(A)(B) (C) (D) (E)

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CHEM 2OB3

Test 1 February 9, 2007

VERSION 1

NAME (First and Last):_________________________ ID#:__________

Lab Station:______

Please circle your lab section.

Group Tut. Room Monday Tuesday Wednesday Thursday Friday

I ABB 162 L01 L02 L03 L04 L05

ABB 270 L18 L19 L20 L21 L22

II ABB 162 L13 L14 L15 L16 L17

ABB 270 L06 L07 L08 L09 L10

Duration: 90 minutes

Instructors: Drs. Capretta and Berti

Instructions:

This examination paper consists of 13 pages, containing 15 (fifteen) multiple choice (MC) questions, and 5 (five) short answer questions. Only Casio FX 991 calculators and a molecular model kit may be used.

You are responsible for ensuring your copy of the question paper is complete.

You are responsible for ensuring all answers are in the correct place, and that you follow the correct procedure for filling out the scan sheet.

All McMaster rules and procedures relating to Academic Dishonesty and Academic Integrity

apply to this exam; all violations will result in a penalty. Students must do their own work. A program designed to detect similar answers will be used for this exam.

You MUST also complete ALL the information at the top of this page.

Questions 1 - 15

Question 16

Question 17

Question 18

Question 19

Question 20

Total

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NOTE: IT IS YOUR RESPONSIBILITY TO ENSURE THAT THE ANSWER SHEET IS PROPERLY COMPLETED. YOUR EXAMINATION RESULT DEPENDS UPON PROPER ATTENTION TO THESE INSTRUCTIONS.

The scanner, which reads the sheets, senses the bubble shaded areas by their non-reflection of light. A heavy mark must be made, completely filling the circular bubble, with an HB pencil. Marks made with a pen will NOT be sensed. Erasures must be thorough or the scanner will still sense a mark. Do NOT use correction fluid on the sheets. Do NOT put any unnecessary marks or writing on the sheet.

1. On SIDE 1 (red side) of the form, in the top box, print your student number, name, course name, and the date in the spaces provided, in pen. Then you MUST write your signature, in the space marked SIGNATURE.

2. In the second box, mark your student number and test or exam version number (1, 2, 3 …) by filling in the corresponding bubbles underneath, in pencil. Then fill in your section number; section 01 is Dr. Capretta’s section, section 02 is Dr. Berti’s section.

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Section 1 – Multiple Choice [1 2/3 marks for each].

NOTE: For the first four questions, choose reagents from the following list that are required to accomplish the transformations shown. For example, if a transformation requires an acid then a base, then the answer would be "d then j".

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O

O

Br

O

O

OH

?

(A) a then p then g (B) a then p then d (C) j then n

(D) e then b then g (E) a then b then p

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CH3O

O OH

CH3

CH3O

O OCH2CH3

CH3 ?

(A) b

(B) m

(C) d (D) h (E) c

O / H+

n. O

p. a. Mg

e. Na

i. HCN

m. HOCH2CH2OH / H+

b. CH3CH2Br

f. 1. LiAlH4, 2. H2O

j. NaH

c. CH3CH2OH / H+

g. CrO3 / H2SO4

k. CH3OH

o. NaOH / H2O

d. H2O / H+

h. PCC

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O

Cl O O OMe

?

(A) m then a then p (B) k then l

(C) n then l (D) m then l

(E) m then a then o

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O OH

NH2

(A) f then k then d (B) k then l

(C) i then d (D) i then f

(E) m then a then o

(5) Which of structures I to III are epimers of α-D-glucopyranose?

O OH HO

HO

HO OH

O OH HO

HO HO

OH

O OH

HO HO

HO OH

I II III

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(6) Which of these represents an epimer of D-glucose? H OH H HO OH H OH H

CH2OH CHO H OH H HO OH H H HO

CH2OH CHO HO H H HO OH H OH H

CH2OH CHO

I II III

(A) I only (B) I, II and III (C) II and III (D) I and II only (E) III only

(7) Melibiose is a disaccharide made up of a D-glucopyranose unit whose C6 hydroxyl is bound to a D-galactopyranose unit through an α-glycosidic linkage (galactose is the C-4

epimer of glucose). Which structure represents α-melibiose?

O O HO HO HO OH O OH HO HO HO O HO HO HO OH O OH HO HO HO O O O HO HO HO OH O OH HO HO HO O HO HO HO OH O OH HO HO HO O O HO HO HO OH O OH HO HO HO O

(A) (B) (C)

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(8) Which of these substances could exhibit mutarotation?

O O

HO HO

HO OH O

OH

HO

HO HO O

OH HO

HO

HO OMe

O

O O H

CH3OCH2 OH

H

I

II

III

(A) II only (B) I, II and III (C) I and III only (D) I only

(E) II and III only

(9) What is the relationship between the following compounds?

H OH

OH H

CH2OH CHO

O

H H

H O

H

CH2OH CHO

(A) anomers (B) enantiomers (C) meso compounds (D) equivalent structures (E) diastereomers

(10) What is the relationship between the following compounds?

O CH2OH

OH OH OH

O CH2OH

OH OH OH

(A) anomers

(B) meso compounds (C) enantiomers

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(11) How many possible intramolecular aldol condensations can this substance undergo? O

O Ph

(A) 0 (B) 1 (C) 2 (D) 3 (E) 4

(12) Which of these starting materials gave this product under acidic conditions?

O

O

O

H

O

O

O O

O

O

O

O

CH3

(A) (B) (C) (D) (E)

(13) Which of the following is the Haworth projection of β-D-galactose (the 4-epimer of β-D-glucose)?

O CH2OH OH

OH

OH

OH O

CH2OH OH

OH

OH OH

O CH2OH OH

OH OH OH

O CH2OH

OH

OH OH OH O

CH2OH

OH OH

HO OH

(A) (B) (C)

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(14) An acetal was hydrolyzed in 18O-labeled water. Which would be the correct products?

O

O OH

H318O+

H

(A)

(B)

(C)

(D)

(E)

O

H H

18O OH HO 18O

H HO OH

HO

O

H H

18O 18OH HO

O

H HO OH H

18O

18O

H H

18O 18OH H18O

(15) Rank the following carbonyl compounds from most to least electrophilic (susceptible to nucleophilic attack at the carbonyl carbon).

O

H O

H

O

F

O

(a) (b) (c) (d)

(A) b > c > d > a (B) a > b > c > d (C) d > c > b > a (D) c > d > b > a (E) a > d > c > b

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Section 2 – Short Answer

Question 16 [10 marks] The syntheses of certain antibiotics called pseudomonic acids include the following transformations.

(i) For the steps labelled (a) - (g), provide the reagents and conditions in the table below that will allow for each conversion.

(ii) The acidic hydrolysis of compound H results in three organic compounds: X, Y and Z. Provide the structures for these compounds in the box provided.

O

O OH

O O O

OH

O O O

Br

O O O

Br OH

O H O O

O

Br O

O O O

O

CN O

O

O O O O

O OH

O

O O O O

O OH

(a) (b)

(c)

(d) (e)

(f)

(g)

H+, H

2O, heat

COMPOUND X COMPOUND Z

Reagents:

(a) (b)

(c) (d)

COMPOUND Y

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Question 17 [12 marks]

Each of the following reactions has been reported in the chemical literature and gives a

predominance of a single product. Provide the MAJOR products necessary to complete TWELVE of the FIFTEEN reactions below. If more than 12 are attempted, the first 12 will be marked.

CH3O CH3O

CH3O

CH2OH Br

(a) PCC

CN 1. LDA

2. CH3I (b)

O

H

KOH

H2O (c)

Br

O

H 1. PPh3 2. n-BuLi

3. (d)

O H

CH3NO2 NaOH, EtOH (e)

O

CH3 HCN

(f)

NH2

O

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O Br2

acetic acid (h)

O

O

NaOCH3, MeOH

heat (i)

H O

CH3

HS SH

1. H+,

2. Raney Ni (j)

CO2H

1. SOCl2

2. LiAlH(OtBu) 3, Et2O

-78C (k)

1. O3

2. Zn , HOAc (l)

CN 1. MeMgI

2. H3O+

(m)

O

H2

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Question 18 [6 marks]

Circle and name all the functional groups in this molecule (there are seven, one of which is already identified). Circle the minimum number of atoms that are required to define each functional group.

O

O

N O

NH2+ OH

O O

H

aldehyde

CN HO

Question 19 [4 marks]

Pyridoxal phosphate is a cofactor in the alanine racemase-catalyzed epimerization of alanine. Starting from the external aldimine with L-alanine (shown), show the mechanism for the next step

of the reaction. Draw arrows as appropriate on the structure shown, and draw the next structure. (Only the next step, not the whole reaction.)

N

N

H

O

2-

O

3

P

O

-H

+

H

+

H

H

3

C

COO

-:B-enzyme

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Question 20 [5 marks]

In order to make dimethylcyclohexanones (2 or 3) from 2-methylcyclohexanone (1) and CH3-I, it

is necessary to form the enolate using either Na+-OEt or LDA.

O O

I CH3

1 2

or

O

3

(a) Which base would give the thermodynamic enolate? (b) Draw the thermodynamic and kinetic enolates:

thermodynamic kinetic

Figure

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References

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