Give a systematic (IUPAC) name for each diol
(a) CH_...

Question

Give a systematic (IUPAC) name for each diol

(a) CH₃CH(OH)(CH₂)₄CH(OH)C(CH₃)₃

(b) HO-(CH2)₈-OH

(c) Chemical structure of a cyclohexanol with hydroxyl groups on opposite sides.

Accepted Answer

All right. Hello everyone. So this question is asking us, what are the Iupac names of the dials given below in here, for parts one and two were given two condensed structural formulas. And for compound number three, here we have a line angle formula or a skeletal structure. So let's go ahead and recall a few general rules when it comes to Iupac nomenclature and then specify a few things about alcohols. In particular, recall the first step in finding an Iupac name should be to locate and name the parent chain. Now, the parent chain is the longest continuous chain of carbons present in the molecule and it's also the longest continuous carbon chain that includes our primary functional group. It just so happens that all of these molecules provided are alcohol specifically dials. So the parrot chain is the longest chain of carbon that incorporates the hydroxy or oh groups. So after identifying the name of the parent chain as well as any modifiers that specify what functional groups are present, then we start talking about identifying and naming substituents that are present the constituents. If you recall are written in alphabetical order before the parent name So with this in mind, let's go ahead and proceed with the first compound here, which was presented to us in a condensed structural formula. Now, in this particular case, I always recommend if possible converting this condensed formula into a skeletal structure because it may be easier to visualize though counting the number of carbons in the parent chain. Here, we can see that there are nine carbons in the parent chain as well as a few substituents attached to them. Recall here that CH two in parentheses with a subscript of three outside of parentheses means there are three repeating CH two units. So that's three additional carbons in the parent chain. So that's nine carbons. And now I'm just adding the hydroxy groups on the appropriate carbons, which would be numbers three and seven. And then we have an extra methyl group here on carbon number nine. Actually, there would be two methyl groups. So now let's go ahead and talk about identifying the parent chain as discussed. Previously, the longest continuous carbon chain was composed of nine carbons. So to understand the locations of our substituents on the carbon chain, we should always go ahead and number each of the carbons in the parent chain. Now, the idea is to make sure that your substituents, especially your higher priority substituents have the smallest possible position number. So let's consider two different possibilities. If I start numbering my carbon chain from left to right, then the first hydroxy group I see would be on carbon number three. Now, if I start numbering from right to left, then the first hydroxy group I see is also on carbon number three. But this time if I number from right to left, then my metal groups also have a small position number. So that's how I'm going to go ahead and number the rest of my carbons here from right to left. So from here, let's go ahead and build our iupac name, our parent chain was composed of nine carbons. And because there are only single bonds in between those carbons that's referred to as non. However, because this molecule is a Dior, I'm going to have to place a modifier after the parent name to specify the presence of these hydroxy groups. No, the hydroxy groups are on carbons three and seven of the parent chain. So after knowing I would add a dash followed by the locations of my hydroxy groups and then the word dial, notice how I am separating numbers from letters using dashes and commas to separate these position numbers from each other. So now our last step is to go ahead and add our substituent names before the parent name. Aside from the hydroxy groups that have already been described in our Iupac name, we do have these two methyl substituents, both of which are on carbon number two. So despite them being on the same carbon, the number two is repeated twice for each metal substituent. So that starts off as two comma two. However, because we have multiple copies of the same substituent in this molecule, recall that a prefix is necessary to specify how many there are. For example, die for two try for three tetro for methyl, et cetera. So here instead of saying 22 methyl, for example, I would say 22 dimethyl and I would write this in front of my parent name with no space in between them. So that gives me 22 dimethyl, none 37 dial. So now let's go ahead and proceed with part two. Now, the good news about part two is that even though were also given a condensed structural formula, we don't have any other substituents aside from the two hydroxy groups. So here by noting the fact that our ch two here in parentheses has a subscript of six outside of the parentheses, this means that we have six carbons in the parent chain. So that would be hexen, that would be Hexane and we have the two hydroxy groups on the outsides of the parent king, which means that the two hydroxy groups are at the terminal position, low carbon to one and six respectively following the same pattern as before. With the first example, I would add a dash after the parent name, add the substituents location. So it's carbons one and six and then add the phrase dial. So that gives me Hexane 16 dial. So now lets go ahead and proceed to part three. So in the case of part three, the longest continuous chain of carbons is composed of five carbons that contain the two hydroxy groups. It just so happens that if I were to number my carbon chain from left to right or in reverse, I would end up with the same position numbers. So let's just say that I go ahead and I label my carbons here in the parent chain from left to right. So starting off with the name of the parent chain, a five carbon Alcaine, it is known as pine. And the two hydroxy groups are on carbons, two and four of the parent chain. So that pen 24 dial once again using dashes to separate numbers from letters and commas to separate numbers from each other. But we do have an additional substituent because we do have a four carbon ring that is branching off of carbon number three in the parent chain. Now a four carbon ring is referred to as Cyclo butane. However, when an ocho group is described as a substituent or referred to as a substituent, the A&E at the end gets dropped and replaced with a YL. So we go from CYO Butane to cyclo butty as in Ayob Beal group. And because the Cyclo beetle group is on carbon number three of the parent chain that is three dash cycled written before the name of the parent chain. So after combining it together, I get three Cy Lobule Pentane 24 dial and there you have it. So here we have the iupac names for all three dials given. And with that being said, if you watch this video all the way through, thank you so very much and I hope you found this helpful.

Give a systematic (IUPAC) name for each diol
(a) CH₃CH(OH)(CH₂)₄CH(OH)C(CH₃)₃
(b) HO-(CH2)₈-OH
(c)

Key Concepts

IUPAC Nomenclature

Diols

Structural Isomerism

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