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Current time:0:00Total duration:10:04

Video transcript

we've done a bunch of examples looking at the actual molecular structure and trying to come up with the name in this video we'll go the other way around we'll start with a name and see if we can actually draw the molecular structure of whatever this might be so let's start so when you first look at these it's very daunting but you always want to start really at the end so you know what kind of the core of the structure is going to be so if you look at the end of this you have an Ain so there's not going to be any double or triple bonds there it's all single bonds it's a hexadecimal was a prefix for 16 so this is 16 single bonded single bonded bonded carbons carbons and cyclo hexa dexing cyclo cyclo hexa decane so 16 single bonded carbons in a ring so this part of it right here so let me just so the cyclo hexa decane let's draw that part first it's not easy to draw even a 16 a 16 carbon ring so let's start here so it's 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 and then 16 I think I got it let me count them again and then I can connect them up into cycle so it's 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 all right I drew the cyclo hexa decane part now if we go back a little to see we have a 2 9 die isopropyl so what is a what does this mean this means that we have an isopropyl at the 2 and the 9 spot now when you are drawing the structure from the name you just arbitrarily on the subway saw this ring pick what your one through your 16 spots are so I'll just arbitrarily pick them one because I could have drawn this ring any which way 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 alright so this is this next piece right here let me do this in magenta - 9 dye isopropyl this is telling us that at spots number two and it's spot number 9 I have isopropyl the dye is just saying I have two isopropyl zatt 2 and 9 so you can kind of ignore the dye so I have an isopropyl and you may or may not remember that an isopropyl looks like this it's 3 carbons so it's going to be 1 2 3 and the connection point to the main ring in this case is going to be in the middle carbon so it kind of forms a why all of the ISOs the isopropyl isobutyl they all look like wise so this is so it's going to be linked right over here it's going to be linked right over there and that's also going to happen at the 9th carbon so the 9th carbon we're going to have another isopropyl we're going to have another isopropyl at the 9th carbon alright we've taken care of the 2 9 isopropyl then we have the 6 ethyl 6 ethyl which is just a two carbon remember meth is one F is two pro is three so this is let me write this down so this is so this is going to be so probe is equal to 3 I so pro is equal to that type of shape right over there in this case F F is equal to 2 so it's a six ethyl group so it's six we have an ethyl group so one two carbons and it's connected at the six carbon on the six carbon on the main ring and then finally we have a cyclo pentene cyclo penta so if we look at let me find a color I haven't used yet see I've already usable this here cyclo penta so pent pent is five but it's five and a cycle so there's a five carbon ring that's branching off of the main ring and it's at the first it's at the first spot so let me draw a five carbon ring so pent is equal to five so it would look like this one two three four five looks just like a Pentagon that's a cyclopentyl group and it's attached to the one carbon on my cyclo hexa decane so it is attached just like that and we're done we've drawn one cyclopentyl six ethyl to nine die isopropyl cyclo hexa decane let's do another one I think we're getting the hang of it so here here maybe we could do this one a little bit faster let's see we have a tetra methyl dodecane so the main route here is the dough decane dough for to Dec for 10 this is a 12 carbon chain it's not in a cycle so let me just draw it out so we have one two three four five six seven eight nine ten eleven twelve and so we can just number them arbitrarily just because I could have drawn this any which way so it's one two three four five six seven eight nine ten eleven twelve that's the dodecane all single bonds and then we have a three six nine nine tetramethyl and although all this is telling us all this remember meth is one carbon so all this is telling us is that the three the six the nine so the three the six and twice at the nine spot we have methyl groups and we have four methyl groups that's all the tetra methyl is saying so it's a little bit redundant we know we have four from here 6 3 6 9 9 we have methyl groups on each of those places so we have one methyl group at 3 and then that just that is bonded with the third carbon on the dodecane chain we have one at six bonded to the six carbon on the dodecane chain and then we have two at nine so we have one that's one at nine and then we have another one at nine bonded to the nine carbon on the dodecane change and we're done that's it that's three six nine nine tetra methyl dodecane let's do another one one three this one one dimethyl ethel cyclopentane so once again just take kind of you know breathe slowly it's it's very daunting right when you look at it but just start with kind of the core cyclopentane that's just a simple five carbon ring five carbon ring it's like a pentagon one two three let me talk a little bit better three four five let me draw that five there you go that is a five carbon ring and we can number it however we want so one two three four and five and this is telling us that the 1 and the 3 position at the 1 and the 3 position so the 1 & 3 position we have and the BIST is kind of redundant this is saying we have two of these things obviously we have two we have one at the one one at the three so you can kind of ignore the bits that's just the convention and we've seen that multiple times but at each of those positions we have a 1 1 dimethyl ethyl so what's a dimethyl Ethel look like so let's think about it a little bit let's think about it let me do it in orange so this is going this is they obviously named it using systematic naming and what we have here we have an ethyl is kind of the core of this sidechain so if when ethyl ethyl is equal to 2 carbons so this is 2 carbons right there so let me draw a two carbon one two that is two carbons right over there I'm just drawing it the 3 spot I'll draw it it also the one spot actually so that is two carbons right there that's the ethyl part and then on one one so if we number and we number where it's connected so it's one two one two this is saying one one dimethyl so on this ethyl chain you have two methyls remember methyl is equal to one so this is one carb you have one carbon that's what methyl is but you have you have two of them you have dimethyl you have it twice at the one spot so you have one methyl here and then you have another methyl there same thing over here you have one methyl on the one spot and then you have another one methyl on one spot and then you are connected at positions one and positions three so you're connected there and you are connected right over there and you're done that's it that is our structure now if you did this with common naming instead of this being instead of this being this group being a 1:1 dimethyl ethyl you might see that okay we're connected to a group that has one two three four carbons in it the carbon that we connected to branches off to three other carbons it is a tert-butyl so you could also call this a you could also call this a one three let me just write it down so another name for this would be one three one three tert or sometimes people just write a T there t-butyl t-butyl cyclo now actually I say die t-butyl because we have two of them one three die t-butyl cyclopentane cyclopentane so that would be the common name