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)
You can get the exam summary answers for this course from 08039407882
Check anoda sample below
