A Facile Access to Fluorinated Pyrrolidines via Catalytic Asymmetric 1,3-Dipolar Cycloaddition of Azomethine Ylides with Methyl a-Fluoroacrylate

Asymmetric 1,3-dipolar cycloaddition of methyl a-fluoroacrylate with azomethine ylides for the construction of optically active fluorinated pyrrolidines bearing one unique fluorinated quaternary and two tertiary stereogenic cen- ters has been achieved with Cu（CH3CN）4BF4/TF-BiphamPhos complexes for the first time. This catalytic system performs well over a broad scope of substrates, providing the synthetically useful adducts in good yields and excel- lent diastereoselectivities and good to high enantioselectivities.

Synthesis, Characterization, Optical and Electrochemical Properties of Fulleropyrrolidines Containing Trifluoromethyl Group

Four novel [60]fullerene pyrrolidines containing trifluoromethyl （--CF3） group have been synthesized via 1,3-dipolar cycloaddition reaction, which have been characterized by UV-Vis spectroscopy, fourier transform in- frared spectroscopy, matrix-assisted laser desorption ionization-time of flight mass spectroscopy, and IH, 13C, 19F nuclear magnetic resonance spectrometer （IH NMR, 13C NMR, 19F NMR）. Their optical and electrochemical prop- erties have been studied, and the results show that those fulleropyrrolidines containing --CF3 group have good fluo- rescence and electrochemical properties. Compared with C60, they have negative shifts in varying degrees for half-wave potentials, and may have potential applications for photovoltaic conversion materials since their lowest unoccupied molecular orbital （LUMO） levels are close to that of [6,6]-phenyl-C6：butyric acid methyl ester.

N-Alkoxyl Templates for Diastereoselective Pyrrolidine Synthesis

Intramolecular cyclization of N-alkoxyl amines are studied for the stereoselective preparation of 2, 4-disubstituted pyrrolidine derivatives. Reduction of oximes under acidic conditions by NaBH3CN afforded the corresponding nucleophilic hydroxylamine derivatives, which subsequently cyclized via SN2' mechanism to give the desired N-alkoxyl pyrrolidines.

First Total Synthesis of Hyacinthacine A_6 from the Protected Derivative of Polyhydroxylated Pyrrolidine

（1S、2R、3R、5R、7aR）-1,2-Dihydroxy-3-hydroxy methyl-5-methylpyrrolizidine（hyacinthacine A6, I） was synthesized by Wittig＇s methodology via the reaction of aldehyde 6, prepared from the partially protected derivative of polyhydroxylated pyrrolidine, with appropriated ylides, followed by cyclization through the intemal reductive amination process of the resulting a,B-unsaturated ketone 7, and total deprotection.

Effect of NF-κB inhibitor PDTC on VEGF and endostatin expression of mice with Lewis lung cancer

Objective:To investigate the effects of NF-κB inhibitor pyrrolidine dithiocarbamate hydrochloride(PDTC) on vascular endothelial growth factor(VEGF) and endostatin expression in mice with Lewis lung cance;and its mechanism.Methods:Mice survival rate and anti-tumor effects were observed in different concentrations of NF-κB inhibitor PDTC after the Lewis lung cancer mice model was established.VEGF and endostatin expressions were detected by immunohistochemical assay.Results:Lewis lung cancer was be inhibited by 0.5 mg/kg.1.5 mg/kg and 3.0 mg/kg of NF-κB inhibitor PDTC(P<0.05).Microvessel density(MVD) in 0.5 mg/kg.1.5 mg/kg and 3.0 mg/kg NF-κB inhibitor PDTC groups were significantly lower than the control group(P<0.05).Immunohistochemical assay results showed that VEGF and endostatin expressions in the 0.5 mg/kg.1.5 mg/kg and 3.0 mg/kg NF-κB inhibitor PDTC groups were significantly lower than the control group(P<0.05).Western blot results also showed that NF-κB inhibitor PDTC could inhibit VEGF and endostatin expressions in tumor tissues.Conclusions:NF-κB inhibitor PDTC can inhibit tumor formation and reduce tumor angiogenesis in mice with Lewis lung cancer;and its mechanism maybe associated to VEGF and endostatin down-regulation.

Pyrrolidine dithiocarbamate alleviates the anti-tuberculosis drug-induced liver injury through JAK2/STAT3 signaling pathway:An experimental study

Objective:To study the effect of pyrrolidine dithiocarbamate(PDTC) on the anti-tuberculosis drug-induced liver injury and the molecular mechanism. Methods:Clean male SD rats were selected as experimental animals and randomly divided into normal group,model group,PDTC group and AG490 group. Animal model of anti-tuberculosis drug-induced liver injury was established by intragastric administration isoniazid + rifampicin. PDTC group received intraperitoneal injection of PDTC,and AG490 group received intraperitoneal injection of AG490. Twenty-eight days after intervention,the rats were executed,and the liver injury indexes,inflammation indexes and oxidative stress indexes in serum as well as JAK2/STAT3 expression,liver injury indexes,inflammation indexes and oxidative stress indexes in liver tissue were determined. Results:p-JAK2,p-STAT3,TNF-α,IL-1β,IL-6,ROS,8-OHdG and MDA expression in liver tissue as well as TBIL,ALT,AST,γ-GT,TNF-α,IL-1β,IL-6,ROS,8-OHdG and MDA levels in serum of model group were significantly higher than those of normal group while p-JAK2,p-STAT3,TNF-α,IL-1β,IL-6,ROS,8-OHdG and MDA expression in liver tissu as well as TBIL,ALT,AST,γ-GT,TNF-α,IL-1β,IL-6,ROS,8-OHdG and MDA levels in serum of PDTC group and AG490 group were significantly lower than those of model group. Conclusions:PDTC can inhibit the inflammation and oxidative stress mediated by JAK2/STAT3 signaling pathway to alleviate the anti-tuberculosis drug-induced liver injury.

Protective effect of pyrrolidine dithiocarbamate on liver injury induced by intestinal ischemia-reperfusion in rats

BACKGROUND: The nuclear translocation of transcription factors may be a critical factor in the intracellular pathway involved in ischemia/reperfusion(I/R) injury. The aim of the study was to evaluate the role of nuclear factor-kappa B (NF-κB) in the pathogenesis of liver injury induced by intestinal ischemia/reperfusion (IIR) and to investigate the effect of pyrrolidine dithiocarbamate (PDTC) on this liver injury. METHODS: Male Wistar rats were divided randomly into three experimental groups (8 rats in each): sham operation group (control group); intestinal/reperfusion group(I/R group): animals received 1-hour of intestinal ischemia and 2-hour reperfusion; and PDTC treatment group (PDTC group): animals that received I/R subject to PDTC treatment (100 mg/kg). The histological changes in the liver and intestine were observed, and the serum levels of tumor necrosis factor-α (TNF-α), alanine aminotransferase (ALT), aspartate aminotransferase (AST), liver superoxide dismutase (SOD), and nitrite/nitrate (NO) were measured. The immunohistochemical expression and Western blot analysis of liver NF-κB and intercellular adhesion molecule-1(ICAM-1) were observed. RESULTS: IIR induced liver injury characterized by the histological changes of liver edema, hemorrhage, polymorphonuclear neutrophil (PMN) infiltration, and elevated serum levels of AST and ALT. The serum TNF-α level was significantly higher than that of the control group(P<0.01) and a high level of liver oxidant product was observed (P<0.01). These changes were parallel to the positive expression of NF-κB and ICAM-1. After the administration of PDTC, the histological changes after liver injury were improved; the levels of SOD and NO in the liver were elevated and reduced, respectively (P<0.01). The expressions of ICAM-1 and NF-κB in the liver were weakened (P<0.01). CONCLUSION: NF-κB plays an important role in the pathogenesis of liver injury induced by HR. PDTC, an agent known to inhibit the activation of NF-κB, can reduce and prevent this injury.

S-adenosyl-L-methionine modifies antioxidant-enzymes,glutathione-biosynthesis and methionine adenosyltransferases-1/2 in hepatitis C virus-expressing cells

AIM: To elucidate the mechanism(s) by which S-adenosyl-L-methionine(SAM) decreases hepatitis C virus(HCV) expression.METHODS: We examined the effects of SAM on viral expression using an HCV subgenomic replicon cell culture system. Huh7 HCV-replicon cells were treated with 1 mmol/L SAM for different times(24-72 h), then total RNA and proteins were isolated. c DNA was synthesized and real time-PCR was achieved to quantify HCV-RNA, superoxide dismutase 1 and 2(SOD-1, SOD-2) catalase, thioredoxin 1, methionine adenosyltransferase 1A and 2A(MAT1A, MAT2A) expression, and GAPDH and RPS18 as endogenous genes. Expression of cellular and viral protein was evaluated by western-blot analysis using antibodies vs HCV-NS5 A, SOD-1, SOD-2, catalase, thioredoxin-1, MAT1 A, MAT2 A, GAPDH and actin. Total glutathione levels were measured at different times by Ellman's recycling method(0-24 h). Reactive oxidative species(ROS) levels were quantified by the dichlorofluorescein assay(0-48 h); Pyrrolidin dithiocarbamate(PDTC) was tested as an antioxidant control and H2O2 as a positive oxidant agent.RESULTS: SAM exposition decreased HCV-RNA levels 50%-70% compared to non-treated controls(24-72 h). SAM induced a synergic antiviral effect with standard IFN treatment but it was independent of IFN signaling. In addition, 1 mmol/L SAM exposition did not modify viral RNA stability, but it needs cellular translation machinery in order to decrease HCV expression. Total glutathione levels increased upon SAM treatment in HCV-replicon cells. Transcriptional antioxidant enzyme expression(SOD-1, SOD-2 and thioredoxin-1) was increased at different times but interestingly, there was no significant change in ROS levels upon SAM treatment, contrary to what was detected with PDTC treatment, where an average 40% reduction was observed in exposed cells. There was a turnover from MAT1A/MAT2 A, since MAT1 A expression was increased(2.5 fold-times at 48 h) and MAT2 A was diminished(from 24 h) upon SAM treatment at both the transcriptional and translational level. CONCLUSION: A likely mechanism(s) by which SAM diminish HCV expression could involve modulating antioxidant enzymes, restoring biosynthesis of glutathione and switching MAT1/MAT2 turnover in HCV expressing cells.

Pyrrolidine dithiocarbamate and saxagliptin ameliorate ulcerative colitis in rats

Objective: To evaluate the antioxidant, immunomodulatory and anti-inflammatory activities of pyrrolidine dithiocarbamate and saxagliptin in rats with thioacetamide-induced ulcerative colitis. Methods: Animals were orally administered with a vehicle, sulfasalazine(500 mg/kg), pyrrolidine dithiocarbamate(100 mg/kg), and saxagliptin(10 mg/kg) for two weeks. Ulcerative colitis was induced by a single intrarectal instillation of thioacetamide on day 8. Colon samples were collected to assess mitogen-activated protein kinase(MAPK), phosphorylated extracellular signal-regulated kinase(ERK), c AMP response element-binding protein(CREB), interleukin-12(IL-12), caspase-3, β-defensin, inducible nitric oxide synthase(i NOS) and glucagon like peptide-1(GLP-1). Moreover, histopathological examination was performed. Results: Rats treated with thioacetamide caused increases in colonic MAPK, phosphorylated ERK, CREB, caspase-3, IL-12, β-defensin, i NOS, as well as decreases in body weight and GLP-1. In addition, distortion of colonic structure was found by histopathological examination. Pyrrolidine dithiocarbamate and saxagliptin mitigated colitis severity by improving body weight decrease and GLP-1, and reducing colonic MAPK, phosphorylated ERK, CREB, caspase-3, IL-12, β-defensin and i NOS. Conclusions: Pyrrolidine dithiocarbamate and saxagliptin are efficient against thioacetamide induced colitis through improving inflammatory and oxidative changes.

IL-1RⅠ/MyD88-TIR mimic AS-1 inhibits the activation of MyD88-dependent signaling pathway induced by IL-1β in vitro

Objective： To test whether IL-1 RI/My088-TIR mimic AS-1 can work as a new compound that targeted at blocking MyD88- dependent signaling pathway, we investigated the physical structure and biological function of AS-1. Methods：The crystallographic structure of AS-1 was examined by 1^H nuclear magnetic resonance. The toxicity of AS-1 was measured with Methyl thiazolyl tetrazolium （MTT） assay. The effect of AS-1 on phosphorylation state of p38 MAPK and IRAK-1 was observed with Western blot. Results：The crystallographic details of AS-1 demonstrated that it was a tri-peptide sequence[（F/Y）-（V/L/I）-（P/G）] of the IL-1R I -TIR domain BBloop. No toxicity of AS-1 was shown to HEK 293A cells. The phosphorylation of p38 MAPK, induced by IL-1β significantly increased from those in the control group. AS-1 significantly reduced the phosphorylation of p38 MAPK induced by IL-1β. IL-1β increased the phosphorylation of IRAK-1 significantly, which was prevented by AS-1. Conclusion：AS-1 is a competitive mimic between IL-1R I-TIR and MyD88-TIR domain, which most likely interferes with MyD88-dependent signaling pathway.

Effects of PDTC on the Proliferation and PCNA Expression of Human Retinal Pigment Epithelial Cells

To investigate the effects of pyrrolidine dithiocarbamate （PDTC） on the proliferation and PCNA （proliferating cell nuclear antigen） expression of cultured human retinal pigment epithelium cells, human retinal pigment epithelium cells （RPE） were cultured from normal adults who died accidentally. The effects of PDTC on the proliferation of RPE cells were examined by using methyl thiazlyl tetrazolium （MTT） assay. The effects of PDTC on the PCNA expression of RPE cells were immunohistochemically examined by employing biological image analysis system （BIAS）. After treatment with PDTC of various of concentration ranging from 0.062 to 1 g/L for 24 h, or concentrations ranging from 0.031 to 1 g/L, the proliferation of RPE cells decreased in a dose-dependent manner. After treatment with PDTC of concentration varying from 0. 062 to 1 g/L for 24 h, the PCNA expression was also suppressed in a dose-dependent manner. It is concluded that PDTC can inhibit the proliferation of RPE cells in vitro in a dose-and time-dependent manner, at least in part, by down-regulating the expression of PCNA. PDTC may be used to prevent and treat the proliferative vitreoretinopathy （PVR）.

Synthesis of novel fullereneα-amino acid conjugates

Aspartic acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fullero pyrrolidine. The products were deprotected, affording two monofuUerene α-amino acids, monofullerene aspartic acid （mFas） and monofullerene glutamic acid （mFgu）. Then a bifullerene glutamic acid conjugate （bFguC） was synthesized by reaction of mFgu containing protected amino group with N-substituted 3,4-fullero pyrrolidine.

Pyrrolidine Dithiocarbamate (PDTC) Attenuates Luteolin-Induced Apoptosis in Human Leukemia HL-60 Cells

Studies have indicated that flavonoid luteolin is a potential inhibitor of tumor cell proliferation and may function as an anticarcinogenic agent. Pyrrolidine dithiocarbamate (PDTC), a synthetic compound, may exhibit biphasic effects on apoptosis depending on the experimental context. Previously, we found that luteolin induced the activation of the proapoptotic proteins, such as Bad, Bid, and Bax, in HL-60 human leukemia cells. We also explored the modulatory effects and molecular mechanisms of PDTC on the cytotoxicity of luteolin in HL-60 cells;PDTC could interfere with luteolin’s ability to cleave poly(ADP-ribose)-polymerase (PARP) and DNA fragmentation of factor-45 (DFF-45). In the current study, we further investigated the effect of PDTC on the luteolin-induced death-receptor pathway and the cleavage of the Bcl-2 family members. We found that the combination of luteolin and PDTC increased the survival of the HL-60 cells such that PDTC inhibited both extrinsic and intrinsic pathways in luteolin-induced apoptosis.

Improved Electrochemical Synthesis of Nitro-substituted 1-Aryl-2-pyrrolidinecarbonitriles

In this paper, we described an improved electrochemical method for synthesis of some 1-aryl-2-pyrrolidinecarbonitrile derivatives bearing an electron-withdrawing group （NO2）. The electrochemical synthesis of titile compounds has been successfully performed in an undivided cell in reasonable yields.

Synthesis of Quinolone Analogues: 7-[(2S,4R)-2-Aminomethyl-4- hydroxypyrrolidin-1-yl] Quinolones

New quinolone derivatives of 7-[(2S, 4R)-2-aminomethyl-4-hydroxypyrrolidin-1-yl] quinolone-3-carboxylic acids were synthesized by condensation of 7-halo substituted quinolone- 3-carboxylic acids with (2S, 4R)-2-aminomethyl-4-hydroxypyrrolidine. These compounds were characterized by FAB-MS and 1H NMR.

Synthesis of 2S-Hydroxymethyl-3R, 4R-dihydroxypyrrolidine

The sythesis of 2S-hydroxymethyl-3R, 4R-dihydroxypyrrolidine from D-arabinose was described in this paper.

The Effects of PDTC on Interleukin-1β-induced Nitric Oxide Production in Chondrocytes

In order to find new drugs to inhibit nitric oxide （NO） production, the effects of pyrrolidine dithiocarbamate （PDTC）, a nuclear factor-kappa B （NF-κB） inhibitor, on recombinant human interleukin-1β （rhIL-1β）-induced NO production in chondrocytes were investigated. Rat chondrocytes were isolated and cultured, divided into control, P0, P1, P2, P3 and P4 groups. The chondrocytes in the P0, P1, P2, P3 and P4 groups were treated with different concentrations of PDTC （0, 3, 10, 30, and 50 p.mol/L respectively） for 1 h and then incubated with 5 U/mL rhIL-1β for 24 h. NO assay kit and RT-PCR were used to detect the NO content and the iNOS mRNA expression in the chondrocytes The expression level of iNOS mRNA in control, P0, P1, P2, P3 and P4 groups was 0.02±0.01, 1.24±0.13, 1.21±0.14, 0.61±0.11, 0.40±0.09, 0.21±0.06, and the relative content of NO was 15.8±2.7, 100±14.8, 92.6±9.3, 68.3±14.2, 27.5±9.8, 19.8±3.6, respectively. In the P0, P1, P2, P3 and P4 groups, the expression of iNOS mRNA and NO production were significantly increased as compared with those in the control group. As compared with the P0 group, the expression of iNOS mRNA and NO content in control group were lower. In the P2, P3 and P4 groups, PDTC could significantly inhibit the expression of iNOS and NO production induced by rhIL-1β in a concentration-dependent manner. It is suggested that PDTC can inhibit NO production and iNOS mRNA expression induced by IL-1β, which may provide an alternative method for the treatment of osteoarthritis.

A two step facile synthesis of new steroidal linear and angular pyranones having anti-mycobacterial activity

Title compounds 2′,2′-dimethylcholesta-2,4-dien[3,2-b]-pyran-4′-one （3）, 2′,2′-dimethyl-3β-substituted cholesta-4,6-dien[7,6- b]-pyran-4′-one （6a,b） and （6c） were prepared by the cyclization of 2-acetylcholesta-2,4-dien-3-ol （2）, 6-acetyl-3β-substituted- cholesta-4,6-dien-7-ol （Sa,b） and （5c） respectively, with pyrrolidine, dry benzene and dry acetone using Dean Stark separator through conventional heating. Furthermore, compounds were also found to be active against Mycobacterium tuberculosis.

Synthesis and Crystal Structure of 1,7,8,9-Tetrachloro-4-benzyl-10,10-dimethoxy-4-azatricyclo(5,2,1,0^(2,6))dec-8-ene-3,5-dione

The crystal structure of 1,7,8,9-tetrachloro-4-benzyl-10,10-dimethoxy-4-azatricyclo- （5,2,1,0^2,6）dec-8-ene-3,5-dione （C18H15Cl4NO4, Mr = 451. 11） has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 18.6488（2）, b = 13.06430（10）, c = 16.1086（2）A, β = 92.9870（10）°, V = 3919.26（7） A3, Z = 8, Dc = 1.529 g/cm3,μ = 5.711 mm-1, F（000） = 1840, the final R = 0.0599 and wR = 0.1664 for 5645 observed reflections. The title compound is composed of a polycyclic fused pyrrolidine ring system. Three symmetric fused five-membered-ring structures were formed by the Diels-Alder reaction between N-benzylmaleimide and 5,5-dimethoxy-1,2,3,4-tetrachlorocydopentadiene.