Hour Test Two S12 - Practice exam PDF

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Chemistry 354: Spring 2012 Hour Test Two Feb 22 2012 This test has 10 pages including this coverpage. You have 50 minutes to complete this test When drawing structures you can use any convention (bond line, condensed etc) EXCEPT when specifically asked otherwise. Be consistent with the convention you choose and include resonance structures where necessary. In questions where you have some choice YOU MUST indicate clearly which parts are to be omitted, if not indicated ONLY the first answers will be graded. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ I hereby pledge that I have neither given nor received unauthorized aid on this test.

________________________________ Signature ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Section I. II. III. IV.

Multiple choice Transformations (8 of 10) Mechanisms (2 of 3) Synthesis (1 of 2)

15 48 24 15 Total 102

____ ____ ____ ____ ____

I.

Multiple choice Provide the answer requested.(1 pt each)

1.

The Diels Alder reaction is a concerted reaction, which means A) The product contains a cyclic ring B) The diene must be in the s-cis conformation to react. C) All changes in bonding (bond making and bond breaking) occur simultaneously. D) It is an endothermic reaction E) Both exo and endo products are formed

2.

Which of the following dienes can undergo the Diels-Alder reaction?

III

II

IV

I

A)

I

B)

II

C)

III

D)

IV

3.

Which of the following compound(s) have the longest

A) E)

(E) 2-pentene B) (Z) 2-pentene 1,3,5-hexatriene

4.

What is the IUPAC name for the following compound?

C)1-pentene

E)

All of the these

max in UV spectroscopy?

D)1,3-hexadiene

OH

Br

A) E)

5.

5-bromophenol B) 3-bromophenol 1-bromophenol

C)

5-bromoaniline

D)

3-bromoaniline

A) B) C) D) E)

Which one of the following statement is not true for a compound to be considered as aromatic? The compound must be cyclic and planar The compound must be monocyclic. The compound must have a conjugated system with p orbital at every vertex The compound must satisfy Hückel’s rule –must have (4n + 2) pi electrons. none of these

6.

The number of π electrons present in an antiaromatic compound:

A)

4n + 2

B)

2n + 2

C)

4n

D)

none

E)

none of these

7.

Which one of the following compound is aromatic?

S

O

II

I

A)

I

8.

IV

III

B)

II

C)

III

D)

IV

E)

Which one of the following compound is antiaromatic? H

H N

H H N

N

N

N H

N

I

III

IV

II

A)

I

9.

Which one of the following compounds is aromatic?

B)

II

C)

H

III

D)

IV

E)

none of these

E)

none of these

H

B

I

B)

O

N

II

III

II

I

10.

Which one of the following compounds is most acidic?

II

I

I

B)

C)

IV

A)

A)

None of these

III

C)

IV

IV

III

II

D)

III

D)

IV

E)

none of these

11. Which one of the following compounds would exhibit seven signals in its 13C NMR spectrum? O

O

O

I

II

12. A) B) C) D) E)

Which of these is the rate-determining step in the electrophilic aromatic substitution of benzene? Formation of an electrophile Formation of sigma complex. Loss of proton from sigma complex. Addition of electrophile & loss of proton None of these

13.

The electrophile in the sulfonation reaction of benzene is: B)

H2SO4

C)

C)

III

D)

SO3+

IV

D)

E)

V

I

SO2+

II

IV

III

A)

A)

B)

O

O

H2SO3

V

E)

SO3

14.

Which one of the following reactions is most likely to give a polysubstituted product?

A) D)

Friedel-Crafts alkylation B) Friedel-Crafts acylation Sulfonation E) Halogenation

C)

Nitration

15. Which one of the following compounds will be most reactive towards bromination reaction? A) D)

nitrobenzene B) benzene E)

anisole C) benzaldehyde

acetanilide

II. Transformations. Supply the missing starting material, reagent(s) or missing products for 8 of the following 10 transformations. Include stereochemistry if needed. If more than one product is formed circle the major product. Indicate clearly which two answers are to be omitted. If you do not indicate the first 8 answers will be graded. OMIT TWO (6 points each) a)

H2SO4

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ b)

Br NO2 NaNH2

NO2 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ c) O NHCCH3

CH 3Cl/AlCl3

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ d) CO2H

Cl

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

e)

Cl

1. NaOH, heat 2. H 3O+

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ f)

MeO Na/NH3 EtOH ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ g) O COH + COH O ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ h) CN + CN

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ i) HBr 40 0C

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

j)

O

Mechanisms. Provide detailed mechanisms for 2 of the 3 reactions below. Partial mechanisms will receive partial credit. Your mechanism must explain the regiochemistry or product distribution of a reaction if appropriate. Use curved arrows properly. OMIT ONE (12 points each)

IV.

a) SO3H SO3H SO3 H2SO4 N

N

N

N

SO3H

MAJOR NOT FORMED For this question your mechanism must explain why the substitution on C-3 is the major product and why C-2 and C-4 products are not formed.

b) NH 2

Cl NaNH 2 O 2N

O 2N

c)

CO2H

CO2H Na/NH3 EtOH

USE NEXT 2 PAGES FOR YOUR ANSWERS

SPACE FOR FIRST MECHANISM

SPACE FOR SECOND MECHANISM

IV.

Synthesis. Design the synthesis of one of the following compounds from benzene. You may use any inorganic and small organic reagents as necessary. Assume ortho and para isomers can be separated. You will receive partial credit for retrosynthetic analysis and/or partial routes. Your answer will be graded based on the efficiency of the route chosen. (15 points) NH2

OH SO3H

Br

NO2...