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21.
Malik Abdul Waseem ShireenAnjali Srivastava Arjita SrivastavaRahila I.R. Siddiqui 《Tetrahedron letters》2014
Reusable [bmIm]OH was found to be a highly efficient renewable homogenous catalyst for the rapid and convenient synthesis of benzoxazine-4-one derivatives from o-iodobenzoic-acid and benzonitrile at 75 °C in moderate to good yields. This methodology provides a facile and straightforward path to construct other related heterocycles in an eco-compatible fashion. 相似文献
22.
AHMED Khan MUHAMMAD Asghar MOHAMMED Yaqoob MASOOD Ahmed Siddiqui SAMAR Ali 《高等学校化学研究》2021,37(3):629-638
Asensitive and selective method employing chemiluminescence(CL) coupled with flow injection(FI) is reported for nalbuphine hydrochloride(NAL) assay in pharmaceutical formulations. The enhancement effect of NAL on the CL reaction between tris(2,2'-bipyridyl)ruthenium(II) chloride-diperiodatocuprate(III) {Ru[(bpy)3]2+-Cu(III) complex} in acidic medium is used as analytical measurement. The optimal conditions of the CL reaction were sulfuric acid 1.0×10-3 mol/L, Ru[(bpy)3]2+ 7.5×10-5 mol/L, Cu(III)/Ag(III) complexes 4.0×10-4/5.0×10-4 mol/L, sample loop volume of 120 μL and flow rate of 2.5 mL/min. The sensitivities of the method in terms of detection(S/N=3) and quantification(S/N=10) limits are 5×10-4 and 0.001 ppm(1 ppm=1 mg/L), respectively. The linear response of the instrument in the form of CL intensity with respect to NAL concentration is over the range 0.001-15.0 ppm(R2=0.9999) with relative standard deviation from 0.8% to 3.2% and injection throughput of 120 injection/h. The applications of the method include the quantitative analysis of NAL in pharmaceutical injection samples. Variations and the average results of the proposed method are not signi-ficantly different from the results of a reported method by applying F- and paired student t-test. The most likely CL reaction mechanism is written in accordance with spectrophotometric and CL studies. 相似文献
23.
Qamar Uddin Ahmed Abdul Hasib Mohd Ali Sayeed Mukhtar Meshari A. Alsharif Humaira Parveen Awis Sukarni Mohmad Sabere Mohamed Sufian Mohd. Nawi Alfi Khatib Mohammad Jamshed Siddiqui Abdulrashid Umar Alhassan Muhammad Alhassan 《Molecules (Basel, Switzerland)》2020,25(23)
In recent years, there is emerging evidence that isoflavonoids, either dietary or obtained from traditional medicinal plants, could play an important role as a supplementary drug in the management of type 2 diabetes mellitus (T2DM) due to their reported pronounced biological effects in relation to multiple metabolic factors associated with diabetes. Hence, in this regard, we have comprehensively reviewed the potential biological effects of isoflavonoids, particularly biochanin A, genistein, daidzein, glycitein, and formononetin on metabolic disorders and long-term complications induced by T2DM in order to understand whether they can be future candidates as a safe antidiabetic agent. Based on in-depth in vitro and in vivo studies evaluations, isoflavonoids have been found to activate gene expression through the stimulation of peroxisome proliferator-activated receptors (PPARs) (α, γ), modulate carbohydrate metabolism, regulate hyperglycemia, induce dyslipidemia, lessen insulin resistance, and modify adipocyte differentiation and tissue metabolism. Moreover, these natural compounds have also been found to attenuate oxidative stress through the oxidative signaling process and inflammatory mechanism. Hence, isoflavonoids have been envisioned to be able to prevent and slow down the progression of long-term diabetes complications including cardiovascular disease, nephropathy, neuropathy, and retinopathy. Further thoroughgoing investigations in human clinical studies are strongly recommended to obtain the optimum and specific dose and regimen required for supplementation with isoflavonoids and derivatives in diabetic patients. 相似文献
24.
Siddiqui Madiha M. Nagargoje Amol A. Akolkar Satish V. Sangshetti Jaiprakash N. Khedkar Vijay M. Pisal Parshuram M. Shingate Bapurao B. 《Research on Chemical Intermediates》2022,48(3):1199-1225
Research on Chemical Intermediates - A simple and efficient protocol has been developed for the synthesis of new1,2,3-triazole-2,3-dihydroquinazolin-4[1H]-one (DHQ) conjugates(6a?j) via... 相似文献
25.
A new heterogeneous catalyst, lanthanum immobilized on chitosan, was synthesized and used for the aza‐Michael reaction of β‐enaminone under microwave irradiation. The characteristic structural features of the catalyst were determined using Fourier transform infrared spectroscopy, powder X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, transmission and scanning electron microscopies and inductively coupled plasma atomic emission spectroscopy. The stability of the catalyst was evaluated using thermogravimetric analysis. The use of recyclable catalyst and glycerol as solvent makes this procedure environmentally benign and economically viable. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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28.
Hélio A. Stefani Amna N. Khan Flávia Manarin Pedro H. Vendramini Marcos N. Eberlin 《Tetrahedron letters》2013
A simple protocol which led to an effective construction of α-alkenyl-α-amino esters was achieved under mild conditions. This transformation proceeded by Yb-catalyzed addition of alkenyltrifluoroborates across the imine double bond. A variety of functional groups could be applicable to both partners. 相似文献
29.
This paper presents the optimized K-means (OKM) algorithm that can homogenously segment an image into regions of interest with the capability of avoiding the dead centre and trapped centre at local minima phenomena. Despite the fact that the previous improvements of the conventional K-means (KM) algorithm could significantly reduce or avoid the former problem, the latter problem could only be avoided by those algorithms, if an appropriate initial value is assigned to all clusters. In this study the modification on the hard membership concept as employed by the conventional KM algorithm is considered. As the process of a pixel is assigned to its associate cluster, if the pixel has equal distance to two or more adjacent cluster centres, the pixel will be assigned to the cluster with null (e. g., no members) or to the cluster with a lower fitness value. The qualitative and quantitative analyses have been performed to investigate the robustness of the proposed algorithm. It is concluded that from the experimental results, the new approach is effective to avoid dead centre and trapped centre at local minima which leads to producing better and more homogenous segmented images. 相似文献
30.
Dr. Mohd Nazish Dr. Mujahuddin M. Siddiqui Dr. Samir Kumar Sarkar Dr. Annika Münch Christina M. Legendre Dr. Regine Herbst-Irmer Prof. Dietmar Stalke Prof. Dr. Herbert W. Roesky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(5):1744-1752
This work describes the synthesis and coordination behavior of a new mixed-donor ligand PhC(NtBu)2SiC6H4PPh2 ( 1 ) containing both silylene and phosphine donor sites. Ligand 1 was synthesized from a reaction of ortho-lithiated diphenylphosphinobenzene (LiC6H4PPh2) with chlorosilylene (PhC(NtBu)2SiCl). Treatment of 1 with Se and GeCl2 resulted in SiIV compounds 2 and 3 by selective oxidation of the silylene donor. This strong σ-donor ligand induces dissociation of CuCl and PhBCl2 leading to formation of ionic complexes 4 and 5 respectively. The reaction of 1 with ZnCl2 and AlCl3 resulted in the formation of chelate complexes 5 and 7 , respectively, while treatment with EtAlCl2 and GaCl3 forms monodentate complexes 8 and 9 . X-ray analysis of 4 showed that the copper is in the spiro center of the two five-membered rings. Moreover, the copper(I)chloride has not been oxidized but dissociates to Cu+ and [CuCl2]−. All the compounds are well characterized by mass spectrometry, elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction studies. 相似文献