Crystal Structure of Nicotinic Acid·3,5-dinitrobenzoic Acid Organic Adduct

The title compound nicotinic acid3,5-dinitrobenzoic acid (NDNT) has been obtained by the reaction of nicotinic acid with 3,5-dinitrobenzoic acid in deionic water at room temperature. The crystal is of monoclinic, space group P21/n with a = 14.053(6), b = 5.046(2), c = 20.105(8) ? ?= 103.573(8)? C13H9N3O8, Mr = 335.23, Z = 4, V = 1385.8(10) 3, Dc = 1.607 g/cm3, (MoK? = 0.137 mm-1, F(000) = 688, R = 0.0435 and wR = 0.0993 for 1239 observed reflections (I > 2(I)). In the crystals, the asymmetric unit contains one nicotinic acid (C6H5NO2) and one 3,5- dinitrobenzoic acid (C7H4N2O6) molecules which are linked by some hydrogen bonds to form a twenty-membered hydrogen-bonded ring and an extended linear structure.

Reactive Extraction of Nicotinic Acid with Trialkylamine in n-Octanol

The distributions of nicotinic acid (NA) between water and trialkylamine (N235) dissolved in n-octanol was studied. The complexes of N235 and NA were investigated by Fourier transformation infrared spectrometry to deduce the reaction mechanism. It was found that N235/n-octanol was an efficient extractant for extracting nicotinic acid. The favorable operation conditions were equilibrium aqueous pH 4.2 to 5.5 and initial N235 concentration<0.42 mol·L-1 . The reaction processes included the reaction between neutral N235 and neutral NA and the reaction between protonated N235 and anionic NA. Based on the mass action law and some assumptions, an expression for distribution coefficient D was proposed. The apparent extraction equilibrium constants were calculated by fitting the experimental data and the results were satisfactory.

Synthesis of Nicotinic Acid by Potassium Dichromate Oxidation

Nicotinic acid was synthesized from 3 methylpyridine with potassium dichromate as the oxidant. The reaction conditions, the product separation and analysis were studied. The results indicate that under the certain reaction conditions, the yield of nicotinic acid can reach 67.4%, the conversion can reach 99.7% and the selectivity can be as high as 99.8%. The final product has a high purity.

Preparation of Nicotinic Acid from Oxidation of 3-Picoline with Oxygen Under Catalysis of T(o-Cl)PPMn

The oxidation of 3-picoline to nicotinic acid took place efficiently in an ethanol solution with 02 as the oxidant under the catalysis of T（o-Cl）PPMn at 40--150 ℃ and 0.5--3.0 MPa oxygen pressure. The influences of temperature, oxygen pressure, reaction time, concentration of 3-picoline, concentration of sodium hydroxide, and concentration of T（o-Cl）PPMn catalyst, etc. on the production of nicotinic acid were investigated. The results show that T（o-Cl）PPMn presented excellent catalytic activity in the oxidation Of 3-pieoiine to nicotinic acid and the yield of nicotinic acid varied greatly with the reaction temperature, oxygen pressure, T（o-Cl）PPMn concentration, etc.

Nicotinic acid induces apoptosis of glioma cells via the calciumdependent endoplasmic reticulum stress pathway

Malignant glioma is one of the most common and deadly tumors in the central nervous system while developing effective treatments for this devastating disease remains a challenge.Previously,we demonstrated that the vitamin nicotinic acid(NA)inhibits glioma invasion.Here,we show that high-dose NA induces apoptosis of malignant glioma cells in vitro and in vivo.In cultured U251 glioma cells treated with NA,we detected ER stress that was likely caused by elevated intracellular calcium levels.The elevated calcium can be attributed to the activation of TRPV1,a cation channel that has been implicated in cutaneous flushing caused by NA administration.Our data further suggested that NA-induced apoptosis is mediated by the calcium-dependent proteases called calpains,whose activities are drastically upregulated by NA.NA-induced apoptosis of U251 cells can be attenuated by blocking calpain activity or knocking down TRPV1.These results reveal a novel function of NA in regulating glioma cell apoptosis via the calcium-dependent ER stress pathway and imply a potential application of NA for the treatment of malignant glioma.

Effect Factors in Synthesis of Nicotinic Acid by Electrooxidation of 3-Picoline

In an electrolytic cell with a proton exchange membrane, nicotinic acid was synthesized at the PbO2 anode. The relationship between the current density and the potential at different concentrations of 3-picoline and sulfuric acid as well as at different temperatures was studied with polarization curves. The effects of the concentrations of sulfuric acid and 3-picoline, the anode potential and the reaction temperature on the selectivity and the current efficiency were explored. The optimum conditions were determined by orthogonal experiments. Under optimum conditions the selectivity and the current efficiency for the synthesis of nicotinic acid might reach 89% and 65%, respectively. The, concentrations of 3-picoline and nicotinic acid were analyzed with high performance liquid chromatography and the product was characterized with elemental analysis, chromatography-mass spectrometry and IR spectrometry.

Efficacy of oral nicotinic acid and choline in the treatment and preventionoffattyliverindairycow

Nicotinic acid (N.C.)and choline were given orally to the periparturient cows to treat and prevent fatty liver.Blood parameters of glucose,β-hydroxybutyrate,albumin,total protein,magnesium,aspartate aminotransferase(AST)and non-esterified fatty acid (NEFA)weremeasured.There were no significant differences betWeen the treated and untreated groups in theplasma concentrations of albumin,total, protein and magnesium.Significant decrease in plasmaconcentrations of β-hydroxybutyrate,NEFA and AST were observed in the treated cows followiug administration of N.C.and choline.All the fatty liver cows(100% )treated with N.C.andcholine recovered within 5 weeks after calving compared with 71.4%(5/7) of untreated cows recovered.The incident rate of fatty liver postpartum in the cows with N.C.and cholinc given 2 weeksbefore calving was 30%(3/10),and the affected cows had a range of mild to moderate fatty liverwhilst the incident rate was 50% (5/10)in the untreated cows,which had a range of mild to ofsevere fatty liver.Meanwhile,the treated cows had a significant higher prodection of milk and shorter intervals from calving to uterine involution, to the first postpartum ovulation and to conception.

ELECTROANALYTICAL CIIARACTERISTICS OF NICOTINIC ACID IN MICELLAR SOLUTION

The electroanalytical characteristies of nicotinic acid in miceilar solution,were studied by cyclic voltammetry,constant potential coulometry and chron ocoulometry.A procedure of the absorptive voltammetric determination of the drug was worked out.

Nicotinic acid: Do we know how it works after 55 years of clinical experience?

Nicotinic acid （NA） comprises the oldest hypolipidemic drug, in use since 1955. Despite its established broad spectrum effect on lipid profle and the associated re-duction in cardiovascular morbidity and mortality, the mechanisms by which NA achieves its benefcial effects remain elusive. Regarding the NA-associated reduction in triglyceride and low density lipoprotein cholesterol levels, data are controversial. The prevailing view which suggested that NA inhibits lipolysis and decreases free fatty acid （FFA） release both via activation of adipose tissue G-protein receptor-109A （GPR109A） and via inhibition of hepatic triglyceride synthesis is currently debated by the observation that the initially decreased FFA levels rebound during long-term NA treatment even though the benefcial NA effects on lipid metabo-lism are preserved, while other mechanisms involving modulation of transcription and translation pathways are emerging. In addition, NA has been demonstrated to affect high density lipoprotein （HDL） particles remod-eling in a number of ways, including reducing choles-terol ester transfer protein levels and activity, increas-ing apolipoprotein A-I levels, eliminating HDL hepatic uptake, increasing cholesterol efflux via ATP-binding cassette A1, inhibiting hepatic lipase, thereby overall in-creasing the plasma residence time of HDL and apoA-I with retention of cholesterol esters in HDL. Focus of this article is to present the mechanisms by which NA exerts its broad spectrum hypolipidemic actions.

Determination of Vitamins B2,B3,B6 and B7 in Corn Steep Liquor by NIR and PLSR

Corn steep liquor(CSL) is an important raw material that has high nutritional value and serves as a nitrogen source.Biotin in CSL is especially of great importance to fermentation.In order to develop a fast,versatile,cheap,and environmentally safe analytical method for quantifying vitamins B2(VB2),B3(VB3),B6(VB6) and B7(VB7) in CSL,the near-infrared spectroscopy(NIR) measurements of 66 samples(22 batches) of CSL were analyzed by partial least-square regression(PLSR).Multivariate models developed in the NIR regions showed good predictive abilities for VB2,VB3,VB6 and VB7.Results confirmed the probability of the multivariate spectroscopic approach as a replacement for expensive and time-consuming conventional chemical methods.

Salting-out Assisted Liquid-Liquid Extraction for Analysis of Caffeine and Nicotinic Acid in Coffee by HPLC-UV/Vis Detector

A salting-out assisted liquid-liquid extraction method followed by high performance liquid chromatography with ultravio-let-visible detector(SALLE-HPLC-UV/Vis)has been proposed for determination of caffeine and nicotinic acid in raw and roasted coffee samples.Various parameters affecting chromatographic separations including mobile phase composition,injec-tion volume,flow rate and column temperature were studied.Experimental parameters affecting the extraction efficiency of SALLE method such as type and volume of the organic solvent,type and amount of salt,pH of the sample,and concentration of the ion-pairing reagent were also studied and thereby optimum conditions were established.The calibration curves which were constructed at five different concentration levels using the optimum conditions exhibited good linearity,with the coef-ficient of determination(R2)0.999 and 0.995 for caffeine and nicotinic acid,respectively.The limits of detection(LOD)and quantification(LOQ)which were determined at 3 and 10 times signal-to-noise ratio were 0.05 and 0.13 mg/L for nicotinic acid and 0.20 and 0.63 mg/L for caffeine,respectively.Intra-and inter-day precision studies were demonstrated satisfactory precision with RSD values below 10.Relative recoveries were also studied,and their results were ranging from 82-122%for both raw and roasted coffee samples.The findings demonstrated that the proposed method could be used as an effective and best alternative for the determination of caffeine and nicotinic acid in raw and roasted coffee samples.

Relationship between Coordination Structure and Biological Activity of Copper(II) Nicotinate

The copper（Ⅱ） complexes of pyridine-3-carboxylic acid （nicotinic acid） and pyridine-2-carboxylic acid （isonicotinic acid） were synthesized, and their structures were characterized by elemental analysis, infrared spectrum, powder X-ray diffraction and so on. The results show that under experimental conditions, the ligands of synthesized copper nicotinate and copper isonicotinate are coordinated simultaneity with copper（Ⅱ） via the nitrogen of pyridine group and an oxygen of carboxylic acid group to form bidentate chelates. The crystal of copper nicotinate with two six-membered chelate rings belongs to monoclinic system, while that of copper isonicotinate having two five-membered chelate rings is of triclinic system. The tests show that the biological activities, such as the improvement of feed utilization, growth, anti-oxidation ability of organism and disease-resistant power, are different when copper nicotinate, copper inicotinate, copper-lysine chelate, copper-methionine chelate and copper sulphate are added in pig＇s feed, respectively. Due to its higher biological activity, less pollution and lower toxicity, copper nicotinate has wide potential applications as a feed additive.

Hydrothermal Synthesis,Crystal Structure and Spectroscopic Investigations of [Y(C_6NO_2H_5)_3(H_2O)_2]_n(1.5nZnCl_4)·nH_2O with Unprecedented Polycationic Chains

A new heterometallic 4f-3d complex [Y（C6NO2H5）3（H2O）2]n（1.5nZnCl4）·nH2O（1）, was synthesized via a hydrothermal reaction and structurally characterized. Complex 1 crystallized in the monoclinic system with space group P21/c： a=0.94847（9） nm, b=2.0947（2） nm, c=1.6001（2） nm, β=104.467（2）°, V=3.0781（5） nm3, Mr=823.04, Dc=1.776 g/cm3, S=1.009, μ（Mo Kα）=3.603 mm-1, F（000）=1632, R=0.0787, and wR=0.2273. Complex 1, with four formula units in a cell, was characteristic of a one-dimensional polycationic chain-like structure. Photoluminescent investigation showed that the title complex displayed a strong emission in the blue region, which was attributed to the intraligand π-π＊ transition of the nicotinic ligands. Optical absorption spectrum of complex 1 revealed the presence of a wide optical bandgap of 4.17 eV.

Synthesis and Crystal Structure of Tetraimidazolium Dinicotinatooctamolybdate

The title compound, [C3H5N2]4[(C6H5NO2)2(Mo8O26)] 1, was synthesized by the reaction of H2MoO4, nicotinic acid and imidazole in aqueous solution. Single-crystal X-ray analysis has revealed that compound 1 (C24H30Mo8N10O30) crystallizes in the monoclinic system, space group P21/n, Mr = 1706.10, a = 12.529(1), b = 12.796(1), c = 14.038(1) , b = 100.2(1), V = 2215.3(2) 3, Z = 2, Dc = 2.558 g/cm3, F(000) = 1640, = 2.299 mm-1, the final R = 0.0527 and wR = 0.0964 for 3064 observed reflections with I > 2s(I). X-ray crystal structure analysis suggests that compound 1 consists of centrosymmetric dinicotinatooctamolybdate anion and four protonated imidazole cations, which are linked into a three-dimensional framework through hydrogen bonding.

Synthesis and Characterization of a Silver(Ⅰ)-indium(Ⅲ) Heterometallic Metalorganic Framework Based on Nicotinate

A heterometallic metal-organic framework, Agln（nicotinate）4.1.5DMF, was obtained from the reaction of nicotinic acid, AgNO3 and In（NO3）3 in DMF. The complex was characterized by elemental analysis, infrared spectrum, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Crystal data are： C28.5H26.5N55O9.5Agln, orthorhombic space group/222, a = 10.775（15）, b = 11.939（18）, c = 13.93（2） A, V= 1792（5） A3, Z = 2, Dc = 1.521 mg/m3,μ = 1.244 mm1, F（000） = 816, the final R = 0.0672 and wR= 0.1812 for 1912 observed reflections with I 〉 2σ（I）. Single-crystal X-ray structure analysis reveals that nicotinate bridges In（III） and Ag（I） through carboxylate chelating with In（III） and pyridyl nitrogen atom coordinating to Ag（I）, generating a new 2D network consisting of tetrahedral building units of [AgN4]＋ and [In（COO）4]-.

Synthesis, Crystal Structure and Luminescence of a Cadmium(Ⅱ) Coordination Polymer with 3,6-Connected rtl Topology

A new cadmium（Ⅱ） coordination polymer,[Cd（Hcna）2]n（1）,was hydrothermally synthesized based on 5-（4-carboxyphenoxy）nicotinic acid（H2cna） organic linker.X-ray singlecrystal diffraction determination reveals that 1 crystallizes in the monoclinic P21/c space group,with a = 10.101（2）,b = 7.9139（17）,c= 15.627（3） A,β= 103.364（3）°,V= 1215.4（4） A^3,Z=2,Mr= 628.81,Dc = 1.718 Mg/m^3,μ= 0.963 mm^（-1）,F（000） = 628,the final R = 0.0177 and wR = 0.0432 for 2263 observed reflections with I 〉2σ（I）.In 1,the Cd（Ⅱ） cations are connected by nicotiniate units to form a two-dimensional（2D） layer,and it is further linked through benzoate units to form a three-dimensional（3D） structure.Topologically,the structure of 1 represents a 3,6-connected 3D rtl topology.Furthermore,thermal stability and photoluminescent property of 1 have also been investigated.

Synthesis,Crystal Structure and DNA-Binding Property of a New Cu(Ⅱ) Complex Based on 4-(Trifluoro-methyl)nicotinic Acid

A new complex[Cu_(1.5)(tfc)_(3)(H_(2)O)_(4)]·3H_(2)O (1,Htfc=4-(trifluoro-methyl) nicotinic acid) has been synthesized and characterized by X-ray single-crystal diffraction,elemental analysis,IR spectra and thermogravimetric analysis.1 belongs to orthorhombic system,space group Pccn with a=44.507(2),b=10.7710(6),c=11.7544(7)?,V=5634.9(6)?^(3),Z=1,D_(c)=1.803 mg·cm^(-3),F(000)=3068,μ=1.266 mm^(-1),the final R=0.0488and w R=0.1103 with I>2σ(I).The Cu(II) ion is coordinated by two N and two O atoms from different Htfc as well as two O atoms from two coordinated water molecules,forming a 0D motif with distorted octahedral geometry.The adjacent 0D units are linked into 2D structures through bridge connection coordination mode.In addition,the binding properties of the complex with CT-DNA were investigated by fluorescence and ultraviolet spectra.UVspectra indicate classical intercalation between the complex and CT-DNA.Moreover,the interactions between the ligand and the complex with CT-DNA were studied by Et Br fluorescence probe,which proved that these compounds bind to CT-DNA through an intercalation mode.The binding constants were 0.76 and 1.15 for Htfc and complex 1,which means 1 has stronger interaction with CT-DNA than Htfc.

Cyclic ADP-ribose and NAADP:fraternal twin messengers for calcium signaling

The concept advanced by Berridge and colleagues that intracellular Ca2+-stores can be mobilized in an agonist-dependent and messenger(IP3)-mediated manner has put Ca 2+-mobilization at the center stage of signal transduction mechanisms.During the late 1980s,we showed that Ca2+-stores can be mobilized by two other messengers unrelated to inositol trisphosphate(IP 3) and identified them as cyclic ADP-ribose(cADPR),a novel cyclic nucleotide from NAD,and nicotinic acid adenine dinucleotide phosphate(NAADP),a linear metabolite of NADP.Their messenger functions have now been documented in a wide range of systems spanning three biological kingdoms.Accumulated evidence indicates that the target of cADPR is the ryanodine receptor in the sarco/endoplasmic reticulum,while that of NAADP is the two pore channel in endolysosomes. As cADPR and NAADP are structurally and functionally distinct,it is remarkable that they are synthesized by the same enzyme.They are thus fraternal twin messengers.We first identified the Aplysia ADP-ribosyl cyclase as one such enzyme and,through homology,found its mammalian homolog,CD38.Gene knockout in mice confirms the important roles of CD38 in diverse physiological functions from insulin secretion,susceptibility to bacterial infection,to social behavior of mice through modulating neuronal oxytocin secretion.We have elucidated the catalytic mechanisms of the Aplysia cyclase and CD38 to atomic resolution by crystallography and site-directed mutagenesis.This article gives a historical account of the cADPR/NAADP/CD38-signaling pathway and describes current efforts in elucidating the structure and function of its components.