Convenient synthesis of 4-tert-butyl 2-ethyl 3-amino-1-benzyl-5-dialkylamino-1H-pyrrole-2,4-dicarboxylate derivatives

Optimization details and limitations of a novel synthetic method of 4-tert-butyl 2-ethyl 3-amino-1-benzyl-5-dialkylamino-1H-pyrrole-2,4-dicarboxylate derivatives are herein disclosed. This synthesis consists of four steps that include a highly selective cyclization, and can be carried out from starting materials to target compounds without column chromatography purification. The high selectivity is controlled by lithium coordination and steric hindrance caused by tert-butyl ester.     

Synthesis of Duloxetine Intermediate (S)-3-Chloro-1-(2-thienyl)-1-propanol with Liquid-Core Immobilized Candida pseudotropicalis 104

(S) -3-Chloro-1-(2-thienyl)-1-propanol was synthesized by the asymmetric reduction of 3-chloro-1-(2-thienyl)propanone with liquid-core immobilized Candida pseudotropicalis 104. The optimum time was 28?h for the re-cultivation of immobilized cells. The optimum film solvent for the liquid-core capsule was 0.3?% chitosan (M _w 1.0?×?10⁵). Conversion decreased with the increase of the liquid-core capsule diameter and with the addition of more substrates at the same reduction time. The immobilized cells show good reduction ability in a potassium phosphate buffer (pH 6.6~7.2). The material outside the spread speed of immobilized cells was not restricted when the shaking speed was higher than 160?r/min. Liquid-core immobilized cells can be reused 11 times. Compared with the batch reduction, the continuous reduction of 3-chloro-1-(2-thienyl)propanone in the membrane reactor with liquid-core immobilized cells as catalyst can relieve the inhibition from a high-concentration substrate. Conversion and enantiometric excess of (S)-3-chloro-1-(2-thienyl)-1-propanol reached 100?% and >99?% in a continuous reduction of 12?g/L 3-chloro-1-(2-thienyl)propanone for 10?days.     

Microdetermination of aliphatic amines and polyamines with cupric ion: Relationship between pK1 and half-complexation potential

The first equilibrium constant for the combination of ligand with cupric ion, K₁, is related to the half-complexation potential, E_HC, by log K₁ = a + b[E_HC]. The coefficients differ for n ? 2 and n ? 2, where n is the number of nitrogen atoms in the molecule. The correlation coefficients, r, based on data available from the literature were ?0.98. The equations can be used for estimating log K₁ of aliphatic amines. Successful titration of aliphatic amines vs cupric ion requires log K₁ ? 4 and an initial pH of a 10^?3M solution of ?9.     

Synthesis,properties and structural characterization of 4-(2-ammonioethyl)piperazin-1-ium tetrasulfidotungstate hemihydrate and 1-ethylpiperazinediium tetrasulfidotungstate

The reaction of ammonium tetrasulfidotungstate with 2-piperazin-1-ylethanamine or 1-ethylpiperazine results in the formation of 4-(2-ammonioethyl)piperazin-1-ium tetrasulfidotungstate hemihydrate (C₆H₁₇N₃)[WS₄]·½H₂O 1 or 1-ethylpiperazinediium tetrasulfidotungstate (C₆H₁₆N₂)[WS₄] 2. The hemihydrate 1 can be dehydrated to the anhydrous compound (C₆H₁₇N₃)[WS₄] 1a, which can be rehydrated to 1. Both 1 and 2 decompose to amorphous carbon containing tungsten disulphide. Compound 1 crystallizes in the centrosymmetric monoclinic space group C2/c, while compound 2 crystallizes in the centrosymmetric orthorhombic space group Pbca. The structures of 1 and 2 consist of a slightly distorted tetrahedral [WS₄]^2? anion and 4-(2-ammonioethyl)piperazin-1-ium (1) or 1-ethylpiperazinediium dication (2) and additionally a lattice water in 1. In the crystal structure of 1 and 2 the organic cation and the [WS₄]^2? anion are linked to each other via several weak N–H?S and C–H?S bonding interactions. The lattice water serves as a link between pairs of cations and pairs of anions with the aid of O–H?S and N–H?O interactions in compound 1.     

Laccase Production by the Aquatic Ascomycete Phoma sp. UHH 5-1-03 and the White Rot Basidiomycete Pleurotus ostreatus DSM 1833 During Submerged Cultivation on Banana Peels and Enzyme Applicability for the Removal of Endocrine-Disrupting Chemicals

This work aimed to study the production of laccase from Pleurotus ostreatus DSM 1833 and Phoma sp. UHH 5-1-03 using banana peels as alternative carbon source, the subsequent partial purification and characterization of the enzyme, as well the applicability to degrade endocrine disruptors. The laccase stability with pH and temperature, the optimum pH, the K _m and V _max parameters, and the molar mass were determined. Tests were conducted for assessing the ability of degradation of the endocrine disruptors t-nonylphenol, bisphenol A, and 17??-ethinylestradiol. Laccase production of 752 and 1,117?U?L^?1 was obtained for Phoma sp. and P. ostreatus, respectively. Phoma sp. laccase showed higher stability with temperature and pH. The laccase from both species showed higher affinity by syringaldazine. The culture broth with banana peels induced the production of two isoforms of P. ostreatus (58.7 and 21?kDa) and one of Phoma sp. laccase (72?kDa). In the first day of incubation, the concentrations of bisphenol A and 17??-ethinylestradiol were reduced to values close to zero and after 3?days the concentration of t-nonylphenol was reduced in 90% by the P. ostreatus laccase, but there was no reduction in its concentration by the Phoma sp. laccase.     

A method for obtaining potential parameters for helium from T1 measurements

The temperature dependence of T₁ for ³He gas in the range 0–4°K is calculated for a Lennard-Jones (12,6) potential. The relaxation of the nuclear spins is assumed to be due to a dipolar interaction between the nuclei. A minimum value in the relaxation time, T_1,min, is found to occur at a temperature denoted by T_min. By repeating the calculation for different pairs of values of the potential parameters ? and σ, we have found that for a density of 10^?2 g/cm³,σ²T_min = 13.0?1.12 × 10³ ?σ², T_1,min/σ²(T_min)^{$\text{1}\text{2}$} = 17.4?6.56 × 10² ?σ², with ?, σ, T_min and T_1,min in eV, Å, °K and minutes, respectively. From measurements of T_min and T_1,min, ? and σ can be determined.     

Configuration interaction in the 6s n d 1 D 2 and 6s n s 1 S 0 states of Yb probed by lifetime measurements

Radiative lifetimes in the even parity 6s n d ¹ D ₂ (n=6?13) and 6s n s ¹ S ₀ (n=8?14) level series of neutral Yb have been measured. In contrast to a monotonicn*³ behaviour which is expected in the absence of configuration interaction a drastic decrease of the lifetime data was observed in the vicinity of multiply excited states. In addition, for certain levels a strong increase of the lifetime values has been found which may be ascribed to destructive interference due to configuration mixing which can also affect the branching ratios of the radiative decay of these levels.     

An electrochemical magneto immunosensor (EMIS) for the determination of paraquat residues in potato samples

An electrochemical magneto immunosensor for the detection of low concentrations of paraquat (PQ) in food samples has been developed and its performance evaluated in a complex sample such as potato extracts. The immunosensor presented uses immunoreagents specifically developed for the recognition of paraquat, a magnetic graphite–epoxy composite (m-GEC) electrode and biofunctionalized magnetic micro-particles (PQ1-BSAMP) that allow reduction of the potential interferences caused by the matrix components. The amperometric signal is provided by an enzymatic probe prepared by covalently linking an enzyme to the specific antibodies (Ab198-cc-HRP). The use of hydroquinone, as mediator, allows recording of the signal at a low potential, which also contributes to reducing the background noise potentially caused by the sample matrix. The immunocomplexes formed on top of the modified MP are easily captured by the m-GEC, which acts simultaneously as transducer. PQ can be detected at concentrations as low as 0.18?±?0.09 μg L^?1. Combined with an efficient extraction procedure, PQ residues can be directly detected and accurately quantified in potato extracts without additional clean-up or purification steps, with a limit of detection (90 % of the maximum signal) of 2.18?±?2.08 μg kg^?1, far below the maximum residue level (20 μg kg^?1) established by the EC. The immunosensor presented here is suitable for on-site analysis. Combined with the use of magnetic racks, multiple samples can be run simultaneously in a reasonable time.     

One-pot multistep synthesis of 3,4-fused isoquinolin-1(2H)-one analogs

We have developed a robust approach for the synthesis of 3,4-fused isoquinolin-1(2H)-one analogs. A benzonitrile or a nicotinonitrile bearing an ortho-substituent, such as -OH, -SH, or -NHR (R = alkyl or aryl) can be deprotonated by KOtBu and then reacted with methyl 2-(bromomethyl)benzoate (8) to form its corresponding O-, S-, or N-alkylation product. The product thus formed is then treated with KOtBu again to initiate a cascade process that will lead to the formation of its corresponding 3,4-fused isoquinolin-1(2H)-one. This multistep synthesis as well as the final product purification is achieved in a one-pot manner.     

Microbial Fed-batch Production of 1,3-Propanediol Using Raw Glycerol with Suspended and Immobilized Klebsiella pneumoniae

The production of 1,3-propanediol (1,3-PD) was investigated with Klebsiella pneumoniae DSM 4799 using raw glycerol without purification obtained from a biodiesel production process. Fed-batch cultures with suspended cells revealed that 1,3-PD production was more effective when utilizing raw glycerol than pure glycerol (productivity after 47 h of fermentation, 0.84 g?L^?1?h^?1 versus 1.51 g?L^?1?h^?1 with pure and raw glycerol, respectively). In addition, more than 80 g/L of 1,3-PD was produced using raw glycerol; this is the highest 1,3-PD concentration reported thus far for K. pneumoniae using raw glycerol. Repeated fed-batch fermentation with cell immobilization in a fixed-bed reactor was performed to enhance 1,3-PD production. Production of 1,3-PD increased with the cycle number (1.06 g?L^?1?h^?1 versus 1.61 g?L^?1?h^?1 at the first and fourth cycle, respectively) due to successful cell immobilization. During 46 cycles of fed-batch fermentation taking place over 1,460 h, a stable and reproducible 1,3-PD production performance was observed with both pure and raw glycerol. Based on our results, repeated fed batch with immobilized cells is an efficient fermentor configuration, and raw glycerol can be utilized to produce 1,3-PD without inhibitory effects caused by accumulated impurities.