Search results
Results from the WOW.Com Content Network
An example of such an enantiomer is the sedative thalidomide, which was sold in a number of countries around the world from 1957 until 1961. It was withdrawn from the market when it was found to cause birth defects. One enantiomer caused the desirable sedative effects, while the other, unavoidably [23] present in equal quantities, caused birth ...
That is, on reflecting the meso compound through a mirror plane perpendicular to the screen, the same stereochemistry is obtained; this is not the case for the non-meso tartaric acid, [3] which generates the other enantiomer. The meso compound must not be confused with a 50:50 racemic mixture of the two optically-active compounds, although ...
These include meso compounds, cis–trans isomers, E-Z isomers, and non-enantiomeric optical isomers. Diastereomers seldom have the same physical properties. In the example shown below, the meso form of tartaric acid forms a diastereomeric pair with both levo- and dextro-tartaric acids, which form an enantiomeric pair.
The two enantiomers can be distinguished, for example, by the right-hand rule. This type of isomerism is called axial isomerism. Enantiomers behave identically in chemical reactions, except when reacted with chiral compounds or in the presence of chiral catalysts, such as most enzymes. For this latter reason, the two enantiomers of most chiral ...
An enantiomeric pair (S,S)- and (R,R)-ethambutol, along with the achiral stereoisomer called meso-form, it holds a diastereomeric relationship with the optically active stereoisomers. The activity of the drug resides in the (S,S)-enantiomer which is 500 and 12 fold more potent than the (R,R)-ethambutol and the meso-form. The drug had initially ...
Two enantiomers of a generic amino acid at the stereocenter. In stereochemistry, a stereocenter of a molecule is an atom (center), axis or plane that is the focus of stereoisomerism; that is, when having at least three different groups bound to the stereocenter, interchanging any two different groups creates a new stereoisomer.
Enantioselective synthesis, also called asymmetric synthesis, [1] is a form of chemical synthesis.It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts."
The stereochemical term enantiotopic refers to the relationship between two groups in a molecule which, if one or the other were replaced, would generate a chiral compound. The two possible compounds resulting from that replacement would be enantiomers. For example, the two hydrogen atoms attached to the second carbon in butane are