Boffis - 4-10-2021 at 08:23
In Vogel's "Textbook of organic Chemistry" (5th ed, p1179) there is a description of the preparation of 2,5-ketopiperazine or glycine anhydride by
dehydrating glycine. The experiment then goes on to describe the cleavage to the dipeptide glycylglyine and finally the preparation of glycylglycine
ethyl ester hydrochloride.
Does anyone know if this reaction is general to most simple amino acids? I can imagine some of the longer chain amino, double ended ones like glutamic
acid prefer to form single unit cyclic "anhydrides".
Also does anyone have a title for a book that deals primarily with the chemistry of amino acids as chemicals rather than components of living things?
ie and old, pre 1950's book.
Dr.Bob - 4-10-2021 at 12:24
Making the anhydride of most amino acids scrambles the stereochemistry (racemizes them). So for most work, that will not work well except for
glycine, which has no stereocenter.
Most people now make peptide on resin with Fmoc chemistry, which is easily automated, or if in solution, they use various coupling agents which are
found not to racemize the amino acids, like HBTU and many others. There are many books on the subject, I likely have a few left around if you want
one or two.
AvBaeyer - 4-10-2021 at 19:45
Boffis,
An encyclopedic source for information about amino acids and their chemistry is:
Greenstein and Winitz, "Chemistry of the Amino Acids" in 3 volumes.
I found my practically new set on ABEbooks for not much more than the cost of shipping. There are volumes available now from sellers in Europe and the
US.
Highly recommended if you are interested in amino acids.
AvB
Boffis - 5-10-2021 at 21:31
@Dr.Bob That's a good point that I hadn't thought about, however, it may not be such a problem. My interest is in the tendency of simple dipeptides to
cyclotize when diazotized to give substituted 1,2,3-triazolone (5-hydroxytriazoles). Glycylglcine ester gives the ester of
5-hydroxy-1,2,3-triazole-1-acetic acid, however, I have found another paper that claims that the simple 5-(4)-hydroxytriazole can be similarly
prepared from glycinamide, which looks like an easier route. These compounds should not be chiral as they are usually planar.
@AvBaeyer, thank you for this lead I checked out ABE books and came up trumps.
dettoo456 - 17-5-2023 at 10:49
@Boffis Do you happen to have the DOI of the paper you mentioned relating to glycinamide diazotization to the triazole? Triazole synth methods that
don’t involve azides or hydrazides are fairly annoying to come across, so one using simple, aliphatic diazo compounds sounds really promising.
Fery - 18-5-2023 at 05:08
Hi Boffis, I did the reaction with glycine. You already wrote one post in the thread. There is a reference about cyclic dipeptides and also cyclo
proline-proline could be maybe synthesized too.
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...
Boffis - 1-6-2023 at 02:16
Hi dettoo456, I'm sorry its taken me a while to get back to you, I've been on holiday without my laptop!! I don't have a doi for the paper but the
reference is:
Curtius & Thompson, 1906, Berichte de Chem. Gesch.; v39, p4140.
I started translating this paper, its not very log but got side tracked, however, if you can wait a few days I finish it. This paper is the one about
glycinamide cyclotisation. The paper dealing with the cyclotisation of glycinylglycine to the hydroxytriazole-N-acetic acid is by the same authors but
on p3398 and the preparation of the intermediate diazo-acetic compounds is ditto page 1383. I will also translate this later paper when time permits.
I can post all of these papers in the references section if you are interested in the German versions.
@Fery, I had seen your thread and the interesting papers you had linked to it. I will pursue some of these later. At the moment I am playing with
lysine.
dettoo456 - 7-6-2023 at 11:09
@Boffis No problem, thanks for the info. While I was looking though, I did find this paper (https://link.springer.com/article/10.1007/BF02256840 ) which uses 2-cuando-2-diazoglycinamde under strong basic conditions to cyclize to the
4-cyano-1,2,3-triazole-5-one. - This may have already been mentioned before though.