Results 191 to 200 of about 22,823 (226)

Cyclobutanes from Combretum albopunctatum

Phytochemistry, 2004
A dichloromethane extract of the aerial parts of Combretum albopunctatum Suesseng afforded five phenolic compounds-three known flavonoids and two novel cyclobutane chalcone dimers. The chemical structures were determined by standard spectroscopic techniques and the structure and relative stereochemistry of one chalcone dimer, rel-(1 alpha,2 beta)-di-(2,
Katerere, D.R., Gray, A.I., Kennedy, A.R., Nash, R.J., Waigh, R.D.   +4 more
openaire   +3 more sources

Infrared and Raman spectra of cyclobutane and cyclobutane-d8

Spectrochimica Acta Part A: Molecular Spectroscopy, 1972
Abstract New i.r. and Raman measurements are reported for cyclo butane and cyclo butane- d 8 . They include i.r. spectra on the gas at room temperature and on the solid at about 100°K. Raman spectra have been measured for the gas and liquid at room temperature and for the solid at 113°K. These data allow the assignments (for D 2d ) to be put on
Foil A. Miller, Robert J. Capwell, R.C. Lord, Donald G. Rea   +3 more
openaire   +1 more source

Cycloreversion of cyclobutanes

Theoretica Chimica Acta, 1980
Semiempirical MO calculations with the method SINDO1 were performed to study the potential energy surface of cyclobutane and several substituted cyclobutanes with substituents F, OCH3 and CN. The reaction pathway with the lowest activation energy leading to two ethylenic fragments is nonconcerted.
Karl Jug, Peter L. Müller
openaire   +1 more source

Nonplanar cyclobutane—II

Tetrahedron, 1967
Abstract NMR spectra and basic equilibration of cis and trans methyl-3-isopropylcyclobutanecarboxylate are reported. Treatment of the nonplanar cyclobutane system by analogy with cyclohexane is potentially possible, but limited by (1) greater dependence of ring puckering on substituents; and (2) intervention of planar conformers.
I. Lillien, R.A. Doughty
openaire   +1 more source

Bioactive cyclobutane-containing alkaloids

Journal of Natural Medicines, 2007
The present review describes research on novel natural cyclobutane-containing alkaloids and synthetic compounds isolated from terrestrial and marine species. More than 210 compounds have been confirmed to show antimicrobial, antibacterial, anticancer, and other activities.
openaire   +2 more sources

Conformations of cyclobutane

Tetrahedron, 1974
Abstract The literature concerning the structures of compounds containing saturated, 4-carbon rings is reviewed critically, and the variety of conformations (dihedral angles of 0° to 30° ± 6°) of the cyclobutane ring are tabulated and discussed.
F.Albert Cotton, Bertram A. Frenz
openaire   +1 more source

Cyclobutan‐tetracarbonsäuren‐(1.2.3.4)

Chemische Berichte, 1960
AbstractDurch Ozonabbau von Truxillsäuren konnten 3 der 4 möglichen Cyclobutantetracarbonsäuren‐(1.2.3.4) hergestellt werden.
Rudolf Criegee, Hermann Höver
openaire   +1 more source

Synthesis of Cyclobutanes

ChemInform, 2007
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
openaire   +1 more source

The Preparation of Methylene Cyclobutane and Methyl Δ' Cyclobutane

1941
No abstract.
openaire   +1 more source

A Cyclobutane possessing Hypotensive Activity

Nature, 1964
A NUMBER of non-quaternary bases have been found to possess ganglionic blocking and hypotensive properties1–5. In investigating the pharmacological properties of a new series of cyclobutanes6, one of them, 3-dimethylamino-2,2,4,4-tetramethyl-cyclobutanol, was found to exhibit a lowering activity of the blood pressure of long duration.
A W, PIRCIO, A, WILSON, S, KUNA, R H, HASEK, J C, MARTIN   +4 more
openaire   +2 more sources