2. Answer ALL parts of this question. (a) Answer BOTH parts (i) and (ii). (i) The diagram shown below shows the electronic structure of pyrrole. Draw similar diagrams for quinoline and oxazole, explaining the contribution of the lone pairs and comment on the aromaticity in each case. H H = H H pyrrole H quinoline oxazole (4 marks) (ii) Thiophene, 1, can be nitrated with acetyl nitrate, 2, to give a mixture of 3 and 4 in an approximate ratio of 6:1. Give a mechanism and account for the regioselectivity of this reaction. . NO2 NO2 3 (7 marks) (b) Pyridine N-oxide, 5, undergoes reaction with acetic anhydride, 6, to give 7 as the major product. Give a mechanism for this reaction. N 5 5 (4 marks)