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41.
Frontera A Saczewski F Gdaniec M Dziemidowicz-Borys E Kurland A Deyà PM Quiñonero D Garau C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(22):6560-6567
Several structures of pi complexes of isocyanuric acid and of several thio derivatives with anions have been computed by using high level ab initio calculations. The nature of the complexes has been studied by means of the method of molecular interaction potential with polarization (MIPp) and Bader's theory of atoms-in-molecules. These molecules form favorable complexes with anions and can be used as binding units for building receptors for the molecular recognition of anions. In several cases, the anion-pi interaction has been demonstrated experimentally by means of X-ray crystallography. 相似文献
42.
Amber L. H. Gray Aleksandra Antevska Benjamin A. Link Bryan Bogin Susan J. Burke Samuel D. Dupuy J. Jason Collier Zachary A. Levine Michael D. Karlstad Thanh D. Do 《Chemical science》2021,12(16):5853
Despite being relatively benign and not an indicative signature of toxicity, fibril formation and fibrillar structures continue to be key factors in assessing the structure–function relationship in protein aggregation diseases. The inability to capture molecular cross-talk among key players at the tissue level before fibril formation greatly accounts for the missing link toward the development of an efficacious therapeutic intervention for Type II diabetes mellitus (T2DM). We show that human α-calcitonin gene-related peptide (α-CGRP) remodeled amylin fibrillization. Furthermore, while CGRP and/or amylin monomers reduce the secretion of both mouse Ins1 and Ins2 proteins, CGRP oligomers have a reverse effect on Ins1. Genetically reduced Ins2, the orthologous version of human insulin, has been shown to enhance insulin sensitivity and extend the life-span in old female mice. Beyond the mechanistic insights, our data suggest that CGRP regulates insulin secretion and lowers the risk of T2DM. Our result rationalizes how migraine might be protective against T2DM. We envision the new paradigm of CGRP : amylin interactions as a pivotal aspect for T2DM diagnostics and therapeutics. Maintaining a low level of amylin while increasing the level of CGRP could become a viable approach toward T2DM prevention and treatment.CGRP concentration is elevated in migraine conditions. The protective effect of migraine against type 2 diabetes is attributed to the ability of CGRP to remodel human amylin aggregation and to suppress the secretion of mouse insulin 2 (the orthologue of human insulin). 相似文献
43.
The interaction between rhenium(VII) and dithio-oxamide in strongly alkaline medium in presence of tin(II) chloride as reluctant has been studied. A purple complex is obtained, with lambda(max) 526 nm and (max) = 4.0 x 10(3) l.mole(-1).cm(-1). The reaction has been applied to the determination of rhenium in tungsten-rhenium alloy after its anodic electrochemical dissolution in alkaline medium. A 1000-fold excess of molybdenum or tungsten does not interfere. A modification of the proposed method can be used as a spot-test for rapid control of rhenium content in industrial solutions. 相似文献
44.
We generalize data on the reactivity of furyl-, dihydrofuryl-, tetrahydrofuryl-, dihydropyranyl-, and tetrahydropyranylsilanes and -germanes in reactions with nucleophilic reagents. We show that upon reaction of heterosilanes and heterogermanes with O-, N-, C-, and H-nucleophiles, sequential substitution of the heterocycles occurs at the nucleophilic group. We consider the rearrangement of (2-tetrahydrofuryl)- and (2-tetrahydropyranyl) hydrosilanes with ring expansion, and also rearrangement of linear acyloxymethyl- and halomethylhydrosilanes to the corresponding acyloxy- and halosilanes.Dedicated to Professor A. R. Katritsky on the occasion of his 65th birthday.Translated from Khimiya Geterosiklicheskikh Soedinenii, No. 7, pp. 869–878, July, 1993. 相似文献
45.
Victor N. Khrustalev Mikhail Yu. Antipin Irina V. Borisova Valery V. Lunin Ghassoub Rima 《Journal of organometallic chemistry》2004,689(2):478-483
The reaction of equimolar quantities of LiOCH2CH2NMe2 and E14(OCH2CH2NMe2)2 (E14=Ge, Sn) in ether yielded new ate complexes [LiE14(OCH2CH2NMe2)3]2 (E14=Ge (1), Sn (2)) with bidentate ligands. The compounds 1 and 2 are white crystalline substances which are highly soluble in THF and pyridine and very sensitive to the traces of oxygen and moisture. The structures of these compounds are studied by X-ray diffraction analysis. The ate complexes 1 and 2 are powerful nucleophiles and may be employed as ligands (neutral) in the coordination chemistry of the transition metals. The electronegative O-substituents at the divalent E14 atoms render them less oxidizable than alkyl- or aryl-substituted derivatives, and the bidentate ligands, owing to intramolecular donor-acceptor interactions, make them more thermodynamically stable compared to monodentate ligands. 相似文献
46.
A. V. Varlamov T. N. Borisova A. É. Aliev I. A. Stazharova A. A. Sinitsyna E. A. Sakhnova 《Chemistry of Heterocyclic Compounds》1993,29(5):582-587
N-Alkyl substituted tetrahydropyrrolo[3,2-c]pyridines have been obtained by alkylation of 4,5,6,7-tetrahydro-4,-5, 7-trimethylpyrrolo[3,2-c]pyridine and its 2-formyl derivative chloroalkyldimethylamines, acrylonitrile, methyl acetylenedicarboxylate and dichloroethane. 2-Formyl substituted tetrahydropyrrolo[3,2-c]pyridine has been reduced with sodium borohydride and condensed with monoethanolamine and hydroxylamine. The stereochemistry of the products has been studied by 1H NMR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 681–687, May, 1993. 相似文献
47.
48.
Iwona E. Głowacka Dorota G. Piotrowska Andrzej E. Wróblewski Aleksandra Trocha 《Tetrahedron: Asymmetry》2017,28(11):1602-1607
A simple and efficient synthetic strategy to all four enantiomerically pure diethyl 1,2-di(N-Boc-amino)propylphosphonates has been elaborated starting from the corresponding N-[(R)-(1-phenylethyl)]aziridine-(2S)- and N-[(S)-(1-phenylethyl)]aziridine-(2R)-carboxaldehydes, employing a one-pot three-components Kabachnik-Fields reaction followed by the hydrogenolytic removal of the chiral auxiliary and aziridine ring opening with simultaneous protection of the amino groups as the N-Boc derivatives. 相似文献
49.
50.
N. E. Gordina V. Yu. Prokof’ev T. N. Borisova A. M. Elizarova 《Russian Journal of Applied Chemistry》2018,91(2):180-186
Possibility was examined of synthesizing zeolites granulated without a binder with the use of a preliminary ultrasonic treatment of the suspension at a frequency of 22 kHz from mixtures of sodium metasilicate and aluminum and silicon oxides with various Si: Al ratios. It was found that, after the preliminary treatment, extrusion of grains, and calcination at 650°C, crystalline phases Na6Al4Si4O17, Na8Al4Si4O18, Na2Al2O4, and Na2SiO3 phases are formed in the sample with Si: Al = 1. These phases are precursors for synthesis of NaA and NaP zeolites and sodalite via hydrothermal crystallization in a NaOH solution with concentration of 2 M. Upon a similar treatment of a sample with Si: Al = 2, there are crystalline phases α- and β-Na2Si2O5, from which only NaP zeolite is formed in the course of crystallization. The hydrothermal crystallization in a 6 M alkali solution yields sodalite, irrespective of the Si: Al ratio. It was shown that an ultrasonic treatment gives a gel-like system at Si: Al = 1 and a powdered material at Si: Al = 2, which yields by the end of synthesis samples with cactus-like or wool-like morphology, respectively. 相似文献