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  2. Absolute configuration - Wikipedia

    en.wikipedia.org/wiki/Absolute_configuration

    Examples of absolute configuration of some carbohydrates and amino acids according to Fischer projection (D/L system) and Cahn–Ingold–Prelog priority rules (R/S system) The R/S system is an important nomenclature system for denoting enantiomers. This approach labels each chiral center R or S according to a system by which its substituents ...

  3. Cahn–Ingold–Prelog priority rules - Wikipedia

    en.wikipedia.org/wiki/Cahn–Ingold–Prelog...

    More generally, for any pair of enantiomers, all of the descriptors are opposite: (R,R) and (S,S) are enantiomers, as are (R,S) and (S,R). Diastereomers have at least one descriptor in common; for example (R,S) and (R,R) are diastereomers, as are (S,R) and (S,S). This holds true also for compounds having more than two stereocenters: if two ...

  4. Nomenclature codes - Wikipedia

    en.wikipedia.org/wiki/Nomenclature_codes

    In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages.

  5. Enantiomer - Wikipedia

    en.wikipedia.org/wiki/Enantiomer

    There are three common naming conventions for specifying one of the two enantiomers (the absolute configuration) of a given chiral molecule: the R/S system is based on the geometry of the molecule; the (+)- and (−)- system (also written using the obsolete equivalents d- and l-) is based on its optical rotation properties; and the D/L system is based on the molecule's relationship to ...

  6. Atropisomer - Wikipedia

    en.wikipedia.org/wiki/Atropisomer

    Alternately, all four groups can be ranked by Cahn–Ingold–Prelog priority rules, with overall priority given to the two groups on the "front" atom of the Newman projection. The two configurations determined in this way are termed R a and S a, in analogy to the traditional R/S for a traditional tetrahedral stereocenter. [12]

  7. E–Z notation - Wikipedia

    en.wikipedia.org/wiki/E–Z_notation

    E–Z configuration, or the E–Z convention, is the IUPAC preferred method of describing the absolute stereochemistry of double bonds in organic chemistry.It is an extension of cis–trans isomer notation (which only describes relative stereochemistry) that can be used to describe double bonds having two, three or four substituents.

  8. Descriptor (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Descriptor_(Chemistry)

    If one molecule contains several stereocenters, a locant must be placed before the descriptor (for example, in (1R, 2S)-2-amino-1-phenylpropan-1-ol, the systematic designation of norephedrine). If all stereocenters are configured the same, the naming of the locants can be omitted in favor of an "all-R" or "(all-S)" spelling.

  9. IUPAC nomenclature of organic chemistry - Wikipedia

    en.wikipedia.org/wiki/IUPAC_nomenclature_of...

    Identification of the ring or chain with the most senior elements (In order: N, P, Si, B, O, S, C). Identification of the parent compound. Rings are senior to chains if composed of the same elements. For cyclic systems: Identification of the parent cyclic ring. The cyclic system must obey these rules, in order of precedence: