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1.
A convenient electrochemical sensing pathway for 17β-estradiol detection was investigated. The system is based on a conducting polymer and horseradish peroxidase (HRP) modified platinum (Pt) electrode. The miniature estradiol biosensor was developed and constructed through the immobilization of HRP in an electroactive surface of the electrode covered with electroconducting polymer – poly(4,7-bis(5-(3,4-ethylenedioxythiophene)thiophen-2-yl)benzothiadiazole). The detection strategy is based on the fact that 17β-estradiol (E2) and pyrocatechol (H2Q) are co-substrates for the HRP enzyme. HRP, which does not react with E2, in the presence of H2O2 catalyses the oxidation of H2Q to o-benzoquinone (Q). With the optimized conditions, such constructed biosensing system demonstrated a convenient level of sensitivity, selectivity in a broad linear range – 0.1 to 200 μM with a detection limit of 105 nM. Furthermore, the method was successfully applied for hormone detection in the presence of potential interfering compounds (ascorbic acid, estriol, estrone, uric acid and cholesterol).A convenient electrochemical sensing pathway for 17β-estradiol detection was investigated. 相似文献
2.
Correction for ‘Electrochemical biosensor for detection of 17β-estradiol using semi-conducting polymer and horseradish peroxidase’ by Kamila Spychalska et al., RSC Adv., 2020, 10, 9079–9087, DOI: 10.1039/C9RA09902F.The authors wish to amend the authorship of this article by adding an additional author, Aleksandra Wiatrowska. The full author list is as shown above.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers. 相似文献
3.
Modified Mg3Al layered double hydroxide (LDH) intercalated with dodecylsulfate anion composites, which were designated as SDS-LDH composites, were synthesized by coprecipitation. The samples were characterized using SEM, EDX, FT-IR, zeta potential analysis, and XRD. The results showed that the SDS-LDH composites contain a thicker and larger porous interconnected network than inorganic LDH due to the enlarged inter-layer distance. The outstanding adsorption performance of SDS-LDH composites toward 17β-estradiol (E2) was investigated under different conditions, including solution pH, adsorbent dosage, ion strength, reaction time, and temperature. When the solution pH was 7 and the adsorbent dosage was 2 g L−1, the removal rate of E2 reached the maximum at 94%, whereas inorganic LDH displayed a poor E2 removal rate of 10%. The presence of various ions (Na+, SO42−, CI−, and H2PO4−) in aqueous solution exerted no significant adverse effects on the adsorption process. The adsorption equilibrium was reached within 20 min, and the adsorption fitted well with the pseudo-second-order model and the Freundlich isotherm. The thermodynamic test revealed that the adsorption process was spontaneous and endothermic. Phosphorus was selected as the index for evaluating the adsorption capacity of SDS-LDH composites for inorganic ions. The removal rates of total phosphorus and PO43− were 43.71% and 55.93% for SDS-LDH composites at 2 g L−1. The removal rate of PO43− reached up to 85% when the contact time was 120 min and the dosage was 3 g L−1 for SDS-LDH composites, which were approximately close to those of inorganic LDH of 30 min and 2 g L−1, respectively. This finding indicates that the removal capacity of SDS-LDH composites for PO43− decreased after the dodecylsulfate anions intercalated into the interlayer. The composites retained their high efficiency and stability after desorption and regeneration with alkali treatment. This study demonstrated that SDS-LDH composites are a promising adsorbent for the recovery and abatement of trace-level E2 in secondary effluents of wastewater treatment plants.SDS-LDH composites were synthesized by coprecipitation. The composites are promising adsorbents for the recovery and abatement of trace-level E2 in secondary effluents of wastewater treatment plants. 相似文献
4.
A novel, efficient, catalyst-free and product-controllable strategy has been developed for the chemoselective α-sulfenylation/β-thiolation of α,β-unsaturated carbonyl compounds. An aromatic sulfur group could be chemoselectively introduced at α- or β-position of carbonyls with different sulfur reagents under slightly changed reaction conditions. A series of desired products were obtained in moderate to excellent yields. Mechanistic studies revealed that B2pin2 played the key role in activating the transformation towards the β-thiolation of α,β-unsaturated carbonyl compounds. This transition-metal-catalyst-free method provides a convenient and efficient tool for the highly chemoselective preparation of α-thiolation or β-sulfenylation products of α,β-unsaturated carbonyl compounds.This catalyst-free method provides a useful and efficient tool for the highly chemoselective preparation of α-thiolation or β-sulfenylation products of α,β-unsaturated carbonyl compounds. 相似文献
5.
The β-selective asymmetric addition of γ-butyrolactam with cyclic imino esters catalyzed by a bifunctional chiral tertiary amine has been developed, which provides an efficient access to optically active β-position functionalized pyrrolidin-2-one derivatives in both high yield and enantioselectivity (up to 78% yield and 95 : 5 er). This is the first catalytic method to access chiral β-functionalized pyrrolidin-2-one via a direct organocatalytic approach.The asymmetric addition of γ-butyrolactam with cyclic imino esters catalyzed by (DHQD)2AQN has been developed, which provides an access to β-position functionalized pyrrolidin-2-one derivatives in high levels yield and enantioselectivity.Metal-free organocatalytic asymmetric transformations have successfully captured considerable enthusiasm of chemists as powerful methods for the synthesis of various kinds of useful chiral compounds ranging from the preparation of biologically important molecules through to novel materials.1 Chiral pyrrolidin-2-ones have been recognized as important structural motifs that are frequently encountered in a variety of biologically active natural and synthetic compounds.2 In particular, the β-position functionalized pyrrolidin-2-one backbones, which can serve as key synthetic precursors for inhibitory neurotransmitters γ-aminobutyric acids (GABA),3 selective GABAB receptor agonists4 as well as antidepressant rolipram analogues,5 have attracted a great deal of attention. Therefore, the development of highly efficient, environmentally friendly and convenient asymmetric synthetic methods to access these versatile frameworks is particularly appealing.As a direct precursor to pyrrolidin-2-one derivatives, recently, α,β-unsaturated γ-butyrolactam has emerged as the most attractive reactant in asymmetric organometallic or organocatalytic reactions for the synthesis of chiral γ-position functionalized pyrrolidin-2-ones (Scheme 1). These elegant developments have been achieved in the research area of catalytic asymmetric vinylogous aldol,6 Mannich,7 Michael8 and annulation reactions9 in the presence of either metal catalysts or organocatalysts (a, Scheme 1). These well-developed catalytic asymmetric methods have been related to the γ-functionalized α,β-unsaturated γ-butyrolactam to date. However, in sharp contrast, the approaches toward introducing C-3 chirality at the β-position of butyrolactam through a direct catalytic manner are underdeveloped (b, Scheme 1)10 in spite of the fact that β-selective chiral functionalization of butyrolactam can directly build up α,β-functionalized pyrrolidin-2-one frameworks.Open in a separate windowScheme 1Different reactive position of α,β-unsaturated γ-butyrolactam in catalytic asymmetric reactions.So far, only a few metal-catalytic enantioselective β-selective functionalized reactions have been reported. For examples, a rhodium/diene complex catalyzed efficient asymmetric β-selective arylation10a and alkenylation10b have been reported by Lin group (a, Scheme 2). Procter and co-workers reported an efficient Cu(i)–NHC-catalyzed asymmetric silylation of unsaturated lactams (b, Scheme 2).10c Despite these creative works, considerable challenges still exist in the catalytic asymmetric β-selective functionalization of γ-butyrolactam. First, the scope of nucleophiles is limited to arylboronic acids, potassium alkenyltrifluoroborates and PhMe2SiBpin reagents. Second, the catalytic system and activation mode is restricted to metal/chiral ligands. To our knowledge, an efficient catalytic method to access chiral β-functionalized pyrrolidin-2-one via a direct organocatalytic approach has not yet been established. Therefore, the development of organocatalytic asymmetric β-selective functionalization of γ-butyrolactam are highly desirable. In conjunction with our continuing efforts in building upon chiral precedents by using chiral tertiary amine catalytic system,11 we rationalized that the activated α,β-unsaturated γ-butyrolactam might serve as a β-position electron-deficient electrophile. This γ-butyrolactam may react with a properly designed electron-rich nucleophile to conduct an expected β-selective functionalized reaction of γ-butyrolactam under a bifunctional organocatalytic fashion, while avoiding the direct γ-selective vinylogous addition reaction or β,γ-selective annulation as outlined in Scheme 2. Herein we report the β-selective asymmetric addition of γ-butyrolactam with cyclic imino esters12 catalyzed by a bifunctional chiral tertiary amine, which provides an efficient and facile access to optically active β-position functionalized pyrrolidin-2-one derivatives with both high diastereoselectivity and enantioselectivity.Open in a separate windowScheme 2β-Selective functionalization of γ-butyrolactam via metal- (previous work) or organo- (this work) catalytic approach.To begin our initial investigation, several bifunctional organocatalysts13 were firstly screened to evaluate their ability to promote the β-selective asymmetric addition of γ-butyrolactam 2a with cyclic imino ester 3a in the presence of 15 mol% of catalyst loading at room temperature in CH2Cl2 (entries 1–6, Entry Cat. Solvent Yielde erf 1 1a CH2Cl2 70% 40 : 60 2 1b CH2Cl2 <5% 57 : 43 3 1c CH2Cl2 70% 65 : 35 4 1d CH2Cl2 68% 70 : 30 5 1e CH2Cl2 58% 63 : 47 6 1f CH2Cl2 71% 77 : 23 7 1f DCE 72% 80 : 20 8 1f CHCl3 70% 80 : 20 9 1f MTBE 68% 79 : 21 10 1f Toluene 63% 78 : 22 11 1f THF 45% 76 : 24 12 1f MeOH 32% 62 : 38 13b 1f DCE : MTBE 75% 87 : 13 14c 1f DCE : MTBE 72% 87 : 13 15d 1f DCE : MTBE 70% 85 : 15