Reaction of Nitrilimines with 2-Aminopicoline, 3-Amino-1,2,4-Triazole, 5-Aminotetrazole and 2-Aminopyrimidine

The reaction of picoline derivatives 3-6 with hydrazonoylhalide 1a produced imidazo[1,2-a]pyridines 7-10, while the reaction of the same picoline derivatives with hydrazonoylhalide 1b afforded imidazo[1,2-a]pyridine-2-ones 11-13. The reaction of 1b, c with 3-amino-1,2,4-triazole 14 produced the acyclic adducts 18 and 19, respectively. Reaction of 1b, 1c with 5-aminotetrazole 20 produced the acyclic products 23 and 24, respectively. Finally, the reaction of 1b with 4, 6-dimethyl-2-aminopyrimidine 27 afforded compound 29 rather than its isomeric structure 28. The structure of the products was confirmed by the different spectroscopic analytical methods including IR, MS, 1HNMR and 13CNMR.

Synthesis and Structural Characterization of Cu(pic)_2[CO(NH_2)_2]_2 and (picH_2)_2[Cu(pic)_2(SCN)_2]

Two new compounds Cu(pic)2[CO(NH2)2]2 1 and (picH2)2[Cu(pic)2(SCN)2] 2 were prepared from the reaction of picolinic acid and copper(II) per-chlorate by using carbamide to adjust pH = 4 in the preparation of compound 1 and KSCN to adjust pH = 6 in the preparation of 2. Crystal data for 1: monoclinic system, space group P21/n with a = 7.441(1), b = 14.291(2), c = 7.790(1) ? b = 95.855(2), V = 824.0(2) ?, Dc = 1.724 g/cm3, F(000) = 438, C14H16N6O6Cu, Mr = 427.87, m(MoKa) = 1.375 mm-1, Z = 2 and the final R = 0.0365 for 1164 observed reflections. Crystal data for 2: monoclinic system, space group P21/c with a = 9.8237(3), b = 10.0409(3), c = 14.5867(2) ? b = 104.190(2), V = 1394.91(6) ?, Dc = 1.595 g/cm3, F(000) = 686, C26H20N6O8S2Cu, Mr = 672.14, m(MoKa) = 0.994 mm-1, Z = 2 and the final R = 0.0442 for 1651 observed reflections. The Cu(II) atom in both 1 and 2 has a 4+2 elongated octahedral environment with the pic ligands locating on the equatorial plane, and carbamide and SCN occupying the axial sites, respectively. In compound 2, there also exist two protonated picolinate cations for charge balance.

Synthesis and Crystal Structure of Copper(II) Complex with N-Acetoxyl-picolinamide

Using Cu(II) as the template, a complex {[Cu2L2(H2O)2]·4H2O}n (L = N-acetoxyl- picolinamide) has been successfully synthesized and characterized by single-crystal X-ray diffrac- tion. The crystal is of monoclinic, space group C2/c, with a = 24.144(5), b = 7.1622(14), c = 17.283(4) ?, C16H24Cu2N4O12, Mr = 591.47, β = 131.73(3)o, V = 2230.3(8) ?3, Z = 4, Dc = 1.761 g/cm3, F(000) = 1208, μ = 1.978 mm?1, R = 0.0400 and wR = 0.1099. The copper (II) ion is five- coordinated with a distorted square pyramidal geometry. The complex can be viewed as a one- dimensional chain structure by carboxylic bridges among copper atoms. In the complex there exist hydrogen bonding interactions to stabilize the structure.

Nano-chromium picolinate and heat stress enhance insulin sensitivity in cross-bred sheep

This study evaluated the effects of heat stress(HS)and dietary nano chromium picolinate(nCrPic)on metabolic responses of sheep to an intravenous glucose tolerance test(IVGTT),an intravenous insulin tolerance test(ITT)and an intramuscular adrenocorticotropin hormone(ACTH)challenge in sheep.Thirty-six sheep housed in metabolic cages were randomly allocated within 3 dietary groups(0,400 and 800 mg/kg supplemental nCrPic)to either thermoneutral(22℃)or cyclic HS(22 to 40℃)conditions for 3 wk.Basal plasma glucose tended to be increased during HS(P=0.052)and decreased by dietary nCrPic(P=0.013)while plasma non-esterified fatty acid concentrations were decreased(P=0.010)by HS.Di-etary nCrPic reduced the plasma glucose area under the curve(P=0.012)while there were no significant effects of HS on plasma glucose area under the curve in response to the IVGTT.The plasma insulin response over the first 60 min after the IVGTT was decreased by HS(P=0.013)and dietary nCrPic(P=0.022)with the effects being additive.In response to the ITT plasma glucose reached a nadir sooner(P=0.005)in sheep exposed to HS,although there was no effect on the depth of the nadir.Dietary nCrPic decreased(P=0.007)the plasma glucose nadir after ITT.Over the duration of the ITT plasma insulin concentrations were lower in sheep exposed to HS(P=0.013)whereas there was no significant effect of supplemental nCrPic.There was no effect of either HS or nCrPic on cortisol response to ACTH.Dietary nCrPic supple-mentation decreased(P=0.013)mitogen-activated protein kinase-8(JNK)and increased(P=0.050)carnitine palmitoyltransferase 1B(CPT1B)mRNA expression in skeletal muscle.Results of this experiment demonstrated that animals under HS and supplemented with nCrPic had greater insulin sensitivity.

Dietary nano chromium picolinate can ameliorate some of the impacts of heat stress in cross-bred sheep

Two studies were conducted to evaluate the effect of nano chromium picolinate(nCrPic)during heat stress(HS)in sheep.In the initial study,36 Merino×Poll cross-bred sheep were individually penned and allocated to 3 dietary treatments(0,400 and 800μg/kg nCrPic)for 8 wk.Body composition was determined at the beginning and end of the experiment using dual energy X-ray absorptiometry.The sheep remained in their dietary groups but were then placed in metabolic cages and randomly allocated within the dietary group to differing ambient temperature regimes,i.e.,thermo-neutral(TN)(n=18)and HS(n=18),for 3 wk.Dietary nCrPic had no effect on growth performance and body composition during the initial study conducted under TN conditions.Heat stress decreased average daily feed intake(ADFI)(P=0.002)whereas sheep under HS had reduced average daily gain(ADG)and indeed lost weight(P<0.001).Dietary nCrPic increased both ADFI(P=0.041)and ADG(P=0.049)under both TH and HS conditions such that the performance of sheep receiving supplemental nCrPic and exposed to HS was similar to that of control sheep maintained under TN conditions.Heat stress increased rectal temperature(P<0.001)and respiration rate(P<0.001),particularly during the hottest parts of the day as indicated by interactions(P<0.001)between time of day and thermal treatment.Rectal temperature was lower in sheep fed nCrPic(P=0.050),particularly under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and time of day(P<0.001)and dietary nCrPic,thermal treat-ment and time of day(P=0.010).Similarly,respiration rate was lower in sheep fed nCrPic under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and thermal treatment(P<0.001)and dietary nCrPic and time of day(P=0.030).In conclusion,dietary nCrPic can partially ameliorate the negative effects of HS as indicated by the maintenance of ADFI and decreased physiological responses,such as elevations in rectal temperature and respiration rate.

Reactivity of Schiff Base Manganese（Ill） Complexes with Different Pendants toward the Hydrolysis of p-Nitrophenyl Picolinate

This paper describes the catalytic performance of two manganese（III） complexes with mono-Schiff base ligands as artificial hydrolases towards the hydrolysis of p-nitrophenyl picolinate （PNPP）. Observations reveal that the one complex （ MnL22C1 ） containing morpholine pendants exhibits 1.2-1.7 fold kinetic advantage over the other one （MnL12C1） containing benzoaza-15-crown-5 group. Especially, optimum molecule structures using a Gaussian 03 software confirm that MnL2CI indeed possesses a relatively open linked site for the approaching of PNPP, result- ing in higher efficiency due to a convenient association between substrate （PNPP） and MnL2C1. In addition, the steric hindrance of two pendants, i.e., benzoaza-15-crown-5 and morpholine, may be a main influencing factor for tuning catalytic activities of the synthesized Mn（III） catalysts. Both Mn（III） catalysts used here were found to have fine tolerance to the operated temperature and pH. Related kinetic and thermodynamic analyses were also given to demonstrate their structure-activity relationships （SAR） of both catalysts used.

Amphichoterpenoids A-C,unprecedented picoline-derived meroterpenoids from the ascidian-derived fungus Amphichorda felina SYSU-MS7908

Amphichoterpenoids A-C(1-3),unprecedented picoline-derived meroterpenoids possessing a pyrano[3,2-c]pyridinyl-g-pyranone scaffold,were characterized from the ascidian-derived fungus Amphichorda felina SYSU-MS7908.Their structures were elucidated by spectroscopic methods,X-ray diffraction and electronic circular dichroism(ECD)calculations.A plausible biosynthetic pathway was proposed.The isolated compounds displayed moderate inhibitory activity against acetylcholinesterase with 50%inhibiting concentration(IC_(50))values of 18.8-53.2 mmol/L.

Copper-catalyzed ortho-Monofluorination of Aniline Derivatives with Selectfluor Directed by Picolinic Acid Amides

A novel and facile method for selective ortho-C--H monofluorination of aniline derivatives was achieved using Selectfluor/Cu（OAc）JHOAc system. The reaction proceeded via electrophilic process with diverse substrates in acceptable moderate to high yields. The position selectivity was controlled by bidentate coordination of picolinic acid amides with copper.

Could zinc dipicolinate be used to“smuggle”zinc into prostate cancer cells?

Although prostate epithelium concentrates zinc for the purpose of promoting citrate secretion,it loses its capacity to import zinc while undergoing malignant transformation.This exclusion of zinc may be necessary for the viability of prostate cancer,as measures which increase the intracellular zinc content of prostate cancers lead to cell death,oxidative stress,and a marked reduction in ATP,suggestive of mitochondrial damage.The anti-fungal drug clioquinol,which can act as a zinc ionophore,can markedly slow the growth of human prostate cancer in nude mice,and has been proposed as a clinical therapy for prostate cancer.However,clioquinol is currently only available as a topical agent,as it was linked to subacute myelo-optic neuropathy with oral use.A more practical option for promoting zinc transport may be offered by the nutraceutical zinc dipicolinate,a stable chelate in which four coordination positions of zinc are occupied by two molecules of the tryptophan metabolite picolinic acid.Zinc dipicolinate is a highly effective supplemental source of zinc that has been shown to be more potent than soluble zinc salts for alleviating the symptoms of acrodermatitis enteropathica,a genetic zinc deficiency disorder reflecting homozygous loss of functional ZIP4 zinc importers in enterocytes.This suggests that the zinc dipicolinate complex is sufficiently stable and lipophilic to transfer zinc across cellular membranes.If so,it may have potential for“smuggling”zinc into prostate cancer cells.Hence,cell culture and rodent studies to evaluate the impact of zinc dipicolinate on human prostate cancer are warranted.