Hashed-wedged line structures

Convert the following condensed formulas into hashed-wedged line structures. 

Draw zigzag hashed-wedged line structures for 2-methylbutane and 2,3-dimethylbutane. 

Figure 2-4 Hashed-wedged line structures of methane through pentane. Note the zigzag arrangement of the principal chain and two terminal hydrogens.

We can use hashed-wedged line structures to depict the three-dimensional arrangement of substituted cycloalkanes. The positions of any remaining hydrogens are not always shown. 

A Fischer (Real Life 5-2) projection is a simphfied way of depicting tetrahedral carbon atoms and their substituents in two dimensions. With this method, the molecule is drawn in the form of a cross, the central carbon being at the point of intersection. The horizontal lines signify bonds directed toward the viewer the vertical lines are pointing away. Hashed-wedged line structures have to be arranged in this way to facilitate their conversion into Fischer projections. 

Conversion of the Hashed-Wedged Line Structures of 2-Bromobutane into Fischer Projections (of the Stereocenter)... 

Conversion of Hashed-Wedged Line Structures into Fischer Projections... 

Draw the hashed-wedged line structures corresponding to Fischer projections A and B, above. Is it possible to transform A into B by means of a rotation about a single bond If so, identify the bond and the degree of rotation required. Use models if necessary. 

A compound that contains two (or, as we shall see, even more than two) stereocenters but is superimposable with its mirror image is a meso compound (mesos, Greek, middle). A characteristic feature of a meso compound is the presence of an internal mirror plane, which divides the molecule such that one half is the mirror image of the other half. For example, in 2,3-dibromobutane, the 2R center is the reflection of the 35 center. This arrangement is best seen in an eclipsed hashed-wedged line structure (Figure 5-11). The presence... 

Fischer Projection and Hashed-Wedged Line Structures for D-(-l-)-Glucose... 

A molecular model can help you see that the aU-ecUpsed form actually possesses a roughly circular shape, as illustrated by the scrolled rendition above (center picture). In the subsequent all-eclipsed hashed-wedged line structure, notice that the groups on the right of the carbon chain in the original Fischer projection now project upward (wedged bonds). From this conformer, we can reach the aU-staggered form by 180° rotations of C3 and C5. 

Amino acids may be depicted by either hashed-wedged line structures or by Fischer projections. 

Draw hashed-wedged line structures for (5)-alanine, (5)-phenylalanine, (i )-phenylalanine, and (5)-proline. 

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