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991.
Jozef Saloň Viktor Milata Nadežda Prónayová Ján Leško 《Monatshefte für Chemie / Chemical Monthly》2000,131(3):293-299
Summary. Reaction of 5-aminoquinoxaline with alkoxymethylene derivatives affords the corresponding quinoxalinoaminoethylenes. These
undergo a thermal cyclization to yield angularly annelated 10H-pyrido[2,3-f]quinoxalines. The structures of all products were deduced from their IR, UV, mass, 1H, and 13C NMR spectra.
Received September 24, 1999. Accepted November 18, 1999 相似文献
992.
Viktor Kettmann Jan Svtlík 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):o419-o421
The reaction between 4‐(4‐methylphenyl)but‐3‐en‐2‐one and aminoguanidine produced an unexpected product of formula C12H15N3O, consisting of a carboxamide moiety joined to a substituted pyrazoline ring at one of the N atoms. The pyrazoline ring adopts a flat‐envelope conformation and the substituted phenyl ring is oriented almost perpendicular to the heterocycle. The carbonyl O atom has partial anionic character as a result of the transfer of π density from the two adjacent sp2 N atoms and is involved in an intermolecular hydrogen bond with the amide group. 相似文献
993.
Lidiya Z. Rogovina Viktor G. Vasilev Vladimir S. Papkov Olga I. Shchegolikhina Grigorii L. Slonimskii Alexandr A. Zhdanov 《Macromolecular Symposia》1995,93(1):135-142
An unusual effect of physical network formation during heating or at room temperature alter previous heating was found for originally liquid poly(dimethylcarbosiloxane) containing 0.5 – 2.5 mol% of side carboxyl groups by means of the measurement of its Theological properties. The reason for this behaviour is supposed to be the predominance of intramolecular hydrogen bonding of COOH groups in original polymer and the intra– to Intermolecular bonds rearrangement during heating. The alternative reason can be the microphase separation with domains of COOH groups. The reversibility of the network is confirmed by the decrease in the elasticity modulus, development of irreversible deformation on further heating and by break-up of Junctions on the addition of small amounts of polar liquids. 相似文献
994.
Zsfia Gardi Mikls Dkny gnes M. Mricz Anik Gal Viktor Papp Szabolcs Bni Attila Vnyols 《Molecules (Basel, Switzerland)》2021,26(18)
Inonotus nidus-pici is a sterile conk which produces macrofungus, a neglected Central-Eastern European relative of the prized Inonotus obliquus, also known as chaga. Investigation of the methanol extract of the poroid fungus I. nidus-pici resulted in the isolation of citropremide (1), 3,4-dihydroxybenzalacetone (2) , lanosterol (3), ergost-6,8,22-trien-3β-ol (4), and ergosterol peroxide (5). The structures of fungal compounds were determined on the basis of one- and two-dimensional NMR and MS spectroscopic analysis. Compounds 1–2 and 4–5 were evaluated for their antioxidant and antimicrobial properties against several bacterial and fungal strains. 3,4-dihydroxybenzalacetone (2) and ergost-6,8,22-trien-3β-ol (4) demonstrated moderate antimicrobial activity, while the former possessed notable antioxidant activity in DPPH assay. The antiproliferative examinations performed on three human cancer (MES-SA, MES-SA/Dx5, A431) cell lines demonstrated that compounds 4 and 5 have notable cytotoxic activity with IC values in micromolar range. The current study represents the first report on the chemical profile of I. nidus-pici, providing a comprehensive study on the isolation and structure determination of bioactive secondary metabolites of this macrofungus. 相似文献
995.
Michael T. Shea Gregory T. Rohde Yulia A. Vlasenko Pavel S. Postnikov Mekhman S. Yusubov Viktor V. Zhdankin Akio Saito Akira Yoshimura 《Molecules (Basel, Switzerland)》2021,26(23)
Hypervalent iodine heterocycles represent one of the important classes of hypervalent iodine reagents with many applications in organic synthesis. This paper reports a simple and convenient synthesis of benziodazolones by the reaction of readily available iodobenzamides with m-chloroperoxybenzoic acid in acetonitrile at room temperature. The structure of one of these new iodine heterocycles was confirmed by X-ray analysis. In combination with PPh3 and pyridine, these benziodazolones can smoothly react with alcohols or amines to produce the corresponding esters or amides of 3-chlorobenzoic acid, respectively. It was found that the novel benziodazolone reagent reacts more efficiently than the analogous benziodoxolone reagent in this esterification. 相似文献
996.
997.
Beneš Viktor Večeřa Jakub Pultar Milan 《Methodology and Computing in Applied Probability》2019,21(3):683-698
Methodology and Computing in Applied Probability - The paper deals with planar segment processes given by a density with respect to the Poisson process. Parametric models involve reference... 相似文献
998.
Dr. Viktor Barát Maja Budanovic Si Man Tam Dr. June Huh Dr. Richard D. Webster Dr. Mihaiela C. Stuparu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(15):3231-3235
It is shown in this work that high electron affinity can be combined with high solubility and practical accessibility in corannulene-based electron acceptors. The electron affinity originates from the presence of three different types of electron-withdrawing groups (imide, sulfone, and trifluoromethyl) on the aromatic scaffold. The imide substituent further hosts a long alkyl chain (C18H37) to boast solubility in a wide range of organic solvents. The synthesis is modular and consists of three simple steps from a commonly available corannulene derivative with an overall isolated yield of 22–27 %. 相似文献
999.
1000.