Molecules 1998, 3, M48

(+)-8-Hydroxy-labdan-17-oic Acid

Ramirez Martha, Tellez Nohemi and Torrenegra Ruben*

Pontificia Universidad Javeriana, Grupo de investigación fitoquímica GIFUJ, Santafé de Bogotá, Colombia
Tel: 2883788 ext. 251. Fax 2850503 E-mail [email protected]

Received: 5 February 1998 / Published: 18 February 1998

1

Hanson [1,2] reported a compound with [a]D = -7° and identical IR and NMR spectral data to our compound. He named this compound (-)-8-hydroxy labdan-17-oic acid. By comparison with the spectroscopy data and the specific rotation of the above compound, our results lead to (+)-8-hydroxy-labdan-17-oic acid (structure 1). It is a stereoisomer of labdanoic acid. The relative configurations of the carbons from C1 to C10 were deduced by comparison of the 13C-NMR resonances with the data for 8-epi-sclareol and sclareol [3]. The configuration at C13 has not yet been established. The HMBC and HMQC spectra confirm the structure 1.

Dried and pulverised leaves ( 1 kg ) of Espeletiopsis muisca were extracted with Petrol ( 69g ) and then 10 g of this extract were subjected to column chromatography on silica gel using Petrol, CH2Cl2 and AcOEt. The fractions in AcOEt were again chromatographed on silica gel with Petrol: AcOEt and the first fraction yielded the pure title compound 1. White crystals, 90 mg from MeOH.

M.p. 68 °C.

[a] D = + 5° (c = 0.025, CHCl3)

IR (l max): 3500, 2700, 3600, 3300, 1690 cm-1.

1H-NMR (d, ppm, CDCl3): 0.75, 0.9, 0.96, 0.98, 1.05, 1.19 (CH3), 4.8 (OH) ; 1.4 and 2.5 (m, CH and CH2).

13C-NMR (d, ppm, CDCl3): 178.5 (C), 74.9 (C), 55.28 (CH), 44.3 (CH2), 42.1 (CH2), 41.2 (CH2), 41.2 (CH2), 40.8* (CH2), 39.2 (CH2), 33.49 (C), 33.2 (CH3), 30.2 (CH), 23.9* (CH3), 22.1* (CH3), 21.5 (CH3), 20.5 (CH2), 20(CH2), 18.5(CH2), 15.5 (CH3).

Acknowledgement: We would like to thank Colciencias, Universidad Javeriana for its financial support, Grant "Química y actividad biológica de especies del género Espeletia" código 1203-5-04-95".

References

1. Dey, P. M.; Harborne, J. B. "Methods in Plant Biochemistry". Terpenoids 1991, 7, 263.

2. Cocker, W. J. Chem. Soc. 1953, 2540.

3. Torrenegra, R.; Pedrozo, J.; Robles, J.; Achenbach, H. Phytochemistry 1992, 31, 2415.

Sample availability: Available from the authors.

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