ORGANIC CHEMISTRY: MALE CONTRACEPTIVES A research chemist executed studies on the synthesis of chemicals which might have potential as male contraceptives. The 'lead' compound chosen was 2,3-diaminopropanoic acid (DAP):
The scientist's reasoning for choosing this particular compound was complicated, though pivotal to the choice were biological and chemical similarities of the following four compounds. Indolyl-3-ethanoic acid, "T", was the first plant growth regulator to be identified and characterized (1934-1936); its effects are observed in the familiar tropic activities of plants (e.g., the phototropism first noted by Charles Darwin in 1880), and it is known to be directly involved in both protein and RNA synthesis. Ethene, "U", perhaps surprisingly, is also a plant growth regulator; in this context, it is used commercially as a method of ripening fruit.
Spermidine, "V", is a natural tri-amine present in the seminal fluid secreted by mammals. 1,2-Diaminoethane, "W", forms numerous platinum(II) compounds; some of these show anti-cancer activity and, therefore, most probably affect the DNA of cancerous cells.
1. Suggest one reason why the exponential increase in human population is causing concern. ___________________________________________________  2. Naturally occurring female hormones, which prevent follicle growth and ovulation, are produced synthetically and incorporated into several contraceptives. Name two such hormones. _______________________________  3. State two functional groups which are shared between DAP and one or more of the compounds "T" to "W". _____________________________________  4. What do the abbreviations RNA and DNA stand for? __________________ _______________________________________________________________________  5. Compounds "T" to "W" are directly or indirectly involved with which two characteristics of living organisms? ______________________________  6. Plants biosynthesize acid "T" in response to the stimulus of light. Name two other tropisms and their corresponding stimuli. ______________ _______________________________________________________________________ 
7. Ripening fruit requires only a small quantity of ethene, "U"; this is obtained by the catalytic dehydration of ethanol. Construct the symbol equation for this reversible reaction. _________________________ _______________________________________________________________________ _______________________________________________________________________  8. Suggest the reason why spermidine, "V", is called a 'tri-amine'. _______________________________________________________________________  9. Noting that certain platinum(II) compounds of "W" show anti-cancer activity, suggest one other metal ion which might also be effective. _______________________________________________________________________  10. The synthetic route chosen by the scientist to 2,3-diaminopropanoic acid, a known compound, is shown below:
(a) State the colour change observed during the course of the addition reaction of bromine with alcohol "X". _________________________________ (b) Alcohols "X" and "Y" are liquids at room temperature, with similar boiling points. What physical technique could be used to separate a mixture of "X" and "Y"? _______________________________________________ (c) Name a reagent which could oxidize alcohol "Y" to dibromo-acid "Z". _______________________________________________________________________ (d) Name the gas evolved when a mixture of dibromo-acid "Z" and aqueous sodium hydrogencarbonate was warmed. __________________________________ (e) The conversion of dibromo-acid "Z" to DAP involves a substitution reaction and a reduction (step 2). Suggest the purpose of the palladium in this second step. __________________________________________________ (f) Suggest one physical test used to confirm that DAP, a crystalline substance, had been obtained. _________________________________________  (g) The scientist considered an alternative to the synthetic route to DAP; specifically, a fermentation process using propene as the starting material. Suggest two potential advantages of this process. ___________ _______________________________________________________________________  (h) Tests on laboratory rats showed that DAP was partially successful; thus, rats injected with DAP were less fertile than the controls (i.e., those used to isolate the independent variable; these were not injected with DAP). Accordingly, more compounds were synthesized - including two isomers obtained by the hydration of compound "X". Draw the structural formula of each isomer. _______________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________  (i) This research was shelved as soon as some potentially devastating news began to circulate in the early 1980s. Suggest one disadvantage in using chemical contraceptives. ________________________________________ _______________________________________________________________________ 
Dr. R. Peters Contents' List
Metals - Introduction (1)