On the allyl protection of the imidazole ring of histidine

✍ Scribed by A Malanda Kimbonguila; S Boucida; F Guibé; A Loffet

• Book ID: 104208007
• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 770 KB
• Volume: 53
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(97)00772-2

✦ Synopsis

The regiospecific synthesis of the N(~)-allyl and the N(r)-allyl derivatives of N(otFtertbutoxycarbonyl-histidine is described. The DCC-mediated coupling of N(~)-tert-butoxycarbonyl-N(~)allyl-(L)-histidine with (L)-prolinamide, used as a test reaction to probe the extent of racemization duriug coupling processes, was found to occur with good (ca. 97%) conservation of enantiomeric purity. Three methods have been devised, all of them based on catalytic palladium n-allyl chemistry, for the selective removal under mild conditions of the N-imidazolic allyl groups. Finally it is shown that the allyl group at N('c)-position may be used as a lemporary protection in the synthesis of N0z)-substituted derivatives of histidine.