Synthesis of optically active oxazoles from phosphorylated 2H-azirines and N-protected amino acids or peptides

✍ Scribed by Francisco Palacios; Ana Marı́a Ochoa de Retana; José Ignacio Gil; José Marı́a Alonso

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 301 KB
• Volume: 13
• Category: Article
• ISSN: 0957-4166
• DOI: 10.1016/s0957-4166(02)00686-9

✦ Synopsis

A simple synthesis of optically active phosphorylated oxazoles 8, 10, 11, and 12 containing amino acid residues from 2H-azirine-phosphine oxides 1 or -phosphonates 6 is described. Ring-opening reaction of 2H-azirines derived from phosphine oxides 1 and phosphonates 6 with N-protected amino acids 2 gives functionalized phosphorylated ketamides 3 and 7. Cyclization of ketamides 3 and 7 with triphenylphosphine and hexachloroethane in the presence of triethylamine leads to the formation of racemic and optically active phosphorylated oxazoles containing N-protected amino acid residues 8 and 10. Deprotection of these oxazoles gives aminoalkyl oxazoles 11 and 12. 2H-Azirines 1 and 6 also react with N-protected peptides 13 and give functionalized ketamides 14 and 15, ring closure of which leads to the formation of phosphorylated oxazoles containing peptide residues 16 and 17.