Nomenclature Problem

[Farcus]

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Ok if you have a benzene and you have both a methyl group, and a hydroxy group what do you know? I mean if there wasn't say that methyl group I can end the compound with phenol, or if there wasn't the hydroxy group I can end it with totulene, but now that there is both what do I do? This is so freaking confusing its pissing me off. I don't find nomenclature hard but this stuff isn't clear in any of the my books or kaplan.

Or say if there is three substituents, all three hydoxy on a benzene, why is it called like 1,3,5-trihydroxy(for example) and not 3,5-dihydoxyphenol?

Please help.

 

[RySerr21]

Ok if you have a benzene and you have both a methyl group, and a hydroxy group what do you know? I mean if there wasn't say that methyl group I can end the compound with phenol, or if there wasn't the hydroxy group I can end it with totulene, but now that there is both what do I do? This is so freaking confusing its pissing me off. I don't find nomenclature hard but this stuff isn't clear in any of the my books or kaplan.

Or say if there is three substituents, all three hydoxy on a benzene, why is it called like 1,3,5-trihydroxy(for example) and not 3,5-dihydoxyphenol?

Please help.

farcus,
the good news is that naming is really not that important. maybe youll see 1 question on it, but thats it. i didnt see any naming questions on my real MCAT.

my memory regarding naming is a little hazy, but i'm pretty sure a benzene with a methyl group is Toluene, not Totulene. thats really not important either tho. there should be a list somewhere that ranks nomenclature in terms of priority. I'm pretty sure hydroxy groups have higher priority than methyl groups, so youd name like 1-methylphenol or something like that. i could be way off, but again, i wouldnt sweat nomenclature too much, its not a big deal AT ALL.

 

[engineeredout]

If its a benzene ring, don't you have to assign ortho/meta/para to the methyl?

 

[Farcus]

If its a benzene ring, don't you have to assign ortho/meta/para to the methyl?

Thats only for disubstituted. But yeh where do you find out the priority of benzene in term of functional groups.

 

[Quantum Chem]

Sorry, but it wouldn't be 1-methylphenol as that implies that the methyl group is on the same carbon as the OH and that can't happen in a benzene ring. So you would use Ortho-methylphenol which would be the same as 2-methylphenol (or M or P where ever the methyl is relative to the OH).

But in a broader sense. When you are naming compounds remember that the higher functional groups will get the ending part.

 

[unsung]

Ok if you have a benzene and you have both a methyl group, and a hydroxy group what do you know? I mean if there wasn't say that methyl group I can end the compound with phenol, or if there wasn't the hydroxy group I can end it with totulene, but now that there is both what do I do? This is so freaking confusing its pissing me off. I don't find nomenclature hard but this stuff isn't clear in any of the my books or kaplan.

Or say if there is three substituents, all three hydoxy on a benzene, why is it called like 1,3,5-trihydroxy(for example) and not 3,5-dihydoxyphenol?

Please help.

A benzene ring with BOTH a hydroxyl group and a methyl group is called a cresol. As in o-cresol (if 2 are ortho), m-cresol, or p-cresol.

My o-chem prof used to take off points if we failed to underline the o (or m or p) on tests to indicate it's supposed to be in italics in print (!)

 

[Farcus]

well so far I know alcohol gets most priority but what about say there is a benzene with alcohol and amine at opposite ends? so would this be p-aminephenol or p-hydoxyaniline? Its stuff like this that I don't get... there is all this common nomenclature that binds into the formal system which isn't bad but then when all these common nomenclature combine in one problem is where i get confused. For another example, alcohol with carboxylic acid.