5
remains within the molecule of ingenol 1 during the MS analysis.9 The prepared labeled compound
has successfully been used to determine the ingenol content in various plant extracts.14
Acknowledgements
The financial support by the Ministry of Education, Youth and Sports of the Czech Republic (grant
LO1204 from the National Program of Sustainability I) is gratefully acknowledged. The Teva Czech
Industries company is gratefully acknowledged for the generous financial and material support and
generous gift of ingenol. We are grateful to Dr. Miloslav Chudík and Dr. Ladislav Cvak (TEVA Czech
Industries) for inspiring discussions and valuable advice.
Supplementary Material
Characterization data for all new compounds and experimental procedures. This material is available
free of charge via the internet.
References and Notes
1.
2.
Dias, D. A.; Urban, S.; Roessner, U. Metabolites 2012, 2, 303.
(a) Wani, M.C.; Taylor, H.L.; Wall, M.E.; Coggon, P.; McPhail, A.T. J. Am. Chem. Soc. 1971, 93, 2325. (b)
Schiff, P.C.; Horwitz, S.B. Proc. Nat. Acad. Sci. 1980, 77, 1561. (c) Cragg, G. M. Med. Res. Rev 1998, 18,
315. (d) Mountford, P. G. In Green Chemistry in the Pharmaceutical Industry; Wiley-VCH Verlag GmbH &
Co. KGaA: 2010, p 145.
3.
(a) Novák, O.; Hauserová, E.; Amakorová, P.; Doležal, K.; Strnad, M. Phytochem. 2008, 69, 2214; (b)
Tarkowská, D.; Novák, O.; Floková, K.; Tarkowski, P.; Turečková, V.; Grúz, J.; Rolčík, J.; Strnad, M. Planta
2014, 240, 55.
4.
5.
6.
Hecker, E. Cancer Res. 1968, 28, 2338.
Vasas, A.; Hohmann, J. Chem. Rev. 2014, 114, 8579.
(a) Jørgensen, L.; McKerrall, S. J.; Kuttruff, C. A.; Ungeheuer, F.; Felding, J.; Baran, P. S. Science 2013, 341,
878; (b) McKerrall, S. J.; Jørgensen, L.; Kuttruff, C. A.; Ungeheuer, F.; Baran, P. S. J. Am. Chem. Soc. 2014,
136, 5799.
7.
8.
Appendino, G. Angew. Chem. Int. Ed. 2014, 53, 927.
Bicchi, C.; Appendino, G.; Cordero, C.; Rubiolo, P.; Ortelli, D.; Veuthey, J.L. Phytochem. Anal. 2001, 12,
255.
For more details, see ESI.
9.
10.
11.
Roeser, H.; Sorg, B.; Hecker, E. Z. Naturforsch. 1992, 47b, 1026.
Appendino, G.; Tron, G. C.; Cravotto, G.; Palmisano, G.; Annunziata, R.; Baj, G.; Surico, N. Eur. J. Org.
Chem. 1999, 1999, 3413.
12.
13.
For detailed MS/MS analysis of ingenol 1 fragmentation, see ESI.
Synthesis of 20-18O-ingenol (18O-1): A solution of ingenol 1 (300 mg, 0.86 mmol, 1.0 equiv.), 18O2-acetic
acid (52 µL, 0.9 mmol, 1.05 equiv.) and PPh3 (263 mg, 0.9 mmol, 1.05 equiv.) in dry THF (9 mL, 0.1 M)
was cooled to 0 °C and the resulting mixture stirred for 5 min prior to DIAD (142 µL, 0.9 mmol, 1.05
equiv.) addition. The resulting mixture was stirred at 0 °C for an additional 2 h and then at RT for 12 h.
The resulting mixture was evaporated to dryness under reduced pressure and the residue purified by
column chromatography on silica gel (CHCl3/EtOAc = 4:1->2:1->1:0->0:100) to give 314 mg (92%) of 20-
1
18O2-acetate ingenol (18O2-4). H NMR (500 MHz, CDCl3) δ = 6.10 (dd, J = 4.7, 1.4 Hz, 1H), 5.94 (q, J = 1.5
Hz, 1H), 4.71 (d, J = 12.5 Hz, 1H), 4.52 (d, J = 12.7 Hz, 1H), 4.44 (s, 1H), 4.09 (broad dd, J = 11.3, 3.5 Hz,
1H), 3.68 (s, 1H), 2.38 – 2.30 (m, 1H), 2.27 (ddd, J = 15.6, 8.9, 3.1 Hz, 1H), 2.06 (s, J = 3.4 Hz, 3H), 1.85 (d,
J = 1.4 Hz, 3H), 1.80 – 1.72 (m, 1H), 1.27 (dt, J = 9.9, 7.2 Hz, 1H), 1.11 (s, 3H), 1.07 (s, 3H), 0.97 (d, J = 7.0
Hz, 3H), 0.71 (td, J = 8.6, 6.3 Hz, 1H); 13C NMR (126 MHz, CDCl3) δ = 207.1, 171.4, 139.1, 136.9, 132.3,
128.7, 84.5, 80.7, 73.9, 72.8, 66.9, 44.2, 40.0, 31.2, 28.7, 24.1, 23.3, 23.1, 21.4, 21.3, 17.6, 15.7. 18O2-