cis-trans isomerism

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cis-trans isomerism

[′si¦stranz ī′säm·ə‚riz·əm]
(organic chemistry)
A type of geometrical isomerism found in alkenic systems in which it is possible for each of the doubly bonded carbons to carry two different atoms or groups; two similar atoms or groups may be on the same side (cis) or on opposite sides (trans) of a plane bisecting the alkenic carbons and perpendicular to the plane of the alkenic system.
References in periodicals archive ?
The predominance of cis-isomers bioaccumulation was widely observed in all species, with R cis/trans varying between 0.60 and 29.7.
Previously, cis-isomers of phenylpropanoid derivatives were understood to exist in minor quantities and, as such, were thought to be biologically insignificant [3].
anticipated three possible cis-isomers for all five of the diCQA positional isomers.
Insight on the chromatographic elution order of these metabolites (both transand cis-isomers) will contribute to ongoing efforts in designing analytical methods for differential identification of isomers contributing to plant sample dimensionality.
A summary of the chromatographic results is represented in Table 1, where the void volume/"dead time" was assessed for each column by the inspection of the chromatograms, and the resulting capacity factors (k) for the trans- and cis-isomers are shown.
softening of cell walls, associated with lycopene's bio-accessibility by production of lycopene in tomato tissues more manageable, and by altering some of the trans-isomers of lycopene to cis-isomers may be necessary.
The test was non-significant for trans-WL for all three varieties and very significant for cis-isomers. The boxplots are presented in Figure 2 for cis-whisky-lactone for all three varieties.
For example, the transisomers of linoleic acid (C18:2, 9t, 12t; C18:2, 9c, 12t) were eluted prior to the cis-isomers of linoleic acid (C18:2, 9c, 12c).
Total [beta]-carotene concentration and the concentration of some [beta]-carotene cis-isomers were measured spectrophotometrically and by high-performance liquid chromatography, respectively.
Similar to the notched IZOD impact strength, there is a gradual increasing trend in the tensile strength with increasing the content of cis-isomers of rubber type.
Concerning the stereoselectivity of glucuronidation, cis-isomers were glucuronidated faster than trans-isomers (15).
As in the case of cis-stilbene and cis-stilbene oxide, the activities of the cis-isomers were much lower than those of the trans-compounds (Sugihara et al.