Structure of 7-hydroxy-lathyrol a further diterpene from euphorbia lathyris L.
✍ Scribed by P. Narayanan; M. Röhrl; K. Zechmeister; D.W. Engel; W. Hoppe; E. Hecker; W. Adolf
- Publisher
- Elsevier Science
- Year
- 1971
- Tongue
- French
- Weight
- 253 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
By multistage Craig distribution of the hydrophilic neutral fraction of the seed oil of the caper spurge (Euphorbia lathyris L.) the crystalline compounds Ll' L2' L3 as well as the resinous compounds L4 and L5 were isolated (1,2). Recently, L1 was characterized as 3-phenyl-acetate-5,10-diacetate I of the parent alcohol 6,20-epoxy-lathyrol II (3,4). Compound L2, c38 H42 09 (MS, anal.), m.p. 205-207°c is the diacetate-dibenzoate III of a diterpene alcohol IV (1,2) which we call 7-hydroxy-lathyrol. Spectral data of 111: uv (M&H): A,, = 229, 273 nm; z= 29800, 14200. The UV spectrum with maximum at 273 nm corresponds with that of I ( bmax = 273 nm; & = 15000), indicating presence of the same chromophore in both molecules. IR (KBr): 1735, 1713 (CO), 1650, 1623
(C=c-cO) , 907 (C=CH2), 712 cm" (C6H5). The NMR spectrum (CDC13) indicates presence of two acetyl-(6= 2,27, 1,37 ppm; 2 x 3H,S) and two benzoyl-groups (d=7,3-8,2 ppm; 10 HIM). The signal of one of the acetyl groups at 1,37 ppm appears at extremely high field indicating strong shielding of its protons by an interatomic diamagnetic effect. It may be caused by the benzoyl groups and suggests a spatial neighbourhood of the ester groups concerned. Using D5-pyridine as solvent, a paramagnetic shift of this acetyl group is noted (0,3 ppm), indicating a diminuation of the interaction between the ester groups.