The nitrous oxide molecule.
Anyone perusing our Chemical of the Week molecules may notice that many pharmacologically active molecules are very large and complex. However, this is not always the case. An interesting exception is nitrous oxide, also known as dinitrogen monoxide. The nitrous oxide molecule is made of only two nitrogen (N) atoms and one oxygen (O) atom and so is very simple.
Nitrous oxide works as a general painkiller and anaesthetic and was first used in dentistry in the 17th and 18th centuries. Interestingly, it is still used today in modern dentistry and some medical procedures. This chemical has a side effect of inducing a supposedly pleasant feeling of euphoria and hence is frequently known by its slang name of “laughing gas.”
Although it is a simple molecule, nitrous oxide appears to produce its effects on the body through a complex series of processes, involving the inhibition of ion transport and other mechanisms. Not that many medical procedures that were popular two hundred years ago are still around, so nitrous oxide deserves some admiration, if only for its longevity!
With the (relatively) warm weather here, it’s a good time to look at sunscreen chemicals! Avobenzene (IUPAC name 1-(4-Methoxyphenyl)-3-(4-tert-butylphenyl)propane-1,3-dione) is a popular ingredient of sunscreens. It is part of the “Helioplex” sunscreen system marketed by Neutrogena. Like almost all sunscreen compounds, it contains benzene rings, since these are good at absorbing UV light. In the case of avobenzene, it absorbs a wider range of UV light than many other similar chemicals and so is well-suited for its purpose of shielding us from the sun. One deficit of avobenzene is that it tends to break down rather rapidly under UV light, so it is normally packaged together with another chemical to help it stay stable. In the case of Helioplex, the compound oxybenzone is used.
The avobenzene molecule.
Since the invention of gunpowder in China over one thousand years ago, much human ingenuity over the years has gone into devising ways to make things explode. The current epitome of this search for bigger and better explosives is CL-20. It was developed in the 1980’s at the U.S. Naval China Lake research facility in California. It’s currently being investigated as a component of new high energy plastic explosives.
The CL-20 molecule.
There are a few interesting things about CL-20. One is that it has an almost unpronounceable formal name; 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (you can see why they named it CL-20!). The second is that it is the world’s most powerful non-nuclear explosive. This explosive energy is provided by the high concentration of nitramine functional groups as well as, to some extent, the appreciable ring strain in the molecular structure.
Aspartame is the commonly used name for the artificial sweetener N-(L-α-aspartyl)-L-phenylalanine, 1-methyl ester. It was discovered when a chemist working in the Searle labs in 1965 accidentally ingested some and realized it tasted sweet. The chemist at the time was working on drugs to control ulcers! It is formed by making the dipeptide of two amino acids and then producing the methyl ester of that molecule.
The aspartame molecule.
It is about 200 times sweeter than sugar and so can sweeten foods without adding a lot of calories, since little is required. Aspartame is very widely used today for numerous foods and beverages, although not without controversy. For decades, there have been concerns and even conspiracy theories associated with the use of aspartame, and it has been claimed to cause numerous health problems ranging from simple headaches to cancer. Many studies over several decades, however, have consistently shown that aspartame is safe at normal levels of ingestion and it continues to be approved for use by the FDA, the EU and other worldwide regulatory agencies.
Heroin is a member of the alkaloid family of chemicals (which normally contain a somewhat basic nitrogen group). It is produced by chemical modification of morphine; the principal opiate obtained from the poppy plant. The synthesis of heroin from morphine is actually fairly simple and involves the acetylation of two hydroxyl groups, hence heroin is also known as diacetylmorphine.
The heroin molecule. Note the two acetyl groups on the left.
Heroin was synthesized and produced commercially in the late 19th century by the Bayer company in Germany and was intended to be a non-addictive substitute for morphine, which was a common medical ingredient at the time. The name “heroin” was meant to reflect the chemical’s heroic properties (an early attempt at branding!). As we all know, this idea didn’t work out so well, since heroin is actually extremely addictive. In fact, heroin is about twice as powerful as morphine, possibly because it is less polar and can more readily move into the brain once it enters the body. The dangers of heroin were quickly recognized and it was banned quite soon after it became available (in 1924 in the U.S., for example).
With the warm weather still here, Californium is a good choice for the element of the week! This element was first created in the labs of the University of California, Berkeley in 1950 and is named after the balmy State of California. That was in the good old days when, if you made it, you got to name it! Californium is produced by bombarding other elements (such as curium) with subatomic particles.
U of California researchers work with Californium in the ‘60s. Note the snappy attire!
The 252 isotope of this element is a very powerful radioisotope, emitting millions of neutrons per second. It has several practical applications, such as providing the initial radiation input for the start-up of nuclear reactors.
Californium has the distinction of being perhaps the most expensive commodity chemical on earth. The price in 1999 was $60 per microgram, or $60,000,000 per gram, which is about two million times more expensive than gold.
Kevlar is the DuPont brand name for an aramid (aromatic amide) polymer first developed in 1965. The para orientation of the benzene substituents in the repeating unit allows a high degree of hydrogen bonding between polymer chains in this material. As a result, the polymer in the solid phase forms rod-like liquid crystal packing structures. Spun fibers of this material are exceptionally strong; Kevlar has about eight times the strength of steel on a per-weight basis.
The molecular structure of Kevlar.
The synthesis and processing of Kevlar is difficult, since a solution of concentrated sulfuric acid is required to dissolve the polymer, and consequently the price for this polymer is quite high. Nevertheless, it’s unique combination of strength, low density and flexibility have led to numerous applications, including body armour, bridge cables and the roof of Montreal’s Olympic stadium.
Tetrodotoxin (TTX) is a very powerful nerve toxin found in the puffer fish and some other marine animals such as starfish.
TTX works by interfering with the ability of nerve membranes to transport sodium. Ingestion of small amounts of TTX produces a feeling of numbness in the face along with a floating sensation. Larger amounts can produce paralysis and death, although “large” is relative here, since less than a milligram can be fatal.
The tetrodotoxin molecule.
Puffer fish (or “fugu”) is considered a delicacy in Japan and even though only carefully trained chefs are allowed to prepare it, 179 deaths were reported in a ten year period due to eating fugu. Interestingly, TTX has been proposed by one anthropologist as an ingredient in the potions of voodoo practitioners in Haiti. The theory is that a victim is given TTX and slips into a paralytic coma indistinguishable from death, only to be revived later as the living dead, or a zombie! Fans of the Simpsons will remember that Homer once believed he was suffering from fugu poisoning.
2,4-dichlorophenoxyacetic acid (2,4-D) is a widely used synthetic herbicide. It affects only “broadleaf” plants (typically the plants we consider weeds) and not grasses or most crops, hence it can be widely applied without harming desirable vegetation. This chemical mimics natural plant hormones and causes rapid, uncontrolled growth of broadleaves, leading to death of the plant. Pure 2,4-D is actually relatively insoluble in water and so other forms, such as esters and salts, are now more widely used.
The 2,4-D structure.
2,4-D is applied so commonly that a 2003 study found that 63% of homes contained traces of this chemical in household dust! It was also a component of the infamous Agent Orange herbicide used during the Vietnam War. Exposure of military personnel to Agent Orange was subsequently connected to a wide variety of health problems. Currently, it is believed that these health issues were actually more likely due to the presence of other chemicals present in Agent Orange, such as traces of dioxin.
Androstenedione (or “andro”) is a naturally occurring human hormone which is produced in the body as a precursor to other hormones such as testosterone and estradiol. Andro does not appear to be anabolic (does not promote muscle growth) but it can possibly enhance sports performance by temporarily raising testosterone levels in the body (meaning it falls into the category of compounds known as “androgenic”).
The structure of androstenedione.
Andro was legal in North America up until the end of the 1990’s and was used by popular sports figures such as Mark McGwire who, in 1998, broke the record for most home runs hit in a season. So perhaps it does help! It’s not recommended as a sport supplement, however; as with other androgenic compounds, it carries the risk of side effects ranging from liver problems to cancer.