Before 1900 there were only 3 known chemical remedies that had specific curative properties: Mercury (for the treatment of syphilis), ipecacuanha (for dysentery) and cinchona bark (for malaria). In the last century, however, we’ve seen an explosion of chemicals used to remedy specific illnesses. Some of these advances share a common idea and can be traced all the way back to the pioneering work of Paul Ehrlich in the early 1900’s.
Even as a young student, Ehrlich was fascinated by the ability of certain dyes to stain specific tissues (gram negative/positive bacteria for example). He reasoned that the dyes stain by chemical reaction with specific elements common in certain tissues. Working with this idea later in life, he reasoned that he might find a chemical with a specific affinity for microorganisms and modify it to destroy it. Ehrlich continued to work with dyes that had been shown to have mild bacteriostatic properties hoping to find a ‘magic bullet’ that would be an effective antibacterial, yet still be safe for human use. His first success was with the dye Trypan Red 1, which was the first drug to show activity against trypanosomal infections in mice. Later in 1906, he deduced the true chemical structure of the chemical Atoxyl, a slighty less toxic arsenic containing compound (when compared to arsenic). This led to the co-discovery (with Sahachiro Hata) of salvarsan, which was found to be an effective treatment for syphilis and trypanosomiasis. He continued his researches to find these “magic bullets” until his death from a stroke in 1915. He was 61 at the time.
In 1935, based on Ehrlich’s work, a German pathologist named Gerhard Domagk found that a dye called prontosil was effective against streptococcal infections. His research was proven further when his young daughter was infected from a pinprick and he gave her an oral dose of the dye. The dye saved her arm from amputation and probably her life too. On a side note, he was awarded the Nobel Prize for his research, but was unable to accept it until after the war due to German law at the time and was also arrested by the ungrateful gestapo. Prontosil later became the first antibacterial drug and the first widely available sulfa drug. In 1936, Ernest Fourneau showed that protosil breaks down into the chemical sulfanilamide and was the active ingredient in the drug.
These drugs work by competitively inhibiting an enzyme called dihyrdopteroate synthetase, which converts the chemical p-aminobenzoic acid (PABA) into folic acid. The structures of the sulfa drugs and PABA are very similar, which accounts for their efficacy at that particular enzyme. Folate is necessary for the production of B vitamins, DNA synthesis and other growth functions. While both humans and bacteria need this chemical, humans can obtain it through dietary sources. Thus, bacteria are more adversely affected by these drugs than human cells.
Cheap and easy to produce, the sulfanilamide structure was the basis of several thousand attempts to make even more effective drugs and gave birth to the class of chemicals known as sulfa drugs. Drugs such as Sulfapyridine (effective against pneumonia), Sulfacetamide (urinary tract infections) and Sulfathiazole saved thousands of lives and changed medicine forever. Though widely displaced by the discovery of penicillin, today they still find a wide variety of uses against antibiotic resistant bacteria, urinary tract infections and acne among other things.
Notice (No, not my handwriting) that sulfanilamide structure is only changed by adding a different functional group to the SO2NH2 group. It was found that the most successful chemicals were usually ones that replaced the hydrogen atom with a heterocyclic ring of some kind.
“But what of the zombie apocalypse!?” “How will this seemingly extraneous knowledge help me survive the hordes,” you say? Admittedly, a chemical synthesis is a large undertaking, yet a healthy understanding of some of the underlying principles could yield a few surprises for the undead army. For example, how could they counter a skillful release of phosgene gas into a cramped hallway? Or, perhaps an area may be denied to them by the fastidious use of certain organophosphate chemicals. I shouldn’t even have to mention the full alphabet of explosives that would become a necessity in the post-apocalyptic world, both as a barter currency and as a problem eliminator. More so, the synthesis of sulfa drugs could potentially save the lives of group mates affected by otherwise ordinary infections, should modern bacterially derived antibiotics become unavailable. This is almost certain as most preparations of penicillin and the like have shelf lives and temperatures they must be kept at to prevent degradation.
The first step would be to gather chemicals and supplies. Most of the necessary components aren’t particularly special and can be readily found in chemical supply warehouses, high school chemistry labs or pharmacies. The benefit of challenging these places is the security would be enough to prevent general wanton destruction and the ordinary pillager would be uninterested in seemingly useless chemicals and other junk. Pharmacies, though, should be a last resort, because these would be high traffic areas for both bandits looking for drugs and the undead looking for food. Here is your shopping list:
Aniline, Acetic anhydride, liquid ammonia, sodium carbonate, chlorosulfonic acid, hydrochloric acid, sulfuric acid, CaCl2, decolorizing charcoal, a hefty amount of distilled H2O, filter paper, a Buchner style suction funnel, an accurate scale, and the usual assortment of general chemistry lab doo dads (spatulas and rubber policemen, etc).
This may seem like a feat to acquire all of this, but most of these things can be found in ordinary places. Sulfuric acid, for example, can be found in car batteries, HCl is also known as muriatic acid and can be found in pool cleaning supplies and liquid ammonia is sold over the counter as a toilet cleaner. It should be noted, though, that obtaining these from pre-used sources would increase the preparation time, the impurities and probably lower the yield of the final product. Low concentration solutions can be distilled, but this takes time and is unnecessary, especially if you happen across some concentrated reagents. After all, you can make a 2% solution of whatever if you have a concentrated source on hand. Don’t waste your time on that 5 gallon, 5% bottle of hydrogen peroxide, unless all of your other options have been exhausted.
Sulfuric acid is produced by the ton in the US, with about 40 million tons produced annually.
The next step is apparatus preparation. Luckily for you, it’s not too complicated and can be assembled easily. First, you will need to find a good reaction flask. If you’re lucky, you could find a typical round bottom flask at one of the warehouses you raid. If not, you’ll have to go the DIY route. This choice should be considered carefully, as a broken vessel is not only dangerous for the operator, but also wastes valuable resources and time. Any glass can break under the strain of heating, but round bottom flasks allow for a more even heat distribution over the area of the flask. A concentration of heat on a specific area, like the edge of a wine bottle can create a local hot spot and weaken the glass causing it to shatter mid reaction. Chemists often use a 3 necked round bottom flask for this kind of work, as this allows options when attaching other components, like mixers, condensers and the like. For this reaction a two necked flask would work, or even a single necked flask with a sturdy cork with two holes drilled in it could do the trick in a pinch. You need to need to pay attention to the scale as well, as a 50 mL micro flask, obviously won’t be useful in a reaction calling for 500mL of reactants. Another consideration is the ability of the flask to withstand the reactants. Keep in mind that acids, especially concentrated sulfuric acid, will attack metal and dissolve it. So this eliminates using paint cans and other similar things to jerry rig a reaction vessel. For this kind of work, glass is really the best choice realistically available, but keep in mind that not all glass is the same and most everyday kinds will crack on reheating. Be picky when, picking.
Speaking of attachments, you will need two: a drop funnel and a decent reflux condenser. A drop funnel is like a closed bottle that has a stopcock on it to allow a controlled amount of whatever to be added to solution when needed. The reflux condenser is a long tube that allows vaporized chemicals to condense and fall back into the boiling solution, concentrating it, while the reaction finishes. Vigreux, Graham or Snyder, most of these common condensers should do the trick, even a Liebig could work, but the efficiency is a little less than the above (It has to do with surface area—more distance for the chemical vapors to travel). Since the reaction evolves HCl gas as a byproduct, the condenser will need to be connected to a sturdy hose running to a pot of H2O. This will act as a trap to dissolve this dangerous byproduct. The drop funnel should also be blocked with a CaCl2 drying tube.
Ideally, the apparatus should be dried in an oven before use to remove the water and the insertions should be lightly greased to ensure they have a good seal. Once upon a time, this was a problem for me in a lab examination as my product vapors leaked from an insecure fitting, costing me time and points on my final grade. It’s of little consolation that zombies are not so picky when choosing which brains to eat.
A three neck round bottom flask, Vigreux, Snyder, Graham, and Liebig columns, and a drop funnel.
The next issue is a heat source. I would advise against using direct flame, as this can very easily lead to broken glassware. Instead you may construct a water or oil bath, both of which yield better control of the reaction conditions, are cheap and can be re-used in a variety of situations. To start a metal box or can could be wrapped in wire and insulated with asbestos tape. The outside can be further insulated with inert packing and wood to trap the heat further. The wire can then be connected to a source of current. If you’re lucky enough to scavenge a variac, you could even have an easy way to regulate the amount of heat produced. Ostensibly, these things could even be scavenged from several electric blankets and some tinkering. Don’t forget to allow for a place to connect the flasks with clamps to keep them locked in place. On a side note, the famous arab chemist Jabir Ibn Hayyan, who was one of the first to distill nitric acid, did a lot of his work on a sand bath. The benefits of using this are that sand is chemically inert, holds heat well and can provide the even heating to a round vessel easily. Furthermore, if an experiment went bad he wouldn’t have to worry about large, explosive fires or a horrible clean up, the sand would absorb the mess. Since the reaction calls for temperature up to 80 C, all of these will do the job, so the choice is up to you.
A good question you probably already should have asked is: how do I know how much of everything to use? This question is the bread and butter of chemistry and the answer can be found by understanding what the reaction equation is really saying. When looking at an equation there are two things you should notice: the chemical equations of the reactants involved and the molar equivalents of each. For the equation:
C6H5NHCOCH3 + ClSO2OH → ClSO2(C6H5)NHCOCH3
The chemical formula for acetanilide is 135 g/mol and the ratio of it to p-acetamido benzene sulfonylchloride is 1 to 1. This means that for every mole we use of acetanilide we should expect a molar equivalent of the p-acetamido product. Likewise from another perspective: for every 135 grams of acetanilide we use, we should expect 233.5 grams of p-acetamido product to be produced. This, however, describes only the theoretical yield. In practice, chemical impurities, unforeseen reactions and experimental error all contribute to lower the actual yield from the ideal. However, by using this information it is still possible to determine the maximum amount you could produce and allows you to make comparisons of actual yields to define probable sources of experimental error. This enables you to improve the process the next time around and get better yields. More information on molar conversions and atomic mass is available in pretty much any general chemistry text.
Finally, one of the most important things you should consider is safety. With chemicals, an MSDS should at least be read before attempting to use them. You can download an MSDS from the manufacturer’s website and save it to disk. When the time comes, you won’t be caught with your pants down and already have it handy on your laptop. I’m sure you’ve already figured out many ways to successful recharge laptop batteries in the case of emergencies (a hand cranked generator, perhaps).
In nature it is quite rare to find any pure substance. The tendency for things to mix is a thermodynamic law and this should tell you something about the reactivities of pure substances in general. In the case of chlorosufonic acid, it can react vigorously or explosively with water especially if hot. Pay very close attention to where it states to use ice water or ice slurry and be sure to cool the solution well before proceeding to other steps. When it calls for the addition to water, patience is your friend; a slow addition over a long period of time will allow it to equibrilate slowly and save you from looking like a comic book villain. Nobody really wants to buy medicine from someone with a ridiculous nom de guerre like ‘two face’ or ‘joker’.
Real Computer generated estimation of damage caused by acid burns.
Furthermore, decent safety gear, like gloves, goggles and a sturdy apron are a must for handling acids like these. It’s important to mention that not all gloves are alike and are rated differently against different chemicals. Neoprene gloves, for example, are rated better at resisting nitric acid than a standard latex examination glove. When using strong solvents, no glove will protect you for long, so it’s good practice to change out if there is a spill. I once had an experiment that called for the use of carbon tetrachloride, a very good solvent. Even though I was double gloved, a small drop on the thumb of the glove quickly ate through both sets such that I could feel the cool vapor pulling through them. To emphasize the point, an environmental chemist named Karen Wetterhahn was famous for her work determining the toxicity of heavy metals. Just the vapor from a drop of dimethyl mercury on her glove killed her of mercury poisoning 6 months after the incident. Chelation therapy was of little use, as the amount she absorbed during that brief period of time of exposure was more than 80 times the lethal dose. Accidents happen, so it’s best to plan a good offensive strategy to counter the event of their occurrence and understand the nature of the chemicals you will be working with.
Another important safety tip is that many of these chemicals vaporize easily, so it’s important to work in an area of good air flow. H2SO4 is also known as ‘fuming sulfuric acid’ for a reason. A well-ventilated area should be secured, or (and) a fume hood constructed. (You can vent these toxic vapors to the zombie hordes on the street if you wish.) Access to a good amount of running water in case of accidental exposure is also paramount. Most labs following OSHA regulations have body/eyewash stations located in every lab, you should at the very least have a large bucket or two of water handy in the case of acid burns and the like. For most acids and bases, flushing with copious amounts of water is enough to take care of the problem. Contrary to popular belief, you generally don’t want to find a base to neutralize it, because this generally complicates the problem by adding another dangerous substance to the site of injury. More so, there’s no way to really know the concentration of the acid causing the burn and if you add too much base, well now you have burns from the base as well. Good luck getting a date for the ball now, Quazimodo.
The work up:
Once you’ve assembled the apparatus and organized your materials, it’s time to start. Let’s look at what we’ll be doing:
1. C6H5NH2 + (CH3CO)2O → C6H5NHCOCH3 + CH3COOH
2. C6H5NHCOCH3 + ClSO2OH → ClSO2(C6H5)NHCOCH3
3. ClSO2(C6H5)NHCOCH3 + NH3 (liq.) → NH2SO2(C6H5)NHCOCH3
4. NH2SO2(C6H5)NHCOCH3 →H2O/HCl→ NH2SO2(C6H5)NH2 + CH3COOH
Looking at the reactions the first step is to acylate your aniline. This is done first to limit the reactivity of the amine group on the benzene ring. Aniline itself is much too reactive by itself and often yields poly-reacted compounds. By acylating first with acetic anhydride, you bypass this problem and are left with a less powerful ortho/para director to control the placement of the next addition to the ring. The acylated product is collected by filtration, cleaned and then used in the next step: chloro-sulfonation. Here the previous product is heated and refluxed with chloro sulfonic acid. This yields the desired sulfonated product at the para position which will be isolated, cleaned and reused in the next step. This attaches a specific amino group to the sulfonic acid portion of the compound. I mentioned earlier that there were many attempts to make these kinds of compounds. This stage in the synthesis of these typically differs only by what amine is chosen for the addition (producing other kinds of amines is a story for another day). However, this time we are using the simplest amine available: ammonia. The final step requires a typical hydrolysis reaction of the acetate blocking group. The product from this reaction is crystallized, cleaned with fresh solvent and recrystallized several times to remove impurities. This can be done with either water or alcohol, where alcohol might give slightly better results. The purity of the product is tested by checking its melting point, which for pure compound is 165C. This can be done by the usual methods.
Next time: "Hey Meathead! Go Make Your Own Methandrostenolone!"
"Methaqualone: Some Things are Better Left Unsaid."