Eighteen novel 5-phenyl-3-(substitutedthioxoquinazolinonyl) isoxazoles (5a-r) were synthesized by cycloaddition of various chalcones with hydroxylaminehydrochloride (NH2OH.HCl). All the newly synthesized compounds were confirmed by their spectral and analytical data. They were evaluated for antimicrobial, antihelminthic, analgesic and anti-inflammatory activities with an objective to evaluate t...

Treatment of oximes with hypervalent iodine leads to substituted isoxazoles via rapid formation of nitrile oxides. Reaction with terminal alkynes led to a series of 3,5-disubstituted isoxazoles with complete regioselectivity and high yield, in a procedure mild enough to prepare a range of nucleoside and peptide conjugates. Exceptionally high reaction rates were found for the formation of 3,4,5-...

Cubic, octahedral, and rhombic dodecahedral Cu2O nanocrystals bound by respectively {100}, {111}, and {110} facets were successfully employed to catalyze the [3 + 2] cycloaddition reaction for the regioselective synthesis of 3,5-disubstituted isoxazoles. Surfactant-free nanocrystals having the same total surface area were used for the catalysis. Strongly facet-dependent organocatalytic activity...

Several 3,5-disubstituted isoxazoles were obtained in good yields by regiospecific 1,3-dipolar cycloaddition reactions between aromatic nitrile oxides, generated in situ from the corresponding hydroxyimidoyl chlorides, with non-symmetrical activated alkynes in the presence of catalytic amounts of copper(I) iodide. Effects of 3,5-disubstituted isoxazoles on nitric oxide and reactive oxygen speci...

Herein we report an oxyboration reaction with activated substrates that employs B-O σ bond additions to C-C π bonds to form borylated isoxazoles, which are potential building blocks for drug discovery. Although this reaction can be effectively catalyzed by gold, it is the first example of uncatalyzed oxyboration of C-C π bonds by B-O σ bonds--and only the second example that is catalyzed. This ...

Galactosides and lactosides bearing triazoles or isoxazoles, regiospecifically prepared by [1,3]-dipolar cycloadditions between alkynes, azides or nitrile oxides, provided specific galectin-1 and -3 inhibitors with potencies as low as 20 microM.

The first photocycloadditions of aromatic and aliphatic aldehydes to methylated isoxazoles are reported. The reactions lead solely to the exo-adducts with high regio- and diastereoselectivities. Ring methylation of the isoxazole substrates is crucial for high conversions and product stability. The 6-arylated bicyclic oxetanes 9a-9c were characterized by X-ray structure analyses and showed the h...

Bicyclic isoxazolines and isoxazoles are obtained in good yields by proceeding through a convenient one-pot, two-step procedure utilizing 2,4,6-trichloro-1,3,5-triazine (TCT) as a dehydrating agent.

A first example of organo-N-heterocyclic carbene (NHC) catalyzed click-type fast 1,3-dipolar cycloaddition of nitrile oxides with alkynes was developed for the regioselective synthesis of 3,5-di- and 3,4,5-trisubstituted isoxazoles. Triethylamine (Et(3)N) was employed as an effective base to generate both nitrile oxide and the organo-NHC catalyst in situ. This catalytic approach was used to att...

In the title compound, C(30)H(31)NO(3), the tolyl ring is almost coplanar with the isoxazole ring [dihedral angle = 12.51 (7)°], whereas the meth-oxy-phenyl ring is almost perpendicular to the isoxazole ring [dihedral angle = 89.77 (5)°]. In the crystal, mol-ecules are connected through C-H⋯O hydrogen bonds, forming chains running along the a axis.