Palladium-Catalyzed Cascade Cyclization/Alkylation of Oxime Ethers: Assembly of 4-Alkylisoxazoles by "Chain-Walking" Strategy.

A reliable and efficient palladium-catalyzed cascade cyclization/alkylation of oxime ethers with unactivated alkenes is described, affording a whole variety of structurally diverse isoxazole derivatives in moderate to good yields with excellent functional group compatibility. Ionic liquid [Aeim]Br not only acts as an environmentally friendly solvent but also acts as an accelerating agent to provide excess bromine source to eliminate bromomethane from oxime ethers. More importantly, the use of "chain-walking" strategy provides a novel methodology in organic synthesis to rapid generation of molecular complexity from readily available starting materials.

Pseudo-cyclic face-to-face rigid structure caused by the intramolecular ion pair effect.

Six 3-methylpyridine zwitterions and six quinoline zwitterions were synthesized through the reaction of 4-hydroxycoumarins, p-benzoquinone and the corresponding N-aromatics. The novel pseudo-cyclic face-to-face rigid structure of the zwitterion was elucidated by (1)H-NMR at different temperatures, and assumed to be caused by both the intramolecular ion pair attraction and the steric interaction.

[Assessment of left ventricular systolic and diastolic function by Doppler tissue imaging in patients with chronic heart failure].

Objective: To investigate the application of pulsed-wave Doppler tissue imaging ( PW-DTI) in evaluating left ventricular systolic and diastolic function in patients with chronic heart failure (CHF).

Methods: Mitral annular velocities (MAV) were measured by PW-DTI in 35 patients with CHF and 25 healthy subjects. Traditional indices for evaluating the global left ventricular function by conventional echocardiography were also studied as a comparison.

Synthesis of zwitterionic 4-hydroxycoumarin derivatives through a unique reaction of 4-hydroxycoumarins with p- benzoquinone and pyridine.

[reaction: see text] A unique reaction of 4-hydroxycoumarins with p-benzoquinone and pyridine was found, and through the reaction, six zwitterionic 4-hydroxycoumarin derivatives were synthesized. The structures of these compounds were determined by IR, MS(ESI), 1H NMR, 13C NMR, and single-crystal X-ray diffraction studies.