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Stereogenic atoms Fischer projections

For molecules with two stereogenic centers, the traditional descriptors are erythro and threo to which, henceforth, a c (short for carbohydrate) is added for a reason that will become apparent (Table 10). They are unambiguously defined for simple sugars. The backbone is given by the carbon chain the reference conformation is the conformation with all carbon atoms eclipsed. This statement is identical with the requirement of a Fischer projection. If two identical substituents X are located on the same side/opposite sides of the plane traced by the backbone, then the c-erythrojc-threo configuration is assigned. [Pg.41]

Models with three or more stereogenic centers create new problems. Again, carbohydrate chemists were first to give efficient and clear, though perhaps to the outsider cumbersome solutions. The following carbohydrate convention (see Table 11) is based on the Fischer projection. i.e., it prescribes an all-eclipsed conformation of the backbone and defines the direction of the backbone by the oxidation numbers of the terminal carbon atoms. [Pg.42]

Know the meaning of stereogenic carbon atom, stereogenic center, R-S convention, priority order, E-Z convention, Fischer projection. [Pg.88]

It is time to return to the initial problem posed for 6 and 7 the enantiomers of 2-butanol. Using the steering wheel model, the absolute configuration of each enantiomer of 2-butanol can be determined. Obviously, one is R and the other is S. The two enantiomers in Fischer projection are 6A and 7A and these are also drawn in tetrahedral forms 6B and 7B. Note the use of the shorthand terms Et (for ethyl, -CH2CHg) and Me (for methyl, -CHg). Using the atomic mass priority scheme, ethyl, methyl, hydrogen, and OH are attached to the stereogenic... [Pg.371]

The affiliation with the d- or L-series is determined by the configuration of the highest numbered stereogenic center, the configurational atom. For the customary Fischer projections the following conventions apply HO-pointing to the right = D, to the left = l horizontal bonds are directed towards the viewer while vertical bonds are in the plane or are orientated away from the viewer. [Pg.156]


See other pages where Stereogenic atoms Fischer projections is mentioned: [Pg.238]    [Pg.68]    [Pg.1266]    [Pg.43]    [Pg.44]    [Pg.1037]    [Pg.51]    [Pg.53]    [Pg.54]    [Pg.72]    [Pg.31]    [Pg.33]    [Pg.34]    [Pg.164]    [Pg.361]    [Pg.381]    [Pg.1365]    [Pg.1038]    [Pg.908]    [Pg.909]    [Pg.910]    [Pg.910]   
See also in sourсe #XX -- [ Pg.238 ]




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