The structure of rupestrol - a new sesquiterpenoid from Verbesina rupestris (urb.) blake

✍ Scribed by V.G.S. Box; W.R. Chan; D.R. Taylor

• Publisher: Elsevier Science
• Year: 1971
• Tongue: French
• Weight: 341 KB
• Volume: 12
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(01)97444-1

✦ Synopsis

We report here the structural elucidation of a new sesquiterpene, rupestrol, which occurs naturally as its orthocinnamate (1) and cinnamate (2) esters in Verbesina rupestris. Rupestrol orthocinnamate (l), C24H3205, m/e 400 (M+), m.p. 206-207", had a trans-styrene unit [Amex 250 nm (E 22,000), vmax 1656,1587,1572,970, 750 and 700 cm", 6 (d6-DMSO) 6.22 and 6.90 (1H each, AB system, JAB 16.5 Hz), 7.39 (5H, m, aromatic H)] and two secondary hydroxy groups (v max 3400 cm -1 , 6 4.67 (lH, d, J 1.5 Hz) and 4.82 (lH, d,J 2.0 Hz) vanishing on treatment with D20]. On mild acid treatment, it afforded rupestrol cinnamate (2) C24H3406, m.p. 222-224O, Xmax 221 and 278.5 nm (E 12,300 and 20,600), vmax 3175, 1724, 1631 and 990 cm -1 , 6 (h6-DMSO)