THE UNIVERSITY OF EDINBURGH
College of Science and Engineering
School of Chemistry
Chairman of the Board of Examiners: Professor D W H Rankin
External Examiners: Professors S T Bramwell, M Schröder and R J K Taylor
Senior Internal Examiners: Professor D A Leigh and Drs A C Jones and R M Paton
CHEMISTRY 3B
Paper 1: Topics from Semester 1
Tuesday 21st August 2007, 9.30am – 12.30pm
Answer SIX questions, taking at least TWO from Section A, TWO from
Section B and ONE from Section C.
Please answer each question in a separate book.
[The bracketed numbers shown against part of a question are only a guide to the
likely allocation of marks in that question.]
This examination will be marked anonymously.
Please enter your student examination number on each answer book.
A data sheet and chemical information booklet are provided with this
examination paper.
Unassembled molecular model kits may be used in this examination.
Only the calculator provided may be used in this examination.
SECTION A
1.
Answer all parts.
(a) Explain the meaning of the terms abstraction and addition in the context of
radical chemistry. Illustrate your answer with an example in each case.
[4]
(b) Describe one method for the generation of phenyl radicals (C6H5●) and give the
major products formed on reaction of phenyl radicals with (i) styrene
(CH2=CHPh) and (ii) 2-phenylpropane (C6H5CHMe2). Outline the mechanisms of
the reactions (i) and (ii).
[8]
(c) Write mechanisms to account for two of the following reactions. Give the
structures of other products that might be formed and identify intermediates
involved.
[8]
+
O
O
O
O
Me
Me
Me
Me
(i)
hν
+
(ii)
CHCl3
EtO- Na+
Cl
Cl
(iii)
N3
O
O
H
Me
Et
hν
O
N
H
O
Me
Et
2.
Answer all parts.
(a)
Suggest synthetic equivalents for the following synthons.
[4]
O
R
O
R
O
R
O
R
(b) Suggest reagents to carry out the t