Concept explainers
(a)
Interpretation:
The number of stereoisomers present in given structure of ephedrine has to be determined.
Concept introduction:
Stereoisomers are isomers which have different spatial arrangement in spite of same bond connectivity. Stereoisomers are due to the presence of stereocenter.
Asymmetric center is a stereocenter which arises to hydrocarbons if the carbon is bonded to four different groups.
The equation for finding Stereoisomers from number of asymmetric centers in compounds is
(b)
Interpretation:
The configuration of each of asymmetric centers has to be given.
Concept introduction:
According to Cahn-Ingold-Prelog system,
The group attached to asymmetric center should be ranked based on the
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 not bonded by a hatched wedge, then interchange this group (lowest priority) by group bonded to hatched wedge and draw the arrow in priority order but the configuration is assigned as just reverse.
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Chapter 4 Solutions
Essential Organic Chemistry, Global Edition
- Focus only on carbon 1 For carbon 1, which group has the highest priority? a,b,c or d?why? What enantiomer is carbon 1? R or S?arrow_forwardAssign an R or S configuration to each stereocenter. Show your work.arrow_forwardFor the following molecules: a. How many stereogenic centers are present? b. How many stereoisomers are possible for these molecules?arrow_forward
- Part B. Mark each chirality center in each molecule with an asterisk (*). Illustrate onto the image Cannot be hand-drawnarrow_forward(a) Draw the ring-flip isomer of the molecule. (b) Show which of the two is favored in the equilibrium between them, and explain why, showing all possible forms of strain in each of the isomers. (c) What is the stereochemical relationship between the two isomers? (d) Draw another stereoisomer of the molecule and show all the strains it contains.arrow_forwardLocate the tetrahedral stereogenic center(s) in each compound. A molecule may have one or more stereogenic centers.arrow_forward
- For each ee value (enantiomeric excess value), calculate the percentage of each enantiomer presentarrow_forwardFor the given molecules, determine if each are in the R or S configuration at the indicated (*) stereo center. Draw each compound and show your work by labelling the priority of each group and using the rotation/swap method as needed.arrow_forwardThe [α] of pure quinine, an antimalarial drug, is −165. a.Calculate the ee of a solution with the following [α] values: −50, −83, and −120. b. For each ee, calculate the percent of each enantiomer present. c.What is [α] for the enantiomer of quinine? d. If a solution contains 80% quinine and 20% of its enantiomer, what is the ee of the solution? e. What is [α] for the solution described in part (d)?arrow_forward
- Citalopram is an antidepressant pharmaceutical that is sold as a racemic mixture. However, it is known that the (S) enantiomer is 30x more biologically active than the (R) enantiomer. Draw the (S) configuration.arrow_forwardLabel the two stereogenic centers in each compound and draw all possible stereoisomers.arrow_forwardcan you explain how you assigned each molecule its priority to get the S configurationarrow_forward
Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning