Name Student Number M B44Y TEST 3 12 February 2003 TIME ALLWED: 100 MINUTES No models, calculators or other electronic equipment allowed. Tests and exams must be written in non-erasable ink. If you write in pencil or erasable ink, your right to have your test re-marked may be forfeit. Please do not use red ink. Answers all of the questions in the spaces provided. The number of marks available are indicated in parantheses by the questioni: total marks for test = 100. For convenience the spectroscopy questions are at the end of the test. Also given at the end of the very end of the paper is a table of characteristic IR, 1 NMR and 13 NMR frequencies and chemical shifts. Question Marks Total Marks Available 1. Reactions 20 2. Reagents 10 3. Synthesis 18 4. Mechanisms 12 5-8. Spectroscopy 40 TTAL MARK 100 1
1. (20 Marks) Give the major products of the following reactions. (There is a product for every question.) 3 N 3, 2 S 4 l l 3 2 2 N 2 1. NaN 2, l, 0 o 2. ul 3 2 l 1. All 3 2. Zn(g), l (d) 3 2 3 excess l 2, Fel 3 (d) (e) 3 2 2 3 KMn 4,, heat (e) (f) 3 2 2 3 2 2 l All 3 (f) (g) 3 N 3, 2 S 4 (g) N (h) (h) Sl 2 Na 3 (i) 3 3 excess PhN 2 (i) (j) 3 2 l NaN (j) 2
2. (10 marks). Provide reagents that achieve the following transformations. Note more than one step may be required. N 2 Br Br Br N 2 2 3 3
3. (18 marks) In the space provided, provide a synthetic route for converting benzene into the indicated compounds. You can use any other reagents. 2 2 2 2 3 N 2 l l N N 4
4. (12 marks). Give mechanisms for the following reactions. Indicte the flow of electrons by using curved arrows, and write the structures of the intermediate structures. The mechanism for the acid hydrolysis of amides. 3 2 N 2 N 2 3 2 4 The mechanism for the reaction known as protodesilylation. SiMe 3 2 S 4, 2 SiMe 3 5
5. (6 marks). ow many peaks would each of the following molecules have in the 1 NMR spectra and in their 13 NMR spectra? 3 3 ( 3 ) 3 3 3 3 2 3 l - No. of 1 NMR peaks No. of 13 NMR peaks 6. (6 marks) Draw a splitting diagram for the b proton if J bc = 8 and J ba = 4. l l c 2 a b 7. (4 marks). ompound A ( 10 18 ) has a single sharp peak at 1.2 ppm in its 1 NMR spectrum. What is its structure? 8. (24 marks). The IR, 1 NMR and 13 NMR spectra for compounds B,, D and E are shown on the next pages. Determine the structure of these compounds and draw them below. B ( 8 8 2 ) ( 5 10 2 ) D ( 7 14 ) E ( 9 10 ) 6
MB44 Test February 12, 2003 - Answers 1. (20 Marks) Give the major of products of the following reactions. (There is a product for every question.) 3 N 3, 2 S 4 3 N 2 3 l l 3 2 2 (d) (e) N 2 3 2 3 3 2 1. NaN 2, l, 0 o 2. ul 2 3 3 2 l excess l 2, Fel 3 1. All 3 2. Zn(g), l KMn 4,, heat (d) (e) N 2 l l l 3 2 2 2 2 3 ortho l 3 2 3 l (f) 3 2 2 3 2 2 l All 3 (f) 3 3 2 2 3 ortho (g) 3 (h) N N 3, 2 S 4 Sl 2 Na 3 (g) (h) 3 N 2 N 3 (i) 3 3 excess PhN 2 (i) 3 NPh PhN 3-3 (j) 3 2 l NaN (j) 3 2 N 1
2. (10 marks). Provide reagents that achieve the following transformations. Note more than one step may be required. N 2 1. 2 /Pd or Fe/l 2. NaN 2,, 0 o 3. eat Excess Br 2, 2 Br Br Br 1. 3 l, All 3 2. KMn 4, 1. Sl 2 2. 1. or -, 2 2. 3 2, or Sl 2, then 3 2 N 2 2 3 3. (18 marks) In the space provided, provide a synthetic route for converting benzene into the indicated compounds. You can use any other reagents. 2 2 2 2 3 l 2 2 2 3, All 3 2 2 2 3 N 3 2 S 4 N 2 Zn(g),l or 2 NN 2, Na 2 2 2 3 N 2 2
l NaN 2 2 S 4 l ul N 2 l 2,Fel 3 N2 2, Pd N 2 NaN 2, l N 2 l l l N N NaN 2, 2 S 4 l N 2 N 2 /Pd 2 l 4. (12 marks). Give mechanisms for the following reactions. Indicte the flow of electrons by using curved arrows, and write the structures of the intermediate structures. The mechanism for the acid hydrolysis of amides. 3 2 N 2 3 2 N 2 3 2 N 2 3 2 N 2 2 2 3 2 N 4 3 2 N 3 3 2 N 3 The mechanism for the reaction known as protodesilylation. SiMe 3 SiMe 3 Me 3 Si 2 Me 3 SiŠ 2 - Me 3 SiŠ 3
5. (6 marks). ow many peaks would each of the following molecules have in the 1 NMR spectra and in their 13 NMR spectra? 3 3 ( 3 ) 3 3 3 3 2 3 l - No. of 1 NMR peaks 4 5 1 No. of 13 NMR peaks 8 7 1 6. (6 marks) Draw a splitting diagram for the b proton if J bc = 8 and J ba = 4. l l c 2 a b 4 z 8 z also 4 z 4 z 4 peaks of equal intensity, each separated by 4 z 7. (4 marks). A compound A 10 18 has a single sharp peak at 1.2 ppm in its 1 NMR spectrum. What is its structure? 8. (24 marks). The IR, 1 NMR and 13 NMR spectra for compounds B,, D and E are shown on the next pages. Determine the structure of these compounds and draw them below. A ( 3 ) 3 ( 3 ) 3 B ( 8 8 2 ) ( 5 10 2 ) 3 3 2 2 3 D ( 7 14 ) E ( 9 10 ) 3 2 2 2 2 3 3 4