kumada cross-coupling between [11-(4′-pentylbiphenyl-4-yl)undecyl]magnesium bromide and 4-(11-bromoundecyl)-4′-iodobiphenyl as the key step. Preliminary studies on the ability of the new ligands to stabilize nanoparticles colloids in nematic liquid crystals are undertaken for the example of quantum dots.
- Prodanov, Maksym F.,Diakov, Maksym Y.,Vlasenko, Ganna S.,Vashchenko, Valerii V.
-
supporting information
p. 1905 - 1910
(2015/08/06)
-
- Synthesis and binding profile of haloperidol-based bivalent ligands targeting dopamine D2-like receptors
-
Homodimers of dopamine D2-like receptors are suggested to be of particular importance in the pathophysiology of schizophrenia and, thus, serve as promising targets for the discovery of atypical antipsychotics. This study describes the development of a series of novel bivalent molecules with a pharmacophore derived from the dopamine receptor antagonist haloperidol. These dimers were investigated in comparison to their monomeric analogues for their D2long, D2short, D3, and D4 receptor binding and the ability to bridge two neighboring receptor protomers. Radioligand binding studies provided diagnostic insights when Hill slopes close to two for the bivalent ligand 13 incorporating 22 spacer atoms and a comparative analysis with monovalent control ligands indicated a bivalent binding mode with a simultaneous occupancy of two neighboring binding sites.
- Salama, Ismail,L?ber, Stefan,Hübner, Harald,Gmeiner, Peter
-
supporting information
p. 3753 - 3756
(2014/09/16)
-
- Physical gels made of liquid crystalline B4 phase
-
The achiral liquid crystalline materials showing two B4 (HN) phases have been found to exhibit strong gelation ability for various organic solvents with reversible sol-gel phase transition. The gel is formed by helical tubules, which build entangled 3D network, encapsulating the solvent. The equilibrium of left- and right-handed tubules is preserved in the gel, even if the chiral solvent is used.
- Zep, Anna,Salamonczyk, Miroslaw,Vaupotic, Natasa,Pociecha, Damian,Gorecka, Ewa
-
supporting information
p. 3119 - 3121
(2013/06/27)
-
- Synthesis, thermal, and photocrosslinking studies of thermotropic liquid crystalline poly(benzylidene-ether)esters containing α,β-unsaturated ketone moiety in the main chain
-
A series of poly(benzylidene-ether)esters containing a photoreactive benzylidene chromophore in the main chain were synthesized from 2,6-bis(4-hydroxy-3-methoxybenzylidene)cyclohexanone (BHMBCH) with various aliphatic and aromatic diacid chlorides by an interfacial polycondensation technique. The intrinsic viscosity of the synthesized homo and copolymers determined by Ubbelohde viscometer was found to be 0.12 to 0.17 dL/g. The molecular structure of the monomer and polymers was confirmed by FT-IR, 1H NMR, and 13C NMR spectral analyses. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that the polymers were stable up to 280 °C and start degrading thereafter. Increase in acid methylene spacer length decreased the thermal stability. The self-extinguishing property of the synthesized polymers was studied by calculating the limiting oxygen index (LOI) value using a Van Krevelen's equation. The influence of the length of methylene spacer on phase transition was investigated using DSC and odd-even effect has been observed. Hot-stage optical polarizing microscopic (HOPM) study showed that most of the polymers exhibited birefringence and opalescence properties. The photolysis of liquid crystalline poly(benzylidene-ether)esters revealed that α,β-unsaturated ketone moiety in the main chain dimerises through 2π + 2π cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking.
- Muthusamy, Athianna,Balaji, Krishnasamy,Murugavel, Salem Chandrasekaran
-
p. 1707 - 1715
(2013/04/24)
-
- Synthesis of N, N'-bis(benzoyl) azelaic acid dihydrazide and its effect on performance of poly (L-lactic acid)
-
In order to synthesize more function amides, N, N'-bis(benzoyl) azelaic acid dihydrazide(NA(A)) was synthesized from benzoyl hydrazine and azelaoyl chloride which was deprived from azelaic acid via acylation. The influence of the reaction ratio, reaction time and reaction temperature to the yield of NA(A) was investigated by orthogonal experiment, the optimization result was: molar ratio of benzoyl hydrazine: azelaoyl chloride 2:3, reaction time 6 h, reaction temperature 70°C.The yield was 89.7%. Non-isothermal crystallization behavior measure indicated that NA(A) showed excellent nucleating effects on Poly(L-lactic acid)(PLLA) crystallization. Compared to the neat PLLA, with the addition of 0.8%NA(A), the crystallization temperature increased from 105.88°C to 122.99°C,the degree of supercooling decreased from 55.33°C to 36.96°C while the crystallization enthalpy increased from 1.379 J·g-1 to 28.58 J·g-1 at a cooling rate of 1°C/min from melt. The tensile strengths and tensile modulus increased with the increasing of NA(A) contents and possessed a maximum value for the critical NA(A) loading 0.3% and 0.5%, respectively. However, the elongations at break of PLLA/NA(A) samples decreased significantly. The hardness of PLLA/NA(A) samples after isothermal crystallization increased, and the largest value of hardness of PLLA/NA(A) with 1%NA(A) after isothermal crystallization was 176N/mm2.
- Cai, Yan-Hua
-
p. 1174 - 1178
(2013/09/23)
-
- Synthesis and biological evaluation of novel sinomenine derivatives as anti-inflammatory agents
-
Sinomenine (1) is clinically available for the treatment of rheumatoid arthritis (RA), however, its efficacy is quite weak. In the present study, a library of novel sinomenine-based homodimers and monomers through variable-length linkers were designed and synthesized, and their bioactivities were evaluated using RAW264.7 cells and mice. Among the compounds, 2f and 3b possessed much more potent inhibitory effects on the production of nitric oxide (NO), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) than 1. Preliminary mechanism investigation revealed that 3b inhibited nuclear factor-κB (NF-κB) signaling pathway specifically, 2f suppressed both NF-κB and mitogen-activated protein kinase (MAPK) cascades. Moreover, 3b and 2f significantly alleviated the lipopolysaccharide (LPS)-induced mortality. These two compounds might serve as valuable candidates for anti-inflammatory drug discovery.
- Teng, Peng,Liu, Hai-Liang,Zhang, Lei,Feng, Li-Li,Huai, Yue,Deng, Zhang-Shuang,Sun, Yang,Xu, Qiang,Li, Jian-Xin
-
experimental part
p. 63 - 74
(2012/07/14)
-
- Synthesis and characteriation of novel poly (ester amide)s containing benzthiazole heterocyclic ring
-
The novel Poly (ester-amide)s (PEAs) were prepared by inrter-facial polycondensation of 5 - hydroxy - 2 - amino benzthiazole with various di-basic acid chlorides. The PEAs were characterized by elements analysis, IR spectra studies, Mn estimated by non aqueous conductometric titration and thermogravimetry. The electric conductivity of all the poly (ester amide)s PEAs was also measured at room temperature and it was found that the PEAs have semiconducting properties.
- Patel,Desai,Patel
-
p. 203 - 208
(2007/10/03)
-
- Synthesis of N,N′-diarylalkanediamides and their antimycobacterial and antialgal activity
-
A set of N,N′-diarylalkanediamides was synthesized. The compounds were tested for their antimycobacterial and antialgal activity. The antimycobacterial activity of N,N′-diarylalkanediamides depends on the lipophilicity of the respective acid. Antimycobacteri-ally active substances were found only in the series of N,N′-diarylethanediamides and N,N′-diarylbutanediamides. Other compounds (derivatives of pentane-, hexane-, octane- and nonanediamide) were inactive against various strains of mycobacteria. The compounds inhibited growth and chlorophyll production in Chlorella vulgaris. Their relatively low antial-gal activity is probably connected with their lowered aqueous solubility, and hence by a restricted passage of the inhibitor through the hydrophilic regions of thylakoid membranes.
- Kubicova, Lenka,Waisser, Karel,Kunes, Jiri,Kralova, Katarina,Odlerova, Zelmira,Slosarek, Milan,Janota, Jiri,Svoboda, Zbynek
-
p. 714 - 726
(2007/10/03)
-
- Design and synthesis of calcium and magnesium ionophores based on double-armed diazacrown ether compounds and their application to an ion-sensing component for an ion-selective electrode
-
The double-armed diazacrown ethers, which have a base diazacrown ether ring with two diamide-type side chains, were designed and synthesized on the basis of the proposed molecular model for the novel neutral Ca2+ and Mg2+ ionophores. The potentiometric ion-selective electrodes were prepared with over 20 kinds of systematically synthesized diazacrown ether derivatives. The relationship between the molecular structures of the ionophores and the ion selectivities was fully discussed. The electrodes based on the 21- and 18-membered diazacrown ether derivatives possessing a glycolic diamide and malonic diamide in their side chains (K23E1 and K22B5) exhibited excellent Ca2+ and Mg2+ selectivities, respectively. The ion-selectivity features of the novel Ca2+ and Mg2+ ionophores supply important structural information about the design of host molecules for alkaline earth metal cations.
- Suzuki, Koji,Watanabe, Kazuhiko,Matsumoto, Yukihiro,Kobayashi, Mitsuru,Sato, Sayaka,Siswanta, Dwi,Hisamoto, Hideaki
-
p. 324 - 334
(2007/10/02)
-
- Conception et synthese de chelatants du fer III pour le traitement de la chlorose ferrique
-
New iron chelates containing pyrocatechol subunits bounded in α-position of a linear dicarboxylic acid are reported.The design of the structure and the choice of the synthetic scheme (with the help of Assisted Organic Synthesis) are presented.The six steps synthesis scheduled, needs the protection-deprotection of the carboxylic acids and the use of gaiacol preferably to pyrochatecol.The synthetic route is discussed.The individual steps and the characteristics of 20 reaction intermediates and products are described.The scope of the study is presented.
- Mhenni, F.,Bouraoui, A.,Mighri, Z.,Gallo, R.
-
p. 824 - 829
(2007/10/02)
-
- Liquid-Crystalline Schiff's Base Polymers
-
Liquid-crystal polymers are reported which are prepared from di-(p-formylphenyl)-α-ω-alkanedicarboxylates and p-phenylenediamine.Neither component forms a mesophase but the polymers are typical main-chain liquid crystal polymers.The synthesis of a series of such polymers is described, and the properties of the products are discussed.
- Al-Dujaili, Amar H.,Jenkins, D.,Walton, David R. M.
-
-
- Synthetic and Structural Studies on Coordination Polymers of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with Azelaic Acid-Bis-(phenyl hydrazide) and Azelaic Acid-Bis-(2,4-dinitrophenyl hydrazide)
-
The coordination polymers of azelaic acid-bis-(phenyl hydrazide) and azelaic acid-bis-(2,4-dinitrophenyl hydrazide) have been prepared by the reaction of the ligands with the acetates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) in dimethylformamide-ethanol (4:1) medium.Thermal stability of each polymer has been investigated by thermogravimetric analysis.Characterization of these polymers has been carried out on the basis of elemental analysis, reflectance spectral (electronic), infrared spectral and magneic moment data.
- Juneja, H. D.,Chakravarty, B. B.,Munshi, K. N.
-
p. 257 - 259
(2007/10/02)
-