Английская Википедия:Erlenmeyer–Plöchl azlactone and amino-acid synthesis

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Версия от 09:55, 4 марта 2024; EducationBot (обсуждение | вклад) (Новая страница: «{{Английская Википедия/Панель перехода}} The '''Erlenmeyer–Plöchl azlactone and amino acid synthesis''', named after Friedrich Gustav Carl Emil Erlenmeyer who partly discovered the reaction, is a series of chemical reactions which transform an ''N''-acyl glycine to various other amino acids via an oxazolone (also known as an azlactone).<ref>{{cite journal | author = Plöchl, J. | title = Über...»)
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The Erlenmeyer–Plöchl azlactone and amino acid synthesis, named after Friedrich Gustav Carl Emil Erlenmeyer who partly discovered the reaction, is a series of chemical reactions which transform an N-acyl glycine to various other amino acids via an oxazolone (also known as an azlactone).[1][2]

Azlactone chemistry: step 2 is a Perkin variation
Azlactone chemistry: step 2 is a Perkin variation

Hippuric acid, the benzamide derivative of glycine, cyclizes in the presence of acetic anhydride, condensing to give 2-phenyl-oxazolone.[3] This intermediate also has two acidic protons and reacts with benzaldehyde, acetic anhydride and sodium acetate to a so-called azlactone. This compound on reduction gives access to phenylalanine.[4]

Variations

Variants of the azlactone synthesis in which analogues of azlactones are used are sometimes advantageous. Hydantoin (in Bergmann modification), thiohydantoin and rhodanine have each been employed as the enolate-forming component of the condensation. [5][6] 2,5-Diketopiperazine can be used as a methylene component as well; its condensation products with aromatic aldehydes, on reduction and hydrolysis give the corresponding amino acids. [7][8][9]

Scope

In one study the Erlenmeyer amino acid synthesis was used in the heart of an L-m-tyrosine synthesis [10][11]

ErlenMeyer Amino Acid Synthesis Tyrosine

See also

References

Шаблон:Reflist

Партнерские ресурсы
Криптовалюты
Магазины
Хостинг
Разное

  1. ↑ Шаблон:Cite journal ; see especially pp. 1623-1624.
  2. ↑ Шаблон:Cite journal ; see especially pp. 3-8.
  3. ↑ Шаблон:OrgSynth
  4. ↑ Шаблон:OrgSynth
  5. ↑ Шаблон:Cite book
  6. ↑ Шаблон:Cite book
  7. ↑ H.D. Dakin. Aromatic aldehyde derivatives of proteins, peptides and amino acids. J. Biol. Chem. 1929, 84:675-682
  8. ↑ Alan D. Borthwick. 2,5-Diketopiperazines: Synthesis, Reactions, Medicinal Chemistry, and Bioactive Natural Products. DrugMolDesign, 15 Temple Grove, London NW11 7UA, U.K. Chem. Rev., 2012, 112 (7), pp 3641–3716. DOI: 10.1021/cr200398y
  9. ↑ A. M. Asiri. New Conjugated Systems Derived from Piperazine-2,5-dione. Molecules 2000, 5, 629-636
  10. ↑ Шаблон:Cite journal
  11. ↑ The benzyl ether of 3-hydroxybenzaldehyde 1 reacts with the N-acetyl amide of glycine 2, acetic anhydride and sodium acetate to the azlactone (not displayed) which is ring-opened with sodium acetate in methanol to dehydroamino acid 3. Hydrogenation gives the N-acyl-m-tyrosine methyl ester 4 (the benzyl ether group is also cleaved). This compound is racemic and kinetic resolution is brought about by an enzyme which is able to only cleave the methyl ester of the S-enantiomer (forming (S)-5 soluble in dichloromethane) leaving water-soluble (R)-4 untouched. The final step is amide cleavage to (S)-L-m-tyrosine 6
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