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INADEQUATE. Some Thoughts on Homework Set 9


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and talk about 2 things that I want to talk about the inadequate technique and then give you some thoughts on homework set 9 and build on some of the stuff that I kind of started to scratch at the black forward and I worked up something last nite with some models that I thought would be would be really useful for some of our thinking and tie in December our conformational analysis so let's talk about the inadequate technique 1st it stands for incredible it is a stretch incredible natural abundance double quantum experiment but and what it is is essential cozy it so it's essentially a CDC closely and what's what's so always incredibly a powerful about this technique is it means that you really can stitch together and carbon skeleton with it and wants inadequate of course about it is the amount of C 13 sells a very powerful 5 requires lots of the same ball for what In lots of time by lots of sample lining like 100 mg in other words if you're dealing with some rare natural product where you've isolated a couple of MG right now it's essentially out of Out of grasp if on the other hand you have some side product in reaction you think this is key you know to optimizing a reaction maybe not only stage intermediate and the synthesis but maybe in a methods project and you're trying to suppress something and you can get yourself 100 MiGs and you just can't get a handle on it any other way this may be the away so I mean that the killer on this thing is because it's a cozy like the experiment what you're relying upon is having received 13 next to receive 13 and since the probability of having a C 13 at either position In a molecule is 1 per cent the probability of having both of those is 1 per cent of 1 per cent it's not the words . 0 0 . 0 1 per cent when that really is the killer because it means you know carbon you've done carbon and strict 9 we loaded up the sample to and she was like 40 megs of strict 9 in the sample to but it's pretty quick but if you're talking about having to concede 13 is next to each other you signal-to-noise is going to be 100 times lower now remember what I said if you're talking about a particular signal to noise level if you drop your concentration of sample by a factor of 10 you've got a collect data 100 times longer to get the the same signal-to-noise ratio if your see 13 if you're dropping to a Percent of a per then you're talking about a hundred times less sensitive so it really can be can be Keller now the tricks that get played and they're not funny if you've got a compound that you really want to get back so 1 of the tricks is that you often can and seize our chromium 3 to increase relaxation member how the plaster Rowe's small Kwok Harbin's small because the relaxation time is typically on the order of many seconds and your pulsing every a couple of seconds so most of your magnet is Asian is not returning to the CIA axis so you can add a pair magnetic compound the metal ions that promotes relaxation that's going to reduce the relaxation time so the magnet isation returns the z axis that'll help you will help you out of a bit but were often talking many hours or days within a moratorium now I will say this the cry problem we haven't really sat down and tried this thing With the quiet for maybe Phil has maybe somebody so the choir probe instrument is super super sensitive because you're cooling the coil in the probe and reducing the amount of noise it's not increasing the amount of signal but if you reduce the amount of noise you reduce you increase the signal to noise ratio the cry probe is like 5 times at 10 times more sensitive than traditional probably say 5 times that's gonna buy you a lot because remember said 5 times more sensitive 5 times more signal-to-noise can translate to cutting your experiment time down by 25 to to get to get the sale I'm sorry no 5 times the current them fight but that's still the can can help you out so again I'd urge you to to think about this I don't walk us through 1 example and then get you started we have to homework problems that have been added .period I wanna get you started on on 1 of them so that their 2 variants of the experiment just different variations of policy points 1 the variance is like a cozy in terms of how it looks Australia both of them in terms of how your Accies looks so it's just like carbon and 1 axis carbon on the other access and you just correlate bike with cozy the other is with what's called a double Quantum Access and also you what that is alright so I think what I'm going to do it is passed out an example and will actually pieced together a pieced together the whole structure on this thing very very easily and quickly if only others the extras over there just sweep them sweep them back to to right the everyone have 1 great sorry that so unfortunately most because this experiment really it really is a tour de force in terms of instrument and so forth most of the examples that you find out out there are not worthy of the technique very didactic examples that sort of are nice but it's like OK we could have done this done this without bringing such a powerful technique to bear a lot of examples and handouts have been giving you are from a book by by Koji Nakanishi whose natural products chemist and basically he put together various nice sort of two-page handouts in the book on various spectroscopic various Cinemark techniques they were recorded on a 400 megahertz machine so this is recorded on 100 megahertz carbon in a more spectrometers and nothing and you know the kind of old so it's nothing nothing nearest powerful was what you have downstairs with the cry probe so what we have here is an example of an alcohol and
it happens to have uh give your formula here it happens to have a formula C 10 each 20 fold and so you have 10 unique resonances in the carbon spectrum in this molecule on what we're going to do is we're going to stitch together the whole structure really painlessly really really effortlessly and really mechanically with this with this inadequate experiment so that number might 10 resonances 1 to 10 just like we always do these letters by the residences remember I mentioned before that that before the debt the experiment was developed there was an older technique called off resonance the coupling so when you win you collector carbon normally it's Proton couple meaning of proton D coupled meaning your radiating the protons there's flipping spins very rapidly she don't see any J. coupled to the card but with and with full the couple with full coupling all of your peaks Avery heavily slept because you've got your 1 bond coupling which splits would like 125 160 hurts coupling splits your lines into doublets and triplets and quartets but you also have on top of that year to bond and 3 bond coupling which means every peak is heavily splits in 2 come into many many lines of becomes like a quartet of triplets would be say what you'd see for the Mathilde the In ethanol underlines a very small in the off residents the decoupling technique your partially decoupling you're applying proton energy to flip the other spins the protons but you're not doing so hot right on the at the exact right frequencies you doing so slowly steer multiplex collapsed down and you don't see you work 2 and 3 bonds couplings in see just 1 bond coupling instead of having like a quartet spread out with the lines 125 hurts apart there just like 10 hurts apart anyway that older notation which isn't used anymore has stuck around so a double-edged means Ch a triplet means C H 2 you'll still sometimes see this is when people reported dead data sometimes they will reported as D & TV for no particular reason deeming CHT meaning CH 2 Q meaning CH theory of course and the rest users aged so Questar molecule contains some methyl groups it contained some methylene groups we have this 1 the final group down here at 70 parts per million I said were an alcohol so obviously know this carbon 70 right and arrange for you'd expect the carbon connected to an oxygen so obviously that's going to be the 1 connected to the oxygen are the double quantum axis is a diagonal and what you're seeing each of these pairs correspondence 2 2 carbons setter coupled to each other and you'll notice that each 1 appears as too low lines Water are those 2 little lines said double and from From the carbon-carbon splitting yes you're seeing the carbon-carbon splitting remember carbon has a much smaller Magneto generic ratio then protons so the carbon-carbon coupling constant the 1 bond 1 C H is going to be smaller then a typical carbon proton 1 bond coupling seemed kind of see this was done at 100 megahertz is done and 400 megahertz spectrometer so each of these tick marks is 100 hertz and you can see the spacing is maybe like 30 her so that your 1 cc couple by here's how the double quantum Access works each of these coupled peaks they come in pairs and there's a diagonal like those between and so if you lock all of these pairs go right around this diagonal I haven't let them exactly down the middle I tried as close as I could so this area centered on the diagonal despair is centered on the diagonal despair is centered on the diagonal this 1 on the diagonal this 1 on the diagonal this 1 and so on and so forth all the double quantum access this is really important because an inadequate you're pushing the signal to noise levels which means you will have noise in spectrum most likely this 1 as a said this is 10 carbon compound in a demonstration experiments so there isn't a lot of signal to noise in it but if you're doing this technique you're basically going to be sitting on spectrometry running like an overnight nite block coming in in the morning may be doing this on a weekend hoping when you 48 transforming process you data that you can get off the the machine but maybe you signed up for all of Saturday you know Friday nite through all of Saturday with the idea that if you need more time you can get it and so You want you will see no Sammy we see noise and our other spectrum with a sum that said did some of that some artifacts rather than noise you will just see basement noise here but would you want to be doing is saying yes I can see a pair of peaks and you know where your parrot peaks is going to be in other words it's not going to be a pair hearing here it's not going to be a pair hearing here it's going to be pair centered around the doubles .period Texas are so let's start to build up a structure making yourself very mechanically I'm just going to trace my peers and it can start anywhere under start hearing will this will just sort of get our get our cross peaks and so this guy pair becomes 6 to 10 OK cases 6 is a online all drawn that as sex ain't and it's coupled the scene 10 8 straight so we're well on our way the building up our structure OK so let's see let's continue In so I will just select my next pair so that is 6 1009 of so that's good C 9 is another methyl groups so 69 H 3 and then I'll continue we have the next 1 looks like 5 to 8 I could start to drive was that right 5 to 8 young so that's over 5 and that one's over 8 so I can start to dry out another chain but I'm just going to sit tight for a moment because I'll figure out where to put everything in just a moment the next 1 looks like Ford 7 the next 1 looks like Ford flying so as soon as I can get figure out where for resolving in pretty good shape the next 1 is Childress said then and the next 1 years Tudor sexy OK that's good no I've got a lot of lot of information I can start building so too it is a method mine so I will say C 2 h in let's see to connect so I think that the other 1 I got is this 7 which is a methylene so that's C 7 H 2 and it looks like we have 47 7 over here and for is another another methylene a 4 H 2 0 OK so I've used up used up the Tudors
7 the afforded to 7 OK it looks like I have 5 and 5 is a but finds so 5 h OK what else do I have a guess I still have 5 5 goes to aid I haven't used him up and 8 it is a natural C 8 H 3 and let's see I think you I used used all of used all of those out so let's see what I have next on the In the last year so I have to redefine that's a naphthalene yeah I was that it just makes you wanna wanna run this this intelligence until it takes you a day while the great thing you know the great thing with the school OK so I think what was happening on the 5 500 was people were getting antsy ovals so you know if you want to sneak back there and now I think I think you know trying to leave a few blocks of time but you've got this free and a modern time on this course here right loans could be around Thanksgiving rights you want A-Rod and inadequate on strictly on the prior approval of the far-right so let's see where are we going to hear a case so we've got that looks like 1 2 3 as the I think we have eliminated what's on their own free will create this new I haven't drawn a straight line here on on the way out of all but 1 of the highest in this city and state the here Todd staring into this thing so slap agreed on Philip Glass have a look if you look at the grid lines they look like they line up I think I put the grid on the axis here I think everything's pairing up look like the look like they're pretty well lined up our it's a 1 2 3 down 9 1 1 is that 1 that has to bear the alcohol also see 1 H that has to be the 1 with the OHL In our last 1 here is is 1 to 2 and so the whole world the whole structure dates built up now we still have issues of Styria chemistry answered at this point so we have we have 3 stereo centers and the molecule and so if you were trying to figure out what the structure was at this point you of course you can get the absolute chemistries you have to get the story chemistry of 2 relative to the remaining 31 In that would be from things like coupling constants in ways in fact this is cycle hexane rings fits in very well to all the models and issues we dealt with with cycle hexane ratings anyway that's that's largely what there is to the experiment and as far as I said very very powerful very tempting and teasing because of course it is so powerful and yet very frustrating because it isn't it isn't something that you can pull out except in heroic circumstances so this is this is the handouts from Nakanishi is bookended the technique which you know what I like about his book as he always has just sort of a short little paragraph on the technique and an example here this particular molecule happens to be the monitor menthol In dumb so as I said there 2 2 basic flavors of the experiment he's demonstrated both of them I I simply took the 1 on the other on the left here and news that forever are example here so this is the 1 with the double quantum access you can see the pulse sequence you notice it's all carbon carbon detected experiment and then then you have them diversion it's the cozy light version and your cozy light version basically just just races up and over just like you would with a Kosovo no no absolutely not the Natural Products Chemistry these days is often pushing the the were so fill Cruz is a great example of medicine and in fact he has really good and about the only thing is in my opinion it's more oriented toward Natural Products Chemistry rather than toward say synthetic again and other sorts of chemists who build molecules so when you're doing that you're often like collecting 10 kilograms of wet sea sponges getting a kilogram at 2 kilograms of dried sea sponge fraction aiding it by extracting Woodson methanol and chloroform and then chromatograph thing and isolating bioactive components and running various credit graphic techniques in the end getting a few milligrams of compounds sometimes less than a milligram so 1 of the frontiers and Adamawa right now is is really small probes and probe volume so that you can concentrate your sample in a very small space and get enhanced signal-to-noise ratio with small samples in a way of 5 9 5 millimeter Adam are to what sort of the this typical standard is putting is a big big sample the center putting a lot of leaders in there but it's a very convenient size for preoperative chemistry it's just that by the time you're dealing with a really late-stage intermediate sing-along total synthesis warrior or a natural product it may not be enough so Lenny get I want to get you started here on whether other thoughts your questions on this somebody while the metals on the ice apropos of the dies during topic when ever you have Asturias Santander molecules and ice approach will group is a methylene group are going to be dire topic if they're very far from mysterious centers they may be coincidence they may show up at the same place but they are always topologically dies during topics of I had like a 5 carbon Justin linear chain with the nicer probable group at the end and mysterious Center way off 5 carbons away yet chances are those 2 mouthfuls would show up at the same position but if it was just a couple of province away probably at least in the heart of an animal which is more sensitive they chop at different positions I I I wonder why I give you just so 1 of the things I want to do this last problems that really is a very very beautiful and we get a lot of stuff in it but it's also pretty tough and I wanted to spend just a couple of moments getting new started on several of the different problems and also talk about some conformational analysis and scary chemistry that's germane to them and actually was germane to the last last problem said as well are it's so this is this is 1 of the problems from the From the problems it and if you look at this I wanna wanna keep this fun fun for you you get a lower as mass spect you're going to be able to basically
infer the molecular formula it's just it's just a carbon hydrogen oxygen oxygen Compaq and you're going to be able to figure out the molecular formula there is yeah 9 resonances In this sea 13 NMR a yet if you look at it you'll see something interesting about the proton NMR if you just work period rolls you'll see 2 1 of the 1 in slapped against what you do usually measure with the role of laugh slap agreed not to interfere if you're feeling feeling lazy for for measuring here during 2 girls and you don't want to be bothered drawing lines with a ruler so my my preferred way if you can get a hydrogen counters always to add up all your integral steer so virus that in itself would be right 1 . 7 1 . 7 1 . 7 1 . 7 and then where we were at about 9 . 3 and then divide by the number of hydrogen is but if you're being lazy you can say OK good that otherwise you putting all that weight of 1 . 7 if the 1 . 7 is really 1 . 5 and you come to a peak that's like 900 genes and that error of 10 per cent is going to make you 9 hydrogen is speedy hydrogen or hydrogen but if you're pretty good here you probably probably can get away get away eyeballing it as 1 in 6 said you probably going to be doubt as well on your way to 80 to a molecular formula that is that right all we've got this guy over here so we got 6 8 9 10 11 and it looks like we've got something here as well all wages and the like are always hard to integrate In part if that mean often broad often the intervals on foreign so accurate because phasing of Europe the world becomes really really important this is scattered bits so some sort of some sort of regional here on With Six You might even might even think about what that means in terms of the structure of the molecule and going to take us on To the inadequate and honestly you can pretty much just by inspection would be inadequate put the thing together and then you're going to have to use your use your head a little bit to think about what's going on or sell they give you To what to expect from the spectrum and an expansion of this crowded region here so this is this is your inadequate and we can go ahead and do 1 2 3 4 5 6 7 8 9 you can identify you double quantum In addressing addressing this spectrum should have 10 carbons what do I miss on it lose this year of the issues you are so that's what we're assuming 6 hydrogen so what is that telling us about the 6 hydrogen now probably not probably not die history topic probably some sort of isopropyl Group in there now so OK so I want to point out a couple of features so 1 feature is I'd still like here for example you can pick up 8 9 and his right across the double quantum axis in here for example you can pick up they've even drawn drawn a line for you you can pick up a but what can you tell me about this and this spot and now I just circled itself so badly that I've circled over what can you tell about those 2 well that that can't be it may be an artifact that maybe noise but they're not 80 not across the because they're not spaced on the double quantum Erickson so some type of artifact but not a product of the devil double quantum annexes you know it it is something off of some what's interesting here so this is our carbon This is our carbon Dublin you see that the seat that's UCC coupling but here the user singletons these all are the user spots there not not doublets so whatever it is it is not 1 cc couple like we have a spot under here here let me transcribed my lines sold so it's 1 2 3 4 5 6 7 so we have a spot on the 6 spot under 7 a spot under won a spot under too but they are not part of our peers that we need to consider and so there and as we continue our double quantum mechanics is here you'll see that you can just just pick up your Paris you're going to get your 47 period get your 45 pair here you've got 80 3 2 6 pair here you have a three-to-five appear below that Judas 7 and a 1 2 6 here here and then what is it about what's going on over here that's gotta be a 1 to 2 pair of 1 and 2 warrant giving across the you wouldn't a spot here so even where they're really close we're seeing worsening a 1 2 "quotation mark speak so that's going to yell at you and you're all set to go go ahead and tackle on around I don't wonder if you know all I think the the answer is it could could be an issue you're perched
books and Silverstein will give you your G 2 and G 3 cc and they're going to be smaller going to be a lot smaller we already saw on problem number on it does tall problem that very nice assessed with Turkey and problem we saw that don't peek from Florida 7 70 which by the way now I have now I've gone ahead and then put a note on the on the problem of so we have seen in some cases you can get some longer-range couplings showing up and surprising so I wouldn't say never but it would surprise me but certainly if you look at your local paired couplings that's gotta be an indication as 1 by coupling I can already tell you said this molecule has a lot of S P 2 carbon in as well as some sp 3 carbons and if you had like sp carbons in it you could imagine them being no further even bigger spacing but I think if you work and that may be what were observed here might be something that's a long-range type of coupling honestly I don't know but there notice for not seeing the spirit alliance here so that's kind of an indicator alright I think this and the IR spectrum are going to be going to be enough you can do a little bit with the cozy on it you can do a little better take a look at the IRA spectrum there's obviously some stuff going on this molecule has carbon hydrogen and oxygen we obviously have some type of alcohol we've got some stuff going on here that's interesting to read ,comma meals available bonds something sell what I say is you of something that's pretty obviously in wage but then something interesting you'll figure it out of this are I think that's all I wanted you wonder what problem to help you get started in let's see what else do I want to do what I think I think the other thing I want to do at this point is to spend some time talking about some of the issues issues that I was talking about on the on the blackboard in discussions section I worked up worked up exercise your welcome your welcome either to follow will follow along or not on your computer's on this it would have it said that if you were to remove them I know then on that would they would at that point the Tom equivalent yes however the most yes a music company going to be equivalent but remember the most rigorous test is always replace 1 methyl group with Likasi 13 received the 3 groups replaced the other methyl group and then ask yourself what's the relationship of those 2 compounds are they die streamers are they not during but remember those 2 Mathilde are interchangeable by symmetry operation a mural claiming the menthol which they are then they're not that history of plain plain and simple alright so I want to talk about some stuff that is directly germane to the homework in also germane to to last week's homework and I want to talk a little bit more about this this concept on some very very basic confirmation analysis and this is fundamental to organic chemistry it's fundamental to carry in Sunburg part areas well it's fundamental to understanding structure so I was quitting before that I can draw out only 2 things and everything else I can fake it and that's really kind of true in the sense of you can fake too if you can do 2 things you can do basic conformational analysis on a whole bunch of cycling by cycling and polycyclic rings so if you understand share cycle hexane then you can basically understand and underworld cyclo painting cycle have has a number of different controversies but you can basically fake cycle hexane you can start to figure out OK hydrogen is hearing here and so forth and you can fake a hole heck of a lot if you can understand nor born Maine if you can understand by Cyclone 2 two-to-one 1 heptane and that really is a poor drawing select me let me do a little bit better here if you can understand by cyclo had today and then you can take a lot of other cycle occurring systems because you can go ahead and say a by cyclo 3 2 1 system this bridge you notice that embedded in the by cyclo three-to-one system you have and I guess this is a little bit better growing which means I probably should be faking faking this like this actually so you notice you have a cycle hexane embedded in the system and it's a chair cycle hexane you can also flip up if you had advanced European direction here you could flip up that would be a boat cyclo Hecht said can you see your boat embedded in them and you can go ahead and if you want to then you can fake other systems of you can fake this system then you can fake like remember we had the the kind and dial problem and you can fake the conformational analysis of this as well and you're drawing and if you can't see this the 1st time around the beautiful thing is a few basic models can help you out and so after thinking about this and thinking that really my own understanding of this comes from sort of playing playing with models I figured well if something is good for me it's going to be good good for you In so both on the class materials and the assignments I created a strength this I created a Web page that links to some basic models of all of those those structures inside created this simple simple conformational analysis of these structures so I can't link these all salt too the PSC files to the prime old files and I guess what you have to do with that point is you sort of have to do what have to open them separately
I've I've program my computer to see if I can turn down the lights here it about lights but all better
yet i've program my computer to open these like this obviously obviously know exactly by this point how you get know what you're probably some of teaching yourself Moss to draw the relationship between between cycle hexane projection and that and you know the three-dimensional structure of the molecule so of course you have your axial indirect with Torry old guide regions on that but what I was saying about 9 below cyclo
pentane structure it is you can go ahead and basically apply that same same conformational analysis 10
Mathilde To cycle painting and CCF sort of continued have chair now this brings up an interesting point why am I talking about this because I'm interested in coupling and being able to identify stereo chemistry from coupling and NO Louise and being able to identify In a wheeze and 1 thing we have already had a young 1 problem on the homework where we had a cycle painting ring system that hydroxy probably 1 where we had to figure out the story chemistry from the interweaves I think was in part confusing because in the 1 Indiana Lederer's nonspecific radiation of the Street topic methylene is 1 of the points when I introduced and always earlier on arm and we were talking about distances and I said Well you know on a cycle of painting ring basically if you've got assists relationship or you've got a trends relationship you know you're gonna have some this difference in distance but it isn't necessarily if I always thought this NO and NO we here and I said all these 2 was the sense to each other because I'm seeing and no 2 . 8 actions of the united strong and away you be absolutely wrong you know ditto if I were looking at say this hydrogen and these 2 hydrogen this is 1 of the reasons I like these canonical structures and I like being able to play play with these models is it really helps me think about what we're talking about in other words you really are ending up having to make comparisons on cycle paintings and 1 2 relationships that end in time from an awaits all primal it's from the Wizard wizard and there is a measurement of the war and it gives you eat distances are a pull-down menu and you can get die grows and so forth so remember that coupling constant calculator we did it 2 ways 1 was by taking it on to the modeling facility computers and using macro model where it had a cop was calculator built-in and the other way was a website that 1 linked to the Tatra Hebron's paper on typical J values with different substituent so you just wide use a Web site you could just get your diet he brawls you polled died he drawls there you click on the 4 Adams you go hydrogen carbon carbon hydrogen you get your diet droll and you put in your substituent summer pull-down menu and attacked calculator or at least a few thinking basic Coppola's curfew say Oh wait a 2nd 90 degree died he'd roll virtually no coupling constant 170 deg height died he roll remember a co-signed weighed basically 170 is going to be a big J. value no 1 thing that's interesting with cycle paintings is 4 1 3 relationships LME hide some of these measurements and Justin clicker is to turn it off for 1 3 relationships you really don't get close trends relationships says ends up and NO we In a 1 3 relationships so we're going 1 2 3 and A 1 3 relationships and NO way is pretty darn diagnostic of being because that's 2 . 7 7 years here we go in the transients 3 . 8 and 3 . 8 never high said and always fall off his distance to the inverse 6 power 3 . 8 ANC streams is going to be a very very small and we just don't know small percentage of what they closer said we would be selected be really really diagnostic art I want to show you at this point as
seven-member during 7 rings as I said Can can have different conformations but
often often you're going to find a
confirmation that the very similar To this canonical cycle hexane is my faking it new notice you have 3 hydrogen that are basically axial and three-letter basically axial here I put the methyl group Equatorial here on the ring and so you can start to see all we had and all those things I was thinking about like a big JB Tweenies hydrogen juror big J. between these sides regions or close contact between these hydrogen is going to apply the
other family I thought that was really useful here's our Norborne instructed these are all minimum energy structures you know the clean function it's sad generated with some with molecular mechanics with the
amendment have forced field so here's the Norborne structure if you want if you wanna go ahead and see the the projection that I drew over there what I badly sketched out on the blackboard that's basic structure but now you can start to a mansion with issues like like when we were dealing with the camphor problem and we were dealing with that issue of 0 yeah what's the distance of a methyl in the Bromo camphor self-ironic acid problem what's the difference distance here are leaving clean this thing up not that we really need to measure a measure of basic distance what's that the distance for saying assessed distances right because that was where we had this issue of is the bromine pointing up or is the bromine pointing down and you'd be able look and say OK you know by golly assist distance is going to be a nice strong and await a trans distance is going to be a much much weaker in a week it also helps to calibrate remember we were dealing like with the methylene or hydrogen off of there and you can start to say Oh yeah I can I can begin to think about about these types of distances as well so that's why I mean this is so integral to understanding stuff so
I'll give you a by but octane by cyclo 3 to 1 on canes structure and
so we've got this this is you notice you have your cycle hexane embedded in it this is what I'm talking about the future cycle hexane embedded in the structure there so it's sort of sir just like just like a chair cycle hexane embedded embedded in the structure so you can play
with that here's the by
cycle have attained this this you could use as a the by cycle 3 1 1 have attained this is 1 that you can use as
a template you did right in your because he said it was flat you told me was flattened you model that the you so this is this is our pining dial problem the other canonical
structure for it so basically if you get a few simple structures as I said you can do so much the other 1 that serve canonical for understanding conformational analysis and so many natural products is trends Decker and which is
basically just cycle hexane with another another ring extended on its chair chair and since :colon it is also share chair and here I've drawn the way way it's you'd get from a projection and here's
Europe here's your suspect :colon adjusted cheering and we have an axial group and another another chair let me last thing I'll do is let me just show you how how these fare
In 2 a couple of things so here's a strict 9
molecule Yuval you won't model best and you notice son seven-member bring here I'll bring it over here you can see the seven-member during even though we have an oxygen in it even though at Seattle hard see there you go even now you have oxygen embedded in your seven-member bring you can see this chair like structures even know you have a double bond in an oxygenated you've got your 3 sort of axial hydrogen so that's going to influence your thinking as you start to assign your protons and assigned history chemistry the problem that from the other previous problems set that I presented as a as a demonstration where I was
talking about drawing things on the blackboard she noticed this you've got your chair cycle hexane during the Limassol your angular Mathilde was the 1 that gave you know we used to these axial protons that helped us scientist stereo chemistry you had during a wheeze like this hydrogen was 1 that was a real I guess this with the real linchpin because this 1 was a hydrogen Octavian week the natural only across Europe gave Vienna we hear all of those Our short distances all of those you just have to basically vendor walls contact their about so all of those are nice Short strong interweaves 2 . 6 2 points to 1 extremes the other 1 which was a little see when we radiated the manifold and we saw the inner we over to this other hydrogen again it's sort of giving us gave us restaurateur industry here and you notice this structure here with that with the cycle hexane and the five-member great is basically what I'm talking about with the trends that :colon and then your five-member during the conformational analysis it said essentially that underworld cycle painting so you understand trends Dekalim you understand all envelopes cycle paintings relationship the cycle hexane to cheer hexane and you can fake the conformational analysis of this system and you just sort of have a double bond coming off kind of in the middle position here Equatorial position during the last spring says a lot of power and being able to model the airline's structures are I I think that's where I'd like to like to end things up in terms of discussion going to attack the homework problems these are some of the prettiest and and most satisfying problems of the costs on some of them if you make a model it's going to be of the actual molecules can be incredibly enriching when you start to get your stereo chemistry get your dies during a topic assignments and you can start with those fears 10 flights if you want only out last last thing I'll mention I but I actually I will I will skip that I believe you on your own for a 4 1 last point you will figure it out you want it up
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Formal Metadata

Title INADEQUATE. Some Thoughts on Homework Set 9
Title of Series Chemistry 203: Organic Spectroscopy
Part Number 25
Number of Parts 29
Author Nowick, James
License CC Attribution - ShareAlike 3.0 USA:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal purpose as long as the work is attributed to the author in the manner specified by the author or licensor and the work or content is shared also in adapted form only under the conditions of this license.
DOI 10.5446/19262
Publisher University of California Irvine (UCI)
Release Date 2012
Language English

Content Metadata

Subject Area Chemistry
Abstract This is a graduate course in organic spectroscopy, focusing on modern methods used in structure determination of organic molecules. Topics include mass spectrometry; ultraviolet, chiroptical, infrared, and nuclear magnetic resonance spectroscopy.

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