NATIONAL OPEN UNIVERSITY OF NIGERIA
14/16 AHMADU BELLO WAY, VICTORIA ISLAND, LAGOS
SCHOOL OF SCIENCE AND TECHNOLOGY
MARCH/APRIL 2014 EXAMINATION
COURSE CODE: CHM 422
COURSE TITLE: NATURAL PRODUCTS CHEMISTRY II.
TIME ALLOWED: 2HOURS
INSTRUCTION: ANSWER ANY 4 QUESTIONS.
(1) Write briefly on the following classes of terpenes.
(a) Hemiterpenes (3½ marks)
(b) Sesquiterpenes (3½ marks)
(c) Diterpenes (3½ marks)
(d) Monoterpenes (3½ marks)
(e) Sesterpenes (4 marks)
(2) (a) Describe any four tests for alkaloids (3 marks each)
(b) State any four properties of alkaloids (1½ mark each)
(3) Write short notes on the following:
(a) Ion-exchange chromatography (4 marks)
(b) Size-exclusion chromatography (3½ marks)
(c) Gas chromatography (3½ marks)
(d) High-Performance Liquid chromatography (3½ marks)
(e) Affinity chromatography (3½ marks)
(4) (a) List three Laboratory Methods of Organic-Solvent Extraction of Compounds (6 marks)
(b) Describe how you would extract the natural products in a plant tissue by Soxhlet extraction of chemical compounds using a 1:1 mixture of methylene chloride/methanol (12 marks)
(5) (a) Classify alkaloids according to the heterocyclic ring system they contain. (12 marks)
(b) Give a named example of each class of alkaloids mentioned above. (6 marks)
(6) (a) List any five spectroscopic tools for the structural elucidation of natural products (1½ mark each)
(b) Highlight the stages involved in the isolation and characterization of natural products (5 marks)
(c) List five properties of terpenes (5 marks)
For the 2015 – till date past questions for this course CLICK HERE
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