Aspirin, part 2 of 3, Physics Heureka page 21-22

Aspirin, part 2 of 3

Aspirin and various NSAID drugs work in the same way in the body, but aspirin differs because it irreversibly affects cyclooxygenase (COX) enzymes. Earlier in history, salicylic acid was often given to patients (this is still in use on the market, for external use though). This is an aromatic carboxylic acid found naturally in small amounts in various plants, as a hormone. Willow wood is most used to extract C7H6O3 from. Salicylic acid has a cyclohexagon with 6 units coal, and then there is one carbon atom too that stands out in that structure. Aspirin also has an aromatic ring, i.e. a cyclohexagon with electrons inside that move around fast (it has been a rearranged salicylic acid since 1899). A chemist named Hoffman added an acetyl group to create aspirin, and it is that part of the molecule (added in the laboratory) that is transferred to the active site of the COX enzyme, so that painful, hormone-like prostaglandin substances do not must be able to be produced.

There are many different kinds of carboxylic acids that have a -COOH group that makes the acid acidic. As a rule, these are not strong and their protolysis is in some sort of equilibrium. This means that the protons move back and forth between the water molecule and its original -COOH group. A simple example of an aromatic carboxylic acid is benzoic acid which has a benzene ring (a cyclohexagon) and a -COOH group. Sodium benzoate, C7H5O2Na, is a preservative (E211) that is abundant in lingonberry jam. Also in the pharmaceutical industry, C7H5O2Na is added, and this is a good lubricant on tablets (it gives a slide), and the preservative is often used in liquid medicines. This function for the tablet form can also be that it is an explosive (opens the item in the body). Carboxylic acids usually have difficulty dissolving in water. The solvent must be organic, because they are organic acids themselves. They are hydrocarbons of different lengths with different numbers of -COOH groups.

C3H6O2 (propanoic acid) + H2O ---> CH2O2 + C2H6O, in this formula we see a carboxylic acid that dissolves in water and becomes formic acid and ethanol respectively. The organic acids with more than 4 carbon atoms are fatty acids and they are not polar like water, with a minus and a plus end. The fatty acid molecule is not attracted and does not dissolve. However, there is a large group of organic solvents that dissolve longer carbon chains, and they are used in e.g. the painting, plastics and pharmaceutical industries. Those means can be aliphatic hydrocarbons, halogenated hydrocarbons, esters, etc. The former is a hydrocarbon that is not cyclic. The other is a solvent in which one or more hydrogens have been replaced by a halogen in group 7 of the periodic table (eg chlorine). Esters, on the other hand, are a solvent obtained when an alcohol reacts with a carboxylic acid, during a water splitting (water repulsion). Then you get an ester such as octyl ethanoate (orange scent and taste), isobutyl methanoate (raspberry) or pentyl ethanoate (banana).

It is common to flavor sweets and soft drinks with esters, but also tablets in the pharmaceutical industry. In order for the chemical reaction to go more smoothly, sulfuric acid, H2SO4 (2 pcs. -OH groups and 2 pcs. double bonds to oxygen are present) is also usually added as a water-absorbing molecule. Chemists sometimes say that like dissolves like. An example of this is when the carrot's carotene (which is a fat) does not come off the cutting board with washing-up liquid, but if you rub in cooking oil and washing immediately afterwards, the carotene is finally gone. This is because carotene is a non-polar substance that thrives with the non-polar oil molecules. Esters were fats (in many cases) that dissolve long hydrocarbon chains, to understand the whole. And now you might wonder, is there any connection between how the esters look at the molecular level? Octyl ethanoate has two methyl groups, -CH3, one at each end of its chain, and here there are also 2 different oxygens that bind to one and the same carbon.

Pentyl ethanoate looks similar, methyl groups are at each end and 2 oxygens (single bond and double bond respectively, just like in the octyl ethanoate structure). The most characteristic are 2 oxygens that bind differently strongly to a carbon. We also have another known ester that needs to be addressed, and this is nitroglycerin, which is an explosive (explosive during an exothermic reaction), and this is also a vasodilator during a stroke or heart attack. When a person receives e.g. stroke, then one can ask which is best to take during such an emergency situation? Is aspirin or nitroglycerin the first aid? The answer here is usually that you should take aspirin right then, unless the victim is allergic. Most strokes are caused by blood clots, something that can be partially combated with the drug in question. However, this is not a solution in the event of a brain haemorrhage. There is a minor risk that the situation worsens. As for nitroglycerin, this can only provide relief for the moment, by widening the vessels.