Interpretation:
The position of the three hydroxyl groups present in cholic acid are to be located and whether they are axial or equatorial are to be identified. Further whether cholic acid is a A-B trans or a A-B cis steroid is to be stated.
Concept introduction:
If the two cyclohexane rings are fused in trans manner the two hydrogens at the ring junction will be diaxial. If the ring fusion is cis, then hydrogen at one ring junction is axial while that in the other junction is equatorial.
Among the disubstituted cyclohexanes, 1,2-cis, 1,3-trans and 1,4-cis substituents will have axial and equatorial arrangements. 1,2-trans, 1,3-cis and 1,4-trans substituents will have either diequatorial or diaxial arrangements.
To locate:
The position of the three hydroxyl groups present in cholic acid.
To identify:
Whether they are axial or equatorial.
To state:
Whether cholic acid is A-B trans or a A-B cis steroid.
Answer to Problem 11VC
The three hydroxyl groups are on C3, C6 and C12. The hydroxyl group on C3 is equatorial while those at C6 and C12 are axial. Cholic acid is A-B cis steroid.
Explanation of Solution
The structure of cholic acid represented by the model is
Since lithocholic acid has the rings A and B fused in cis manner, the methyl group on C9 has to be equatorial and the H C10 has to be axial for ring A. In lithocholic acid, the -OH on C3 (in ring A), is in 1,4 trans relationship with the methyl on C9. Hence the –OH on C3 occupies the equatorial position.
For ring B the methyl group on C9 is axial and the H C10 is equatorial. The OH group on C6 has 1,4 trans relationship with methyl on C9 it has to occupy the axial position.
The rings C and D are trans fused. The methyl on C13 and H on C14 has diaxial arrangement. Since the OH group on C12 has 1,2 trans relationship with methyl on C13 it has to occupy the axial position.
The H on C7 is axial for ring C. Since the OH group on C12 is three carbons away from C7 it has to occupy the axial position.
The three hydroxyl groups are on C3, C6 and C12. The hydroxyl group on C3 is equatorial while those at C6 and C12 are axial. Cholic acid is A-B cis steroid.
Want to see more full solutions like this?
Chapter 27 Solutions
Organic Chemistry - With Access (Custom)
- Q1: Answer the questions for the reaction below: ..!! Br OH a) Predict the product(s) of the reaction. b) Is the substrate optically active? Are the product(s) optically active as a mix? c) Draw the curved arrow mechanism for the reaction. d) What happens to the SN1 reaction rate in each of these instances: 1. Change the substrate to Br "CI 2. Change the substrate to 3. Change the solvent from 100% CH3CH2OH to 10% CH3CH2OH + 90% DMF 4. Increase the substrate concentration by 3-fold.arrow_forwardExperiment 27 hates & Mechanisms of Reations Method I visual Clock Reaction A. Concentration effects on reaction Rates Iodine Run [I] mol/L [S₂082] | Time mo/L (SCC) 0.04 54.7 Log 1/ Time Temp Log [ ] 13,20] (time) / [I] 199 20.06 23.0 30.04 0.04 0.04 80.0 22.8 45 40.02 0.04 79.0 21.6 50.08 0.03 51.0 22.4 60-080-02 95.0 23.4 7 0.08 0-01 1970 23.4 8 0.08 0.04 16.1 22.6arrow_forward(15 pts) Consider the molecule B2H6. Generate a molecular orbital diagram but this time using a different approach that draws on your knowledge and ability to put concepts together. First use VSEPR or some other method to make sure you know the ground state structure of the molecule. Next, generate an MO diagram for BH2. Sketch the highest occupied and lowest unoccupied MOs of the BH2 fragment. These are called frontier orbitals. Now use these frontier orbitals as your basis set for producing LGO's for B2H6. Since the BH2 frontier orbitals become the LGOS, you will have to think about what is in the middle of the molecule and treat its basis as well. Do you arrive at the same qualitative MO diagram as is discussed in the book? Sketch the new highest occupied and lowest unoccupied MOs for the molecule (B2H6).arrow_forward
- Q8: Propose an efficient synthesis of cyclopentene from cyclopentane.arrow_forwardQ7: Use compound A-D, design two different ways to synthesize E. Which way is preferred? Please explain. CH3I ONa NaOCH 3 A B C D E OCH3arrow_forwardPredict major product(s) for the following reactions. Note the mechanism(s) of the reactions (SN1, E1, SN2 or E2).arrow_forward
- (10 pts) The density of metallic copper is 8.92 g cm³. The structure of this metal is cubic close-packed. What is the atomic radius of copper in copper metal?arrow_forwardPredict major product(s) for the following reactions. Note the mechanism(s) of the reactions (SN1, E1, SN2 or E2).arrow_forwardPredict major product(s) for the following reactions. Note the mechanism(s) of the reactions (SN1, E1, SN2 or E2).arrow_forward
- Q3: Rank the following compounds in increasing reactivity of E1 and E2 eliminations, respectively. Br ca. go do A CI CI B C CI Darrow_forwardQ5: Predict major product(s) for the following reactions. Note the mechanism(s) of the reactions (SN1, E1, SN2 or E2). H₂O דיי "Br KN3 CH3CH2OH NaNH2 NH3 Page 3 of 6 Chem 0310 Organic Chemistry 1 HW Problem Sets CI Br excess NaOCH 3 CH3OH Br KOC(CH3)3 DuckDuckGarrow_forwardQ4: Circle the substrate that gives a single alkene product in a E2 elimination. CI CI Br Brarrow_forward
Chemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage Learning
Chemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning
Chemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning
General Chemistry - Standalone book (MindTap Cour...ChemistryISBN:9781305580343Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; DarrellPublisher:Cengage Learning
ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage Learning