Deadly Strychnine - Periodic Table of Videos

today we're gonna learn a little bit about this molecule here this crazy complex looking piece of molecular architecture which is called strychnine which no doubt you probably will have heard of is a well known poison these days it's used for killing rats but in the past it was a medicinal compound especially in the Victorian area so at that point in time it was used for all sorts of ailments like headaches it was a one of the very first athletic performance enhancers believe it or not and of course it's a poison it's really not useful in any of these respects whatsoever it comes from the seeds of a tree in the Philippines and over a hundreds of years the Filipinos had used the extracts of this Sabine as they called the seed to treat various ailments so it was a sort of hairball type of medicine and it works on the nervous system so I'll give you a bit of a tingle obviously in high doses or actually not that high doses have very severe effects on you but if if something you take something it interacts with your body get a bit of a tingle and perhaps you feel that like it's doing good rather than harm so in small quantities it was used for centuries but actually is it's got no real beneficial effect as a medicine and indeed you know famously it's been used in all sorts of murder mystery cases I have just one story about strychnine but I really liked it just before I started as a PhD student a Brazilian professor visiting the chemistry department took some strychnine out of the store because he wanted to poison his wife but being a professor he was bit absent-minded and he mislaid the strychnine he lost it and he got really worried that somebody might get poisoned other than his wife so he went to the police and admitted everything and then the strychnine was found in his jacket pocket hanging in his wardrobe so his wife was safe I have no idea one of the founders of Stanford University is poisoned by strict being murdered by strychnine in her last words were that this is the most horrible and painful death and fiction it's been used a lot and I give the Christie three or four novels of hers how to strychnine and in the grand Budapest hotel it's in there is a poison it actually there hasn't been many deaths or murders through the use of strychnine luckily so this was given to us by sigma-aldrich for the use in the periodic videos so thank you very much to them yes about a gram in here and it takes about 10 to 50 milligrams to kill a human being this tree gives beautiful white flowers very fragrant smelling but presumably it's in there to stop animals from eating the seeds you know the animal takes a bite of it and doesn't finish its meal like many of the compounds that I talked about it works on the nervous system means it knew all your muscles go out of control and you know you die of asphyxiation of not being able to breathe because your lungs aren't working properly imagine it is a series of electrical cables with junction boxes in between and at the ends you got sensors and muscles at the other end so sensors build up using ions a concentration of a positive charge using generally sodium potassium calcium ions that then fires an electric charge down the cable to the other end and then calcium ions allowing the release of neurotransmitters to go and tell the muscle or a brain or whatever is on the other end what to do so this interferes of that process at the junction boxes so this inhibits both sodium and chlorine ion channels which is unusual normally a molecule will interact with just one type of receptor as this interacts of two types of receptor yeah that's a good question so if you ingest something it will go obviously into your gut once it's in the gut it can then pass through the guts of blood berry app needs to be charged to do that so we've got basic aiming on here it then gets into your bloodstream in the bloodstream then transports it around your body this obviously with the blood will go to all your muscles and start to interfere with any neuromuscular junctions that it comes across it's not a very good murder weapon stay in the body for years traces of it so be very easily identifiable now it's new and glass just strictly tastes like well they say it tastes bitter and on strychnine there's this tertiary a mean here this this blue atom in anything when the tertiary a mean always tastes incredibly bitter a lot lot of insects have these two tertiary aiming molecules on the back so that they taste horrible so a bit like a licking a brass or copper spoon yeah really bitter and really not very pleasant at all so again not not the best poison because you get a tasty in your cup of tea here we are away from the bag the high-security containment system and just take a little look at what strychnine looks like so there we have the top it's not a lot in here actually I was maybe it maybe 100 milligrams not not a gram at all let's just take that okay so there we go just a white powder essentially looks fairly innocuous I mean the majority of chemicals that you work with they're not toxic there may be it was so-called harmful maybe slightly crazy for majority and not that way I wouldn't want my PhD students to work with anything that's extremely toxic although we have made of few natural products over the years which which are really quite patient but this is quite dangerous substance and not something that the likes of which we would normally be working with I look at that and I think wow that's beautiful such a really unique architecture all of these ring systems we've got hydrogens pointing into this cavity here seven membered rings five hundred rings six membered rings all sorts of different molecular architectural pieces in there and for the synthetic chemists that makes this an absolutely outstanding challenge this is the Everest if you like of the total synthesis type of world so as isolated by two French chemists in 1818 so you know nearly 200 years ago now and it was about 120 years later by the time chemists had figured finally figured out what on earth the structure was because it's just so complex so there are over a hundred 250 papers attempting to find out what the structure of strychnine was and eventually in 1947 two chemists Robert Robinson whose later became Sir Robert Robinson in Oxford University he proposed the correct structure and Luke's and completely separate chemists also did birth brought Robinson was very famous in his day and this was a culmination of two decades worth of work in his laboratories seven years later Robert Burns Woodward was the first group to synthesize it and Robinson had said for its molecular size it's the most complex molecule ever known since Woodward's original synthesis has been seventeen the syntheses so in 1954 is the first synthesis I was around 28 synthetic steps so different things that you had to do and the yield was minuscule it was they were starting from tens of kilos and getting milligrams oh-oh-oh-oh six percent yield which is a very small amount and and quite a lot of steps twenty eight steps actually is for the the complexity of this molecule is still quite competitive the next synthesis was carried out in 1992 so it was a many years later by philip magnus that was again twenty eight steps but he got up to 0.03 percent yield it's considerably more efficient about a thousand times more efficient but still a very low yield in each case all of these people were developing a new type of bonds connection connecting reaction and they are putting that into operation so Magnus in in his synthesis was making this bond in this bond and the key step using a diels-alder type of reaction Woodward had used obviously that the synthetic chemistry of the day in in you know forty years had passed by the time Magnus came to doing it in 1994 was the next synthesis and that one own went up to three percent yield using Larry over men's chemistry these are all you know incredible eases the the rock stars of the organic chemistry world that are coming to play here so at time moves on 2007 Padua got it down to sixteen steps two percent yield by 2011 we had the shortest synthesis ever nine steps by Chris Vander Val terrible yield there was one really difficult step in there but nine steps when you think the original was twenty eight was quite incredible and probably the best synthesis out there is by David McMillan twelve steps is but six percent yield so considerably stronger and thousand times more efficient than the original synthesis and this is the progress the organic chemistry has made not only in structure elucidation so twenty years worth of work in the 1930s and 40s 250 papers to determine the straw of this today one of my PhD students would be able to determine the structure in an afternoon because spectroscopic techniques have have come an incredibly long way there were almost none back in 1946 and infrared there was an x-ray of this in 1952 so that was one of the very first x-rays but in 1946 that didn't exist so back then they had to literally chemically react it and figure out what bonds would have been broken through that type of reaction so it's a real detective story back then using evidence chemical evidence to determine structure whereas now we can use spectroscopy well I'll put some of that back in the bottle and the rest will have destroyed it a lot cupboard yeah just in case you get some rats in the lab but every few seconds your brains saying breathe in breathe out breathe in breathe out it does it automatically or move your muscles so if you stop any of those signals then obviously your muscles stop and if you stop breathing you're going to die pretty quick

Channel: Periodic Videos

Views: 566,775

Rating: 4.9576101 out of 5

Keywords: chemistry, periodicvideos, periodic table, periodic table of videos, chemicals, strychnine

Id: oBqTDGQ_szw

Length: 11min 23sec (683 seconds)

Published: Mon Nov 16 2015

Reddit Comments

[u/Ferrocenium]

I love it when Professor Poliakoff's stories go nowhere. He's got one for every element and compound and they all inevitably end with "and I don't know what happened next" so you know that he's telling the truth. I wish he was my grandad.

[u/threeoneoh]

Ca2+

!!!

[u/handyandy86]

Molecules must be charged to cross the gut into the blood stream? That does not seem right to me. Can someone explain? Active transport aside, ionisation greatly reduces the ability for a molecule to pass into the blood stream, no?

[u/Red5446]

Aaaand now I have The Sonics stuck in my head. No ragrets.

[u/bowlingtrophy]

Thanks. Good stuff.

[u/liqxtal]

Cool video but Vanderwal's synthesis was actually only 6 steps, making it even more impressive!