نتایج جستجو برای: pyran annulated hetrocyclic systems
تعداد نتایج: 1185076 فیلتر نتایج به سال:
In the title compound, C12H15IO7, the 3,4-di-hydro-2H-pyran ring is in a distorted half-boat conformation with the atom bearing the acet-yloxy group adjacent to the C atom bearing the methyl-acetate group lying 0.633 (6) Å above the plane of the remaining ring atoms (r.m.s. deviation = 0.0907 Å). In the crystal, mol-ecules are linked into a supra-molecular chain along the a axis through two C-H...
[reaction: see text] Aryl coumaryl ethylenes undergo oxidative photocyclization readily to yield helical pyrone-annulated condensed aromatics. The pyrones are conveniently converted to the corresponding photochromic diphenylpyrans/chromenes. Both pyrones and chromenes exhibit helicity-dependent fluorescence efficiency and persistence, respectively.
The requirements for the self-assembly of 2,3-annulated core-substituted NDIs into discrete worm-like nanostructures are explored in MeOH-CHCl(3) solutions. AFM was used to visualize and characterize the structures formed at precise proportions of solvent mixes.
Abstract Inverse electron-demand Diels–Alder additions (iEDDA) between 1,2,4,5-tetrazines and suitable unsaturated dienophiles such as olefins, alkynes, or enol ethers provide facile access to pyridazines. Herein the use of cyclic ether derivatives for preparing pyridazines bearing 2-hydroxyethyl, 3-hyproxypropyl, 3-oxopropyl substituents at 4-position is disclosed second order rate constants r...
A novel acrylate monomer containing 4H-pyran-4-one and 1,2,3-triazole ring, {1-[4-(4-oxo-6-phenyl-4H-pyran-2-yl)benzyl]-1,2,3-triazol-4-yl}methyl acrylate was synthesized by the reaction of 2-{4-[(4-(hydroxymethyl)-1,2,3-triazol-1-yl)methyl]phenyl}-6-phenyl-4H-pyran-4-one with acryloyl chloride in the presence of triethylamine. The structure of the acrylate monomer was established on the basis ...
In the title compound, C(28)H(22)O(6), the chromeno ring system is almost planar, with a dihedral angle between the mean planes of the pyran and benzene rings of 1.87 (8)°. The pyran ring bearing the methyl-phenyl substituent has a half-chair conformation while the other pyran ring has an envelope conformation with the tetra-substituted C atom as the flap. The benzene ring of the chromeno ring ...
The immunomodulator pyran markedly protected 5-week-old mice from lethal intravenous infection with herpes simplex virus type 2. The 50% lethal dose was increased almost 100-fold in pyran-treated mice as compared with controls. Although the protection was not as marked in older mice (10 and 16 weeks old), there was a significant increase in mean survival time. When the pathogenesis of herpesvir...
Mouse resistance to foot-and-mouth disease virus (FMDV) was induced by intraperitoneal injections of pyran copolymer. A biphasic pattern of protection occurred with greatest resistance 4 and 48 hr after injection of this polyanion. Viremia was not detectable in pretreated mice challenge-exposed with FMDV. Incubation of virus with pyran did not alter viral infectivity in mice or tissue culture. ...
ABSTRACT. The aim of present study was the uses a series α,β-unsaturated carbonyl compounds (chalcones), in synthesis pyridine, pyran, thiophene, thiazole, together with their heterocyclic synthesis. work has resulted variety 2,5-dihydropyridine, hydrazide-hydrazone, thiophene derivatives, coumarin, pyran and thiazolo[4,5-d]thiazole derivatives. antitumor activities newly synthesized products w...
The 1,6-annulated 2-pyridone motif is found in many biologically active compounds and its close relation to the indolizidine and quinolizidine alkaloid core makes it an attractive building block. A nickel-catalyzed C-H functionalization of 2-pyridones and subsequent cyclization affords 1,6-annulated 2-pyridones by selective intramolecular olefin hydroarylation. The switch between the exo- and e...
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