Understanding Amino Acid Acidity and Basicity in Reactions

[jsmith613]

Homework Statement

How does the following reaction demonstrate an amino acid as an acid:
H₂NCH₂COOH + CH₃OH → H₂NCH₂COOCH₃ + H₂O

How does the following reaction demonstrate an amino acid as a base:
H₂NCH₂COOH + CH₃COCl → CH₃CONHCH₂COOH + HCl

Homework Equations

The Attempt at a Solution

An acid is a species that DONATES a proton and a base is a species that ACCEPTS a proton

In both situations it seems more like an esterfication reaction than an acid / base reaction.

Also in the second reaction the H₂N loses an H+ for water (I would call that acidic behaviour but it is actually basic behaviour) and the first example COOH loses OH (basic behaviour but is classified as acidic)

I am confused :S

 

[Borek]

This is not about a standard Bronsted acid definition. Think outside of the box. What is an ester?

That's what they ask about, doesn't mean I like the question.

 

[jsmith613]

This is not about a standard Bronsted acid definition. Think outside of the box. What is an ester?

That's what they ask about, doesn't mean I like the question.

well an ester is a type of condensation reaction in which a small molecule is eliminated?

 

[Borek]

No, ester is not a type of a reaction. It is a product of a reaction. Reaction of what with what?

 

[jsmith613]

No, ester is not a type of a reaction. It is a product of a reaction. Reaction of what with what?

a carbonyl carbon (e.g: COOH or COCl) and a hydrogen attached to an electronegative atom (e.g: OH, H₂N)

 

[jsmith613]

In fact another site says its when the hydrogen of an organic acid is replaced by an organic group (e.g: alkyl)

BUT the acid LOSES OH not just the H?

 

[Borek]

The other site is wrong. That is, it is wrong when you look at the mechanism, but it is OK when you look just at the product structure.

Ester is produced by a reaction of an acid (even doesn't have to be organic - think sulfuric, phosphoric) with an alcohol.

 

[jsmith613]

The other site is wrong. That is, it is wrong when you look at the mechanism, but it is OK when you look just at the product structure.

Ester is produced by a reaction of an acid (even doesn't have to be organic - think sulfuric, phosphoric) with an alcohol.

ok so I get the first one but how does the second rxn demonstrate basic behaviour?

 

[Borek]

To be honest - I don't see how. I told you I don't like the question.

 

[jsmith613]

To be honest - I don't see how. I told you I don't like the question.

nm
thanks for your help :)