Nonalkaloidal constituents of Buxus microphylla var. suffruticosa
✍ Scribed by T. Nakano; S. Terao; K. H. Lee
- Book ID
- 102398237
- Publisher
- John Wiley and Sons
- Year
- 1965
- Tongue
- English
- Weight
- 303 KB
- Volume
- 54
- Category
- Article
- ISSN
- 0022-3549
No coin nor oath required. For personal study only.
✦ Synopsis
Investigation of the nonalkaloidal constituents from the leaves and stems of Buxus micropbylla Sieb. et Zucc. var. SuJruticosa Makino has led to the isolation of methyl syringate, betulic acid, lupeol, and betulin. HE MEDICINAL properties (1) of the alkaloidal T extracts from buxus plants have long been known. A recent investigation (2) has indicated that the leaves and stems of Buxus microphylla Sieb. et Zucc. var. suffruticosa Makino, like the leaves of Bums sempervirens L. (3), contain a new type of tetracyclic triterpenoid alkaloids with a cyclopropane ring. From a biogenetic point of view, the authors have been interested in examining the nonalkaloidal constituents of this same plant. Chromatography of the alkali-soluble portion on silica gel and elution with chloroform yielded a phenolic compound (Ia), C1OHlSO6, m.p. 106-107"; Am-. 3.00 (hydroxyl), 5.90 (ester carbonyl), and 6.20, 10.05, and 13.15 p (benzenoid absorption); A, =.
277 mp ( B 1080) (substituted methyl benzoate); NMR peaks a t 2.70 (2H, singlet, aromatic protons), 4.00 ( l H , OH), 6.08 (6H, singlet, OCH,), and 6.10 T (3H. singlet, COOCHs). Methylation of Ia with diazomethane led to methyl trimethylgallate (Ib) (4). Ia was hydrolyzed by alkali to syringic acid (Ic) (5). The identity of Ia was established by synthesizing this compound from gallic acid (5). (Scheme I.)
The chloroform-methanol (1 : 1) eluate fraction was methylated with ethereal diazomethane, and the resultant methyl ester was rechromatographed on alumina. Elution with ether-benzene (1: 1) yielded a compound (IIb), C31H6003. m.p. 230";
[a]$' + 1.1' (c, 3); M/e 470 (molecularion peak).
The difficulty (6) of the alkaline hydrolysis of IIb suggested that its carbomethoxy group is attached to the quaternary carbon atom and possesses the axial orientation. I I b exhibited infrared absorption bands at 2.80 (nonassociated hydroxyl), 5.85 (ester carbonyl), and 6.07 and 11.36 p (terminal methylene); NMR signals a t 9.26 (3H), 9.19 (3H), 9.10 (3H), 9.06 (6H) (quaternary C-methyl), 8.31 (3H, vinyl methyl), 6.94 ( l H , )CH-OH), 6.34 (3H, COOCHa), and 5.39 and 5.26 7 (2H, terminal methylene). Hydrogenation of I I b with palladium charcoal in ethanol gave the dihydro derivative (IIIa), oxidation with Jones' reagent (7) the 0x0 derivative (IV); ozonolysis, formalin and a methyl ketone (V); and lithium aluminum hydride reduction the diol