Functional groups to know?

[SiakTiDoc]

Hi everyone
I was wondering if there were any particular functional groups that aren't too common that you should be aware of?

I ran into a question asking be about what a sulfonylurea group would look like and I managed got it correct over a 50/50 after reasoning the other two structures as incorrect.

So just looking to see what other groups I should be aware of.

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[JustinM88]

Maybe they were just checking to see if you know what a sulfonyl group looks like and a urea molecule looks like? I've come across both of these over my pre-med studies...

 

[aldol16]

No, you shouldn't focus on remembering stuff like this. You should, however, be able to deduce the chemical properties of a functional group given a structure. For instance, you should be able to tell sulfur is electrophilic in a sulfonyl group.

 

[SiakTiDoc]

Maybe they were just checking to see if you know what a sulfonyl group looks like and a urea molecule looks like? I've come across both of these over my pre-med studies...

So have I, but I've never really took it upon myself to memorize it unfortunately haha.

@aldol16
awesome thanks!
Also just to double check...
With your example, the Oxygen since it has lone pairs would be considered a nucleophile through right? And the Sulfur is an electrophile due to the slight (+) charge due to the oxygen?

 

[aldol16]

With your example, the Oxygen since it has lone pairs would be considered a nucleophile through right? And the Sulfur is an electrophile due to the slight (+) charge due to the oxygen?

Which oxygen? In a sulfonyl group with two alkyl chains attached, the oxygen isn't nucleophilic because it holds its lone pairs pretty tightly. If it formed another bond, i.e. nucleophilically attacked something else, oxygen would end up with a full positive charge and it doesn't like that. If one of the R's is an oxygen (i.e. sulfonic acid), then the negatively-charged oxygen with only one bond to it is nucleophilic. This is very similar to the case of phosphates and is actually how high-energy phosphate bonds (e.g. in ATP) are made.

The sulfur is electrophilic due to the positive charge generated by the oxygen withdrawing effect, yes. Nucleophilic attack at the sulfur would break the S=O double bond and localize that lone pair on the oxygen.

 

[SiakTiDoc]

Which oxygen? In a sulfonyl group with two alkyl chains attached, the oxygen isn't nucleophilic because it holds its lone pairs pretty tightly. If it formed another bond, i.e. nucleophilically attacked something else, oxygen would end up with a full positive charge and it doesn't like that. If one of the R's is an oxygen (i.e. sulfonic acid), then the negatively-charged oxygen with only one bond to it is nucleophilic. This is very similar to the case of phosphates and is actually how high-energy phosphate bonds (e.g. in ATP) are made.

The sulfur is electrophilic due to the positive charge generated by the oxygen withdrawing effect, yes. Nucleophilic attack at the sulfur would break the S=O double bond and localize that lone pair on the oxygen.

Ahh I see! Thanks for clearing that up for me!
I assumed that the oxygen would end up being nucleophilic similar to that of a ketone simply due to it's lone pairs.

 

[aldol16]

I assumed that the oxygen would end up being nucleophilic similar to that of a ketone simply due to it's lone pairs.

I wouldn't really call the oxygen atom of ketones nucleophilic. There are many better nuceophiles out there and a ketone doesn't generally act as a nucleophile in chemical reactions.