All Matches
Solution Library
Expert Answer
Textbooks
Search Textbook questions, tutors and Books
Oops, something went wrong!
Change your search query and then try again
Toggle navigation
FREE Trial
S
Books
FREE
Tutors
Study Help
Expert Questions
Accounting
General Management
Mathematics
Finance
Organizational Behaviour
Law
Physics
Operating System
Management Leadership
Sociology
Programming
Marketing
Database
Computer Network
Economics
Textbooks Solutions
Accounting
Managerial Accounting
Management Leadership
Cost Accounting
Statistics
Business Law
Corporate Finance
Finance
Economics
Auditing
Ask a Question
Search
Search
Sign In
Register
study help
chemistry
organic chemistry
Questions and Answers of
Organic Chemistry
Circle and identify by name all the functional groups in any three of the steroids illustrated in Section 4-7. Label any polarized bonds with partial positive and negative charges (δ+ and δ-).
Several additional examples of naturally occurring molecules with strained ring structures are shown here.Identify the terpenes (if any) in the preceding group of structures. Find the
If cyclobutane were flat, it would have exactly 90° C-C-C bond angles and could conceivably use pure p orbitals in its C-C bonds. What would be a possible hybridization for the carbon atoms of the
Compare the structure of cyclodecane in an all-chair conformation with that of trans-decalin. Explain why all-chair cyclodecane is highly strained, and yet trans-decalin is nearly strain free. Make
Fusidic acid is a steroid like microbial product that is an extremely potent antibiotic with a broad spectrum of biological activity. Its molecular shape is most unusual and has supplied important
The enzymatic oxidation of alkanes to produce alcohols is a simplified version of the reactions that produce the adrenocortical steroid hormones. In the biosynthesis of corticosterone from
Iodobenzene dichloride, formed by the reaction of iodobenzene and chlorine, is a reagent for the chlorination of alkane C-H bonds. Chlorinations in which iodobenzene dichloride is used are initiated
As Problem 50 indicates, the enzymatic reactions that introduce functional groups into the steroid nucleus in nature are highly selective, unlike the laboratory chlorination described in Problem 51.
Consider the following compounds:Conformational analysis reveals that, though compound A exists in a chair conformation, compound B does not. (a) Make a model of A. Draw chair conformations and label
Which of the following cycloalkanes has the greatest ring strain? (a) Cyclopropane (b) Cyclobutane (c) Cyclohexane (d) Cycloheptane
The following moleculehas (a) One axial chlorine and one sp1 carbon, (b) One axial chlorine and two sp2 carbons, (c) One equatorial chlorine and one sp2 carbon, or (d) One equatorial chlorine and two
In this compound,(a) The D is equatorial (b) The methyls are both equatorial (c) The CI is axial (d) The deuterium is axial.
Which of the following structures has the smallest heat of combustion?(a)(b) (c) (d)
Each part of this problem lists two objects or sets of objects. As precisely as you can, describe the relation between the two sets, using the terminology of this chapter; that is, specify whether
For each pair of the following molecules, indicate whether its members are identical, structural isomers, conformers, or stereoisomers. How would you describe the relation between conformations when
Which of the following compounds are chiral?(a) 2-Methylheptane(b) 3-Methylheptane(c) 4-Methylheptane(d) 1,1-Dibromopropane(e) 1,2-Dibromopropane(f) 1,3-Dibromopropane(g) Ethene, H2C=CH2(h) Ethyne,
Each of the following molecules has the molecular formula C5H120. Which ones are chiral?
Draw either one of the enantiomers for each chiral molecule in Problem 34 and label its stereocenter as R or S.Problem 34
Which of the following cyclohexane derivatives are chiral? For the purpose of determining the chirality of a cyclic compound, the ring may generally be treated as if it were planar.
Label every stereocenter in the molecules in Problem 36 as R or S.
Circle each chiral molecule. Put a star (*) next to each chiral carbon and label it as R or 5.
For each pair of Structures shown, indicate whether the two species are constitutional isomers, enantiomers, diastereomers of one another, or identical molecules.
For identify every structural isomer containing one or more stereocenters, give the number of stereoisomers for each, and draw and fully name at least one of the stereoisomers in each case (a)
Assign the appropriate designation of configuration (R or S) to the stereocenter in each of the following enantiomers. (Hint: Regarding cyclic structures containing stereocenters, treat the ring as
Mark the stereocenters in each of the chiral molecules in Problem 33. Draw any single stereoisomer of each of these molecules, and assign the appropriate designation (R or 5) to each stereocenter.
The two enantiomers of carvone [systematic name: 2-methyl-5-(l-methylethenyl)-2-cyclohexenone; Chemical Highlight 5-1] are drawn in the margin. Which is R and which is S?
Draw structural representations of each of the following molecules. Be sure that your structure clearly shows the configuration at the stereocenter. (Hint: You may find it useful to first draw the
Draw structural representations of each of the following molecules. Be sure that your structure clearly shows the configuration at each stereocenter.(a) (R)-3-bromo-3-methylhexane;(b)
Draw and name all possible stereoisomers of (CH3)2CHCHBrCHClCH3.
For each of the following questions, assume that all measurements are made in 10-cm polarimeter sample containers, (a) A 10-mL solution of 0.4 g of optically active 2-butanol in water displays
Natural epinephrine, [a]D25oC = -50, is used medicinally. Its enantiomer is medically worthless and is. in fact, toxic. You, a pharmacist, are given a solution said to contain 1 g of epinephrine in
Sodium hydrogen (S)-glutamate [(S)-monosodium glutamate], [a]D25oC = +24, is the active flavor enhancer known as MSG. The condensed formula of MSG is shown in the margin, (a) Draw the structure
The molecule in the margin is menthol, with the stereochemistry omitted, (a) Identify all stereocenters in menthol, (b) How many stereoisomers exist for the menthol structure? (c) Draw all the
Natural (-)-menthol, the essential oil primarily responsible for the flavor and aroma of peppermint, is the 1R,2S,5R -stereoisomer. (a) Identify (-)-menthol from the structures you drew for Problem
Of the stereoisomers described in the two problems above, (-)-menthol ([a]D = -51) and ( +)-neomenthol ([a]D = +21) are the major constituents in mentha oil, their main natural source. The
For each of the following pairs of structures, indicate whether the two compounds are identical or enantiomers of each other.
Determine the R or S designation for each stereocenter in the structures in problem 53.
The compound pictured in the margin is a sugar called (-)arabinose. Its specific rotation is -105. (a) Draw the enanfiomer of (-)-arabinose. (b) Does (-)-arabinose have any other enantiomers? (c)
Write the complete IUPAC name of the following enantiomer (Do not forget stereochemical designations).Reaction of this compound with 1 mol of Cl2 in the presence of light produces several isomers of
Monochlorination of methylcyclopentane can result in several products. Give the same information as that requested in Problem 56 for the monochlorination of methylcyclopentane at Cl, C2, and C3.
Draw all possible products of the chlorination of (S)-2-bromo-l,l-dimethylcyclobutane. Specify whether they are chiral or achiral, whether they are formed in equal or unequal amounts, and which are
Illustrate how to resolve racemic 1-phenylethanamine (shown in the margin), using the method of reversible conversion into diastereomers.
Draw a flowchart that diagrams a method for the resolution of racemic 2-hydroxypropanoic acid (lactic acid, Table 5-1), using (5)-1-phenylethanamine.
How many different stereoisomeric products are formed in the monobromination of (a) racemic l,2-dimethylcyclohexane and (b) pure (R,R)-1,2-dimethylcyclohexane? (c) For your answers to (a) and (b),
Make a model of cis-1,2-dimethylcyclohexane in its most stable conformation. If the molecule were rigidly locked into this conformation, would it be chiral? (Test your answer by making a model of the
Morphinane is the parent substance of the broad class of chiral molecules known as the morphine alkaloids. Interestingly, the (+) and (-) enantiomers of the compounds in this family have rather
We will learn in Chapter 18 that hydrogens on the carbon atom adjacent to the carbonyl functional group (C=0) are acidic. The compound (S)-3-methyl-2-pentanone, loses its optical activity when it is
The enzymatic introduction of a functional group into a biologically important molecule is not only specific with regard to the location at which the reaction occurs in the molecule (see Chapter 4,
Studies have shown that one stereoisomeric certain types of neurodegenerative disorders, system, as illustrated in structure B, and that form of compound A is an effective agent against Recognize
Which compound will not exhibit optical activity? (Note that these are all Fischer projections.)(a)(b) (c) (d)
The enantiomer of(a) Is (b) Can exist only at low temperatures (c) Is nonisomeric (d) Is incapable of existence
The molecule that is of the R configuration according to the Cahn-Ingold-Prelog convention is (remember these are Fischer projections):(a)(b) (c) (d) (e)
Which compound is not a meso compound?(a)(b) (c) (d) (e)
Name the following molecules according to the IUPAC system.
Draw structures for each of the following molecules: (a) 3-ethyl-2-iodopentane: (b) 3-bromo-1.1 -dichlorobutane; (c) Cis- l-(bromomethyl)-2-(2-chloroethyl(cyclobutane: (d)
Draw and name all possible structural isomers having the formula C3H6BrCl.
Draw and name all structurally isomeric compounds having the formula C5H11Br.
For each structural isomer in Problems 33 and 34, identify all stereocenters and give the total number of stereoisomers that can exist for the structure.
For each reaction in Table 6-3, identify the nucleophile, its nucleophilic atom (draw its Lewis structure first), the electrophilic atom in the substrate, and the leaving group.
A second Lewis structure can be drawn for one of the nucleophiles in Problem 36. (a) Identify it and draw its alternate structure (which is simply a second resonance form), (b) Is there a second
For each reaction shown here, identify the nucleophile, its atom, the eletrophilic atom in the substate molecule, and the leaving groups. Write the organic product of the reaction.
For each reaction presented in Problem 38, write out the mechanism using the curved-arrow notation.(a) CH3I + NaNH2 (b)(c) (d) (e) (f)
A solution containing 0.1 M CH3C1 and 0.1 M KSCN in DMF reacts to give CH3SCN and KC1 with an initial rate of 2 × 10-8 mol L-1 s-1. (a) What is the rate constant for this reaction? (b) Calculate the
Write the product of each of the following bimolecular substitutions. The solvent is indicated above the reaction arrow.(a)(b) (c) (d) (e) (f)
Determine the R/S designations for both starting materials and products in the following SN2 reactions. Which of the products are optically active?(a)(b) (c) (d)
For each reaction presented in Problems 41 and 42, write out the mechanism using curved-arrow notation.
List the products of the reaction of 1-bromopropane with each of the following reagents. Write "no reaction" where appropriate. (Carefully evaluate the nucleophilic potential of each reagent.) (a)
Formulate the potential product of each of the following reactions. As you did in Problem 44, write "no reaction" where appropriate. (Identify the expected leaving group in each of the substrates and
Show how each of the following transformations might be achieved.(a)(b) (c) (d)
Rank the members of each of the following groups of species in the order of basicity, nucleophilicity, and leaving-group ability. Briefly explain your answers. (a) H2O, HO-, CH3CO2-; (b) Br-, Cl-,
Write the product (s) each of the following. Write"no reaction" as your answer, if appropriate.
For each reaction presented in Problem 48 that actually proceed to a product, write out the mechanism using the curved-arrow notation.Problem 48:
The substance l-butyl-3-methylimidazolium (BMIM) hexafluorophosphate (margin) is a liquid at room temperature, even though it is a salt composed of positive and negative ions. BMIM and other ionic
(2S, 3S)-3-Hydroxyleucine is an amino acid (Chapter 26) that is a key component in the structures of many "depsipeptide" antibiotics, such as sanjoining (margin),(a) Find the part of the sanjoinine
Iodoalkanes are readily prepared from the corresponding chloro compounds by SN2 reaction with sodium iodide in acetone. This particular procedure is especially useful because the inorganic
Using the information in Chapters 3 and 6, propose the best possible synthesis of each of the following compounds with propane as your organic starting material and any other reagents needed. (a)
Propose two syntheses of trnas-1-methyl-2-(methylthio)cyclohexane (shown in the margin), beginning with the starting compound(a) cis-1-chloro-2-methylcycIohexane;(b)
In each pair of molecules that follows, indicate the member of the pair that would be better suited in its indicated function for an SN2 reaction.(a) Nucleophile: NH3, PH3(b)(c) (d) Leaving group:
Rank each of the following sets of molecules in order of increasing SN2 reactivity.(a) CH3CH2Br, CH3Br, (CH3)2CHBr(b) (CH3)2CHCH2CH2Cl, (CH3)2CHCH2Cl, (CH3)2CHCl(c)(d)
Predict the effect of the changes given below on the rate of the reaction(a) Change substrate from CH3Cl to CH,I; (b) Change nucleophic from CH3O- to CH3S-; (c) Change substrate from CH3C1 to
The following table presents rate data for the reactions of CH3I with three different nucleophiles in two different solvents. What is the significance .of these results regarding relative reactivity
Explain the outcome of the following transformations mechanistically.(a)(b) (c)
SN2 reactions of halocyclopropane and halocyclobutane substrates are very much slower than those of analogous acyclic secondary haloalkanes. Suggest an explanation for this finding.
Nucleophilic attack on halocyclohexanes is also somewhat retarded compared with that on acyclic secondary haloalkanes, even though in this case bond-angle strain is not an important factor. Explain.
Compounds A through H are isomeric bromoalkanes with the molecular formula C5H11br. With your team, draw all eight constitutional isomers. Indicate any stereo-center) (s), but do not label it (them)
The SN2 reaction mechanism best applies to (a) cyclopropane and H2 (b) 1-chlorobutane and aqueous NaOH (c) KOH and NaOH (d) Ethane and H2O
The reaction CH3Cl + OH- → CH3OH + Cl- is first order in both chloromethane and hydroxide. Given the rate constant k = 3.5 × 10-3 mol L-1 s-1, what is the observed rate at the following
Which ioh is the strongest nucleophile in aqueous solution? (a) F- (b) Cl- (c) Br- (d) I- (e) All of these are equally strong.
Only one of the following processes will occur measurably at room temperature. Which one?
What is the major substitution product of each of the following solvolysis reactions?(a)(b) (c) (d) (e) (f)
For each reaction presented in Problem 25, write out the complete, step-by-step mechanism using curved-arrow notation. Be sure to show each individual step of each mechanism separately, and show the
Write the two major substitution products of the reaction shown in the margin, (a) Write a mechanism to explain the formation of each of them, (b) Monitoring the reaction mixture reveals that an
Give the two major substitution products of the following reaction.
Carbocations are stabilized by hyperconjugation: Tertiary are the most stable, followed by secndary. Primary and methyl cations are too unstable to form in solution.
Rank the following carbocations in decreasing order of stability.
Rank the compounds in each of the following groups in order of decreasing rate of solvolysis in aqueous acetone(a)(b) (c)
Give the products of the following substitution reactions. Indicate whether they arise through the SN1 or the SN2 process. Formulate the detailed mechanisms of their generation(a)(b) (c) (d)
Give the product of each of the following substitution reactions. Which of these transformations should proceed faster in a polar, aprotic solvent (such as acetone or DMSO) than in a polar, protic
Propose a synthesis of (R)-CH3CHN3CH2CH3, starting from (R)-2-chlorobutane.
Two substitution reactions of (S)-2-bromobutane are shown here. Show their stereochemical outcomes.
Showing 15300 - 15400
of 15575
First
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156