DHS_H3_CHEM

© DHS 2011 This question paper consists of 15 printed pages and 1 blank page. [Turn over Name: Index Number: Class: DUNMAN HIGH SCHOOL Preliminary Examination 2011 Year 6 H3 CHEMISTRY 9812/01 Paper 1 23 September 2011 2 hours 30 minutes Additional Materials: Data Booklet Writing papers INSTRUCTIONS TO CANDIDATES 1 Write your name, index number and class on this cover page. 2 Answer any five questions. 3 Start each question on a fresh sheet of paper. 4 Write in dark blue or black pen on both sides of the paper. 5 You may use a soft pencil for any diagrams, graphs or rough working. 6 Do not use staples, paper clips, highlighters, glue or correction fluid. 7 You are reminded of the need for good English and clear presentation in your answers. 8 The number of marks is given in brackets [ ] at the end of each question or part question. 9 At the end of the examination:  Fasten all work securely together with the Cover Sheet on top.  Hand in the question paper separately. 10 The total marks for this paper is 100 marks.

2 © DHS 2011 9812/01 [Turn over 1 (a) 1H NMR is a common analytical technique used to determine the molecular structures of various compounds. (i) Outline the basic working principles of NMR. [2] An unknown compound A, C 5H10O2, was synthesised in the laboratory. It is used to manufacture various propionates which are used as anti–bacterial agents. Its MS, IR and 1H NMR spectra data given below. (ii) Deduce the structure of compound A, giving your reasoning. [8]

3 © DHS 2011 9812/01 [Turn over (b) Opium is the air–dried milky exudate, or latex, obtained by incising the unripe capsules of the opium poppy Papaver somniferu. It contains up to 12% morphine, an alkaloid, which is frequently processed chemically to produce heroin for the illegal drug trade. Morphine is also used as a narcotic analgesic and for the treatment of dry cough and diahorrea. morphine (i) Explain the term narcotic analgesic, using morphine as an example. [1] (ii) Narcotic and non–narcotic analgesics act differently to prevent pain. Briefly outline the modes of action of non–narcotic analgesics. [1] (iii) Assign the stereochemical configuration at C1, C2 and C3. [2] (c) Many drugs, like morphine, contain cyclic ether in their structures. Shown below is the puckered conformation of a cyclic ether, tetrahydrofuran. tetrahydrofuran (i) Suggest a simple synthetic pathway for the formation of the cyclic ether, C, from compound B. State clearly all reagents and conditions required for the proposed steps of the synthesis. [4]     (ii) Draw two different conformers of cyclic ether, C, showing the positioning of the substituent on the ring. State whic