An efficient route towards R-2-phenoxypropionic acid synthesis for biotransformative production of R-2-(4-hydroxyphenoxy)propionic acid

R2(4hydroxyphenoxy)propionic acid(RHPPA)is a key intermediate for the synthesis of classic herbicides with high selectivity against grassy weed.The main route for RHPPA biosynthesis is to hydroxylate the substrate R2phenoxypropionic acid(RPPA)at C4 position with microbes.In order to provide sufficient RPPA for the industrial production of RHPPA,an effective RPPA synthesis method was established and optimized in this work.The synthesis process mainly consisted of two steps:(1)synthesis of S2chloropropionic acid from Lalanine via diazotization and chlorination reactions;and(2)synthesis of RPPA from S2chloropropionic acid and phenol via etherification reaction.The optimal reaction conditions were as follows:HCl:NaNO_(2):KI:LAla=2.0:1.2:0.7:1.0(in molar),125℃reflux for 1.5 h,with KI as catalyst,and KI:S2chloropropionic acid:phenol=0.075:1.2:1.0(in molar).Under these conditions,an improved molar conversion rate(74.9%,calculated in phenol)was achieved.After extraction using anionic exchange resin Amberlite IRA400(CI),RPPA product with a purity of 95.08%was obtained.The purified RPPA was identified and evaluated in the application of the biotransformative production of RHPPA.The results indicated that the synthesized RPPA supported the RHPPA biosynthesis with a comparable yield as that of the standard RPPA.The RPPA synthesis method provided herein exhibited the advantages of low price and easy availability of raw materials,less toxicity of reagents,simple manipulations,and low equipment/instrument requirements.

Effect of lactic acid bacteria and propionic acid on conservation characteristics,aerobic stability and in vitro gas production kinetics and digestibility of whole-crop corn based total mixed ration silage

This study was conducted to evaluate the effect of lactic acid bacteria and propionic acid on the fermentation quality, aer- obic stability and in vitro gas production kinetics and digestibility of whole-crop corn based totalmixed ration （TMR） silage. Total mixed ration was ensiled with four treatments： （1） no additives （control）; （2） an inoculant （Lactobacillus plantarum） （L）; （3） propionicacid （P）; （4） propionic acid＋lactic acid bacteria （PL）. All treatments were ensiled in laboratory-scale silos for 45 days, and then subjected to an aerobic stability test for12 days. Further, four TMR silages were incubated in vitro with buffered rumen fluid to study in vitro gas production kinetics and digestibility. The results indicated that all TMR silages had good fermentation characteristics with low pH （〈3.80） and ammonia nitrogen （NH3-N） contents, and high lactic acid contents as well as Flieg points. Addition of L further improved TMR silage quality with more lactic acid production. Addition of P and PL decreased lactic acid and NH3-N contents of TMR silage compared to the control （P〈0.05）. After 12 days aerobic exposure, P and PL silages remained stable, but L and the control silages deteriorated as indicated by a reduction in lactic acid and an increase in pH, and numbers of yeast. Compared to the control, addition of L had no effects on TMR silage in terms of 72 h cumulative gas production, in vitro dry matter digestibility, metabolizable energy, net energy for lactation and short chain fatty acids, whereas addition of PL significantly （P〈0.05） increased them. L silage had higher （P〈0.05） in vitro neutral detergent fiber digestibility than the control silage. The results of our study suggested that TMR silage prepared with whole-crop corn can be well preserved with or without additives. Furthermore, the findings of this study suggested that propionic acid is compatible with lactic acid bacteria inoculants, and when used together, although they reduced lactic acid production of TMR silage, they improved aerobic stability and in vitro nutrients digestibility of TMR silage.

Synthesis and Crystal Structure of 2-[(2-Chloropyridin-4-yl)oxy]-3,3-diphenyl-3-methoxypropionic Acid

The title compound was synthesized and its crystal structure was determined by single-crystal X-ray diffraction.The crystal is of orthorhombic system（C21H18ClNO4,Mr = 383.81）,space group Pca21 with a = 13.913（3）,b = 10.273（2）,c = 26.488（5）,V = 3786.1（13） 3,Z = 8,Dc = 1.347 g/cm3,F（000） = 1600,μ = 0.228 mm-1,the final R = 0.0550 and wR = 0.1278 for 5065 observed reflections（I 2σ（I））.The title compound in a racemic form was found to exist as a mixture of two enantiomers in an equal ratio in the unit cell.The intermolecular hydrogen bonds link the molecules in a head-to-end manner to generate an infinite chain.

HPLC Determination of Neurotoxin β-N-oxalyl-L-α, β-diaminopropionic acid and Its α -Isomer in Lathyrus sativus by Precolumn Derivatisation with 1-Fluoro-2,4-dinitrobenzcne

A rapid and simple method is presented for determining β-N-oxalyl-α. β- diaminopropionic acid (β -ODAP) and its much less toxic α -isomer (α -ODAP) in Lathyrus sativus. Seed and foliage extracts of Lathyrus sativus were treated with 1-fluoro-2,4-dinitrobenzene (FDNB) and a reversed-phase high-performance liquid chromatographic method for the separation of the derivatives in the pmol range is reported.

Synthesis of Optical Active 2-Arylpropionic Acids

S)-2-(6’-methoxyl-（-naphthyl） propionic acid （（S）-Naproxen, ee 99%） has been prepared starting from （6-methoxyl-α-naphthyl）propan-1-one and D-sorbitol under SmCl3 catalysis.

Basic fibroblast growth factor increases the numbe of endogenous neural stem cells and inhibits the expression of amino methyl isoxazole propionic acid receptors in amyotrophic lateral sclerosis mice

This study aimed to investigate the number of amino methyl isoxazole propionic acid （AMPA） receptors and production of endogenous neural stem cells in the SOD1 G93AG1H transgenic mouse model of amyotrophic lateral sclerosis, at postnatal day 60 following administration of basic fibroblast growth factor （FGF-2）. A radioligand binding assay and immunohistochemistry were used to estimate the number of AMPA receptors and endogenous neural stem cells respectively. Results showed that the number of AMPA receptors and endogenous neural stem cells in the brain stem and sensorimotor cortex were significantly increased, while motor function was significantly decreased at postnatal days 90 and 120. After administration of FGF-2 into mice, numbers of endogenous neural stem cells increased, while expression of AMPA receptors decreased, whilst motor functions were recovered. At postnatal day 120, the number of AMPA receptors was negatively correlated with the number of endogenous neural stem cells in model mice and FGF-2-treated mice. Our experimental findings indicate that FGF-2 can inhibit AMPA receptors and increase the number of endogenous neural stem cells, thus repairing neural injury in amyotrophic lateral sclerosis mice.

Enantioselective esterification of(R,S)-2-(4-methylphenyl)propionic acid via Novozym 435:Optimization and application

This paper reports on the resolution of(R,S)-2-(4-methylphenyl)propionic acid(MPPA)enantiomers by enzymatic esterification in organic solvent.Novozym 435(CALB)has the best catalytic performance compared with other lipases.Of the alcohols screened,n-hexanol is the best acyl acceptor and gives the highest enzyme activity and enantioselectivity in n-hexane.Response surface methodology(RSM)was used to evaluate the influence of the factors,such as temperature,enzyme amount,substrate concentration and reaction time on the substrate conversion(c)and enantiomeric excess(ee).The correlation coefficient R2 for enantiomeric excess and the conversion are 0.9827 and 0.9910,respectively,indicating that can accurately predict the experimental results.By simulation and optimization,the optimal conditions were obtained,involving 600 mmol·L^-1 MPPA concentration(0.60 mmol),850 mmol·L^-1 hexanol concentration(0.85 mmol),58 mg enzyme amount,75℃temperature and 4.5 h reaction time,respectively.Under the optimized conditions,the experimental values of conversion and enantiomeric excess were 89.34%and 97.84%,respectively,which are in good agreement with the model predictions.

Association Mechanism Between Propionic Acid and Trioctylamine

Tertiary amines dissolved in diluents are attractive extractants for recovery of carboxylic acids from dilute aqueous solutions. Quantitative Fourier transform infrared (FTIR) analysis of organic solutions containing various concentrations of trioctylamine (TOA), n octanol, and propionic acid was carried out, and liquid liquid equilibrium was investigated using TOA in n octanol as the solvent. The fraction of ion pair association between TOA and propionic acid in the organic phase was quantitatively determined by FTIR. The apparent reactive extraction equilibrium constant, K 11 , was calculated using the quantitative FTIR spectrum and the equilibrium data. The results show that the fraction of ion pair association depends on diluent concentration, complex dissolution for propionic acid, and association between TOA and propionic acid. The K 11 based on quantitative FTIR has the same loading trend as that from the equilibrium data.

Heterocyclic compounds from 3-(4-phenyl) benzoyl propionic acid

3-(4-Phenyl) benzoyl propionic acid was used as the starting material for the synthesisof furanones (2), pyrrolinones (5), pyridazinones (7), benzoxazinones (8) and quinazolinones (9-11). The behaviour of the derivatives of furanones and benzoxazinones toward different nucleophiles is reported.

In vitro investigation of the effect of dairy propionibacteria on rumen pH,lactic acid and volatile fatty acids

Ruminal acidosis is a prevalent disorder in ruminants such as dairy cows and feedlot beef cattle, caused primarily by the inclusion of a high percentage of readily fermentable concentrates in the diet. The disorder presents as an accumulation of lactic acid, a decrease of pH in the rumen and a subsequent imbalance of the rumen fermentation process with detrimental impacts on the animal＇s health and productivity. Dairy propionibacteria, a group of bacteria characterised by utilization of lactic acid as the favoured carbon source, with propionic acid produced as a by-product, were evaluated in this study as potential direct-fed microbials for use in controlling ruminal acidosis. Acidosis was simulated by introduction of high concentrations of lactic acid into rumen fluid samples and a multi-strain in vitro analysis was conducted, whereby changes in pH and lactic acid metabolism were compared in identical acidified rumen samples, following inoculation with various propionibacteria. This was followed by a study to evaluate the effect of bacterial inoculation dosage on acid metabolism. The results indicated that lactic acid levels in the rumen fluid were significantly reduced, and propionic acid and acetic acid concentrations both significantly increased, following addition of propionibacteria. Significant ＇between strains＇ differences were observed, with Propionibacterium acidopropionici 341, Propionibacterium freudenreichfi CSCC 2207, Propionibacterium jensenfi NCFB 572 and P. jensenii 702 each producing more rapid reduction of lactic acid concentration than P. freudenreich# CSCC 2206, P. acidopropionici ATCC 25562 and Propionibacterium thoenii ATCC 4874. Furthermore, the efficacy of this application was dosage related, with the rates of reduction in lactic acid levels and production of propionic acid, both significantly greater for the higher （10^10 cfu mL-1） compared with lower （10^5 cfu mL-1） dosage inoculation. The results confirmed that the introduction of propionibacteria could promote more rapid reduction of lactic acid levels than would occur without their addition, demonstrating their potential in controlling ruminal acidosis.

Synthesis and Characterization of Quaternary Complex of Sm-CH_3C(CH_2OH)_2COOH-Phen

A new quaternary complex with 2,2-dihydroxymethyl propionic acid and 1,10-phenanthroline, Sm(CH3C(CH2OH)2COO)(NO3)2(phen), was synthesized in ethanol solution and characterized by elemental analysis, IR and solid-state 13C NMR. The result of molar electrolytic conductivity of the complex indicates that it is non-electrolyte. Solution and thermal properties of the complex further verifies that the complex and ligant are different. In addition, the analytical results also imply that the two hydroxyl groups of 2,2-dihydroxymethyl propionic acid are not involved in the coordinate reaction. This will provide a new way for producing new multifunctional polymer materials with excellent fluorescent property. The fluorescence spectra of the complex were also studied. The main fluorescence emission peak of the complex appeared at 555, 604 and 646 nm. These fluorescent emission peaks correspond to transitions from 4G5/2 to 6H5/2, 6H7/2 and 6H9/2 energy levels of samarium(Ⅲ) ion, respectively. The most intense peak is at 646 nm, which lies in the range of absorption wavelength of chlorophyll a and chlorophyll b (600～680 nm), and it is beneficial to the crops to grow up.

Study on Ni/C catalysts for vapor phase carbonylation of ethanol

Activated carbon-supported Ni catalysts for vapor phase carbonylation of ethanol to propionic acid in the presence of ethyl iodide as promoter were investigated. Under optimum reaction conditions, the conversions of carbon monoxide and ethanol were measured to be 81.4% and 98.4%, respectively, while the selectivity for propionic acid was found to be 98.65%. The catalyst was stable within 48 h on stream. XRD and XPS methods were used to characterize the structures and surface properties of the fresh and tested catalysts. The characterization results indicated that aggregation of nickel particles and formation of nickel iodide on the catalyst surface should be responsible for the deactivation of the catalysts.

Naproxen-induced liver injury

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) have been reported to induce liver injury. Patterns of the injury usually range from mild elevations of liver enzymes to sometimes severe fulminant hepatic failure. Likewise, naproxen is a propionic acid derivative NSAID that was introduced in 1980 and has been available as an over-the- counter medication since 1994, but has rarely been reported to cause liver injury. METHODS: We treated a 30-year-old woman with jaundice and intractable pruritus that developed shortly after taking naproxen. We reviewed the medical history and liver histopathology of the patient as well as all previously published case reports of naproxen-associated liver toxicity in the English language literature. RESULTS: The liver biochemical profile of the patient revealed a mixed cholestasis and hepatitis pattern. Consecutive liver biopsies demonstrated focal lobular inflammation, hepatocyte drop-out, and a progressive loss of the small interlobular bile ducts (ductopenia). The biopsy performed two years after onset of the disease showed partial recovery of a small number of bile ducts; however, 10 years passed before the biochemical profile returned to near normal. CONCLUSIONS: Naproxen-associated liver toxicity remains a rare entity, but should be considered in any patient presenting with cholestasis shortly after its use. Liver injury is most commonly seen in a mixed pattern characterized by cholestasis and hepatitis. The resulting liver damage may take years to resolve.

The Pattern of Eosinophil Count among Nigerians with Frequent Use of the Commonly Available Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Introduction: Non-steroidal anti-inflammatory drugs (NSAIDs) use is very common. NSAIDs use could be associated with elevated eosinophil count which could be a class effect or patient-related. Inflammation could be the link between NSAIDs use and eosinophilia. Aims: To compare the pattern of eosinophil count in the peripheral blood of frequent users of NSAIDs and healthy controls. Methodology: Two hundred (one hundred frequent users of NSAIDs and 100 healthy controls) participants who had no known risk factor for kidney disease and had given informed consent were recruited. Blood was taken to determine the white cell count and differentials, serum electrolyte and creatinine, and random blood sugar. Results: The mean age of NSAIDs users was not significantly different from controls, P = 0.3. The mean eosinophil count was higher in males than females. The incidence of eosinophilia in NSAIDs users was 4%. The mean Eosinophil count of NSAIDs users was insignificantly higher than controls, 164.3 ± 51 6 vs 135. 6 ± 53.4, P = 0.4. The mean platelet count of NSAIDs users was significantly higher compared to controls, P = 0.04. The mean hematocrit of NSAIDs users was significantly lower than the controls, P = 0.02. Propionic acid derivatives were associated with the highest eosinophil count. Eosinophil count was positively related to age and serum creatinine and inversely related to blood glucose, hematocrit and glomerular filtration rate. Conclusion: The incidence of eosinophilia was 4%. The eosinophil count was higher in frequent NSAIDs users than occasional and non-users, in males than females and with use propionic acid derivatives compared to other NSAIDs. The Eosinophil count was positively related to age and platelet count. Being commoner in inflammatory states, the tissue destruction associated with elevated EC can be avoided by the prevention and prompt treatment of inflammatory conditions.

Kinetic Study of Homogeneous Rhodium-Catalyzed Ethanol Carbonylation Using Bis(diphenylphosphino)methane Ligands

Homogeneous rhodium-catalyzed carbonylation of ethanol is a potential route for the preparation of propionic acid,although its commercialization has been hindered by a low reaction rate.In this work,various bis(diphenylphosphine)ligands were evaluated in the rhodium-catalyzed reaction system in an effort to improve the reaction rate.By comparing the space-time yield and selectivity of the catalytic system in a Hastelloy autoclave reactor,the effects of the choice of ligand,ligand:rhodium ratio,carbon monoxide pressure,temperature,rhodium concentration,ethyl iodide content,and lithium iodide content were investigated.In the presence of the ligand bis(diphenylphosphino)methane disulfide(dppmS_(2)),the activity of the catalyst was improved significantly.The results revealed that the optimal conditions included a dppmS_(2):Rh molar ratio of 0.5:1,a rhodium concentration of 1000μg/g,an ethyl iodide content of 10%,and a lithium iodide content of 10%.The most suitable reaction temperature and carbon monoxide pressure were 463 K and 3.0 MPa,respectively,which resulted in a maximum space-time yield of 4.30 mol/(h·L).A kinetic model was established in the temperature range of 442-463 K,and the model data were regressed and validated,revealing an activation energy of 28.01 kJ/mol.Residual analysis and statistical tests demonstrated the reliability of the kinetic experiments.

A Study on the Mechanism Regulating Acetate to Propionate Ratio in Rumen Fermentation by Dietary Carbohydrate Type

The research direction of our team is nutrition and physiology of ruminants, including dietary nutrition metabolism and rumen microorganisms. Previous research has shown that ruminal acetate-to-propionate ratio is related to diet utilization efficiency. At present, it is believed that the main factors affecting the ruminal acetate-to-propionate ratio are the degradation rate of the diet and the rumen microbial structure, but the main mechanism is unclear. This study found that the effect of ruminal acetate-to-propionate ratio was not affected by the concentration of the fermentation substrate, but was affected by the structure of the rumen microbiota. We believe that changes in the rumen microflora structure are the main mechanism for regulating the ruminal acetate-to-propionate ratio. This will help people to further understand the rumen physiology, thereby gradually improving feed conversion efficiency and reducing production costs. Abstract: In order to explore the mechanism by which diet regulates the acetate-to-propionate molar ratio (A: P ratio), we compared the effect on rumen fermentation parameters and the microbiome by altering the ratio of dietary concentrates to roughage ratio and calcium pyruvate infusion. The test animals were Laoshan dairy goats, and were fed continuously through an automatic feeder. The test groups were fed a base diet of low concentrates, and intraruminally infused with calcium pyruvate at two concentrations. The infusion concentrations were derived from the difference in the rate of carbohydrate degradation of the high and low concentrate diets, and they were artificially set such that the high concentration infusion group was infused with twice the concentration as the low concentration infusion group. The control groups were fed high concentrate (6:4) and low concentrate (3:7) diets, respectively. The following results were obtained by measuring rumen fermentation parameters and microbial composition: the rumen A: P ratio was significantly lower in the high-concentrate diet group than in the low concentrate diet group (P < 0.05). Infusion of low concentration calcium pyruvate had no significant effect on rumen A: P ratio (P > 0.05), while infusion of high concentration calcium pyruvate significantly increased the rumen A: P ratio (P < 0.05). Relative to goats fed the low concentrate diet, those fed the high concentrate diet had a greater abundance of microbes related to propionate production and a reduced abundance of microbes related to fiber degradation. Infusion of pyruvate had no significant effect on rumen microbial structure. The above results indicate that increasing the concentration of the fermentation substrate without affecting the composition of the microflora does not reduce the A: P ratio. Microbiological results showed that the A: P ratio was more closely related to the rumen microflora structure. Therefore, it is believed that rumen microflora structure is the main mechanism regulating A: P ratio in rumen fermentation.

2-(3-羧甲基-4-苯硫基苯基)丙酸的制备

2-(3-羧甲基-4-苯硫基苯基)丙酸(1)是消炎镇痛药扎托洛芬(zaltoprofen)的关键中间体[1]。文献以5-丙酰基-2-苯硫基苯乙酸甲酯(2)为原料,在碘和氧化亚铜复合催化下,与原甲酸三甲酯经碘代缩酮、重排、水解一锅反应制得1,总收率为72%[1],方法中碘成本较高,不宜在工业上采用。