نتایج جستجو برای: pyran annulated hetrocyclic systems
تعداد نتایج: 1185076 فیلتر نتایج به سال:
The title compound, C(14)H(11)ClN(2)O(3)S, with fused thiophene and pyran rings, was synthesized via the condensation of dihydro-thio-phen-3(2H)-one 1,1-dioxide and 2-(3-chloro-benz-yl-idene)malononitrile catalysed by triethyl-amine in ethanol. The thio-phene ring adopts an envelope conformation and the pyran ring is planar (r.m.s. deviation = 0.0067 Å). The dihedral angle between the pyran and...
While the exploitation of the Sharpless asymmetric dihydroxylation as the source of chirality in the synthesis of acyclic molecules and saturated heterocycles has been tremendous, its synthetic utility toward chiral benzo-annulated heterocycles is relatively limited. Thus, in the search for wider applications of Sharpless asymmetric dihydroxylation-derived diols for the synthesis of benzo-annul...
Two novel acrylate monomers, [5-(benzyloxy)-4-oxo-4H-pyran-2-yl]methyl acrylate and {1-[(5-(benzyloxy)-4-oxo-4H-pyran-2-yl)methyl]-1,2,3-triazol-4-yl}methyl acrylate were synthesized by the reaction of 5-benzyloxy-2-(hydroxymethyl)-4H-pyran-4-one and 5-(benzyloxy)-2-{[4-(hydroxymethyl)-1,2,3-triazol-1-yl]methyl}-4H-pyran-4-one with acryloyl chloride in the presence of triethylamine, respectivel...
Benzo-, furo-, thieno-, and pyrido[f]coumarins were prepared by generating the 2H-pyran-2-one moieties from the oxidation of the corresponding 2H-pyran rings, which were formed in situ from the electrocyclization of cis-dienals.
The pyran-oside ring in the title compound, C(21)H(24)O(11), has a chair conformation with the substituted benzene ring occupying an equatorial position. The crystal packing is dominated by C-H⋯O inter-actions that lead to the formation of supra-molecular layers in the ab plane.
Tthe structure of the title compound, C(15)H(24)O(5), has been redetermined at 103 (2) K, with much improved precision. The title compound was first reported by Luo, Yeh, Brossi, Flippen-Anderson & Gillardi [Helv. Chim. Acta (1984). 67, 1515-1522]. It is a derivative of the anti-malaria compound artemisinin and consists primarily of three substituted ring systems fused together. A cyclo-hexane ...
A series of dibenzannulated phenyl-annulated [4,2] peri -acenoacenes have been synthesized in three straightforward steps from 4,10-dibromoanthanthrone (vat orange 3).
In the structure of the title compound, C12H12O3, the di-hydro-pyran ring is fused with the benzene ring. The di-hydro-pyran ring is in a half-chair conformation, with the ring O and methyl-ene C atoms positioned 1.367 (3) and 1.504 (4) Å, respectively, on either side of the mean plane formed by the other four atoms. The meth-oxy group is coplanar with the benzene ring to which it is connected ...
3-Acyl-5-( 1 -am inoalkylidene)-4-hydroxy-2 Hpyran-2,6(3 //)-d ione derivatives carrying lipophilic am ino groups were found to be highly potent inhibitors o f photosynthetic electron transport, and bo th the acyl and the am inoalkylidene groups on the pyran ring appeared to be indispensable for high activity. The structural features needed for activity in the 3-acyl-5(l-am inoalkylidene)-4-hyd...
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