Write the IUPAC name for each of the following alcohols and phenols: (12.1)
a.

Question

Write the IUPAC name for each of the following alcohols and phenols: (12.1)

a.

Accepted Answer

Hi, welcome back everyone. Our next problem says, provide the correct Iupac name or the following compound. And we have a benzene ring with four different substituents, an oh group adjacent to that a chlorine, two carbons away, a methyl and adjacent to that another chlorine. Our answer choices are a 24 di Chloro four hydroxy Taine B 25 chop P methyl fen C two chloro four methyl, five chlorphen or D 25 di Chloro four methyl phenol. So the first thing that can help us cross out one of these answer choices right away is that we have more than two substituents. So we can't use the Ortho meta pera system. That's only when you have a dye substituted benzene. So choice B can be crossed out right away since it has P methyl phenol in there. So more than two substituents mean that is an incorrect answer. Now, let's look at our compound here and think about what is the base compound. Well, as we know, we have this benzene ring and as we know, there are several special names for certain substituents on a benzene ring and we have two of them that get their own special name. We have the oh group, the alcohol group, which you would call phenol. When a benzene ring has an oh substituent, we also have a methyl group. And when you have a benzene with a methyl group substituent, that is toluene. However, since both are on here, the phenol group is going to be a higher priority substituent than the methyl group. So we're going to use the base name phenol rather than ta you mean? So when we look at our answer choices, if you recall choice, A had the base compound hydroxy tomine. So this is not the correct name because the oh group will be more important. So it's going to be phenol with a methyl substituent. So choice A is incorrect as well. So we have our base compound name of phenol. So now we need to number are carbon atoms around the ring. Since the oxygen group is the most important substituent or the primary substituent, we would start with the carbon attached to the O group. So that will be carbon one. So in red, I'm just going to number around the ring. So carbon one has the alcohol group and then we just go around 23 oops, I missed 123, putting my numbers inside the ring. You can see why. Maybe that's not a great choice because they're kind of squished together. So we've numbered our six carbons in the benzene ring starting with carbon one being the one with the alcohol group. So we have our base name and we don't need to number the oh group because again, it's not named as substituent, it's the base compound. And so it's assumed it's on carbon one. So let's name and locate our substituents. So as we go around from our hydroxy group in clockwise order, we have a chlorine but we have another chlorine as well. So with two chorines that's going to be Di Chloro to name those and we just need to locate them. So first chlorine is on carbon two, the second on chlorine on carbon five. So we'll have two comma five hyphen di Chloro using commas to separate the numbers a hyphen to separate number from letter and then our other substituent is that methyl group. So just one. So that will be methyl and it's on carbon four. So we'll have four hyphen methyl. So finally, before we put it all together, we need to decide what order they should be put in. And we recall, we name substituents in alphabetical order is for ABC order for short, not including any numerical prefixes. So we don't include the dye in front of coral. We just look at the C of Coro and the M of methyl. So the coins will be first. So our name will then be two comma five hyphen Dyke Lao hyphen four hyphen methyl one last and we don't need a methyl because excuse me we don't need a hyphen. We'll remove that because we don't have a number in front of phenol again, that number one is assumed. So after methyl, we just go straight into phenol and we see that that matches choice D we'll just take a quick look at Choice C to understand why it's incorrect. That gives us two chloro four methyl, five chlorphen, but we don't want to separate those two chlorine. We lump them together as di Chloro and then put both numbers there. So that's why choice C is incorrect. You can see that makes a really bulkier name than we need. So once again, the correct iupac name for our compound is choice T 25 Di Chloro for methylal. See you in the next video.

Write the IUPAC name for each of the following alcohols and phenols: (12.1)
a. <IMAGE>

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Key Concepts

IUPAC Nomenclature

Alcohols

Phenols