Aminosäuren, 17 – Eine neue Synthese von Didehydrodipeptiden und Didehydrotripeptiden

✍ Scribed by Effenberger, Franz ;Kühlwein, Jürgen ;Hopf, Martin ;Stelzer, Uwe

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 968 KB
• Volume: 1993
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.1993199301212

✦ Synopsis

Amino Acids, 17. – A New Synthesis of Didehydro Dipeptides and Didehydro Tripeptides

Esters of N‐phthaloyl‐protected (R)‐ or (S)‐didehydro dipeptides 5–7 were obtained in good yields by the perrhenate‐catalyzed decomposition of 2‐azidocarboxylates 1 with N‐phthaloyl‐protected (R)‐ or (S)‐amino acid chlorides 2 in presence of at least equimolar amounts of N‐methyl‐2‐pyridone (4) as acylation catalyst. Esters of didehydro tripeptides 16 were obtained in a comparable procedure from the optically active amino acid chlorides 2 and 2‐(2‐azidoacyl)amino acid esters 15, which were prepared from 2‐azidocarboxylic acids 12 or the corresponding chlorides 13 with 2‐amino acid ester hydrochlorides (S)‐14. – As an example, the unprotected (S)‐alanly‐didehydrovalin 20 was prepared from the didehydro dipeptide 18a without any racemization by hydrolysis of the benzyl ester and subsequent hydrogenolytic removal of the N‐phthaloyl group.