Fischer projection formulas are also used for compounds like aldohexoses that contain several stereogenic centers. In this case, the molecule is drawn with a vertical carbon skeleton and the stereogenic centers are stacked one above another. Using this convention, all horizontal bonds project forward (on wedges). [Pg.1031]

Convert each compound to a Fischer projection and label each stereogenic center as R or S. [Pg.1068]

FIGURE 2.5 Different drawings of D- and L-glucose in the Fischer projection = stereogenic reference center. [Pg.48]

Fischer projection formula (Section 27.2A) A method for representing stereogenic centers with the stereogenic carbon at the intersection of vertical and horizontal lines. Fischer projections are also called cross formulas. [Pg.1201]

SampI Probl6m 27.2 Re-draw each Fischer projection formula using weages and dasnes for the stereogenic center, and [Pg.1030]

Next, translate the Fischer projection of t-serine to a three-dimensional representation, and orient it so that the lowest ranked substituent at the stereogenic center is directed away from you. [Pg.1056]

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]

Sometimes the terms erythro and threo are used to specify fee relative configuration of two adjacent stereogenic centers. The terms are derived fom fee sugars erythrose and threose. The terms were originally defined such feat a Fischer projection formula in which two adjacent substituents were on the same side was fee erythro isomer and feat in whidi the substituents were on opposite sides was the threo isomer. [Pg.84]

Review carbohydrate terminology by referring to text Table 25.1. A ketotetrose is a four-carbon ke-tose. Writing a Fischer projection for a four-carbon ketose reveals that only one stereogenic center is present, and thus there are only two ketotetroses. They are enantiomers of each other and are known as d- and L-erythrulose. [Pg.706]

PROBLEM 7.19 There are two other stereoisomeric tartaric acids. Write their Fischer projections, and specify the configuration at their stereogenic centers. [Pg.286]

The eclipsed conformation shown, when oriented so that the aldehyde carbon is at the top, vertical bonds back, and horizontal bonds pointing outward from their stereogenic centers, is readily transformed into the Fischer projection of L-erythrose. [Pg.702]

If you view the second formula from the top, you will see that it is just a three-dimensional representation of the Fischer projection. Horizontal groups at each stereogenic center come up toward you, and vertical groups recede away from you. The second formula represents an eclipsed conformation of D-threose. The third and fourth formulas represent sawhorse and Newman projections, respectively, of a staggered conformation of D-threose. [Pg.295]

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