Organic Chemistry II CHM 2211 Sample Exam 2 Answer Key

35 downloads 75236 Views 101KB Size Report
CH3CH2P(C6H5)3. CH3. C. H3C. NH. CH. CH2. C. CH2. CH2. CH2. O. O. Organic Chemistry II. CHM 2211. Sample Exam 2 Answer Key. I. Write Structures for ...
Organic Chemistry II CHM 2211 Sample Exam 2 Answer Key I.

Write Structures for the compounds named below: (12 points) CHO

O H2N

C H3C

NH2

CH3

_______________________ Acetone

_________________________ Hydrazine

________________________ Cyclohexane carbaldehyde

NH

II.

H3C

O

CH2 CH2 CH2 C CH2 CH

C

CH3CH2P(C6H5)3 _______________________ An ethyl ylide of triphenylphosphine

O

CH3

_________________________ Any imine

________________________ 3-Oxo-6-phenylhexanal

Name the compounds whose structure is shown below: (6 points) O

O CH3

C

O

CH3

CH3

CH3 CH CH2 CH 2-methylcyclopentanone _______________________

OH

3-methylbutanal _________________________

O

C

CH3 CH CH2 C CH3 4-hydroxy-2-pentanone _______________________

CH3

O

O

H

acetophenone ________________________

H

formaldehyde (methanal) _________________________

O

CH3 CH CH2 CH2 CH 4-methoxypentanal ________________________

III.

Fill in the Blanks (13 points)

1.

Why does the carbonyl carbon have a partial positive charge? Because of the electron withdrawing nature of the oxygen

2.

When an aldehyde is considered as a group, it is called carbaldehyde group. When a ketone cannot be named as an -one, it is named as an oxo- group.

3.

An oxidizing agent that can oxidize an alcohol to an aldehyde without going all the way to an acid is (write the whole name) pyridinium chlorochromate (PCC).

4.

CrO3 in H2SO4 is called Jones’ Reagent while R2LiCu is called Gilman’s reagent.

5.

A positive Tollen’s test for aldehydes is indicated by the formation of a silver mirror on the test tube.

6.

Two important types of diols are geminal and vicinal. Which is the least stable? Geminal diols are unstable.

7.

The Clemmenson reduction will reduce a(n) ketone or aldehyde to a(n) alkane (-CH2).

8.

Which would be easier to identify using IR spectroscopy, an ether or a ketone? ketone

9.

Alcohols are capable of hydrogen bonding with water but aldehydes are not. (T/F) False

10.

Which would be easier to oxidize with Jones' Reagent, a ketone or an aldehyde? aldehyde

IV. Write a multi step reaction mechanism for the reaction of phenylmagnesium bromide ( MgBr) with acetone to form an alcohol. Indicate intermediates that may or may not be isolated. Use curved arrows to indicate electron attack and show charges and intermediates. (9 points) O C

H

H3C

CH3

MgBr

OH2

O C

H3C

CH3

MgBr

OH H3C

V. 1.

CH3

H2O

Complete the following reaction equations by filling in the missing information: (40 points) HCN CH3CH2OH

H2SO4

CN -

Cl

SOCl2

CH3 CH2 C O

H2O, heat CH3

CH3

O

MnO4- , OH-

2.

heat O

O

3. AlBr3

+ t-But-Br

CH3

4.

OH

tert-butylbenzene

Na2Cr2O7 H

MnO4 , OH

No Reaction (no benzylic H)

No Reaction (tertiary alcohol)

/ H2O

O

5.

O

CH2

AlCl3

+ H3C Cl

6.

H3C

O

CH2 CH2

LiAlH(OtBu)3

O CH3 CH2 CH2 CH

Cl

CH3O

O

OCH3

H

7. + 2 CH3OH

O

OH

H3O

8.

C

+

H3C

HCl

C

H3C

CH3

CH3

Cl

9.

O

Na2CrO7

CH2 OH

C

OH CH3

H3O

HC

CH3

O

CH3

10.

HC

+ HCN

CH3 CH2 CH CH2 C CH3

CH3

CH2

1. LiAlH4

CH2

2. H3O

HC

CH2 OH

CH2

O

11.

CH2

HC

OH

CN

CH3

CH3

+ CH3-NH-CH 3

NH2

N CH3

12.

NH

OH

CH2O + NH3

C

H2O 13.

CH 3CH 2P(

H

CH 2O

H

CH3CH=CH2

OH

14. O

+ N2H4

O

CH2 OH

15.

PCC

C H

16.

1. DIBAlH

CH3CH2CHO

CH3CH2COOH 2. H3O O

17.

CH3 CH CH C O CH3 O

1. LiAlH4 2. H3O OH

18. 1. NaBH4 2. H3O

CH3CH=CH-CH2-OH + HO-CH3

O

O

19. + HCN

O

H3C

20.

C

NC

O

Ag2O, NH4OH

H

+ Ag (mirror) OH

VI. Multiple Choice (Circle the letter of the best answer) (20 points)

1.

Below might be the spectrum of a carboxylic acid. Which two features make this likely?

a. b. c. d.

2.

Which compound will reduce C=O but not C=C (at least not much)? a. b. c. d. e.

3.

Jones’ Reagent PCC LiAlH4 NaBH4 Chromic Acid

Which of these is not an oxidizing agent? a. b. c. d. e.

4.

The broad peak above 3000 cm-1 and the sharp peak at 1710 cm-1 The peaks at 1240 and 1090 cm-1 The sharp peak at 3000 cm-1 and the sharp peak at 1240 cm-1 This is probably not the spectrum of a carboxylic acid.

PCC DIBAH Na2Cr2O7 in H2SO4 Jones’ Reagent Hypochlorite

Alkoxymercuration followed by borohydride reduction would be used to produce a. b. c. d. e.

an alcohol from an alkene. an aldehyde from alcohol. an acid from and alkyne. an ether from an alkene. an alkene from an aryl halide.

5.

Which of the following is not a common reaction of aldehydes? a. b. c. d. e.

6.

When CN-1 is reacted with carbonyl compounds followed by protonation of the oxygen, what do we call the products? a. b. c. d. e.

7.

make the compound soluble. oxidize the compound. confirm the identity of a compound by the MP of the derivative. make the compound colored. produce a Grignard reagent for further reaction.

How would you easily tell the difference between a proton NMR (1HNMR) and a carbon (13CNMR) spectrum? a. b. c. d. e.

10.

Alcohols Aldehydes Ketones C=O Methyl on a carbonyl

2,4 DNP derivatives of carbonyl compounds are often made to a. b. c. d. e.

9.

Cyanohydrins Nitriles Ketones Imines Enamines

In proton NMR, which compound or groups will show a characteristic peak near 10 ppm? a. b. c. d. e.

8.

Nucleophilic acyl addition Nucleophilic acyl substitution alpha Substitution Carbonyl condensation Reduction to a ketone

by looking at the size of the peaks by looking at the location of the peaks by looking at the horizontal scale by looking at peak splitting by looking for the internal standard peak

Hemiacetals and acetals are often found in a. b. c. d. e.

carbohydrates. proteins. fats. oils. DNA.