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

Result Not Found

Books FREE
Tutors
Study Help
Hire a Tutor
AI Study Help New

Search
Sign In
Register

study help
chemistry
organic chemistry

Questions and Answers of Organic Chemistry

In addition to not undergoing substitution reactions, the alkyl bromide shown in Problem 11 .45 also fails to undergo an elimination reaction when treated with base. Explain.
1-Chioro-1, 2-diphenylethane can undergo E2 elimination to give either as- or trans-1, 2-diphenylethylene (stilbene). Draw Newman projections of the reactive conformations leading to both possible
Predict the major alkene product of the following E1reaction:
The tosylate of (2R, 3S)-3-phenyl.2-butanol undergoes E2 elimination on treatment with sodium ethoxide to yield (Z)-2-phenyl-2-hutene. Explain, using Newmanprojections.
In light of your answer to Problem 11.49, which alkene, F or Z, would you expect from an E2 reaction on the tosylate of (2R, 3R)-3-phenyl-2-butanol? Which alkene would result from E2 reaction on the
How can you explain the fact that franc-i -hromo-2-methylcyclohcxane yields the non-Zaitsev?s elimination product 3-methylcyclohexene on treatment with base?
Predict the product(s) of the following reaction, indicating stereochemistry wherenecessary:
Metabolism of S-AdenosyIhomo cysteine (Section 11.6) involves the following sequence. Propose a mechanism for the secondstep.
Reaction of iodoethane with CN– yields a small amount of isonitrile, CH3CH2N ≡ C, along with the nitrile CH3CH2C ≡ N as the major product. Write electron-dot structures for both products,
A Alkynes can be made by dehydrohalogenation of vinylic halides in a reaction that is essentially an E2 process. In studying the stereochemistry of this elimination, it was found that
(S)-2-Butanol slowly racemizes on standing in dilute sulfuric acid.Explain.
Reaction of HBr with (R)-3-methyl-3-hexanol leads to racemic 3-brorno-3-mcthylhcxane.Explain.
Treatment of 1 .bromo-2-deuterio-2-phenylethane with strong base leads to a mixture of deuterated and non-deuterated phenylethylenes in an approximately 7: 1 ratio.Explain.
A Propose a structure for an alkyl halide that gives only (E)-3-methyl-2-phenyl-2-pentene on E2 elimination, Make sure you indicate the stereochemistry.
One step in the urea cycle for ridding the body of ammonia is the conversion of arginino succinate to the amino acid arginine plus fumarate. Propose a mechanism for the reaction, and show the
Although anti periplanar geometry is preferred for E2 reactions, it isn?t absolutely necessary. The deuterated bromo compound shown here reacts with strong base to yield an un-deuterated alkene.
In light of your answer to Problem 11.61, explain why one of the following isomers undergoes E2 reaction approximately 100 times as fast as the other. Which isomer is more reactive, andwhy?
There are eight diastereomers of 1, 2, 3, 4, 5, 6-hexachlorocyclohexane. Draw each in its more stable chair conformation. One isomer loses HCI in an E2 reaction nearly 1000 times more slowly than the
Methyl esters (RCO2CH3) undergo a cleavage reaction to yield carboxylate ions plus iodomethane on heating with LiI in dimethyl form amide: The following evidence has been obtained: (1) the reaction
The reaction of 1-chlorooctane with CH3CO2– to give octyl acetate is greatly accelerated by adding a small quantity of iodide ion. Explain.
Compound X is optically inactive and has the formula C16H16Br2. On treatment with strong base, X gives hydrocarbon Y, C16H14. Compound Y absorbs 2 equivalents of hydrogen when reduced over a
When a primary alcohol is treated with p-toluenesulfonyl chloride at room temperature in the presence of an organic base such as pyridine, a tosylate is formed. When the same reaction is carried out
SN2 reactions take place with inversion of configuration, and SN1 reactions take place with racemization. The following substitution reaction, however, occurs with complete retention of
Propose a mechanism for the following reaction, an important step in the laboratory synthesis ofproteins:
The amino acid methionine is formed by a methylthio reaction of homo?cysteine with N-methyltetrahydrofolate. The stereochemistry of the reaction has been probed by carrying out the transformation
Amines are converted into alkenes by a two-step process called the Hofmann elimination. SN2 reaction of the amine with an excess of CH3I in the first step yields an intermediate that undergoes E2
Tell whether the following compounds are ortho-, meta-, orpara-di-substituted:
Give IUPAC names for the followingcompounds:
Draw structures corresponding to the following IUPAC names:(a) p-Bromo chloro benzene(b) p-Bromo toluene(c) m-Chloro aniline(d) 1 -Chloro-3, 5-dimethyl benzene
Pyridine is a flat, hexagonal molecule with bond angles of 120?. It undergoes substitution rather than addition and generally behaves like benzene. Draw a picture of the ? orbital?s of pyridine to
To be aromatic, a molecule must have 4n + 2? electrons and must have cyclic conjugation. 1, 3, 5, 7, 9-Cyclodecapentaene fulfills one of these criteria but not the other and has resisted all attempts
Draw the five resonance structures of the cyclopentadienyl anion. Are all carbon— carbon bonds equivalent? How many absorption lines would you expect to see in the 1H NMR and 13C NMR spectra of the
Cyclooctatetraene readily reacts with potassium metal to form the stable Cyclooctatetraene dianion, C8H82?1. Why do you suppose this reaction occurs so easily? What geometry do you expect for the
Draw an orbital picture of furan to show how the molecule isaromatic.
Thiamin, or vitamin Bi, contains a positively charged five-membered nitrogen?sulfur heterocycle called a thiazolium ring. Explain why the thiazolium ring is aromatic
Show the relative energy levels of the seven π molecular orbitals of the Cycloheptatrienyl system. Tell which of the seven orbital’s are filled in the cation, radical, and anion, and account for
Azulene, a beautiful blue hydrocarbon, is an isomer of naphthalene. Is azulene aromatic? Draw a second resonance form of azulene in addition to thatShown.
How many electrons does each of the four nitrogen atoms in purine contribute to the aromatic ? system?
Give IUPAC names for the following substances (red = O, blue =N):
A All-cis Cyclodecapentaene is a stable molecule that shows a single absorption in its 1H NMR spectrum at 5.67 ?. Tell whether it is aromatic, and explain its NMR spectrum.
A 1, 6-Methanonaphthalene has an interesting 1H NMR spectrum in which the eight hydrogen?s around the perimeter absorb at 6.9 to 7.3 ?, while the two CH2 protons absorb at ?0.5 ?. ?Tell whether it is
The following molecular model is that o a carbocation. Draw two resonance structures for the carbocation, indicating the positions of the doublebonds.
Azulene, an isomer of naphthalene, has a remarkably large dipole moment for a hydrocarbon (? = 1.0 D). Explain, using resonance structures.
Give IUPAC names for the followingcompounds:
Draw structures corresponding to the following names:(a) 3-Methyl-1, 2-benzenediamine(b) 1, 3, 5-Benzenetriol(c) 3-Methyl-2-phenylhexane(d) o-Amino benzoic acid(e) m-Bromo phenol(f) 2, 4,
Draw and name all possible isomers of the following:(a) Dinitrobenzene(b) Bromo dimethyl benzene(c) Trinitrophenol
Draw and name all possible aromatic compounds with the formula C7H7C1.
Draw and name all possible aromatic Compounds with the formula C8H9Br.
Propose structures for aromatic hydrocarbons that meet the following descriptions:(a) C9H12; gives only one C9H11Br product on substitution with bromine(b) C10H14 gives only one C10H13C1 product on
Look at the three resonance structures of naphthalene shown in Section 15.7, and account for the fact that not all carbon—carbon bonds have the same length. The C1—C2 bond is 136 pm long, whereas
There are four resonance structures for anthracene, one of which is shown. Draw the otherthree.
There are five resonance structures of Phenanthrene, one of which is shown. Draw the otherfour.
Look at the five resonance structures for Phenanthrene (Problem 15.26) and predict which of its carbon—carbon bonds is shortest.
In 1932, A. A. Levine and A. G. Cole studied the ozonolysis of o-xylene and isolated three products: glyoxal, 2, 3-butanedione, and pyruvaldehyde: In what ratio would you expect the three products to
3-Chlorocyclopropene, on treatment with AgBF4, gives a precipitate of AgCl and a stable solution of a product that shows a single 1H NMR absorption at 11.04 ?. What is a likely structure for the
Draw an energy diagram for the three molecular orbitals of the cyclopropenyl system (C3H3). How are these three molecular orbitals occupied in the cyclopropenyl anion, cation, and radical? Which of
Cyclopropanone is highly reactive because of its large amount of angle strain, but methylcyclopropenone, although even more strained than Cyclopropanone, is nevertheless quite stable and can even be
Cycloheptatrienone is stable, but cyclopentadienone is so reactive that it can?t be isolated. Explain, taking the polarity of the carbonyl group into account.
Which would you expect to be most stable, cyclononatetraenyl radical, cation, or anion?
How might you convert l, 3, 5, 7-cyclononatetraene to an aromatic substance?
Calicene, like azulene (Problem 15.17), has an unusually large dipole moment for a hydrocarbon. Explain, using resonancestructures.
Pentalene is a most elusive molecule and has never been isolated. The pentalene dianion, however, is well known and quite stable. Explain.
Indole is an aromatic heterocycle that has a benzene ring fused to a pyrrole ring. Draw an orbital picture of indole. (a) How many ? electrons does indole have? (b) What is the electronic
Ribavirin, an antiviral agent used against hepatitis C and viral pneumonia, contains a 1, 2, 4-triazole ring. Why is the ringaromatic?
Bextra, a COX-2 inhibitor used in the treatment of arthritis, contains an isoxazole ring. Why is the ringaromatic?
On reaction with acid, 4-pyrone is protonated on the carbonyl-group oxygen to give a stable cationic product. Using resonance structures and the Hückel 4n + 2 rule, explain why the protonated
Compound A, C8H10, yields three substitution products, C8H9Br, on reaction with Br2. Propose two possible structures for A. The 1H NMR spectrum of A shows a complex four-proton multiplet at 7.0 δ
N-Phenylsydnone, so-named because it was first studied at the University of Sydney Australia, behaves like a typical aromatic molecule. Explain, using the H?ckel 4n + 2 rule.
1-Phenyl-2-butene has an ultraviolet absorption at λ max = 208 nm (ε = 8000). On treatment with a small amount of strong acid, isomerization occurs and a new substance with λ max = 250 nm (ε =
What is the structure of a hydrocarbon that has M+ = 120 in its mass spectrum and has the following 1H NMR spectrum?7.25 δ (5 H, broad singlet); 2.90 δ (1 H, septet, J = 7 Hz); 1.22 δ (6 H,
Propose structures for compounds that fit the following descriptions:(a) C10H14H NMR: 7.18 δ (4 H, broad singlet); 2.70 δ (4 H, quartet, J = 7 Hz); 1.20 δ (6 H, triplet, J = 7 Hz)IR: 745 cm
Propose structures for aromatic compounds that have the following 1H NMR spectra: (a) C8H9Br IR: 820 cm ?1 (b) C9H12Br IR: 750 cm ?1 (b) C11H16Br IR: 820 cm ?1
Propose a structure for a molecule C14H12 that has the following 1H NMR spectrum and has IR absorptions at 700, 740, and 890 cm?1:
Aromatic substitution reactions occur by addition of an electrophile such as Br+ to the aromatic ring to yield an allylic carbocation intermediate, followed by loss of fl. Show the structure of the
The substitution reaction of toluene with Br2 can, in principle, lead to the formation of three isomeric bromotoluene products. In practice, however, only o-and p-bromotoluene are formed in
Name the followingcompounds:
Draw structures corresponding to the following IUPAC names:(a) Triisopropylamine(b) Triallylamine(c) N-Methyl aniline(d) N-Ethyl-N-Ethylcyclopentylamine(e) N-Isopropylcyclohexylamine(f) N-Ethylpyrrole
Draw structures for the following heterocyclic amines:(a) 5-Methoxyindole(b) 1, 3-Dimcthylpvrrole(c) 4-(N, N-Dimethvlamino pyridine(d) 5-Aminopyrimidine
Which compound in each of the following pairs is more basic?(a) CH3CH2NH2 or CH3CH2CONH2(b) NaOH or CH3NH2(c) CH3NHCH3 or pyridine
The benzyl ammonium ion (C6H5CH2NH3) has pKa 9.33, and the propyl ammonium ion has pKa = 10.71. Which is the stronger base, benzyl amine or propylamine? What are the pKb’S of benzyl amine and
Without looking at Table 24.2, rank the following compounds in order of ascending basicity. (a) p-Nitro aniline, p-aminobenzaldehyde, p-Bromoaniline (b) p-Chloroanilinc, p-aminoacetophenone, p-methyl
Calculate the percentages of neutral and protonated forms present in a solution of 0.0010 M pyrimidine at pH = 7.3. The pKa of pyrimidinium ion is 1.3.
Propose structures for either a nitrile or an amide that might be a precursor of each of the following amines:(a) CH3CH2CH2NH2(b) (CH3CH2CH2)2NH(c) Benzyl amine, C6H5C2NH2(d) N-Ethyl aniline
Write the mechanism of the last step in the Gabriel amine synthesis, the base-promoted hydrolysis of a phthalimide to yield an amine plus phthalate ion.
Show two methods for the synthesis of dopamine, a neurotransmitter involved in regulation of the central nervous system. Use any alkyl halideneeded.
How might the following amines be prepared using reductive amination reactions? Show all precursors if more than one ispossible.
How could you prepare the following amine using a reductive aminationreaction?
How would you prepare the following amines, using both Hofmann and Curtius rearrangements on a carboxylic acidderivative?
What products would you expect from Hofmann elimination of the following amines? If more than one product is formed, indicate which ismajor.
Propose a synthesis of the drug sulfathiazole from benzene and any necessaryamine.
Propose syntheses of the following compounds from benzene:(a) N, N-Dimethylaniline(b) p-Chloroaniline(c) m-Chloroaniline(d) 2, 4-Dimethylaniline
How would you prepare the following compounds from benzene, using a diazonium replacement reaction in your scheme?(a) p-Bromobenzoic acid(b) m-Bromobenzoic acid(c) n-Bromo chloro benzene(d) p-Methyl
Propose a synthesis of p-(dim-ethylamine) azobenzene from benzene as your only organic starting material.
Draw an orbital picture of thiazole. Assume that both the nitrogen and sulfur atoms are sp2-hyhridized, and show the orbitals that the lone pairs occupy.
What is the percent Protonation of the imidazole nitrogen atom in histidine at a physiological pH of 7.3?
Electrophilic aromatic substitution reactions of pyridine normally occur at C3. Draw the carbocation intermediates resulting from reaction of an electrophile at C1, C2, and C3, and explain the
Which nitrogen atom in the hallucinogenic indole alkaloid N, N-dimethyltryptamine is more basic?Explain.
Indole reacts with electrophile at C3 rather than at C2. Draw resonance forms of the intermediate cations resulting from reaction at C2 and C3, and explain the observed results.
Compound A, C6H12O, has an IR absorption at 1715 cm?1 and gives compound B, C6H15N, when treated with ammonia and NaBH3CN. The IR and 1H NMR spectra of B are shown. What are the structures of A and B?
Name the following amines, and identify each as primary, secondary, ortertiary:

Showing 3000 - 3100 of 15575

First
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
Last

Services

Sitemap
Fun
Definitions
Become Tutor
Study Help Categories
Recent Questions
Expert Questions

Company Info

Security
Copyrights
Privacy Policy
Terms & Conditions
SolutionInn Fee
Scholarship

Get In Touch

About Us
Contact Us
Career
Jobs
FAQ
Campus Ambassador

Secure Payment

Download Our App

© 2024 SolutionInn. All Rights Reserved