نتایج جستجو برای: pyran
تعداد نتایج: 1454 فیلتر نتایج به سال:
In the title compound, C(22)H(21)N, the pyridine ring adopts a distorted boat conformation, while the adjacent pyran ring adopts a chair conformation; the heterocyclic rings make a dihedral angle of 40.1 (2)° with each other.
The subfamily Gonyleptinae is the second largest in Gonyleptidae, harboring over 100 species. polyphyletic, nestled clade K92, and despite its richness, several species of that have not had their chemicals defensive secretions analyzed. Among these are Gonyleptes curticornis (Mello-Leitão, 1940) G. horridus Kirby, 1819, latter being particularly important, because it type genus, which turn name...
We designed a ceria-vanadia/silica (Ce-V/SiO2) heterogeneous catalyst and used it for the green and efficient synthesis of 2-amino-3-cyano-4H-pyran derivatives. The green reaction was a multicomponent one-pot condensation of 5,5-dimethylcyclohexane-1,3-dione, aromatic aldehyde, and malononitrile in an eco-compatible solvent (ethanol). The catalyst was synthesized and fully characterized by powd...
In the title compound, C16H15BrN2O4, the six-membered carbocyclic ring of the chromene moiety adopts an envelope conformation with the disordered methyl-ene C atom as the flap. The pyran ring is almost orthogonal to the chloro-phenyl ring, making a dihedral angle of 87.11 (12)°. The amine-group N atom deviates significantly from the pyran ring [0.238 (3) Å]. The mol-ecular structure is stabiliz...
The title compound, C21H14O3, crystallizes with eight independent mol-ecules (A-H) in the asymmetric unit which are arranged in four groups of two mol-ecules each (AB, CD, EF and GH). In each mol-ecule, the pyran-2-one ring is planar (r.m.s. deviations vary from 0.001 to 0.017 Å), while the pyran ring has a screw-boat conformation. In the crystal, mol-ecules stack in two columns, along the [10-...
The title compound, C(36)H(31)N(2)O(3) (+),C(2)H(3)O(2) (-)·2C(2)H(5)OH, the product of a domino condensation of dibenzyl ketone with salicylic aldehyde and ammonium acetate, crystallized as the ethanol disolvate. The cation of the salt comprises a fused tricyclic system containing three six-membered rings (piperidine, dihydro-2H-pyran and benzene). The piperidine ring has the usual chair confo...
An enantioselective, convergent total synthesis of the antiviral marine natural product (-)-hennoxazole A is completed in 14 steps (longest linear sequence) from commercially available 4-methyloxazole-2-carboxylic acid. Synthesis of the C(1)-C(15) pyran/bisoxazole fragment takes advantage of an aldol-like coupling between a dimethyl acetal and an N-acetylthiazolidinethione for the direct, stere...
The title compound, C16H15ClN2O4, contains a chiral centre and crystallizes as a racemate. The methyl-ene group β-positioned to the carbonyl group is partially (21%) disordered. It flips to the opposite sides of the corresponding six-membered carbocycle by -0.304 (3) and 0.197 (11) Å, producing alternative envelope conformations. The planes of the pyran and chloro-phenyl rings form a dihedral a...
The 4H-pyran ring of the title compound, C(17)H(16)N(2)O(2), is nearly planar [maximum deviation = 0.077 (2) Å] and the cyclo-hexene ring adopts a flattened chair conformation [puckering parameters: Q(T) = 0.435 (2) Å, θ = 122.0 (3)° and ϕ = 53.5 (3)°]. The 4H-pyran ring is almost perpendicular to the benzene ring [dihedral angle = 87.23 (8)°] and is almost coplanar with the mean plane of the c...
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