A new directconversion of O,O-acetals to esters via O,P-acetal intermediates was developed. The regioselective cleavage of unsymmetrical cyclic acetals occurred to give the more crowded esters as single isomers.
Oxidative transformation of 1,3-dioxacycloalkanes induced by chlorine dioxide
作者:A. R. Abdrakhmanova、N. N. Kabal’nova、L. Z. Rol’nik、G. G. Yagafarova、V. V. Shereshovets
DOI:10.1007/s11172-005-0030-0
日期:2004.8
The products and kinetic regularities of the reactions of 1,3-dioxacycloalkanes with chlorine dioxide were studied. The effects of the nature of solvent and the temperature on the reaction rate were considered and the activation parameters were determined.
Effect of the rigidification of propranolol, a mixed β-adrenoceptor and 5-HT1AR antagonist
作者:Franchini、Sorbi、Linciano、Brasili、Tait
DOI:10.1691/ph.2019.8878
日期:——
Propranolol is a popular β adrenergic antagonists that, together with pindolol, binds also to serotoninergic receptors, namely 5-HT1A/B. In this work the rigidification of the propranolol structure by locking its hydroxyl group within a 1,3-dioxolane ring was investigated. Constrained derivatives of propranolol were synthesized, fully characterized and tested for their affinity at β-adrenoreceptors and 5-HT1A/B/C receptors using radioligand binding assay. The constrained derivatives were inactive, as expected, at β1/2/3 adrenergic receptors. Although less expected, these derivatives failed to bind also to 5-HT1A/B/C receptors. The rigidification of propranolol is detrimental for 5-HT1AR activity.
<i>N</i>-Benzyl Pyridinium Salts as New Useful Catalysts for Transformation of Epoxides to Cyclic Acetals, Orthoesters, and Orthocarbonates
作者:Sang-Bong Lee、Toshikazu Takata、Takeshi Endo
DOI:10.1246/cl.1990.2019
日期:1990.11
In the presence of catalytic amount of N-(4-methoxybenzyl)-2-cyanopyridinium hexafluoroantimonate, the reaction of a few epoxides with aldehydes, ketones, lactones, and carbonates efficiently afforded corresponding cyclic acetals, orthoesters, and Orthocarbonates under mild conditions.
The present invention relates to a novel method for preparing methylene-1,3-dioxolanes of the general formula (1)
in which R
1
and R
2
have the meanings stated in the description. Methylene-1,3-dioxolanes are important intermediates for preparing pyrazoles and anthranilic acid amides, which may be used as insecticides.