organic chemistry, review organic chemistry, review Z 0200 17 -282 Chemical Structure and Antibacterial Activity of 4-Quinolones: Incidence in Nature, Preparations and Properties -[205 refs.]. -(MILATA, V.; CLARAMUNT, R. M.; ELGUERO, J.; ZALUPSKY, P.; Targets
The regiocontrol of palladium(II)-catalysed oxycarbonylation of pentenetriols was studied for its potential exploitation in the carbonylation methodology for construction of tetrahydrofuran derivatives with defined stereochemistry. Synthesis of model substrates, the partially protected pentenetriols with diverse protecting groups was carried out starting from D-mannitol. The availability of the protecting group for carbonylation was tested, from the chemo-, regio-, and stereoselectivity point of view. It was found that course as well as stereochemistry of the process may be controlled by β-OH with silyl protected O-function in the α-position.
Site-selectivity of dipolar cycloaddition to the title compound was studied. Azomethine X afforded a 1 : 1 cycloadduct XI at the deactivated double bond at room temperature; upon thermolysis at 110 °C it afforded the acetylated enamine XIII which was formed via a direct cycloaddition at the mentioned temperature. The cycloaddition course was investigated in various solvents; the enamine XIV formed by solvolysis of XIII was the final product in methanol. Cycloaddition of the title compound to azides, benzoylnitrile N-oxide and C-acetyl-N-phenylnitrilimine furnished the product of cycloreversion instead of the not isolable 1 : 1 cycloadducts. 5-Azido-2-furancarbaldehyde and 4-nitrophenylazide yielded cycloaddition products to both multiple bonds in an approximately 1 : 1 ratio; NH3, tosylazide, benzoylnitrile N-oxide and C-acetyl-N-phenylnitrilimine gave the addition products to the deactivated double bond. The solvent-effect of site-selectivity of 1,3-dipolar cycloaddition was investigated and the title compound was found to be an excellent synthetic equivalent for acetylene and dimethyl butinedioate.
System. -A new route towards 1,4:2,5-dianhydroalditols by Pd 2+ -catalyzed bicyclization of sugar-derived alkenitols is developed. The reaction requires an all-syn configuration of the vinylic stereotriad. -(BABJAK, M.; REMEN, L.; SZOLCSANYI, P.; ZALUPSKY, P.; MIKLOS, D.; GRACZA*, T.; J. Organomet. Chem. 691 (2006) 5, 928-940; Dep. Org. Chem., Slovak Univ. Technol., SK-812 37 Bratislava, Slovakia; Eng.) -Nuesgen 25-163
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