TEST1:Alkanes, alkenes, dienes, bond polarization, optical isomerism
1. Give systematic names
2. Draw energy diagram for the rotation of 1-chloro-2-methylpropane about the C-1–C-2 bond showing the relative height of energy minima and maxima together with the corresponding conformations (Newman projections)!
3. Draw energy diagram for the rotation of 2-methylbutane about the C-2–C-3 bond showing the relative height of energy minima and maxima together with the corresponding conformations (Newman projections)!
4. Which method can be used to differentiate enantiomers?
a. melting point b. boiling point c. direction of rotation d. value of rotation
e. absolute configuration f. solubility in water g. solubility in chloroform
h. solubility in (+)-2-chloropentane i. solubility in (+)-2-chloropentane
j. solubility in (–)-2-chloropentane
5. What are the simplest alcohols, which can correspond to the following equations?
6. There are 4 isomers of dimethylcyclopropane.
a) Write the structural formula of each isomer!
b) Which of the four show optical activity?
c) Which are meso compounds?
d) Having a mixture containing 1 mol of each isomer and performing fractional distillation,
how many fractions can be collected? Give the composition of each fraction!
7. The reaction of buta-1,3-diene with bromine at room temperature yields 1,4-dibromobut-2-ene. Determine if it is the product of kinetic or thermodynamic control.Interpret! Draw the structure of the other isomer andthe energy diagram of the reaction!
8. Halogenation of isobutane(Reactions)+Draw the energy diagram of the reaction and interpret product distributions!
9. The reaction of buta-1,3-diene with HBr(Reactions)+Draw the energy diagram of the reaction and interpret!
10. The reaction of propene with HBr(Reactions)+Draw the energy diagram of the reaction and interpret product distribution!
11. Draw the structure of the alkenes, which can be transformed to following alcohols by acid-catalyzed hydration.
ethanol, butan-2-ol, 2-methylpropan-2-ol, 2-methylpropan-1-ol, butan-1-ol
12. Give an interpretation for the strained structure of cyclopropane!
13. Draw the Fischer projection of the following compounds
(R)-2-chloropentane(S)-CH3CHDOH(R)-2-methylpentan-3-ol
14. Draw the structural formula of the following compounds with the lowest possible carbon numbers, which are chiral! a) alkane (two isomers) b) dibromoalkane c) monoalkohol d) alkene e) allene
15. Determine the absolute configuration of the following compounds! (detailed step-by-step method)
16. Explain why the boat conformation of cyclohexane is characterized by an energy maximum (draw stereo structure and Newman projection)!
17. Draw the structural formula of the following compounds and indicate which can be separated into optically active isomers. When isomerism does not exist, give the corresponding symmetry element.
a) CHFClBr b) CHDClBr c) 2,3-dimethylpentane d) cis-1,2-dimethylcyclobutane e) 2-chloropropane f) butan-2-ol
g) methylcyclohexane h) trans-1,2-dibromoethylene i) 3,3-dimethylpentane j) chloroacetone k) 1,1-dibromoallene l)1,3-dibromoallene
18. Draw conformational equilibrium for each compound and indicate the more stable chair conformer!
a) ethylcyclohexane b) cis-1,2-dimethylcyclohexane c) trans-1,2-dimethylcyclohexane
19. Which of the isomeric C8H18 compounds has a single monochloro derivative?
20. Draw the structural formula of the C8H18meso compound
21. Rank the following substituents using the Cahn-Ingold-Prelog convention!
CH2Br, CCl3, CH=CH2, CN, CH2NH2
22. Determine the absolute configuration of each asymmetric carbon of the following compound (detailed step-by-step method). Determine whether it shows optical activity. Give explanation!
23. Draw the structural formula of the products formed after hydrogenation of the following compounds! Give the isomeric relationship and the method for their separation!
24. Indicate bond polarizations in the following compounds/ions and give the corresponding symbols!
25. Draw resonance hybrids for the following compounds/ions indicate bond polarization (give symbols if possible)!
Reactions: 1–16
Important terms
conformation, conformer, chiral compound, prochiral compound, chiral center, racemic mixture, meso compound, configuration, retention, inversion, racemization, resolution, enantiomers, asymmetric synthesis, molecular asymmetry, diastereoisomerism, nucleophile, electrophile, degree of oxidation, tertiary/secondary/primary carbon, addition, elimination, substitution, functional group, isomerism, homologous series, atomic orbital, angular (Baeyer) strain, torsional (Pitzer) strain, tautomerization, molecularity
TEST2Aromatic compounds
1. Prepare the following compounds from benzene using the necessary reagents:
a) m-toluenesulfonic acidb) m-bromobenzoic acidc) p-bromobenzoic acidd) p-chloroacetophenone
e)o-chloroacetophenonef) m-nitrobenzoic acidg) 3-isopropylbenzenesulfonic acid
h) m-chloroacetophenonei) p-nitrobenzyl bromidej)3-nitroisopropylbenzene
2. Prepare the following compounds from toluene using the necessary reagents:
a) o-bromobenzoic acidb) m-bromobenzoic acidc) p-nitrobenzyl bromided) m-nitrobenzoic acid
3. Draw the structure of the following compounds and rank them according to their reactivity in aromatic electrophilic substitution!
a) aniline, benzaldehyde, chlorobenzene, benzeneb) phenol, benzene, 2-aminoacetophenone, benzoic acid
c) toluene, acetophenone, acetanilide, o-dinitrobenzened) nitrobenzene, phenol, benzene, toluene
e) aniline, o-nitrobenzaldehyde, bromobenzene, toluenef) phenol, benzene, acetanilide, benzoic acid
4. Give the mechanism of aromatic SE reactions using, as example, i. nitration, ii. bromination, iii. sulfonation iv. Friedel–Crafts alkylation with tert-butyl chloride, v. Friedel–Crafts acylation with acetyl chloride. Show the formation of the electrophile and draw the detailed structure (resonance formulae) of the complex!Draw detailed energy diagram of the reaction!
5. Write equations and interpret the following:
i) in Friedel–Crafts alkylations polysubstituted products are often formed. In contrast, polyacylation in Friedel–Crafts acylation does not occur;
ii) catalytic amount of Lewis acid is sufficient in alkylations, whereas acylation requires the use of stoichiometric quantity.
6. Interpret the effect of the substituent (orientation, effect on rate) in SE-Ar reactions of nitrobenzene/ phenol/aniline (indicate and give symbols for bond polarization and draw mesomeric structures)!
7. Give the three conditions necessary to have aromatic structures. Analyze the structure of cyclopentadiene/ cycloheptatriene whether they satisfy these conditions! Transform them to aromatic derivatives!
8. Determine the stabilization (resonance) energy of benzene using the following data: 130 kJ/mol, 240 kJ/mol. What kind of data are these? Interpret all calculations!
Organic halides, hydroxy compounds
9. Draw the structural formulae of the following compounds and rank them according to their reactivity in SN2/SN1 reactions! 2-chloro-2-methylbutane, 1-chloropentane, 1-iodopentane, vinyl chloride
iodobenzene, tert-butyl chloride, 1-chloropentán, 1-iodopentane
vinyl chloride, 1-chlorobutane, 2-bromobutane, 1-iodopentane
bromobenzene, benzyl chloride, 2-chlorobutane, 1-bromopentane
benzyl chloride, 2-fluoropentane, sec-butyl bromide, iodobenzene
tert-butyl chloride, propyl chloride, isobutyl chloride, 2-chlorobutane
10. Write conformational equilibriums and on the basis of information for E2 eliminationsinterpret the following observations. Use appropriate chair conformations for interpretation!
i) why are 2 products formed in reaction a) and why not in equal amounts,
ii) why is it that only one product is formed in reaction b),
iii) what is the reason for the rate difference?
11. Draw the energy diagram of SN2/SN1/E2/E1 reactions and insert structure/formula of the corresponding starting materials/products/intermediates/transition states. Indicate activation energies and interpret molecularity.
12. Draw the structure of the leaving groups formed in the nucleophilic substitution of the following compounds and the corresponding conjugate acids. Rank the leaving groups according to their leaving ability.
13. Interpret the acidity of alcohols/ phenols on the basis of ground-state polarization and stability of the alcoholate/phenolate anion (indicate and give symbols for bond polarization and draw mesomeric structures)!
14. Give part steps of the following nucleophilic substitution!
15. Indicate, which statements are true for SN2, SN1, E2 or E1 transformations!
a) takes place via carbocationg) rearrangement is possible
b) first-order kineticsh) reaction rate increases with increasing substitution on carbon
c) second-order kineticsi) reaction rate decreases with increasing substitution on carbon
d) anti eliminationj) pentacoordinate transition state
e) inversion during substitutionk) synchronous process
f) racemization during substitution
Reactions: 23–41
TEST3
Nitrogen-containing compounds
1. Interpret the basicity of ammonia and aliphatic/aromatic amines in the gas phase and in aqueous solution considering electronic factors and solvation.How basicity is the interpreted?Indicate and name bond polarizations and draw mesomeric structures when necessary; show formulae for the effect of solvation)! Use also graphical representation!
2. Give the synthesis of aromatic diazonium salts and interpret the reasons for using the acid in high excess!
3. Write the reaction of diazo coupling!Give reaction type, discuss the electrophilic nature of the diazonium ion (draw resonance structures) and interpret the necessity, character and role of the substituents!
4. Interpret the facile racemization of chiral amines (draw structures)!
Carbonyl compounds, carboxylic acids
5. Interpret the changes in reactivity of aliphatic and aromatic carbonyl compounds in AN reactions induced by substitution (indicate and name bond polarization and draw mesomeric structures when necessary)!
6. Most AN reactions of carbonyl compounds are equilibrium process. Exceptions are reductions (hydride addition) and addition of the Grignard reagent. Write the first step of each reaction and interpret!
7. Compare the characteristic reactions of alkenes and carbonyl compounds and interpret equilibrium nature of the latter!
8. Interpret acidity of enols on the basis of ground-state polarization and stability of the enolate anion (indicate and name bond polarizations and draw mesomeric structures)!
9. Interpret easy dehydration of aldols (write the reaction)!
10. Interpret easy enolization of pentane-2,4-dione (draw structures)!
11. Give a general definition for the active methylene group. Interpret the acidic character of hydrogens attached to the -carbon using nitromethane/acetaldehyde as examples (indicate and name bond polarization and draw mesomeric structures)!
12. Draw the structure of product(s) formed in each cyanohydrin synthesis. Which products are chiral, which show optical activity, and what is the isomeric relationship of these products? What method can be used to separate the isomers?
a) acetaldehydeb) benzaldehydec) acetoned)cyclohexanone
e) (R)- or (S)-glyceraldehydef) (R)-2-methylcyclohexanone
13. 2-Methylcyclohexanone and 3-methylcyclohexanone are chiral. One of the compounds undergoes racemization in the presence of a strong base. Draw the corresponding enol forms and interpret!
14. Which of the following chiral ketones undergo racemization in the presence of a strong base? Draw the corresponding enol forms and interpret!
15. Prepare the following compounds (give reagents and reaction conditions)!
I. from propanal
a) propan-1-olb) ethyl methyl ketonec) butan-2-old) propionic acid
e) dimethyl acetalf) propanamineg)cyclic acetal
II. using Grignard reaction (write also the mechanism!)
ethanol, isopropyl alcohol, tert-butyl alcohol, cyclohexanemethanol, diphenylmethanol, butan-2-ol (2 methods)
III.a) iodoform b) acetaldolc) acetaldehide cyanohydrind) benzenesulfonamide
16. Draw the structure of the product formed when acetaldehyde and pentan-3-one are reacted with the following reagents!
a) NaBH4b) PhMgBrc) OH–/ heatd) KMnO4 (cold or warm)e) EtOH/H+
f) ethylene glycol /H+g) Ag(NH3)2+h) I2/OH–
17. Write the haloform reaction and draw the formula of the following compounds. Which of these give the iodoform test? Interpret!
isopropyl alcohol, acetophenone, 2-methylcyclohexanone, pentan-3-one, ethanol
Carboxylic acids
18. Interpret the acidity of carboxylic acids on the basis of ground-state polarization and stability of the carboxylate anion (indicate and name bond polarizations and draw mesomeric structures)!
Reactions: 47–68
TEST SCHEDULES
Test1October 6 / 13Alkanes, alkenes, dienes, bond polarization, optical isomerism (21 pts)
Consultation: September 30
Test2October 27/November 10Aromatic compounds, organic halides, hydroxy compounds (22 pts)
Consultation: October 21
Test3November 24 / December 1Nitrogen-containing compounds, carbonyl compounds,
carboxylic acids (22 pts)
Consultation: November 18
General preconditions
To be qualified for exam: 3 successful tests
Conditions: 6 possibilities, any variations. Missed tests are considered to be unsuccessful (one of the six possibilities is lost).
Passing the tests (minimum requirement):12 points each
Each successful test can be retaken (improved) once.
Special conditions
An average of 80% (12 mark points out of 15, that is, in mark combinations: 3+4+5, 4+4+4, 2+5+5 or better) and no missed/failed testhas a bonus: exam written test is not required!
However, questions of nomenclature, stereochemistry and definitions are mandatory for everybody in exam. In exam, each test can be retaken (improved) once.
Internet materials:
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tests_1semester
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Exam1st
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