Organic chem fun! URGENT

[runnersfeet]

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Ok, so Im hoping someone can pull through and help me out with this last study guide of mine for my upcoming final! A few questions:
*Which base is weakest out of the three: KOH, LDA, NaNH2?
*Which functional group is most difficult to reduce? amide, amine or imine?
*Which substance is best nucleophile? propanamine, propanamide, propanenitrile?
*In the structure of crotonaldehyde, CH3CH=CH-COH, why are the gamma(methyl group) hydrogens acidic?
*In looking at structures of tryptophan and histidine, why is tryptophan less basic that histidine?
*Which has highest pKb? P-nitroaniline, p-aminophenol, ammonia
*Which is most water soluble? acetoacetic acid, triethylamine, malonic ester
Ok, those are the ones that some of us are debating on, so I wanted to get others opinions
thanks in advance!

 

[scpod]

Ok, so Im hoping someone can pull through and help me out with this last study guide of mine for my upcoming final! A few questions:
*In looking at structures of tryptophan and histidine, why is tryptophan less basic that histidine?

Let's just look at one of them:

Histadine is imidazole-substituted alanine, while trytophan is an indole-substituted alanine. The lone pair on the N of tryptophan is needed to maintain aromaticity, so it is a weak base. It can't be protonated under biological conditions, but histidine can.

 

[runnersfeet]

Thanks! Yes, I noticed that the lone pair was in conjugation with the aromatic ring....your further explanation helps! I just love that I got at least one response from this🙂 thanks again

Let's just look at one of them:

Histadine is imidazole-substituted alanine, while trytophan is an indole-substituted alanine. The lone pair on the N of tryptophan is needed to maintain aromaticity, so it is a weak base. It can't be protonated under biological conditions, but histidine can.

 

[doctor-wanabe]

Ok, so Im hoping someone can pull through and help me out with this last study guide of mine for my upcoming final! A few questions:
*Which base is weakest out of the three: KOH, LDA, NaNH2?
*Which functional group is most difficult to reduce? amide, amine or imine?
*Which substance is best nucleophile? propanamine, propanamide, propanenitrile?
*In the structure of crotonaldehyde, CH3CH=CH-COH, why are the gamma(methyl group) hydrogens acidic?
*In looking at structures of tryptophan and histidine, why is tryptophan less basic that histidine?
*Which has highest pKb? P-nitroaniline, p-aminophenol, ammonia
*Which is most water soluble? acetoacetic acid, triethylamine, malonic ester
Ok, those are the ones that some of us are debating on, so I wanted to get others opinions
thanks in advance!

The gamma carbon of CH3CH=CH-COH is acidic becuase there's a double bond between carbons 2 and 3. The double bond makes the hybridization become sp2 which has more "s" character than sp3 bonds. What that means is that the inductive effect is more localized toward the double bonds, which are also shorter than single bonds, so the pull away from the gamma carbon is stronger and the hydrogens there will like be taken away by a base. Good luck!

 

[doctor-wanabe]

Ok, so Im hoping someone can pull through and help me out with this last study guide of mine for my upcoming final! A few questions:
*Which base is weakest out of the three: KOH, LDA, NaNH2?
*Which functional group is most difficult to reduce? amide, amine or imine?
*Which substance is best nucleophile? propanamine, propanamide, propanenitrile?
*In the structure of crotonaldehyde, CH3CH=CH-COH, why are the gamma(methyl group) hydrogens acidic?
*In looking at structures of tryptophan and histidine, why is tryptophan less basic that histidine?
*Which has highest pKb? P-nitroaniline, p-aminophenol, ammonia
*Which is most water soluble? acetoacetic acid, triethylamine, malonic ester
Ok, those are the ones that some of us are debating on, so I wanted to get others opinions
thanks in advance!

And one more thing. LDA is a VERY strong nucleophile so it is the strongest base. I'd guess NaNH2 would be the weakest out of the 3 because it reminds me of NH3 which is weakest in basicity overall: NHR2> NH2R>NR3>NH3 in aqueous solution. So, I'd say the basicity would go something like LDA>KOH>NaNH2. Good luck!

 

[scpod]

Ok, so Im hoping someone can pull through and help me out with this last study guide of mine for my upcoming final! A few questions:

*Which substance is best nucleophile? propanamine, propanamide, propanenitrile?

Since everyone's getting into it now, I'll look at another one:

The three are pretty similar in size, so steric hindrance probably has little effect. Without worrying about the effects of solvents, I'd say that you should look at the basicity. A higher pka = a stronger base = a better nucleophile. Check the pka's, but from memory I would expect the amine to be highest, the nitrile in the middle, and the amide the lowest.

 

[runnersfeet]

All of you who have helped are awesome! Keep the responses coming if you think of more answers🙂 thanks again!!

 

[jonwill]

Man, this takes me back

 

[runnersfeet]

Well, just keep letting it take you back to where you can help out and participate in the fun!!

Man, this takes me back

😉

 

[densmore22]

Ok, so Im hoping someone can pull through and help me out with this last study guide of mine for my upcoming final! A few questions:
*Which base is weakest out of the three: KOH, LDA, NaNH2?
*Which functional group is most difficult to reduce? amide, amine or imine?
*Which substance is best nucleophile? propanamine, propanamide, propanenitrile?
*In the structure of crotonaldehyde, CH3CH=CH-COH, why are the gamma(methyl group) hydrogens acidic?
*In looking at structures of tryptophan and histidine, why is tryptophan less basic that histidine?
*Which has highest pKb? P-nitroaniline, p-aminophenol, ammonia
*Which is most water soluble? acetoacetic acid, triethylamine, malonic ester
Ok, those are the ones that some of us are debating on, so I wanted to get others opinions
thanks in advance!

Oh gosh, is it bad if I don't remember much of this stuff when I start my first year? I'm starting to freak out.

 

[doclm]

Oh gosh, is it bad if I don't remember much of this stuff when I start my first year? I'm starting to freak out.

Yeah, I hear you. I don't remember anything either.

 

[jays2cool4u]

Ok, so Im hoping someone can pull through and help me out with this last study guide of mine for my upcoming final! A few questions:
*Which base is weakest out of the three: KOH, LDA, NaNH2?
*Which functional group is most difficult to reduce? amide, amine or imine?
*Which substance is best nucleophile? propanamine, propanamide, propanenitrile?
*In the structure of crotonaldehyde, CH3CH=CH-COH, why are the gamma(methyl group) hydrogens acidic?
*In looking at structures of tryptophan and histidine, why is tryptophan less basic that histidine?
*Which has highest pKb? P-nitroaniline, p-aminophenol, ammonia
*Which is most water soluble? acetoacetic acid, triethylamine, malonic ester
Ok, those are the ones that some of us are debating on, so I wanted to get others opinions
thanks in advance!

You should pm QofQuimica. She has a phD in chemistry.

Jays2cool4u 😎

 

[runnersfeet]

Very cool, thanks for the tip!!

You should pm QofQuimica. She has a phD in chemistry.

Jays2cool4u 😎

 

[runnersfeet]

Oh man, I sure hope I don't have to remember this stuff from the minute I finish my final, much less next year when Im actually in pod school! Only a few more days!!!

Oh gosh, is it bad if I don't remember much of this stuff when I start my first year? I'm starting to freak out.

 

[capo]

Man, this takes me back

Wait, did I take this? I don't remember a base from an acid, except something people dropped during 60's baseball games to hallucinate. 😛

 

[densmore22]

Oh man, I sure hope I don't have to remember this stuff from the minute I finish my final, much less next year when Im actually in pod school! Only a few more days!!!

Thank God, I was seriously getting concerned. I was great at it when I went through it, but forgot it the second I finished, glad to see I'm not the only one. Good luck on the final. What school are you going to next year?

 

[capo]

Thank God, I was seriously getting concerned. I was great at it when I went through it, but forgot it the second I finished, glad to see I'm not the only one. Good luck on the final. What school are you going to next year?

Yeah, but what's worse is after a lecture in med school I won't even remember what THAT was about! How bad is that?

 

[runnersfeet]

Thanks for the luck..much needed. Although, it doesnt really matter since Im already in for next year...but I like to finish this post-bac stuff on a good note🙂 I am headed to AZPOD for the fall and Im very excited!!!

Thank God, I was seriously getting concerned. I was great at it when I went through it, but forgot it the second I finished, glad to see I'm not the only one. Good luck on the final. What school are you going to next year?

 

[whiskers]

Sigh...

That final sounds really rough.... Those questions are killer!

I hope that AZ podiatry school isn't as difficult!


Lol!

 

[runnersfeet]

Thanks to those of you who helped! I am now done with the class and done with these pre-reqs for pod school....off to AZPOD!!!