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Methyl 8-Acetyl-labdanolate (-)-(3S)-5-((1R,2R,4aS,8aS)-2-Acetoxy-2,5,5,8a-tetramethyldecahydro-1-naphthalenyl)-3- methylpentanoic Acid Methyl Ester
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8-Acetyl-labdanolic Acid (-)-(3S)-5-((1R,2R,4aS,8aS)-2-Acetoxy-2,5,5,8a-tetramethyldecahydro-1-naphthalenyl)-3-methylpentanoic Acid

Molbank 2003, 2003(1), M299; https://doi.org/10.3390/M299

Short Note
8-Formyl-labdanolic Acid (-)-(3S)-5-((1R,2R,4aS,8aS)-2-Formyloxy-2,5,5,8a-tetramethyldecahydro-1-naphthalenyl)-3-methylpentanoic Acid
Departamento de Química Inorgánica y Orgánica, Facultad de Ciencias Experimentales, Universidad de Jaén, 23071 Jaén, Spain
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Author to whom correspondence should be addressed.
Received: 12 December 2001 / Accepted: 19 September 2002 / Published: 8 March 2003
Keywords:
Diterpenes; labdanes; labdanolic acid; Cistus ladaniferus; formylation; FAM; tertiary alcohol
Molbank 2003 m299 i001
A sample (0.85 mL, 6.5 mmol) of formic acid-acetic anhydride mixture (FAM), prepared from Ac2O and formic acid as described in the literature [1], was added to the alcohol 1 [2](255 mg, 0.79 mmol) at 10 °C. After stirring for 48 h at room temperature, water (10 mL) was added and the mixture extracted with Et2O (3×25 mL). The combined organic layers were washed with 2N HCl (25 mL), saturated aq. Na2CO3 (25 mL) and brine (25 mL). The organic phase was dried over anhydrous Na2SO4 and the solvent evaporated under reduced pressure to yield a residue (258 mg) which was purified by flash chromatography on silica gel, using a 3:2 hexane/EtOAc mixture as eluent, to give the pure title compound 2 (180 mg, 0.51 mmol, 65%).
Mp: 102.4-105.5 °C (pale yellow crystals, from hexane).
[a]D = -33.7° (c 1.2 cg·mL-1, CHCl3).
IR (neat, n, cm-1): 3600-2500, 1719 (COOH), 1719, 1200, 1180 (OOCH).
1H NMR (300 MHz, CDCl3, d, ppm): 0.79 (3H, s, Meb-4), 0.84 (3H, s, Me-10), 0.87 (3H, s, Mea-4), 0.98 (3H, d, J=6.6 Hz, Me-13), 1.49 (3H, s, Me-8), 0.99-2.00 (16H, m, H-1,2,3,5,6,7a,9,11,12,13), 2.15 (1H, dd, J=15.0 Hz, 8.0 Hz, H-14), 2.36 (1H, dd, J=15.0 Hz, 5.9 Hz, H'-14), 2.57 (1H, dt, J=12.3 Hz, 3.2 Hz, Hb-7), 8.00 (1H, s, OOCH).
13C NMR (75 MHz, CDCl3, d, ppm): 39.46 (C-1), 18.23 (C-2), 41.78 (C-3), 33.05 (C-4), 55.51 (C-5), 19.98 (C-6), 39.36 (C-7), 89.17 (C-8), 58.91 (C-9), 39.42 (C-10), 22.99 (C-11), 39.63 (C-12), 30.88 (C-13), 41.44 (C-14), 179.48 (C-15), 19.63 (C-16), 21.09 (C-17), 33.24 (C-18), 21.37 (C-19), 15.65 (C-20), 160.61 (OOCH).

Supplementary materials

Supplementary File 1Supplementary File 2Supplementary File 3

Acknowledgements

We wish to thank the Junta de Andalucía for financial support and the Ministerio de Educación, Cultura y Deporte for a Fellowship to J. M. Castro.

References and Notes

  1. Strazzolini, P.; Giumanini, A. G.; Cauci, S. Acetic Formic Anhydride. A Review. Tetrahedron 1990, 46, 1081–1118. [Google Scholar] [CrossRef]
  2. Urones, J. G.; Basabe, P.; Marcos, I. S.; González, J. L.; Jiménez, V.; Sexmero, M. J.; Lithgow, A. M. Ambergris Compounds from Labdanolic Acid. Tetrahedron 1992, 48, 9991–9998. [Google Scholar] [CrossRef]
  • Sample availability: Available from the authors and from MDPI
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