Concept explainers
(a)
Interpretation:
The structure of D-erythrose has to be identified from the given structures.
Concept introduction:
The configuration of stereoisomer is determined by Cahn-Ingold-Prelog system rules.
According to Cahn-Ingold-Prelog system,
The group attached to asymmetric center should be ranked based on the
For Fischer projection formula: Check the direction of arrow drawn in the direction of decreasing priority. If the arrow points clockwise direction, then the compound has R configuration. If the arrow points counterclockwise direction, then the compound has S configuration. If the group with lowest priority is bonded in horizontal line, then the configuration is assigned as just reverse.
(b)
Interpretation:
The structure of D-threose has to be identified from the given structures.
Concept introduction:
The configuration of stereoisomer is determined by Cahn-Ingold-Prelog system rules.
According to Cahn-Ingold-Prelog system,
The group attached to asymmetric center should be ranked based on the atomic number of atom which directly connected to asymmetric center. The higher the atomic number of atom, higher the priority. If there is tie, then consider the next atoms attached to the connected atom and so on.
For Fischer projection formula: Check the direction of arrow drawn in the direction of decreasing priority. If the arrow points clockwise direction, then the compound has R configuration. If the arrow points counterclockwise direction, then the compound has S configuration. If the group with lowest priority is bonded in horizontal line, then the configuration is assigned as just reverse.
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ORGANIC CHEMISTRY W/ST.GDE W/ACCESS
- The structure of 4 isomers of an aldotetrose carbohydrate are given. 1) select every structure that is a diastereomer of structure D A, B, or C? 2) select every structure that is a enantiomer of structure C D, B, or A? 3) select every structure that is a stereoisomer of structure D A, B, or Carrow_forwardThe structure of 4 isomers of ketopentose are shown. 1) select every structure that is a diastereomer of structure D A, B, or C? 2) select every structure that is a enantiomer of structure C A, B, or D 3) select every structure that is a stereoisomer of structure C A, B, or Darrow_forward-Sketch the Fischer projection and make a model of each stereoisomer (R and S) of the alcohol 2-butanol, CH3CHOHCH2CH3. Also sketch the monosaccharide glyceraldehyde, HOCH2CHOHCHO. Prioritize the four groups attached to the stereocenter with 1 being the highest priority and 4 being the lowest priority.arrow_forward
- The specific rotation of α-d-galactose is 150.7 and that of β-d-galactose is 52.8. When an aqueous mixture that was initially 70% α-d-galactose and 30%β-d-galactose reaches equilibrium, the specific rotation is 80.2. What is the percentage of α-d-galactose and β-d galactose at equilibrium?arrow_forwardIdentify pairs of molecules that represent enantiomers and diastereomers and identify each center stereogenic by writing R or S next to it.arrow_forwardConvert the following chair conformation of the sugar beta-D-galactose into a structure that shows all the cis & trans relationships as hashed (down) and wedge (up) bonds. Use the wedge/hash bond tools to indicate stereochemistry where it exists. In cases where there is more than one answer, just draw one. Use “flat” representations of rings, not chairs, in your drawing.arrow_forward
- What is the configuration of each of the asymmetric centers in the Fischer projection of a. D-glucose? b. D-galactose? c. D-ribose? d.D-xylose? e.D-sorbose?arrow_forwardWhich configuration (R or S) does the bottom asymmetric carbon have for the d seriesof sugars? Which configuration for the l series?arrow_forwardStereoisomers differ from each other in what respect? A.) Composition B.) Constitution C.) Configuration D.) Steric hindrance E.) Nonearrow_forward
- When a pyranose is in the chair conformation in which the CH2OH group and the C-1 OH group are both in axial positions, the two groups can react toform an acetal. This is called the anhydro form of the sugar (it has “lost water”). The anhydro form of d-idose is shown here. Explain why about 80% of d-idose exists in the anhydro form in an aqueous solution at 100 °C, but only about 0.1% of d-glucose exists in the anhydro form under the same conditions.arrow_forward(a) assign R or S configuration to each chiral center, (b) Which compound are enantiomers? (c) Which compounds are diastereomers?arrow_forwardWhen a pyranose is in the chair conformation in which the CH2OH group and the C-1 OH group are both in axial positions, the two groups can react to form an acetal. This is called the anhydro form of the sugar (it has “lost water”). The anhydro form of D-idose is shown here. Explain why about 80% of d-idose exists in the anhydro form in an aqueous solution at 100 °C, but only about 0.1% of D-glucose exists in the anhydro form under the same conditions.arrow_forward
- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning