Results 151 to 160 of about 2,936 (205)
Some of the next articles are maybe not open access.
On the barriers to planarity and the isotope effect in cyclobutane and cyclobutane-d8
Journal of Molecular Spectroscopy, 1975Abstract The infrared and Raman data on the ring-puckering vibration in cyclobutane and cyclobutane-d8 have been reexamined including the coordinate dependence of the reduced mass in the Hamiltonian. This was done for the purpose of estimating the importance of these small terms in the determination of barrier heights for four-membered rings and also
Thomas B. Malloy, Walter J. Lafferty
openaire +1 more source
Cycloreversion of cyclobutanes
Theoretica Chimica Acta, 1980Semiempirical 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
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
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
Rearrangements of Cyclobutanes
ChemInform, 2007AbstractChemInform 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
Detailed Dynamics of the Photodissociation of Cyclobutane
The Journal of Physical Chemistry A, 2007Semiclassical electron-radiation-ion dynamics simulations are reported for the photodissociation of cyclobutane into two molecules of ethylene. The results clearly show the formation of the tetramethylene intermediate diradical, with dissociation completed in approximately 400 fs.
Yusheng, Dou +6 more
openaire +2 more sources
Cyclobutanes from Combretum albopunctatum
Phytochemistry, 2004A 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. +4 more
openaire +4 more sources
The Preparation of Methylene Cyclobutane and Methyl Δ' Cyclobutane
1941No abstract.
openaire +1 more source
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
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
A Cyclobutane possessing Hypotensive Activity
Nature, 1964A 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 +4 more
openaire +2 more sources
A Novel Strategy for Cyclobutane Formation. Fine Tuning of Cyclobutanation vs Cyclopropanation
The Journal of Organic Chemistry, 1998The reactions of (E)-1-(phenylseleno)-2-(trimethylsilyl)ethene (1a) and (E)-1-(phenylseleno)-2-(triethylsilyl)ethene (1b) with dimethyl 1,1-dicyanoethene-2,2-dicarboxylate (2) in the presence of SnCl4 in CH2Cl2 at −78 °C for 1 h exclusively afforded [2 + 2] cycloadducts 3a and 3b in 71% and 78% yields, respectively. The exclusive [2 + 2] selectivity in
Shoko Yamazaki +3 more
openaire +1 more source