Microsoft word - optd- medicinenew.doc

Nicotine
Nicotine is, of course, present in tobacco, in fact about 5 mg in each cigarette, although only
between 0.2 and 3.5 mg are actually absorbed. Once in the body it quickly reaches the
central nervous system where it has several effects including a reduction in urine output (no,
really!) and a lowering of reflex times. The knee jerk reaction is significantly slower in
smokers.
Long term, things get much more serious as the table above indicates. Remember that nicotine is just one of many chemicals inhaled when smoking and from the others any number of ailments can be acquired. Lung cancer is the most obvious. Nicotine is also used as an agricultural insecticide – a thought to ponder on when next reaching for a cigarette! Nicotine (left) and Caffeine, both tertiary amines and both stimulants Nicotine is what is called a tertiary amine. This means there is (at least) one nitrogen atom which has three carbon fragments coming from it, so for nicotine it is the N in the pentagon with the methyl group (-CH3) coming of it. Caffeine has no less than three tertiary amine groups and has a passing resemblance to
nicotine. It is of course the stimulant that is found in tea, coffee and cola and can promote
mild dependence. It is also a mild diuretic, which means it does the opposite of nicotine and
encourages the production of urine. A cup of coffee may contain 100 mg of the drug and for
those who are not used to it, four cups a day may have a noticeable effect on behaviour, in
particular an increase in anxiety and problems with sleeping (insomnia).
Stage 2: The three products from stage 1 are now mixed and then split into three separate containers. Each container is then exposed to an excess of one of the three amino acids. This results in all combinations of dipeptides (2 joined amino acids) being formed. Once again the excess reactant is washed away. Stage three: Once more the three containers are mixed and once more they are split into three. As before each container is exposed to an excess of one of the three amino acids, which after the reaction is washed away. At this point we will have tri-peptides, and all of the 27 possible structures will have been made. There is no need to stop there, and quite quickly a combinatorial library of thousands of different structures will have been created. Note that a solid phase is being used as a base upon which the reactions take place. Once you have got the peptides as long as required it is a relatively simple step to detach them from the resin bead. This technique is now being used by pharmaceutical companies to synthesise a wide range of potentially useful molecules. It is now fully automated. 10. Mind-altering Drugs (HL)
Lysergic Acid Diethylamide –better known as LSD, or as The Beatles put it, ‘Lucy in the Sky with Diamonds’

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