Stable heterocumulene monomer in water; Synthesis and polymerization of (meth)acrylates having an isothiocyanate structure

Novel methacrylate and acrylate monomers having an isothiocyanate structure, 2‐isothiocyanatoethyl methacrylate (ITEMA) and 2‐isothiocyanatoethyl acrylate (ITEA), were synthesized, and their radical polymerizations were examined, respectively. ITEMA and ITEA were synthesized by addition of carbon disulfide to 2‐aminoethyl methacryrate or 2‐aminoethyl acrylate, followed by treatment with ethyl chloroformate. Radical polymerizations of the obtained monomers ( ITEMA , ITEA ) were carried out methyl ethyl ketone using 2,2'‐azobisisobutyronitrile (AIBN) as an initiator to obtain the corresponding polymers. The glass transition temperatures of the poly‐ITEMA and poly‐ITEA were determined to be 55 and 2 °C by differential scanning calorimetry, respectively. The 5 wt % decomposition temperatures of the poly‐ITEMA and poly‐ITEA were determined to be 277 and 269 °C by thermogravimetric analysis, respectively. Isothiocyanato groups in the monomers did not react with water in acetone solution at 60 °C for 24 h to be tolerable to water. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4522–4529     

Access to Intrinsically Glucoside‐Based Microspheres with Boron Affinity

Intrinsically glucoside‐based microspheres are prepared in olive oil via a water in oil inverse suspension polymerization. The microspheres are characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) microscopy, and X‐ray photoelectron spectroscopy (XPS), evidencing the intrinsic glucose character of the spheres. A novel boronic acid fluorescent molecule was subsequently conjugated to the microspheres in an aqueous environment, exhibiting the spatial and uniform distribution of glucoside as well as the affinity of the microspheres to bind with boron, evidenced via fluorescence spectroscopy measurements.

     

Applying the hydrodistillation process to Pentadiplandra brazzeana Baill. root: a chemical assessment

A chemical study of the volatile components obtained by applying the hydrodistillation and reflux processes to Pentadiplandra brazzeana roots was performed by GC-FID and GC-MS. The hydrodistillation process showed a total yield of 0.97% with 0.11% of essential oil and 0.86% of volatile compounds from the aqueous reaction medium; in the reflux process, the volatile extract yield was 1.03%. Benzylic-type isothiocyanates were the major degradation products of glucosinolates in the essential oil (95.0%); the CH₂Cl₂ extracts obtained from the aqueous solutions were characterised by alcohols and amines in both processes. This study has shown that during hydrodistillation, only 10% of the glucosinolate degradation products are recovered in the essential oil whereas 90% remain in the aqueous medium, being converted into alcohols and amines. The relative percentages of the different chemical classes recovered in our experimental conditions are discussed in relation with the glucosinolate composition in the raw material.     

一锅合成异硫氰酸酯

以N,N-二乙基乙胺(Et₃N)为碱,甲苯为溶剂,伯胺和CS₂为原料,叔丁基碳酸二乙基磷酸酐(3)为脱硫试剂,在n(伯胺):n(CS₂):n(Et₃N):n(3)=1:1.1:3.3:1.1,二硫代甲酸盐合成段反应温度为室温,脱硫反应段为-5 ℃至室温的实验条件下,两步一锅合成了系列烷基、芳基和双功能基异硫氰酸酯化合物,收率77%96%。 本方法底物适用范围广,操作简单,对胺的各种保护基团耐受,不引起消旋化副反应。 脱硫剂3作为一种新的脱硫试剂,商业易得,安全有效。     

Controlled release matrix tablet formulation using synthesized N-acyl Thiolated Chitosan derivatives

Chitosan derivative was successively synthesized by initial preparation of acyl thiourea reagent using ammonium thiocyanate and making it to react with at primary amino groups of chitosan and then reduced to yield Thiolated Chitosan. Due to the formation of disulphide bonds with mFucus glycoproteins, mucoadhesiveness is augmented. The thiol groups were then quantified using Ellman’s reagent. The derivatives inherit good swelling property in neutral and alkaline media. The different derivatives containing thiol groups were formulated into tablets using reference drug for evaluation. The Thiolated Chitosan display in situ gelling features due to the pH-dependent (alkaline pH) formation of inter-molecular disulphide bonds which makes the application of Thiolated Chitosan on intestinal mucosa and can guarantee prolonged controlled release of embedded therapeutic ingredients.     

An improved method for ratiometric fluorescence detection of pH and Cd using fluorescein isothiocyanate–quantum dots conjugates

In this study, thioglycolic acid capped-CdTe quantum dots (QDs) were modified by polyethylenimine (PEI), and then combined with fluorescein isothiocyanate (FITC) to fabricate FITC–CdTe conjugates. The self-assembly of FITC, CdTe and PEI was ascribed to electrostatic interactions in aqueous solution. The resulting conjugates were developed toward two routes. In route one, ratiometric photoluminescence (PL) intensity of conjugates (I_FITC/I_QDs) was almost linear toward pH from 5.3 to 8.7, and a ratiometric PL sensor of pH was favorable obtained. In route two, firstly added S²⁻ induced remarkable quenching of QDs PL peak (at the “OFF” state), which was restored due to following addition of Cd²⁺ (at the “ON” state). In the conjugates, successive introduction of S²⁻ and Cd²⁺ hardly influenced on FITC PL peaks. According to this PL “OFF-ON” mode, a ratiometric PL method for the detection of Cd²⁺ was achieved. Experimental results confirmed that the I_FITC/I_QDs exhibited near linear proportion toward Cd²⁺ concentration in the range from 0.1 to 15 μM, and the limit of detection was 12 nM. Interferential experiments adequately testified that the proposed sensors of pH and Cd²⁺ were practicable in real samples and complex systems. In comparison with conventional analytical techniques, the ratiometric PL method was simple, rapid, economic and highly selective.     

A novel HPLC-UV method for determining alendronate in rat plasma through precolumn derivatization with phenyl isothiocyanate: Application to pharmacokinetics

The determination of alendronate (ALE) in biofluids using a low-cost instrument is potentially useful in preclinical pharmacokinetic studies. This study developed and validated a high-performance liquid chromatography with ultraviolet method for ALE determination in rat plasma using precolumn derivatization with phenyl isothiocyanate (PITC). Inhibiting compounds in the samples were first eliminated using solid-phase extraction. ALE in the sample was subsequently allowed to react with PITC to form a phenylthiocarbamoyl derivative for further analysis. The assay was linear within the concentration range of 0.29–25.0?µg/mL. The precision and accuracy were less than 3.9% and 98.0?±?3.9%, respectively. The limits of detection and quantification were 0.08 and 0.20?µg/mL, respectively. The method was successfully used to evaluate the pharmacokinetic parameters of ALE in rats following a single oral administration (30.0?mg/kg). The results show that the peak plasma ALE concentration is 0.69?±?0.18?µg/mL. The area under the plasma concentration–time curve value of ALE was 2.14?±?0.68?µg/mL hr. This method can suitably evaluate the bioavailabilities of different ALE dosage forms in preclinical pharmacokinetic studies.     

Edman降解中异硫氰酸苯酯新修饰位点的发现和验证

Edman降解是最早建立的一种用于多肽和蛋白质氨基端测序的方法,该方法现在仍被广泛用于生物化学领域。随着高通量蛋白质组学技术的发展和应用,该方法中的异硫氰酸苯酯反应被用于修饰蛋白质氨基端,并用于检测蛋白质水解位点。但还没有异硫氰酸苯酯是否可以修饰其他氨基酸侧链并影响多肽序列分析的研究。为了探究其修饰其他氨基酸的可能性,本文利用基质辅助激光解吸电离飞行时间质谱（MALDI-TOF-MS）和液相色谱-串联质谱（LC-MS/MS）研究了异硫氰酸苯酯对一个模型肽的化学修饰。质谱数据解析后发现在高浓度异硫氰酸苯酯的反应条件下,组氨酸上可以引入一个新的异硫氰酸苯酯修饰位点。这一修饰位点的发现预示着通过改变实验条件或分析方法,可以更准确地利用Edman降解和蛋白质组学技术分析多肽和蛋白质。     

The Effects of Heteroatoms Si and S on Tuning the Optical Properties of Rhodamine‐ and Fluorescein‐Based Fluorescence Probes: A Theoretical Analysis

The effects of the incorporated heteroatoms Si and S on tuning the optical properties of rhodamine‐ and fluorescein‐based fluorescence probes is investigated using DFT and time‐dependent DFT with four different functionals. As previously proposed, the large redshift (90 nm) produced by a Si atom in both the absorption and emission spectra can be attributed to the σ*–π* conjugation between the σ* orbital of the Si atom and the π* orbital of the adjacent carbon atoms. However, the presence of a Si atom does not alter the fluorescence quenching mechanism of the nonfluorescent forms of the investigated compounds. For the first time, these theoretical results indicate that the n orbital of the S atom plays an important role in determining the optical properties of the nonfluorescent form of rhodamine‐based fluorescence probes. It alters the fluorescence quenching mechanism by lowering the energy of the dark nπ* state, which is due to breakage of the C10?S52 bond upon photoexcitation.     

顶空进样气相色谱-质谱法测定山葵中异硫氰酸酯

建立了山葵中异硫氰酸酯的测定方法。样品装入顶空进样瓶中,加热平衡后顶空进样,经HP-5MS毛细管柱分离,质谱测定。传输线温度250℃,离子源温度230℃,顶空瓶平衡温度60℃,平衡时间15min。通过计算机检索与NIST库中标准质谱图比较定性。在山葵样品中分离鉴定出8种异硫氰酸酯。方法具有操作简单、快速等特点。