Synthesis of 1-oxacephems from D-arabinal and L-rhamnal

✍ Scribed by Czesław Bełżecki; Romuald Urbański; Zofia Urbańczyk-Lipkowska; Marek Chmielewski

• Book ID: 104208076
• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 867 KB
• Volume: 53
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(97)00917-4

✦ Synopsis

Readily available from D-arabinal and L-rhamnal 2-C:l-N-carbonyl-2-deoxy-I%D-arabinoand -a-L-gluco-pyranosylamines 5, 25 and 26 were transformed into cephems 45 and 49 via a sequence of reactions consisting of alkylation of the 15-1aetam nitrogen atom, deprotection of pyranoid hydroxy groups, glycolic cleavage of the vic diol grouping, discrimination of carbon atoms which were separated by pcriodatc oxidation, and formation of the 1,3-oxazine six-membered ring fused to the 13-1actam fragraent. Discrimination of two aldehyde groups obtained during the glycolic cleavage step was achieved after their reduction and protection of one of the hydroxymethyl group by a bulky silyl substituent or by laetonization.