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Glycine and ammonia

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magnet:
This is something I haven't found in several books... what are the products formed when glycine reacts with ammonia? I guessed that the products should be an amide and water but I need to know the exact products and the catalyst, if used.

shelanachium:
You would probably just get an ammonium salt H2NCH2CO2.NH4 but this would easily lose NH3 as glycine is a weak acid. Heating glycine causes it to self-condense giving polymers and cyclic compounds such as diketopiperazine (NHCH2CO)2 in which the carboxylic acid group forms an amide with the amino group, eliminating water.

The amide of glycine H2NCH2CONH2 is probably better obtained not from glycine itself but by reacting ammonia with chloroacetamide:

NH3 + ClCH2CONH2 -> H2NCH2CONH2 + HCl. (actually hydrochloride obtained, base added to obtain free glycinamide).

magnet:
Hmm... an ammonium salt would probably be the product. In the preparation of glycine, chloroacetic acid and ammonia react to give glycine in the first step, then the excess ammonia reacts with glycine to give the mentioned ammonium salt. But, is there any catalyst involved or required like Magnesium ions?

Albert:
I don't know what kind of experiment you're carrying out, but in order to yield polypeptides, there's a common synthesis, you can easily do in lab:

- protect the N-terminal with tBocCl (tert-Butyl carbonochloridate);
- add DCC;
- add another amino acid...and you'll have a dipeptide.

I think that, in your experiment, you can forget about tBocCl and use only DCC.

magnet:
I'm not carrying out any experiment, just studying for my finals and this reaction of glycine with ammonia is very much part of the syllabus but is not in my text book. That's why I wanted to know what the reaction would be with or without a catalyst.

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