Paper chemical organic

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© Copyright 1997 by the American Chemical Society and the American Society of Pharmacognosy

Volume 60, Number 2

February 1997

Full Papers
Resorcinol Derivatives and Flavonoids of Ononis natrix Subspecies ramosissima
Alejandro F. Barrero,*,† M. Mar Herrador,† Pilar Arteaga,† Ignacio Rodrıguez-Garcıa,‡ and ´ ´ Manuel Garcıa-Moreno‡ ´
Departamento de Quımica Organica, Facultadde Ciencias, Universidad de Granada, 18071 Granada, Spain, and ´ ´ Departamento de Quimica Organica, Facultad de Ciencias Experimentales, Universidad de Almeria, 04120 Almeria, Spain Received April 22, 1996X

From extracts of Ononis natrix subsp. ramosissima two new resorcinol derivatives, 5-(2-acetoxy8-oxotridecyl)resorcinol (1) and 5-(2-acetoxy-7-hydroxy-8-oxotridecyl)resorcinol (2) wereisolated and identified, as well as chavicol -D-glucoside, betulaprenol 6 (13), two steroids, four chalcones, six dihydrochalcones, two flavanones, and three pterocarpans.
The more polar extracts of Ononis species (Leguminosae) contain mainly phenolic compounds such as flavonoids and phenylpropanoids, while the less polar extracts of these species may include among their components resorcinolderivatives with an alkyl chain at position C-5. This chain may be saturated or unsaturated and may have several oxygenated functions.1-8 The botanical classification of the species Ononis natrix comprises three subspecies that grow in the Iberian Peninsula: O. natrix, O. hispanica, and O. ramosissima. We have previously studied the chemical composition of the O. natrix subsp. natrix3,4 and hispanica.5 Inorder to get a chemotaxonomic differentiation of these three subspecies we present here the results obtained with O. natrix L. subsp. ramosissima (Desf.) Batt., a plant that grows in coastal zones of southern Spain and Portugal. Results and Discussion Ononis natrix subsp. ramosissima was extracted with tert-butyl methyl ether and then with EtOH. Two new natural alkylresorcinols were isolated,5-(2-acetoxy-8oxotridecyl)resorcinol (1) and 5-(2-acetoxy-7-hydroxy-8oxotridecyl)resorcinol (2). Additionally, the following
* Author to whom correspondence should be addressed. Phone: 958 243318. FAX: 958 243318. E-mail: afbarre@goliat.ugr.es. † Departamento de Quımica Organica, Universidad de Granada. ´ ´ ‡ Departamento de Quimica Organica, Universidad de Almeria. X Abstract published in AdvanceACS Abstracts, December 15, 1996.

known compounds were identified: the steroids -sitosterol and -sitosterol -D-glucoside;9-11 four chalcones, 2′,4′-dihydroxychalcone (3),12-14 2′-hydroxy-4′-methoxychalcone (4),15 4,2′,4′-trihydroxychalcone (5),16 and 4,2′dihydroxy-4′-methoxychalcone (6);17 six dihydrochalcones, 2′,4′,6′-trihydroxydihydrochalcone (7),18 2′,6′dihydroxy-4′-methoxydihydrochalcone(8),18 2′,4′dihydroxy-6′-methoxydihydrochalcone (9),19 4,2′,6′trihydroxy-4′-methoxydihydrochalcone (10),20,21 4,2′,4′trihydroxy-6′-methoxydihydrochalcone (11),21 and 2′,6′dihydroxy-4,4′-dimethoxydihydrochalcone (12);15 two flavanones, 7-hydroxyflavanone13 and 5,7-dihydroxyflavanone;22,23 three pterocarpans, medicarpin,24 homopterocarpin,24 and trifolirhizin;25 the phenylpropanoid, chavicol-D-glucoside;26-28 and the polyprene, betulaprenol 6 (13).29 The structures of the known compounds were determined by comparison of their physical and spectroscopic features with those reported in the literature. Table 1 shows previously unpublished 13C-NMR data of the above-mentioned chalcones and dihydrochalcones.

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© 1997 American Chemical Society and AmericanSociety of Pharmacognogy

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66

Journal of Natural Products, 1997, Vol. 60, No. 2
13C-NMR

Barrero et al.

Table 1. carbon

(75 MHz) Data for Chalcones and Dihydrochalcones 3, 3a, 4, 5a, 6a, 8a, 9a, 10, 11, 12aa 3b 3ab 190.4 119.2 145.4 134.4 128.5d 129.1e 130.8 129.1e 128.5d 129.7 149.6 117.1 153.4 125.0 130.8 169.0 168.6 21.1 20.9 4b 191.8 120.3 144.3 134.7 128.9d 128.4e 130.5...