Lecture 16. Introduction to Carbohydrates: Structure and Stereochemistry.


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Lecture 16. Introduction to Carbohydrates: Structure and Stereochemistry.
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Nowick, James
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This is the third quarter course in the organic chemistry series. Topics covered include: Fundamental concepts relating to carbon compounds with emphasis on structural theory and the nature of chemical bonding, stereochemistry, reaction mechanisms, and spectroscopic, physical, and chemical properties of the principal classes of carbon compounds. Index of Topics: 3:12-Carbohydrates 8:39-Lactose 12:47-Subunits of Lactose 15:38-Alpha-D-Glucose 18:04-Anomers 21:51-Interconversion of Glucose Anomers 25:29-Interconverting Lactose? 28:26-Forms of Galactose 32:15-Optical Rotation 37:25-Chair Representation of Glucose 39:11-Haworth Representation of Glucose 42:40-Open Form Representation of Glucose 46:56-Fischer Projection 51:15-Converting Haworth Projection to a Fischer Projection 53:48-PyMOL Demonstration 1:02:49-Using Fischer Projections to Make Different Sugar Molecules 1:04:32-8 D Sugars
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I get yourself a big hand we got the highest elected official backfired last year and that was the
last 1 to go which is sort of a bonus in the sense that I dropped the lowest squares we've also gone through what I considered to be some of the most intellectually challenging material of the course we broaden ideas of mechanism we want and ideas of synthesis and now we're kind of winding up the costs and I wanted cover some topics that are I think more more interesting and in some ways to bring back some old streams and bring in some new themes as well so we're going to spend today we're going to spend Thursday talking about carbohydrates and carbohydrates and 1 way is a very old topic in order in organic chemistry carbohydrates sugars are central there's so much of life they are of course the sugar that you put in your coffee they are the glucose and fruit those that make up that sugar they are the components of starch and cellulose in other words paper on your desk and the corn starch and so forth and potato starch in Europe in the vegetables that you will be there the backbone of with along with phosphates shoulders right those are the backbone of DNA they're attached to many biologically active natural products sugar called the services of yourselves your blood types are determined by which types of sugars you have on the surface of your blood cells and in turn give you a indigenous to give you any of the body responds to getting the wrong sort of blood type if you get an infusion so sugar served fantastically important we are coming back to an old theme that you learned in 51
day and that's scarier chemistry and I think the toughest thing about learning sugars isn't the stereo chemistry it's the different representations and interrelationships among going to spend some time today talking about structure in Styria chemistry of sugars I spent last nite and this morning making some special tools for you to help understand
some of the representations that are often used personally I'm a big fan of plastic models remember the darling models used in 51 and maybe in some of the so-called dry drylands associated with your course and I recommend you bring them back after learning this chapter of no OIC tears here from dropped from the models you can also use your computer I will let you use models on the final exams so it's useful to have them plastic models so it's useful to have them complement things right I wanna start with AC literally a simple sugar with Jordan the most fundamental may be the most common come and sugar we're going to draw it in a chair conformation and the sugar Chevrolet underlined here is glucose it's kind of kind of easy I like it because when I drop my chair lights so all of the substituent are in the equatorial position so it's very easy to remember the structure of glucose now should have and now the high group were going to talk more in a 2nd but for the most part they exist a cycle Akamai acid towels and I'm going to draw we have another serious center for a site like him I ask the talent I'm going to draw that hydroxy group at this position that the 1 positionable will learn is called the an American position of dried Equatorial this molecule is called data the glucose and so it's a member of the class of carbohydrates like this and you go to the gym you might call them cobs of course it's a nickname molecular formula is seized 6 page 12 0 6 and if you think about it then is the reason it gets its name as a carbohydrate is that the formula is carbon was staged to well and literally if I take some sugar if I take some table sugar and I take sulfuric acid which is very dehydrating and
Yang Paul the water out and carry out a whole bunch of reactions if you've ever seen this time you just put it in a beaker 4 inputs and sugar in a beaker pour on some kind sulfuric acid and this big snake of carbon comes out of the beaker this big roared of frothy carbon and sulfuric acid along with a little bit of smoke in that and so forth anyway not going
to do that demonstration here in part because it's kind of that kind hazardous but it's a lot of fun so glucose is a member of a class of carbohydrates and broad broad class of Thai carbohydrates that we call al-Ghozi is In the reason we call it and held those fears that when we go ahead and the structure when we break up the MIS it's at the 1 you get and how the hide their also sugars were few break up him I a towel you get the tone and those recalled Tito's his will talk about those later glucose the 6 carbon sugar number renumbered from this position 1 2 3 4 5 6 and so glucose is called and Aldo hacks taxes 6 it gets to be consistent right now indicate it's 1 of many many None a bunch of other
things things get called because glucose has a six-member grain containing an
oxygen in the closed form and have my ass italso form we call it a pure no sugar Taiwan is
a six-member bringing containing an oxygen atom detector Hydro Pyrenees saturated six-member drink containing an oxygen atoms of glucose is a derivative of detector hydropower I ran so we called pure knows the other important art ring containing oxygen is a five-member drink containing an oxygen the aromatic compound would double bonds and is called Duran and if you have all hydrogen is on the ring of the ring is fully saturated you Texas high-growth Koran pie Ranch texture of growth here and we've seen that th efforts the solvent and so there are other servers that have five-member brings in and that you would call a furor no surf your nose form of the sugar and I guess as long as we're talking about
names Sierra we would also referred in glucose as a memento sacked arrived the motto of course means 1
satirize will sugar I wanna give us some contrasts in structuring and stereo chemistry by drawing us in drawing a dissect arrived at this point and
it's going to introduce some basic concepts here so we're going to start withdrawing another period out form of ring we're going to have to work these linked together said to cheer cycle aims and I'm going to go ahead I enjoy everything the same on this rating as I did for glucose except that the 4 position I'm going to instead of having the hydroxy group in the act would Tory opposition up but the hydroxy group in the axial position
and we're going to make a molecule with 2 sugars in it's 1 that you might have consumed this morning 1 that actually
is good for you well maybe this also OK in moderation OK so we're going to link to another rainy here in
this ring will have as a glucose ring thanks so
so here's our heroes are dissect arrived dissected writers lacked goes against my
drawing isn't the prettiest in the world I'm
always delighted when I look at people's notebooks and see the drawing so much prettier than mine so like Dallas is the dye sack arrived here I think there
are a couple of couple of
interesting take all messages that we get from this 1st of all sugars can be linked together 1 to the next to the next starch for example is a long long chain of sugars as cellulose basically a polymer of almost infinite length now you might luck and say What's a little different looking there and I then loco 17 we basically formally
removed 1 water molecule Soviet right out the molecular formula of lactose it's 12 page 22 11 concedes say Well we don't have the
same ratio of carbon and the hydrogen as we had because we connect in glucose but if you notice it's stale the carbohydrate still
effectively carbon plus duo in this case
12 carbons plus 11 h 2 woes in the case of glucose 6 carbons for 6 h to others so if you want to know if you look at
that our lacked as I said we have to units and we have our low-post unit and now we have another server unit in it and this is a
galacticos unit
so galacticos let me drive out galacticos in glucose in just the 2nd but I just want to make 1 last point we have a linkage from the 1 position of glucose writes that this is the 1 position and end to the war of the 1 position I'm sorry galacticos that's the 4 position of glucose right we number away around the ring 1 2 3 4 by 5 60 and so we call this a a 1 2 4 like acidic bonds glycans cynically linkage or glycoside want to draw out the units the subunits here In galacticos all dry out petitioner the units but read are drawn glucose again the pays to practice a little bit your drawings and I've gotta say I'm no artists as far as cycle hexane rings stone basically the theory is that you're going to be making parallel lines of the equatorial bond for this OH group is parallel to the CEO bond for this 1 the equatorial bond to this OH group is parallel to this 1 as I said I'm not much of an artist but I can get my dad my ideas across to confidently alright so Sokolac said this is glucose more specifically beaded the glucose will talk about what they did means in the 2nd and I will draw galacticos more specifically the leaders the the Galacticos of talk more about that began in the 2nd alright so everything is the same Over here except as I was indicating when I drew our molecules now we have a different area chemistry at the 4 possessions the the so too
isomers that have the same connectivity all of the same Adams connected together and in the same way but just differ in this area chemistry of 1 positions are dire streamers their stereo isomers that not in India murders but I remember when you
learned about Styria
chemistry you learned about in empty Amir's compounds that are non superimpose a ball mirror images you learned about dire stereo isomers died hysteria murders stereo isomers that are not Indiana Amerson then you learned about constitutional isomers molecules that have different connectivity in different arrangements of Adams Our at this point I wanted another structure and and deliberately proceeding reasonably slowly and methodically here because I think it really takes some time to bring all these ideas into your head to dust
off the cobwebs on some of the history of chemistry and structure that you learned that 51 a son going to draw a different structure here we're going to do everything the same as glucose but with 1 exception I'm going to know instead of having our Syria chemistry at the 1 position be Equatorial instead of having the hydroxy group at the 1 position be equatorial I'm going to have our hydroxy group at the 1 position be axial but this is Alford the glucose In the Convention of organic
chemistry you have data as the opposition the top face of the the ring with Alpha is the bottom face of the ratings to the all-ages pointing down to the bottom face as we've drawn at what we call the Panamera carbon so the
carbon that makes up
the ham I assets is very even occupy sort of a privileged position if you think about it because unlike all the other positions use chemistry there depends just on how you've close their hair my answer town whether you've closed it so that the OH group is Equatorial or axial and so because of this very special
the highest theory America relationship and sugar chemistry we often have yet another word for word the dire America involving the him I the town to lay buyout position so we call it we give it a special name as I said this is the hemline acetaldehyde solutions and so we call this an animal so just as we would say that day-to-day
glucose invaded the Galacticos are Dyess serial murders we would say that Alford the glucose invaded the glucose or anniversay have a special Dyess Air America relationship to each other there's still the highest area embarrassed but there is a special type of dire streamer that often gets called in Panama
it's all right said down but so
most diets Mercer Street chemically stable in other words if I have a bottle of lacked dose and I go away go away for a long time and travel around the world and come back I still have a bottle of lacked doses would never become a bottle of sorry if I have a bottle of Galacticos it would never become a model of glucose if I have a buoy a solution of Galacticos it is stable and the lack but this is not the case for an Emerson which you have him I ascertain town we've already learned that have my answer Talsarnau stable compounds staring equilibrium With Al-Jihad now on the case of site like MIS italso we learned that they attentive for favor the close confirmation in the case of glucose that's really really really strongly a preference and nevertheless said equilibrium you have a teeny tiny bit of the the hybrid form of the open form in other words alpha and beta D glucose can enter converge in water
and exist equilibrium it's all right this as an equilibrium pulsating water because the solid state the crystal lattice keeps them stable in water you have all sorts of of chemistry occurring involving carbon groups and so the alpha and beta forms of D glucose can enter converge at equilibrium you have a 36 To authority to
564 and I want us to think ourselves through this in conversion process and I'm going going the statute out here in our in our mind's eye so all
start with Alford the glucose were not going to write a detailed mechanism I think by this point I'm hoping that you were on top of carbon yield chemistry and not to be able to work through the mechanism to remember
in the case of a site like him I acetaldehyde catalyzed by acid or by based basement warming gasses even water you have a little bit of acid you have 10 to the negative several smaller H 3 0 plus a neutral water you can probe all your oxygen atoms if you program made this
oxygen atom you can open the cycle Akamai Ossett Town and so all right taught Amir here I will write the the isomer in which we've opened this linkage and so now we have our elder hired but everything else is the same so we've just opened link did cheered a form the elder remember mechanistic way you can think of protein made on this oxygen push electrons down kicked out that oxygen now you have an of being Neumeier and take off the protons all right now if we imagine rotating about
this volunteer lights Owen and just gonna say we're talking equivalent structures here generally when you rotate about the bond you don't think about a structure is being different you think about it as being a related as just being overrode Mercer liable rewrite rotating
about the volunteer right so so all I've done differently now His rotated out the bond to the elder hired and now if you want magic closing up the structure here so we started without deep glucose we've envisioned opening it to form the AO the Hyde had equilibrium here you have about 0 . 0 0 0 3 per cent of the open format people every year and now if you unimagined just read closing this but we've done to the beta
form we've gone from the alphanumeric to the data animal question can you do that for a lack great question yes and no In calling itself the question is very very good
and I'm glad you asked that focus all like those not re-elected prime absolutely very good question and I am delighted delighted that you asked it so let's go back to our lack of structure are
here I like those structure there are 2 types of an America problems 2 types of problems at the 1 position there's this hard-bitten
which has that have my assets and then there's this part of the year which has an an asset to our member in him I as a talent has a hydroxy group on
a towel doesn't have a hydroxy group on it and so the MIS italic on Form absolutely 10 equilibrated and so the structure that I drove for lack states in your Malkin whatever you do you drink in the morning on your cereal cream in your coffee the like those that's there the like those that in your ice cream has in equilibrating mixture the data an alpha and emerged in the glucose unit however unless you will have strong acid and by strong acid now I don't mean neutral water a little bit of ACL but unless you have a very strong has said that can break apart and acetaldehyde boiling HCl solution of boiling answers the linkage the a bigger linkage off the galacticos unit is stable and doesn't doesn't undergoing through conversion so I will
write stable Over here and when we say when something data converts we say it's a late filed for this position good
question good thought other good questions I had a lot of our life a like every year and the like you of can so the Galacticos unit this subunit here at carbon 1 frame galacticos absolutely OK great another great question itself and
once somebody tend to answer for me here so we saw that we had I drove the beta compounds what do we call this form of galacticos health so this is out of the galacticos I didn't can't
tell you something else right now so it's really good to have a new pieces of core knowledge that you keep in your head because you use them we've done this week when we talk about the case I talked about the end of the pier the tone :colon 20 whether to the toner now the height of the PGA know the PTA of LDA decor knowledge is very useful because you can build up there are lots and lots of different models that all I do not in my own head I'm not a practicing sugar cane as keep all of the structures of all the different motorcycle I could if I wanted to purchase not useful for me like glucose and say the 1 Syria white 1 streamer Galacticos are useful things to know because it's something that you can hold on to win and you can build on it so when you see various other sugary he tells you something you can understand relationships to other questions at this at this point yes thank you why is it that if you change that position that the 1 group if you change the stereo chemistry the 1 position it's not a different sugar and a few changes before it is the same basic idea because Alpha and Beta D glucose are laid buyout because they enter convert we'd say rapidly into converting their Inter converting the the same basic molecule but for once were you have stable highest theory emerged then you'd say the difference here vary widely in the bolt different but there's this question of timescale if I put data the glucose into a bottle and come back I have a mixture and water of alpha and beta D glucose so they're different but they're not that different data converts so that's why we categorize them and actually let build on although so there are indeed
Wilco's has an optical rotation optical rotation
means the amount that you rotate plane polarized light if you've ever taken a pair of polarized sunglasses and cross the lines is you know that when you get to a 90 degree angle like doesn't come through for a few ever have a pair polarized sunglasses and you put them over if you have an LCD watch on LCD maybe even the LCD screen on your phone or computer and you rotated you will blacked out because you have polarized light in many of these sorts of devices it will go black and 1 angle at a right angle it will be completely transmitting of fully transmitting of white and it's the same type of thing with sugars they rotate that polarized light and this is 1 of the characteristics of optically active molecules of molecules were you have a single 1 in timber and hysteria chemically active and the degree to which glucose rotates plane
polarized light is called the specific rotation and if it used traditional the sodium deal line that bright yellow line if you've ever been East Coast you've seen lamps on the other you've seen lights on the highways there those bright yellow lights are sodium lights that 522 I believe anatomy delight anyway that 1 is often used and you were located by by 19 degrees now out of the Broncos is a different Samarra and so it rotates the plane polarized light to a different extent the optical rotation of Alpha glucose is 112 degrees for the cod specific rotation if you wanna be exactly what you calling this rather than optical rotation by optical rotation I think is also easier to
understand now what's cool about glucose and this comes back to your question there about why we don't consider them different molecules or we consider them different but not that different
is if I go ahead and take solution abated the globe coast with 12 degree optical rotation of 12
degrees specific rotation and I let that solutions said you can say the glucose Inter converting from the Bader isomer to the 36 64 mixture of data and al-Qaida because the rotation changes with time and it goes
so upon standing will say both of these things are not going to 53 degrees
rotation 53 degrees specific rotation because the 2 and emerged during the conversion converted we call this process Nuno rotation at Mugello
changed so basically
that's a fancy way of saying changing rotation that it's going to be catalyzed by a little bit of a center of the
square you as I said he'd be neutral water has acid-base inattentive negative 7 smaller hydroxide tentative 7 smaller Hydro numerous remove the words the catalyst we just speed up the process I'm
not certain questions at this point I want to talk about how we represent Chavira structures and the sort of form different notations for drawing in the big problem we have is the fact that we're dealing with the plots of land black forward and yet you're talking about molecules that are rich in Styria chemistry and still thinking about understanding communicating in danger relating stereo chemistry is really critical when we think about sugars and the structures so we spend drawing the chair form abated D glucose all draw
that again because we're going to start to compare and so here we go here is outdated the glucose and at this point I want to remind us of something I want to remind us of where our hydrogen sorry not the hydrogen is the LH group but the hydrogen that had been implicit in the molecules of course at the acts of course even tho all of our troops on the cycle hexane rain are at our Equatorial except if you have alpha
glucose in which the Alfa Group the Alpha the glucose LH is axial where hydrogen so invaded
Day-Glo colors we have an axial hydrogen and that the 2 opposition we have another axial hydrogen and at the 3 positions on the war position and the position that galacticos had an axial hydroxy group we have an axial hydrogen and finally at the 5 position as well so the way we have 5 Serie Gen-X centers in the molecule the stated Jeremic centers at positions too 3 4 and 5 at a fixed the 1 position 1 that played by 1 of course positions 6 being the CH to OH group you have to hydrogen on the carbon it's not a Carol carpet so there are other ways that we can represent the structure here so again on this right data as indeed glucose it's good to remind us of the structures I'm going to be right writing for all of these there is another way of representing the structure that doesn't
try to represent confirmation of the ring member lining a cycle hexane rang writing a six-member agreeing in the confirmation that I've written there is a projection if you physically take a plastic models Of cycle hexane in a chair conformation and hold it in front of a light source like an LCD projector and let the physical model projected on the screen and tilted into just the correct angle you will see all of the bonds project on the screen like this it's still a six-member ring
but that's the projection that's why we write it that way to think about and to communicate Styria chemistry if we choose not to trying to represent the shape of the molecule you can still communicate history chemistry so 1 of the ways that people do it is just to do a flattering and again it's sort of tell more than a dollar a news wedges to to represent what's coming out of the at us so we sort of have a ring till they like this but we're just representing a planar structure and now you can think about it we can simplify things we can write an American wage offer and the hydrogen down so obviously this is a more stylized representation it's not trying to capture the physical structure of the molecule we can take our next position member we have our hydrogen down ROH up we can take our next position we have our hydrogen up and always down so we can represent that like do the we come to our next position now the hydrogen is down the OH is up so we can represent that like this position for hydrogen up low-wage down and finally position 5 and we have hydrogen down C H 2 0 wage we call this representation of all worth projection and you'll see it used liberally in your text
so those still projections kind of represent the cycling structure of the molecule and a catch all the keys is chemistry but they also require a little bit of artistry to represent the ways of representing the structure that may be involved less artistry we imagine opening the structure of we imagine opening the structure to an at this position and now we want to get all of our scarier chemistry just in a zigzag structure of the molecule so I
can't imagine going from 1 end to the other we have 6 carbons and an oxygen on unions 1 1 common 2 3 4 6 in let's make let's
start with the Al the hydrocarbon here remember I'm just opening their hair my ass italso structures so that's going to be the elder hide in our chains it is up so in looking at the chain at this point the all H is going to be coming out at us the hydrogen is going back so in a zigzag structure we're going to represent this as
are always coming out the hydrogen coming
back it's important to be able to visualize these relationships and it can also be very hard to to do this the 1st time around because you're having to train your head to really recognize 3 dimensionality embodied in a two-dimensional drawings OK our next position on the chain weaves it down the all wage is again coming out ahead of us and the hydrogen is coming back so we're going to represent that over
here but always hydrogen going back
now you almost want to
continue to walk around and look at this molecule From over here like I'm doing Olivette OH is coming out and the hydrogen is going back as we come around the chain
now we continue along here you have the sort of position your a from
back here and say OK now that awaits is going back so we sort of followed are where you've unwrapped the chain you're visualizing from here that OH is going back that
hydrogen is coming out and this is just
the association to all
groups and so what I've done here in part because I'm used to seeing molecules like this is i've unwrapped the structure drawn it in a linear fashion as the AL the and honestly when I think about what lots of stereo chemistry in organic molecules the structures that I think about early news exact structures like the In cycle extract cheers like that the what's there him my I that's how yes so can I point
to the MIS at that position 1 and so we just imagine the center conversion of the MIS Tal anti-alcohol member
this open form is present .period 0 0 3 % amidst the closed form of the molecule in the closed form is a 64 2 36 ratio all the data and the alpha emerges other thoughts and questions are now the 1 that I am not in love with her represent for a representation of molecules of sugars but that has been used traditionally to such an extent that it is absolutely integrated into almost all textbooks to discuss sugars is what's called the Fisher projection the
Indian official projection what we're going
to do is represent the molecule in a straight line and we're going to represent did so it curves backwards but we're going to show it is linear will put the album I group on top
traditional way and now we're gonna look down this way so you can sort of say are intentionally indigenous were going to get CHO and then always and age were basically citing down this position you are going to help you out with this some more in just a moment so reciting down this position here but the key thing in the
Fisher projection is were basically wrapping the molecule on itself so you would have to imagine has we continue we're gonna go ahead we rotate about this bond 180 degrees bringing it
down that's gonna throw the all H. pointing out pointing back on the other side so we're going to rotate 180 degrees like so I know that's hard to see me the way I
see this is really the relationship I can easily say the relationship between the site like structure and say site which structure I just sort of walk around in my mind looking at it and it helps to train yourself with models and will come to that 2nd plastic models of the
best computer one's work the hot worth projection is perfect for converting to the Fisher projection because the hot worth projection you say the molecules are ready to act on itself here's the molecule and remember that's just now the so we're going to ignore ignore Styria chemistry there I'm gonna pick that up this awaits when I picked it up is going to go walk that way this H is going to go off that way I take the structure I pick it up here was the OH I bring a vertical ladder wages that way I take this structure and here was here is this OH I bring it this way that once pointing to the left and we
can continue around like so
and now the only .period
they gets confusing is over here let me draw the glucose is drawn 1st and then I'll show you how we how we get over there so the last position
doesn't matter well and also you widen the 2nd so here's our last position and
in fact for all of the D sugar they have this stereo chemistry at this position at the
position that's next to the terminus of an so dean at this position they didn't know it when they 1st started Fisher started to study the Sterry chemistry the sugars but the deal means this area chemistry and it means stereo
chemistry member or interest at this position here's are all
worth projection again I want to show you what I see when I go ahead and do this
when I go ahead and do it but the whole drawn as spot here so we look and we say always each page of age in each of old age now we come down to this
position remember I've picked up this range were curving back at ourselves picked up this ring it's like this I
brought it like this so we have this I OH over here this 2nd awaits the 1 of the 3 position here the 1 at the floor position over there now we come to the 5 positions if I pick this up and look at what I have over here is now I have a carbon but I have wage continuing down and I have a hydrogen and I have besieged always over here in other words I picked this up I look I say how does that go OK well now what I picked this up that hydrogen is off to the right the C H 2 0 wages off to to the left the oxygen is down when I pick this stuff but now you say OK how do we get from there to there you can just imagine that you rotate about this despondency rotate like so like so like so you move those 3 Adams all inner circle you're rotating about this fund Everything the same until we get to the bottom positions in its representation and now we rotated so we rotated the always over here we rotated hydrogen over to hear and we rotated the C H 2 0 wage Over I'm not hard to see its heaving as saying with physical or computer models it is hard to say In your head for the 1st time particularly representing seeing this representation
remember this representation of the molecule the sugar molecule wrapped around the cylinder here it is taking that worth projection and
wrapping it and so 1 of the things that I didn't try to help you get ready to see this is I set up some stuff and we can proper computers here at this point because I'm going to go ahead and you're welcome
to play along Johnny in him and I will be able to help you with this
in in your discussion section or in
Europe In our office hours if you like but I've set up Bahia it's all for
us here on the Web site and I just set it
up in primal so if you remember back to 2
weeks we had time all
and we had some exercises in you downloaded primal on your computer and a civil use later I wanna use it later in the course so OK 7 hours later side made made some molecular models for you and what I've done is I've started with those drawings that I just made on the blackboard I started with the chair conformation of site hexane for glucose I started with the hall where the projection the zigzag structure that I just talk drew an official projections and what I did for you last nite was I created molecular models of each of these so here for example
is the chair conformation
abated the glucose and remember what I talked about it with the idea what's let me kill the argues that is is killed as it not OK I go better set OK so member I talked about projections and this goes
right back to you take care much Obery beginnings so there's the six-member grain when you go ahead the rotated like so your chair emerges I've linked by the way have linked Firefox in my computers that PDB is downloading open automatically in primal so OK if you want a go-ahead remembers show Shokan show the Dexia and select and show you structure and sticks I just want to show and sticks we can get a structure that can get a bounce back I want to show you what I laid out for you
right now so OK so the hot worth projections should just pop up if it doesn't or so there's so I made an unnaturally flak cycle hexane an unnaturally flat sugar molecule and so now when you start to lock so there's our worth projection pretty much just as I've drawn it and I'll show you a couple of couple of other things here I'll show you what I laid out now and I'll show you how I use these tools to think OK I'm going to show you the
open formed a zigzag form so there's our zigzag form that I just threw out on the on the
blackboard for you you can get a good look at it you can see all your stereo chemistry on there and now
the last thing I laid out for you Was the Fisher projection with unnaturally flat which is next to the
last thing I laid out was the Fisher projection so I'm just going to move the elder ride to the top and so that's
the that's the Fisher projection so let me
see if I can get worth rejection next to official projections barring so remember what I said about rotating the structure itself here we go so that's the that's around America a bit of the whole Ruth projection debts
owed to carbon and you'll notice the hydrogen is often the left the awaits is off on the right this is our 3 carbon you notice the awaits is often the left the hydrogen is off on the right will continue around I'm going to rotate my haul worth projections and now we come to the fore carbon and now you notice the awaits is off on the right that's the 4 carbon here and then I'm going to continue to rotate here and now this is the conundrum I mentioned now we're at the 5 the 5 carbons and so the 5 carbon we have here the hydrogen all in the cycling form the CH 2 off on the left and the oxygen that so often you just have to imagine rotating about this bonds here which is going to bring that hydrogen there the C H 2 OH down and this of the universe and always projection year Whitesell as best as I can because of course the territory grow and so there there we go now you can see our 5 position the hydrogen is off to the left the OH oxygen the oxygen that was the end American acid tower is now off to the right the last thing I've done for
you to give you some Josie these structures and this is what I was saying before glucose is really an archetype of all the sugars if you can master glucose you can master all the other sugars in you thinking and if
you can understand the structures so have 1 sort of tool here 1 sort of toy OK The other
thing I've done for you it is finals native
file format PDB is sort of an interchange file format it's also 1 that I've linked so my computer opens its final when I downloaded Firefox PSE files are the native format for prime also they contain all of them so I made a composite structure and I want to show you how to use this on your own so here's a 1 I call glucose composite it's just going to go to my downloads Our it's so there's my glucose composites and I want to show you what's in here so there's glucose in the chair form if I click on the right here
and I closed the chair foreigners my Harworth worth projection and if I clicked again on the open form there's the open form me if I clicked on the Fisher projection there's the Fisher projection I can just rotated off and sell these tools or plastic models should help you visualize this area chemistry and really really internalizing now
the last thing I want to do it's just come back to ah drawings and I just wanna play off of the author of these showings that we
we had here OK so
come back this is our This is our Fisher projection of glucose so far as know what I want to do now is to come back and show how the structures these Fischer projections visualizing others very chemistry so remember we send galacticos was identical to glucose extract In the 4 positions so now I look at galacticos but I say right hind on how it is clearly no the glucose structure of all I need to do To make galacticos from the official projection of glucose is to change the stereo chemistry at the 4 position 1 2 3 4 are all IDA were mailed to swap those 2 substituent and this structure is made of the well I'm sorry actually technically because
because we're not showing the site like structure I should say this is D glucose and so on technically this is not a data or althought
bodies regardless of the galacticos Our accident main point is that we go through a
lot of work to get to the Fischer projections but once you're at their you can say all I can immediately start to interrelated all my structures and we know that there are 8 the
assurance of the aid the sugars because the data indicates the position at 5 is always affects weakened per mu the positions 2 3 and 4 to come up with the other stereo isomers I'm not going to bother to ask you to know them but they are Al troves of their cool names glucose man-hours grew lows of the I of Galacticos and tells of so these are the 8 Dyess Air America D sugars apart from of alright but I think that wraps up what I want to say about the introduction to the structure and Styria chemistry and sugars we will think up the next time talking from the 4 carbon sugars on up and then moving into reactions of sugars


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