Constitution, stereochemistry and conformational behaviour of the photoreaction product of 7-deacetoxy-7-oxokhivorin

✍ Scribed by Joseph I. Okogun; Helmut Duddeck; Gerhard Habermehl; Hans C. Krebs; Gábor Tóth; András Simon

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 186 KB
• Volume: 36
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199805)36:5<371::aid-omr279>3.0.co;2-5

✦ Synopsis

By means of 2D NMR experiments (COSY, HMQC, HMBC, ROESY), the constitution of the photoreaction product 3-deoxo-1a,3 a-diacetoxy-1,2,3,3,8,30-hexahydro-18bH-andirobin (2), obtained by photolysis of 7-deacetoxy-7-oxokhivorin (1) in methanol, was shown to be a ring B seco-limonoid with the 14,15-epoxide intact. The conÐguration of C-8 is R. Ring C adopts a twist-boat conformation. No conformational preferences for the rotation of ring A in 2 with respect to rings C/D and for the side-chain C-6/C-7 could be detected. Nearly all 1H and all 13C resonances were assigned unambiguously.