Structures of some hexa-1,5-diene-1,1,3,3,4,4,6,6-octacarboxylic esters
作者:C. W. Shoppee、N. W. Hughes
DOI:10.1039/j39710003673
日期:——
The structures of the octamethyl ester, m.p. 139°, and the octaethyl ester, m.p. 86°, obtained by condensation of two molecules of methyl or ethyl sodiodicarboxyglutaconate, as derivatives of hexa-1,5-diene have been proved. The complete lack of normal electrophilic olefinic reactivity shown by these esters cannot be explained by intramolecular cyclisation to isomeric derivatives of bicyclo[2,1,1]hexane
The disintegration of bromhexin tablets was monitored by magnetic resonance imaging. The fast imaging method FLASH with spoiling gradients was used to obtain images of the tablets in short time intervals. The rate of the disintegration depends on the preparation method, kind and percentage of the carrier (polyethylene glycol, lactose). Solid dispersion with slow evaporation of solvent yields materials with decreased dissolution rate, Increasing molecular mass of polyethylene glycol and its percentage content also hampers disintegration.