[Super Newb]

Hi all, I have some queries on the mechanism. When ninhydrin reacts with the alpha-amino acid, it will undergo a decarboxylation (eliminate and produce CO2). However, if the ninhydrin would to react with the free amine, am I right to say that it will not under go the decarboxylation to azomethine ylide, but instead it will skip that step? Much tks:)

[discodermolide]

Hi all, I have some queries on the mechanism. When ninhydrin reacts with the alpha-amino acid, it will undergo a decarboxylation (eliminate and produce CO2). However, if the ninhydrin would to react with the free amine, am I right to say that it will not under go the decarboxylation to azomethine ylide, but instead it will skip that step? Much tks:)

How can a reaction skip a step, it does not know what it is doing!
have a look at this page
http://en.wikipedia.org/wiki/Ninhydrin

[Super Newb]

However, a free amine e.g. R-NH2 does not have a carboxylic acid, then how does it -CO2? Tks

[discodermolide]

However, a free amine e.g. R-NH2 does not have a carboxylic acid, then how does it -CO2? Tks

It stops at the Schiff's base.