About this Journal Submit a Manuscript Table of Contents
Organic Chemistry International
Volume 2011 (2011), Article ID 170196, 35 pages
http://dx.doi.org/10.1155/2011/170196
Review Article

A Review on the Chemistry of Eremanthine: A Sesquiterpene Lactone with Relevant Biological Activity

Departamento de Química, Instituto de Ciências Exatas, Universidade Federal Rural do Rio de Janeiro, 23890-970 Seropédica, RJ, Brazil

Received 10 December 2010; Accepted 2 February 2011

Academic Editor: Bill Baker

Copyright © 2011 José C. F. Alves. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Linked References

  1. W. Vichnewski and B. Gilbert, “Schistosomicidal sesquiterpene lactone from Eremanthus elaeagnus,” Phytochemistry, vol. 11, no. 8, pp. 2563–2566, 1972. View at Scopus
  2. P. M. Baker, C. C. Fortes, E. G. Fortes et al., “Chemoprophylactic agents in schistosomiasis: eremanthine, costunolide, α-cyclocostunolide and bisabolol,” Journal of Pharmacy and Pharmacology, vol. 24, no. 11, pp. 853–857, 1972. View at Scopus
  3. M. S. Silvério, O. V. Sousa, G. Del-Vechio-Vieira, M. A. Miranda, F. C. Matheus, and M. A. C. Kaplan, “Pharmacological properties of the ethanol extract from Eremanthus erythropappus (DC.) McLeisch (Asteraceae),” Brazilian Journal of Pharmacognosy, vol. 18, no. 3, pp. 430–435, 2008. View at Publisher · View at Google Scholar
  4. A. Corbella, P. Gariboldi, G. Jommi, F. Orsini, and G. Ferrari, “Structure and absolute stereochemistry of vanillosmin, a guaianolide from Vanillosmopsis erythropappa,” Phytochemistry, vol. 13, no. 2, pp. 459–465, 1974. View at Scopus
  5. M. Garcia, A. J. R. da Silva, P. M. Baker, B. Gilbert, and J. A. Rabi, “Absolute stereochemistry of eremanthine, a schistosomicidal sesquiterpene lactone from Eremanthus elaeagnus,” Phytochemistry, vol. 15, no. 2, pp. 331–332, 1976. View at Scopus
  6. P. D. D. B. Lima, M. Garcia, and J. A. Rabi, “Selective extraction of α-methylene-γ-lactones. Reinvestigation of Vanillosmopsis erythropappa,” Journal of Natural Products, vol. 48, no. 6, pp. 986–988, 1985. View at Scopus
  7. J. F. M. Pérez, J. R. S. Scolforo, A. D. de Oliveira, J. M. de Mello, L. F. R. Borges, and J. F. Camolesi, “Management system for native candeia forest (Eremanthus erythropappus (DC.) MacLeish)—the option for selective cutting,” Cerne, vol. 10, no. 2, pp. 257–273, 2004.
  8. A. D. de Oliveira, I. S. A. Ribeiro, J. R. S. Scolforo, J. M. de Mello, F. W. Acerbi Jr., and J. F. Camolesi, “Market chain analysis of candeia timber (Eremanthus erythropappus),” Cerne, vol. 15, no. 3, pp. 257–264, 2009. View at Scopus
  9. One of the industries of essential oils that extract the oil from Eremanthus erythropappus is Citróleo Indústria e Comércio de Óleos Essenciais Ltda, http://www.citroleo.com.br/.
  10. G. P. P. Kamatou and A. M. Viljoen, “A review of the application and pharmacological properties of α-bisabolol and α-bisabolol-rich oils,” Journal of the American Oil Chemists' Society, vol. 87, no. 1, pp. 1–7, 2010. View at Publisher · View at Google Scholar · View at Scopus
  11. A. T. de Souza, T. L. Benazzi, M. B. Grings et al., “Supercritical extraction process and phase equilibrium of Candeia (Eremanthus erythropappus) oil using supercritical carbon dioxide,” The Journal of Supercritical Fluids, vol. 47, no. 2, pp. 182–187, 2008. View at Publisher · View at Google Scholar · View at Scopus
  12. S. Yuuya, H. Hagiwara, T. Suzuki et al., “Guaianolides as immunomodulators. Synthesis and biological activities of dehydrocostus lactone, mokko lactone, eremanthin, and their derivatives,” Journal of Natural Products, vol. 62, no. 1, pp. 22–30, 1999. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  13. J. W. de Kraker, M. C. R. Franssen, M. Joerink, A. de Groot, and H. J. Bouwmeester, “Biosynthesis of costunolide, dihydrocostunolide, and leucodin. Demonstration of cytochrome P450-catalyzed formation of the lactone ring present in sesquiterpene lactones of chicory,” Plant Physiology, vol. 129, no. 1, pp. 257–268, 2002. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  14. N. H. Fischer, E. J. Olivier, and H. D. Fischer, “The biogenesis and chemistry of sesquiterpene lactones,” in Progess in the Chemistry of Organic Natural Products, W. Herz, H. Grisebach, and G. W. Kirby, Eds., vol. 38, pp. 47–390, Springer, New York, NY, USA, 1979.
  15. J. L. P. Ferreira, Studies on the chemical reactivity of epoxides derived from eremanthine, M.Sc. dissertation, NPPN, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 1985.
  16. E. C. Fantini, Study on the chemical reactivity of eremanthine. The α-methylene-γ-lactone moiety, Ph.D. thesis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 1985.
  17. N. H. Fischer, Y. F. Wu-Shih, G. Chiari, F. R. Fronczek, and S. F. Watkins, “Molecular structure of a cis-decalin-type eudesmanolide and its formation from a guaianolide-1(10)-epoxide,” Journal of Natural Products, vol. 44, no. 1, pp. 104–110, 1981. View at Scopus
  18. J. E. Barquera-Lozada and G. Cuevas, “Biogenesis of sesquiterpene lactones pseudoguaianolides from germacranolides: theoretical study on the reaction mechanism of terminal biogenesis of 8-epiconfertin,” The Journal of Organic Chemistry, vol. 74, no. 2, pp. 874–883, 2009. View at Publisher · View at Google Scholar · View at Scopus
  19. A. Ortega and E. Maldonado, “A one step transformation of 4α,5β-epoxygermacranolide into pseudoguaianolide,” Heterocycles, vol. 29, no. 4, pp. 635–638, 1989. View at Scopus
  20. M. J. Bordoloi, R. P. Sharma, and J. C. Sarma, “Biomimetic transformation of a guaianolide to a pseudoguaianolide,” Tetrahedron Letters, vol. 27, no. 38, pp. 4633–4634, 1986. View at Scopus
  21. B. M. Fraga, “Natural sesquiterpenoids,” Natural Product Reports, vol. 27, no. 11, pp. 1681–1708, 2010. View at Publisher · View at Google Scholar
  22. D. N. Cavalcanti, M. A. V. Gomes, A. C. Pinto, C. M. de Rezende, R. C. Pereira, and V. L. Teixeira, “Effects of storage and solvent type in a lipophylic chemical profile of the seaweed Dictyota menstrualis,” Brazilian Journal of Oceanography, vol. 56, no. 1, pp. 51–57, 2008. View at Scopus
  23. J. C. De-Paula, L. B. Bueno, D. N. Cavalcanti, Y. Yoneshigue-Valentin, and V. L. Teixeira, “Diterpenes from the brown alga Dictyota crenulata,” Molecules, vol. 13, no. 6, pp. 1253–1262, 2008. View at Publisher · View at Google Scholar · View at Scopus
  24. M. A. Vallim, V. L. Teixeira, and R. C. Pereira, “Feeding-deterrent properties of diterpenes of Dictyota mertensii (phaeophyceae, dictyotales),” Brazilian Journal of Oceanography, vol. 55, no. 3, pp. 223–229, 2007.
  25. X. Zhang, H. Wang, J. Sheng, and X. Luo, “A new guaiane diterpenoid from Euphorbia wallichii,” Natural Product Research, vol. 20, no. 1, pp. 89–92, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  26. S. A. Kolesnikova, A. I. Kalinovsky, S. N. Fedorov, L. K. Shubina, and V. A. Stonik, “Diterpenes from the far-eastern brown alga Dictyota dichotoma,” Phytochemistry, vol. 67, no. 19, pp. 2115–2119, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  27. J. W. Blunt, B. R. Copp, M. H. G. Munro, P. T. Northcote, and M. R. Prinsep, “Marine natural products,” Natural Product Reports, vol. 23, no. 1, pp. 26–78, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  28. J. W. Blunt, B. R. Copp, M. H. G. Munro, P. T. Northcote, and M. R. Prinsep, “Marine natural products,” Natural Product Reports, vol. 22, no. 1, pp. 15–61, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  29. M. A. Vallim, J. C. de Paula, R. C. Pereira, and V. L. Teixeira, “The diterpenes from Dictyotacean marine brown algae in the tropical Atlantic American region,” Biochemical Systematics and Ecology, vol. 33, no. 1, pp. 1–16, 2005. View at Publisher · View at Google Scholar · View at Scopus
  30. P. Siamopoulou, A. Bimplakis, D. Iliopoulou et al., “Diterpenes from the brown algae Dictyota dichotoma and Dictyota linearis,” Phytochemistry, vol. 65, no. 14, pp. 2025–2030, 2004. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  31. S. R. Gedara, O. B. Abdel-Halim, S. H. El-Sharkawy, O. M. Salama, T. W. Shier, and A. F. Halim, “Cytotoxic hydroazulene diterpenes from the brown alga Dictyota dichotoma,” Zeitschrift für Naturforschung Section C, vol. 58, no. 1-2, pp. 17–22, 2003. View at Scopus
  32. S. E. N. Ayyad, O. B. Abdel-Halim, W. T. Shier, and T. R. Hoye, “Cytotoxic hydroazulene diterpenes from the brown alga Cystoseira myrica,” Zeitschrift für Naturforschung Section C, vol. 58, no. 1-2, pp. 33–38, 2003. View at Scopus
  33. V. L. Teixeira, D. N. Cavalcanti, and R. C. Pereira, “Chemotaxonomic study of the diterpenes from the brown alga Dictyota menstrualis,” Biochemical Systematics and Ecology, vol. 29, no. 3, pp. 313–316, 2001. View at Publisher · View at Google Scholar · View at Scopus
  34. R. C. Pereira, D. N. Cavalcanti, and V. L. Teixeira, “Effects of secondary metabolites from the tropical Brazilian brown alga Dictyota menstrualis on the amphipod Parhyale hawaiensis,” Marine Ecology Progress Series, vol. 205, pp. 95–100, 2000. View at Scopus
  35. M. Gavagnin and A. Fontana, “Diterpenes from marine opisthobranch molluscs,” Current Organic Chemistry, vol. 4, no. 12, pp. 1201–1248, 2000. View at Publisher · View at Google Scholar · View at Scopus
  36. D. J. Faulkner, “Marine natural products,” Natural Product Reports, vol. 15, no. 2, pp. 113–158, 1998. View at Scopus
  37. R. Durán, E. Zubía, M. J. Ortega, and J. Salvá, “New diterpenoids from the alga Dictyota dichotoma,” Tetrahedron, vol. 53, no. 25, pp. 8675–8688, 1997. View at Publisher · View at Google Scholar · View at Scopus
  38. G. M. König, A. D. Wright, O. Sticher, and H. Ruegger, “Four new hydroazulenoid diterpenes from the tropical marine brown alga Dictyota volubilis,” Planta Medica, vol. 59, no. 2, pp. 174–178, 1993. View at Scopus
  39. V. L. Teixeira, S. A. D. S. Almeida, and A. Kelecom, “Chemosystematic and biogeographic studies of the diterpenes from the marine brown alga Dictyota dichotoma,” Biochemical Systematics and Ecology, vol. 18, no. 2-3, pp. 87–92, 1990. View at Scopus
  40. V. L. Teixeira and A. Kelecom, “A chemotaxonomic study of diterpenes from marine brown algae of the genus Dictyota,” Science of the Total Environment, vol. 75, no. 2-3, pp. 271–283, 1988. View at Scopus
  41. J. T. Vázquez, M. Chang, K. Nakanishi, E. Manta, C. Pérez, and J. D. Martín, “Structure of hydroazulenoid diterpenes from a marine alga and their absolute configuration based on circular dichroism,” The Journal of Organic Chemistry, vol. 53, no. 20, pp. 4797–4800, 1988. View at Scopus
  42. S. de Rosa, S. de Stefano, and N. Zavodnik, “Hydroazulenoid diterpenes from the brown alga Dictyota dichotoma var. Implexa,” Phytochemistry, vol. 25, no. 9, pp. 2179–2181, 1986. View at Scopus
  43. A. Kelecom and V. L. Teixeira, “Diterpenes of marine brown algae of the family dictyotaceae: their possible role as defense compounds and their use in chemotaxonomy,” The Science of the Total Environment, vol. 58, no. 1-2, pp. 109–115, 1986. View at Scopus
  44. H. H. Sun, F. J. McEnroe, and W. Fenical, “Acetoxycrenulide, a new bicyclic cyclopropane-containing diterpenoid from the brown seaweed Dictyota crenulata,” The Journal of Organic Chemistry, vol. 48, no. 11, pp. 1903–1906, 1983. View at Scopus
  45. J. Finer, J. Clardy, W. Fenical et al., “Structures of dictyodial and dictyolactone, unusual marine diterpenoids,” The Journal of Organic Chemistry, vol. 44, no. 12, pp. 2044–2047, 1979. View at Scopus
  46. A. E. Greene, “Synthesis of (+)-pachydictyol-A,” Tetrahedron Letters, vol. 19, no. 9, pp. 851–854, 1978. View at Scopus
  47. B. Danise, L. Minale, R. Riccio, et al., “Further perhydroazulene diterpenes from marine organisms,” Experientia, vol. 33, no. 4, pp. 413–415, 1977.
  48. D. J. Faulkner, B. N. Ravi, J. Finer, and J. Clardy, “Diterpenes from Dictyota dichotoma,” Phytochemistry, vol. 16, no. 7, pp. 991–993, 1977. View at Scopus
  49. L. Minale and R. Riccio, “Constituents of the digestive gland of the molluscs of the genus Aplysia. I. Novel diterpenes from Aplysia depilans,” Tetrahedron Letters, vol. 17, no. 31, pp. 2711–2714, 1976. View at Scopus
  50. E. Fattorusso, S. Magno, L. Mayol et al., “Dictyol A and B, two novel diterpene alcohols from the brown alga Dictyota dichotoma,” Journal of the Chemical Society, Chemical Communications, no. 14, pp. 575–576, 1976. View at Publisher · View at Google Scholar · View at Scopus
  51. D. R. Hirschfeld, W. Fenical, G. H. Y. Lin, R. M. Wing, P. Radlick, and J. J. Sims, “Marine natural products. VIII. Pachydictyol A, an exceptional diterpene alcohol from the brown alga, Pachydictyon coriaceum,” Journal of the American Chemical Society, vol. 95, no. 12, pp. 4049–4050, 1973. View at Scopus
  52. Y. Ye, X. Q. Li, and C. P. Tang, “Natural products chemistry research 2006's progress in China,” Chinese Journal of Natural Medicines, vol. 6, no. 1, pp. 70–78, 2008. View at Publisher · View at Google Scholar · View at Scopus
  53. Q. L. Dang, Y. H. Choi, G. J. Choi et al., “Pesticidal activity of ingenane diterpenes isolated from Euphorbia kansui against Nilaparvata lugens and Tetranychus urticae,” Journal of Asia-Pacific Entomology, vol. 13, no. 1, pp. 51–54, 2010. View at Publisher · View at Google Scholar · View at Scopus
  54. Q. C. Wu, Y. P. Tang, A. W. Ding, F. Q. You, L. Zhang, and J. A. Duan, “13C-NMR data of three important diterpenes isolated from Euphorbia species,” Molecules, vol. 14, no. 11, pp. 4454–4475, 2009. View at Publisher · View at Google Scholar · View at Scopus
  55. E. Sulyok, A. Vasas, D. Rédei, G. Dombi, and J. Hohmann, “Isolation and structure determination of new 4,12-dideoxyphorbol esters from Euphorbia pannonica Host,” Tetrahedron, vol. 65, no. 20, pp. 4013–4016, 2009. View at Publisher · View at Google Scholar · View at Scopus
  56. Z. Q. Lu, M. Yang, J. Q. Zhang et al., “Ingenane diterpenoids from Euphorbia esula,” Phytochemistry, vol. 69, no. 3, pp. 812–819, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  57. A. R. Jassbi, “Chemistry and biological activity of secondary metabolites in Euphorbia from Iran,” Phytochemistry, vol. 67, no. 18, pp. 1977–1984, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  58. J. K. Cha and O. L. Epstein, “Synthetic approaches to ingenol,” Tetrahedron, vol. 62, no. 7, pp. 1329–1343, 2006. View at Publisher · View at Google Scholar · View at Scopus
  59. M. E. Krafft, Y. Y. Cheung, S. A. Kerrigan, and K. A. Abboud, “Synthesis of ‘inside-outside’ medium-sized rings via ring-closing metathesis,” Tetrahedron Letters, vol. 44, no. 4, pp. 839–843, 2003. View at Publisher · View at Google Scholar · View at Scopus
  60. J. H. Rigby and M. Fleming, “Construction of the ingenane core using an Fe(III) or Ti(IV) Lewis acid-catalyzed intramolecular [6+4] cycloaddition,” Tetrahedron Letters, vol. 43, no. 48, pp. 8643–8646, 2002. View at Publisher · View at Google Scholar · View at Scopus
  61. M. Blanco-Molina, G. C. Tron, A. Macho et al., “Ingenol esters induce apoptosis in Jurkat cells through an AP-1 and NF-κB independent pathway,” Chemistry and Biology, vol. 8, no. 8, pp. 767–778, 2001. View at Publisher · View at Google Scholar · View at Scopus
  62. J. H. Rigby, H. Jingdan, and M. J. Heeg, “Synthetic studies on the ingenane diterpenes. Construction of an ABC tricycle exhibiting trans-intrabridgehead stereochemistry,” Tetrahedron Letters, vol. 39, no. 16, pp. 2265–2268, 1998. View at Publisher · View at Google Scholar · View at Scopus
  63. J. A. Marco, J. F. Sanz-Cervera, F. J. Ropero, J. Checa, and B. M. Fraga, “Ingenane and lathyrane diterpenes from the latex of Euphorbia acrurensis,” Phytochemistry, vol. 49, no. 4, pp. 1095–1099, 1998. View at Publisher · View at Google Scholar · View at Scopus
  64. J. A. Marco, J. F. Sanz-Cervera, and A. Yuste, “Ingenane and lathyrane diterpenes from the latex of Euphorbia canariensis,” Phytochemistry, vol. 45, no. 3, pp. 563–570, 1997. View at Publisher · View at Google Scholar · View at Scopus
  65. J. D. Winkler, B. C. Hong, A. Bahador, M. G. Kazanietz, and P. M. Blumberg, “Synthesis of ingenol analogs with affinity for protein kinase C,” Bioorganic & Medicinal Chemistry Letters, vol. 3, no. 4, pp. 577–580, 1993. View at Publisher · View at Google Scholar · View at Scopus
  66. G. Brooks, A. T. Evans, D. P. Markby, M. E. Harrison, M. A. Baldwin, and F. J. Evans, “An ingenane diterpene from belizian Mabea excelsa,” Phytochemistry, vol. 29, no. 5, pp. 1615–1617, 1990. View at Scopus
  67. P. A. Wender, C. L. Hillemann, and M. J. Szymonifka, “An approach to the tiglianes, daphnanes, and ingenanes via the divinylcyclopropane rearrangement,” Tetrahedron Letters, vol. 21, no. 23, pp. 2205–2208, 1980. View at Scopus
  68. J. Y. Hong, J. W. Nam, E. K. Seo, and S. K. Lee, “Daphnane diterpene esters with anti-proliferative activities against human lung cancer cells from Daphne genkwa,” Chemical & Pharmaceutical Bulletin, vol. 58, no. 2, pp. 234–237, 2010. View at Publisher · View at Google Scholar · View at Scopus
  69. L. Pan, X. F. Zhang, Y. Deng, Y. Zhou, H. Wang, and L. S. Ding, “Chemical constituents investigation of Daphne tangutica,” Fitoterapia, vol. 81, no. 1, pp. 38–41, 2010. View at Publisher · View at Google Scholar · View at Scopus
  70. S. A. Ayatollahi, A. Shojaii, F. Kobarfard, M. Nori, M. Fathi, and M. I. Choudhari, “Terpens from aerial parts of Euphorbia splendida,” Journal of Medicinal Plant Research, vol. 3, no. 9, pp. 660–665, 2009. View at Scopus
  71. P. Y. Hayes, S. Chow, M. J. Somerville, J. J. de Voss, and M. T. Fletcher, “Pimelotides A and B, diterpenoid ketal-lactone orthoesters with an unprecedented skeleton from Pimelea elongata,” Journal of Natural Products, vol. 72, no. 12, pp. 2081–2083, 2009. View at Publisher · View at Google Scholar · View at Scopus
  72. R. Yazdanparast and A. Meshkini, “3-hydrogenkwadaphnine, a novel diterpene ester from Dendrostellera lessertii, its role in differentiation and apoptosis of KG1 cells,” Phytomedicine, vol. 16, no. 2-3, pp. 206–214, 2009. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  73. C. V. Diogo, L. Félix, S. Vilela et al., “Mitochondrial toxicity of the phyotochemicals daphnetoxin and daphnoretin—relevance for possible anti-cancer application,” Toxicology in Vitro, vol. 23, no. 5, pp. 772–779, 2009. View at Publisher · View at Google Scholar · View at Scopus
  74. B. Y. Park, B. S. Min, K. S. Ahn et al., “Daphnane diterpene esters isolated from flower buds of Daphne genkwa induce apoptosis in human myelocytic HL-60 cells and suppress tumor growth in Lewis lung carcinoma (LLC)-inoculated mouse model,” Journal of Ethnopharmacology, vol. 111, no. 3, pp. 496–503, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  75. L. Pan, X. F. Zhang, H. F. Wu, and L. S. Ding, “A new daphnane diterpene from Daphne tangutica,” Chinese Chemical Letters, vol. 17, no. 1, pp. 38–40, 2006. View at Scopus
  76. R. Yazdanparast and M. A. Moosavi, “Daphnane-type diterpene esters as powerful agents for the treatment of leukemia,” Medical Hypotheses, vol. 67, no. 6, pp. 1472–1473, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  77. A. Tempeam, N. Thasana, C. Pavaro, W. Chuakul, P. Siripong, and S. Ruchirawat, “A new cytotoxic daphnane diterpenoid, rediocide G, from Trigonostemon reidioides,” Chemical & Pharmaceutical Bulletin, vol. 53, no. 10, pp. 1321–1323, 2005. View at Publisher · View at Google Scholar · View at Scopus
  78. Z. J. Zhan, C. Q. Fan, J. Ding, and J. M. Yue, “Novel diterpenoids with potent inhibitory activity against endothelium cell HMEC and cytotoxic activities from a well-known TCM plant Daphne genkwa,” Bioorganic and Medicinal Chemistry, vol. 13, no. 3, pp. 645–655, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  79. A. T. Tchinda, A. Tsopmo, M. Tene et al., “Diterpenoids from Neoboutonia glabrescens (Euphorbiaceae),” Phytochemistry, vol. 64, no. 2, pp. 575–581, 2003. View at Publisher · View at Google Scholar · View at Scopus
  80. W. He, M. Cik, L. van Puyvelde et al., “Neurotrophic and antileukemic daphnane diterpenoids from Synaptolepis kirkii,” Bioorganic and Medicinal Chemistry, vol. 10, no. 10, pp. 3245–3255, 2002. View at Publisher · View at Google Scholar · View at Scopus
  81. J. R. Carney, J. M. Krenisky, R. T. Williamson et al., “Maprouneacin, a new daphnane diterpenoid with potent antihyperglycemic activity from Maprounea africana,” Journal of Natural Products, vol. 62, no. 2, pp. 345–347, 1999. View at Publisher · View at Google Scholar · View at Scopus
  82. F. Abe, Y. Iwase, T. Yamauchi et al., “Minor daphnane-type diterpenoids from Wikstroemia retusa,” Phytochemistry, vol. 47, no. 5, pp. 833–837, 1998. View at Publisher · View at Google Scholar · View at Scopus
  83. F. Abe, Y. Iwase, T. Yamauchi, K. Kinjo, and S. Yaga, “Daphnane diterpenoids from the bark of Wikstroemia retusa,” Phytochemistry, vol. 44, no. 4, pp. 643–647, 1997. View at Publisher · View at Google Scholar · View at Scopus
  84. P. C. B. Page, D. C. Jennens, and H. McFarland, “An IMDA approach to tigliane and daphnane diterpenoids: generation of the tetracyclic ring system of the tiglianes,” Tetrahedron Letters, vol. 38, no. 39, pp. 6913–6916, 1997. View at Publisher · View at Google Scholar · View at Scopus
  85. P. C. B. Page, D. C. Jennens, and H. McFarland, “An IMDA approach to tigliane and daphnane diterpenoids: introduction of the C-12, C-13 C ring oxygenation of phorbol,” Tetrahedron Letters, vol. 38, no. 30, pp. 5395–5398, 1997. View at Publisher · View at Google Scholar · View at Scopus
  86. Y. Shiryo, K. Kazuhiko, H. Hiroya, M. Naochika, A. Fumiko, and Y. Tatsuo, “Diterpenoids with the daphnane skeleton from Wikstroemia retusa,” Phytochemistry, vol. 32, no. 1, pp. 141–143, 1992. View at Scopus
  87. T. Terai, K. Osakabe, M. Katai et al., “Preparation of 9-hydroxy grayanotoxin derivatives and their acute toxicity in mice,” Chemical & Pharmaceutical Bulletin, vol. 51, no. 3, pp. 351–353, 2003. View at Scopus
  88. M. Shimizu, Y. Nakagawa, Y. Sato, et al., “Studies on endophytic actinomycetes (I) Streptomyces sp. isolated from rhododendron and its antifungal activity,” Journal of General Plant Pathology, vol. 66, no. 4, pp. 360–366, 2000.
  89. L. Q. Wang, B. Y. Ding, G. W. Qin, G. Lin, and K. F. Cheng, “Grayanoids from Pieris formosa,” Phytochemistry, vol. 49, no. 7, pp. 2045–2048, 1998. View at Publisher · View at Google Scholar · View at Scopus
  90. M. Sato, Y. Katsube, M. Katai, J. Katakawa, and T. Tetsumi, “Crystal and molecular structure of asebotoxin IV,” Bulletin of the Chemical Society of Japan, vol. 67, no. 3, pp. 866–868, 1994.
  91. N. Harada, “Pharmacological studies on the mechanisms of asebotoxin III-induced centrogenic pulmonary hemorrhagic edema in guinea pigs,” Nippon Yakurigaku Zasshi, vol. 81, no. 2, pp. 105–113, 1983.
  92. K. Takeya, Y. Hotta, N. Harada, G. Itoh, and J. Sakakibara, “Asebotoxin-induced centrogenic pulmonary hemorrhage in guinea pigs,” The Japanese Journal of Pharmacology, vol. 31, no. 1, pp. 137–140, 1981. View at Scopus
  93. H. Hikino, M. Ogura, S. Fushiya, C. Konno, and T. Takemoto, “Stereostructure of asebotoxin VI, VIII, and IX, toxins of Pieris japonica,” Chemical & Pharmaceutical Bulletin, vol. 25, no. 3, pp. 523–524, 1971. View at Scopus
  94. H. Hikino, T. Ohta, M. Ogura, Y. Ohizumi, C. Konno, and T. Takemoto, “Structure activity relationship of ericaceous toxins on acute toxicity in mice,” Toxicology and Applied Pharmacology, vol. 35, no. 2, pp. 303–310, 1976.
  95. H. Hikino, M. Ogura, and T. Takemoto, “Stereostructure of asebotoxin VII, toxin of Pieris japonica,” Chemical & Pharmaceutical Bulletin, vol. 19, no. 9, pp. 1980–1981, 1971.
  96. R. J. Peters, “Two rings in them all: the labdane-related diterpenoids,” Natural Product Reports, vol. 27, no. 11, pp. 1521–1530, 2010. View at Publisher · View at Google Scholar
  97. F. Berrue and R. G. Kerr, “Diterpenes from gorgonian corals,” Natural Product Reports, vol. 26, no. 5, pp. 681–710, 2009. View at Publisher · View at Google Scholar · View at Scopus
  98. T. Busch and A. Kirschning, “Recent advances in the total synthesis of pharmaceutically relevant diterpenes,” Natural Product Reports, vol. 25, no. 2, pp. 318–341, 2008. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  99. J. R. Hanson, “Diterpenoids,” Natural Product Reports, vol. 24, no. 6, pp. 1332–1341, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  100. R. A. Keyzers, P. T. Northcote, and M. T. Davies-Coleman, “Spongian diterpenoids from marine sponges,” Natural Product Reports, vol. 23, no. 2, pp. 321–334, 2006. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  101. J. R. Hanson, “Diterpenoids,” Natural Product Reports, vol. 22, no. 5, pp. 594–602, 2005. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  102. J. B. Hendrickson, “Molecular geometry. I. Machine computation of the common rings,” Journal of the American Chemical Society, vol. 83, no. 22, pp. 4537–4547, 1961. View at Scopus
  103. J. B. Hendrickson, “Molecular geometry. II. Methyl-cyclohexanes and cycloheptanes,” Journal of the American Chemical Society, vol. 84, no. 17, pp. 3355–3359, 1962. View at Scopus
  104. J. B. Hendrickson, “Sesquiterpenes-IV. Conformational analysis in the perhydroazulenic sesquiterpenes,” Tetrahedron, vol. 19, no. 9, pp. 1387–1396, 1963. View at Scopus
  105. J. B. Hendrickson, “Molecular geometry. IV. The medium rings,” Journal of the American Chemical Society, vol. 86, no. 22, pp. 4854–4866, 1964. View at Scopus
  106. J. B. Hendrickson, “Molecular geometry. V. Evaluation of functions and conformations of medium rings,” Journal of the American Chemical Society, vol. 89, no. 26, pp. 7036–7043, 1967. View at Scopus
  107. J. B. Hendrickson, “Molecular geometry. VI. Methyl-substituted cycloalkanes,” Journal of the American Chemical Society, vol. 89, no. 26, pp. 7043–7046, 1967. View at Scopus
  108. J. B. Hendrickson, “Molecular geometry. VII. Modes of interconversion in the medium rings,” Journal of the American Chemical Society, vol. 89, no. 26, pp. 7047–7061, 1967. View at Scopus
  109. J. B. Hendrickson, R. K. Boeckman, J. D. Glickson, and E. Grunwald, “Molecular geometry. VIII. Proton magnetic resonance studies of cycloheptane conformations,” Journal of the American Chemical Society, vol. 95, no. 2, pp. 494–505, 1973.
  110. P. J. de Clercq, “Systematic conformational analysis. General method for rapid conformational evaluation. Its application to the hydroazulene system,” The Journal of Organic Chemistry, vol. 46, no. 4, pp. 667–675, 1981. View at Scopus
  111. P. J. de Clercq, “Systematic conformational analysis. Torsion constraint evaluation in cyclic systems,” Tetrahedron, vol. 37, no. 24, pp. 4277–4286, 1981. View at Scopus
  112. P. J. de Clercq, “Systematic conformational analysis. A microcomputer method for the semiquantitative evaluation of polycyclic systems containing five-, six- and seven-membered rings. 1. Program characteristics,” Tetrahedron, vol. 40, no. 19, pp. 3717–3727, 1984. View at Scopus
  113. P. J. de Clercq, “Systematic conformational analysis. A microcomputer method for the semiquantitative evaluation of polycyclic systems containing five-, six- and seven-membered rings. 2. Scope and limitations,” Tetrahedron, vol. 40, no. 19, pp. 3729–3738, 1984. View at Scopus
  114. J. Hoflack and P. J. de Clercq, “The sca program: an easy way for the conformational evaluation of polycyclic molecules,” Tetrahedron, vol. 44, no. 21, pp. 6667–6676, 1988. View at Scopus
  115. P. J. de Clercq, “Systematic conformational analysis. General method for rapid conformational evaluation. Its application to the hydroazulene system,” The Journal of Organic Chemistry, vol. 46, no. 4, pp. 667–675, 1981, Supplementary material and references cited therein.
  116. Z. Hassan, H. Hussain, V. U. Ahmad et al., “Absolute configuration of 1β,10β-epoxydesacetoxymatricarin isolated from Carthamus oxycantha by means of TDDFT CD calculations,” Tetrahedron Asymmetry, vol. 18, no. 24, pp. 2905–2909, 2007. View at Publisher · View at Google Scholar · View at Scopus
  117. S. Bercion, T. Buffeteau, L. Lespade, and M. A. C. D. Martin, “IR, VCD, 1H and 13C NMR experimental and theoretical studies of a natural guaianolide: unambiguous determination of its absolute configuration,” Journal of Molecular Structure, vol. 791, no. 1–3, pp. 186–192, 2006. View at Publisher · View at Google Scholar · View at Scopus
  118. F. A. Macías, V. M. I. Viñolo, F. R. Fronczek, G. M. Massanet, and J. M. G. Molinillo, “11,16 Oxetane lactones. Spectroscopic evidences and conformational analysis,” Tetrahedron, vol. 62, no. 33, pp. 7747–7755, 2006. View at Publisher · View at Google Scholar · View at Scopus
  119. S. Milosavljevic, I. Juranic, V. Bulatovic et al., “Conformational analysis of guaianolide-type sesquiterpene lactones by low-temperature NMR spectroscopy and semiempirical calculations,” Structural Chemistry, vol. 15, no. 3, pp. 237–245, 2004. View at Publisher · View at Google Scholar
  120. K. Schorr, A. J. García-Piñeres, B. Siedle, I. Merfort, and F. B. da Costa, “Guaianolides from Viguiera gardneri inhibit the transcription factor NF-κB,” Phytochemistry, vol. 60, no. 7, pp. 733–740, 2002. View at Publisher · View at Google Scholar · View at Scopus
  121. T. J. Schmidt, “Helenanolide type sesquiterpene lactones. Part 1. Conformations and molecular dynamics of helenalin, its esters and 11,13-dihydro derivatives,” Journal of Molecular Structure, vol. 385, no. 2, pp. 99–112, 1996. View at Publisher · View at Google Scholar · View at Scopus
  122. T. J. Schmidt, F. R. Fronczek, and Y.-H. Liu, “Helenanolide-type sesquiterpene lactones. Part 2. The molecular conformations of arnifolin and some related helenanolides as determined by X-ray crystallographic and NMR spectroscopic analyses,” Journal of Molecular Structure, vol. 385, no. 2, pp. 113–121, 1996. View at Publisher · View at Google Scholar
  123. M. de Bernardi, L. Garlaschelli, L. Toma, G. Vidari, and P. Vita-Finzi, “The chemical basis of hot-tasting and yellowing of the mushrooms Lactarius chrysorrheus and L. scrobiculatus,” Tetrahedron, vol. 49, no. 7, pp. 1489–1504, 1993. View at Publisher · View at Google Scholar · View at Scopus
  124. M. T. Scotti, M. B. Fernandes, M. J. P. Ferreira, and V. P. Emerenciano, “Quantitative structure-activity relationship of sesquiterpene lactones with cytotoxic activity,” Bioorganic & Medicinal Chemistry, vol. 15, no. 8, pp. 2927–2934, 2007. View at Publisher · View at Google Scholar · View at PubMed · View at Scopus
  125. H. Matsuda, T. Kagerura, I. Toguchida, H. Ueda, T. Morikawa, and M. Yoshikawa, “Inhibitory effects of sesquiterpenes from bay leaf on nitric oxide production in lipopolysaccharide-activated macrophages: structure requirement and, role of heat shock protein induction,” Life Sciences, vol. 66, no. 22, pp. 2151–2157, 2000. View at Scopus
  126. T. J. Schmidt, “Toxic activities of sesquiterpene lactones: structural and biochemical aspects,” Current Organic Chemistry, vol. 3, no. 6, pp. 577–608, 1999. View at Scopus
  127. E. Rodriguez, G. H. N. Towers, and J. C. Mitchell, “Biological activities of sesquiterpene lactones,” Phytochemistry, vol. 15, no. 11, pp. 1573–1580, 1976. View at Scopus
  128. S. M. Kupchan, M. A. Eakin, and A. M. Thomas, “Tumor inhibitors. 69. Structure-cytotoxicity relationships among the sesquiterpene lactones,” Journal of Medicinal Chemistry, vol. 14, no. 12, pp. 1147–1152, 1971. View at Scopus
  129. R. L. Hanson, H. A. Lardy, and S. M. Kupchan, “Inhibition of phosphofructokinase by quinone methide and α-methylene lactone tumor inhibitors,” Science, vol. 168, no. 3929, pp. 378–380, 1970. View at Scopus
  130. S. M. Kupchan, D. C. Fessler, M. A. Eakin, and T. J. Giacobbe, “Reactions of alpha methylene lactone tumor inhibitors with model biological nucleophiles,” Science, vol. 168, no. 3929, pp. 376–378, 1970. View at Scopus
  131. B. T. Zhuzbaev, S. M. Adekenov, and V. V. Veselovsky, “Approaches to the total synthesis of sesquiterpenoids of the guaiane series,” Russian Chemical Reviews, vol. 64, no. 2, pp. 187–200, 1995.
  132. C. H. Heathcock, C. M. Tice, and T. C. Germroth, “Synthesis of sesquiterpene antitumor lactones. 10. Total synthesis of (±)-parthenin,” Journal of the American Chemical Society, vol. 104, no. 22, pp. 6081–6091, 1982. View at Scopus
  133. C. H. Heathcock, E. G. DelMar, and S. L. Graham, “Synthesis of sesquiterpene antitumor lactones. 9. The hydronaphthalene route to pseudoguaianes. Total synthesis of (±)-confertin,” Journal of the American Chemical Society, vol. 104, no. 7, pp. 1907–1917, 1982. View at Scopus
  134. P. de Clercq and M. Vandewalle, “Total synthesis of (±)-damsin,” The Journal of Organic Chemistry, vol. 42, no. 21, pp. 3447–3450, 1977. View at Scopus
  135. J. A. Marshall and W. R. Snyder, “Total synthesis of (±)-4-deoxydamsin. Structure correlation of pseudoguaianolide sesquiterpenes,” The Journal of Organic Chemistry, vol. 40, no. 11, pp. 1656–1659, 1975. View at Scopus
  136. J. H. Rigby and J. Z. Wilson, “Total synthesis of guaianolides: (±)-dehydrocostus lactone and (±)-estafiatin,” Journal of the American Chemical Society, vol. 106, no. 26, pp. 8217–8224, 1984. View at Scopus
  137. T. J. Brocksom, U. Brocksom, and F. P. Barbosa, “The enantioselective synthesis of (R)-(+)-6-isopropenyl-3-methyl-2-cycloheptenone,” Journal of the Brazilian Chemical Society, vol. 17, no. 4, pp. 792–796, 2006. View at Scopus
  138. D. A. Foley and A. R. Maguire, “Synthetic approaches to bicyclo[5.3.0]decane sesquiterpenes,” Tetrahedron, vol. 66, no. 6, pp. 1131–1175, 2010. View at Publisher · View at Google Scholar · View at Scopus
  139. J. Méndez-Andino and L. A. Paquette, “Tandem development of aqueous indium chemistry and ring-closing metathesis as a general route to fused-ring α-methylene-γ-butyrolactones,” Advanced Synthesis and Catalysis, vol. 344, no. 3-4, pp. 303–311, 2002. View at Publisher · View at Google Scholar · View at Scopus
  140. N. Petragnani, H. M. C. Ferraz, and G. V. J. Silva, “Advances in the synthesis of α-methylenelactones,” Synthesis, no. 3, pp. 157–183, 1986.
  141. H. M. R. Hoffmann and J. Rabe, “Synthesis and biological activity of α-methylene-γ-butyrolactones,” Angewandte Chemie International Edition in English, vol. 24, no. 2, pp. 94–110, 1985. View at Scopus
  142. P. A. Grieco, “Methods for the synthesis of α-methylene lactones,” Synthesis, no. 2, pp. 67–82, 1975. View at Scopus
  143. R. B. Gammill, C. A. Wilson, and T. A. Bryson, “Synthesis of α-methylene-γ-butyrolactones,” Synthetic Communications, vol. 5, no. 4, pp. 245–268, 1975.
  144. M. Garcia, Study on the chemical reactivity of eremanthine, M.Sc. dissertation, NPPN, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 1975.
  145. A. J. R. da Silva, Techniques of nuclear magnetic resonance applied to the study of some sesquiterpenes, M.Sc. dissertation, NPPN, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 1976.
  146. F. W. L. Machado, Structural modifications of isoeremanthine. Synthesis of eregoyazin and eregoyazidin, M.Sc. dissertation, NPPN, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 1977.
  147. L. A. Maçaira, Structural modifications of eremanthine. Synthesis of dehydrocostus lactone and estafiatin, M.Sc. dissertation, NPPN, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 1978.
  148. A. A. S. Rodrigues, Biomimetic transformations of costunolide and eremanthine, M.Sc. dissertation, NPPN, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 1979.
  149. P. D. D. B. Lima, Development of a new specific method for the isolation of α-methylene lactones. Reinvestigation of Vanillosmopsis erythropappa Sch. Bip., M.Sc. dissertation, NPPN, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 1983.
  150. J. C. F. Alves, Inversion of the lactonic fusion on eremanthine derivatives and synthesis of micheliolide, M.Sc. dissertation, Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro, Brazil, 1993.
  151. L. A. Maçaira, M. Garcia, and J. A. Rabi, “Chemical transformations of abundant natural products. 3. Modifications of eremanthin leading to other naturally occurring guaianolides,” The Journal of Organic Chemistry, vol. 42, no. 26, pp. 4207–4209, 1977. View at Scopus
  152. S. B. Mathur, S. V. Hiremath, G. H. Kulkarni et al., “Terpenoids-LXX. Structure of dehydrocostus lactone,” Tetrahedron, vol. 21, no. 12, pp. 3575–3590, 1965. View at Scopus
  153. W. Vichnewski, F. W. L. Machado, J. A. Rabi, R. Murari, and W. Herz, “Eregoyazin and eregoyazidin, two new guaianolides from Eremanthus goyazensis,” The Journal of Organic Chemistry, vol. 42, no. 24, pp. 3910–3913, 1977. View at Scopus
  154. J. A. Rabi, M. Garcia, L. A. Maçaira, and F. W. L. Machado, “Chemical transformations of eremanthine: a way for the synthesis of cercareacide agents,” Anais da Academia Brasileira de Ciências, vol. 49, no. 4, pp. 563–565, 1977.
  155. F. Sánchez-Viesca and J. Romo, “Estafiatin, a new sesquiterpene lactone isolated from Artemisia mexicana (Willd),” Tetrahedron, vol. 19, no. 8, pp. 1285–1291, 1963. View at Scopus
  156. L. A. Maçaira, F. W. L. Machado, M. Garcia, and J. A. Rabi, “Unambiguous transformation of eremanthin into (-)-estafiatin,” Tetrahedron Letters, vol. 21, no. 9, pp. 773–776, 1980. View at Scopus
  157. M. Garcia, F. W. L. Machado, L. A. Maçaira, and J. A. Rabi, “The reaction of eremanthin and isoeremanthin with bromine. Unprecedented simultaneous addition of Br2 to two isolated but topographically related double bonds,” Tetrahedron Letters, vol. 21, no. 9, pp. 777–780, 1980. View at Scopus
  158. A. J. R. da Silva, M. Garcia, P. M. Baker, and J. A. Rabi, “13C NMR spectra of natural products. 1-guaianolides,” Organic Magnetic Resonance, vol. 16, no. 3, pp. 230–233, 1981.
  159. E. C. Fantini and J. A. Rabi, “Methoxyl group as protector of α-methylene-γ-lactones,” Ciência e Cultura, vol. 35, no. 7, suplemento, p. 403 (49-D.2.3), 1983.
  160. E. C. Fantini and J. A. Rabi, “Synthesis of 6-epi-eremanthine,” Ciência e Cultura, vol. 37, no. 7, suplemento, p. 417 (27-D.2.3), 1985.
  161. J. L. P. Ferreira, E. C. Fantini, and J. A. Rabi, “Participation of neighboring-group on the methanolysis of α-methylene-γ-lactones derived from eremanthine,” Ciência e Cultura, vol. 35, no. 7, suplemento, p. 403 (48-D.2.3), 1983.
  162. E. C. Fantini, J. L. P. Ferreira, and J. A. Rabi, “Participation of neighboring-groups on the methanolysis of α-methylene-γ-lactones derived from eremanthine. II-Reaction conditions and structural requirements,” Ciência e Cultura, vol. 36, no. 7, suplemento, p. 487 (73-D.2.3), 1984.
  163. E. C. Fantini, J. L. P. Ferreira, and J. A. Rabi, “Metal ion promoted methanolysis of sesquiterpene lactones leading to O6,15-cycloguaiane methyl esters,” Journal of Chemical Research (Synopses), no. 8, pp. 298–299, 1986.
  164. E. C. Fantini and J. A. Rabi, “Elimination versus formation of 15,6-α-oxidos on 4-α-hydroxy-15-iodine derived from eremanthine,” Ciência e Cultura, vol. 38, no. 7, suplemento, p. 521 (55-D.2.3), 1986.
  165. M. Ogura, G. A. Cordell, and N. R. Farnsworth, “Anticancer sesquiterpene lactones of Michelia compressa (magnoliaceae),” Phytochemistry, vol. 17, no. 5, pp. 957–961, 1978. View at Scopus
  166. J. C. F. Alves, J. A. Rabi, and E. C. Fantini, “Trans-cis inversion of the lactonic fusion on eremanthine derivatives. I—preliminary studies,” in Abstracts of the 14a Reunião Anual da Sociedade Brasileira de Química, (IC-32), Caxambu, Brazil, 1991.
  167. J. C. F. Alves and E. C. Fantini, “Trans-cis inversion of the lactonic fusion on eremanthine derivatives. II—study with substrates bearing double bonds at the positions 1,10; 3,4 and 9,10; 1,10 and 4,15,” in Abstracts of the 16a Reunião Anual da Sociedade Brasileira de Química, (QO-24), Caxambu, Brazil, 1993.
  168. J. C. F. Alves and E. C. Fantini, “Chemical transformations of eremanthine. Synthesis of micheliolide and 1(R),10(R)-dihydromicheliolide,” Journal of the Brazilian Chemical Society, vol. 16, no. 4, pp. 749–755, 2005.
  169. J. C. F. Alves and E. C. Fantini, “Erratum: Chemical transformations of eremanthine: Synthesis of micheliolide and 1(R),10(R)-dihydromicheliolide,” Journal of the Brazilian Chemical Society, vol. 21, no. 5, p. 946, 2010.
  170. J. C. F. Alves and E. C. Fantini, “Study of the inversion reaction of the lactonic fusion on eremanthine derivatives,” Journal of the Brazilian Chemical Society, vol. 18, no. 3, pp. 643–664, 2007. View at Scopus
  171. J. C. F. Alves, “Study of catalytic hydrogenation and methanol addition to α-methylene-γ-lactone of eremanthine derivatives,” Organic Chemistry International, vol. 2010, Article ID 603436, 11 pages, 2010. View at Publisher · View at Google Scholar
  172. H. Deshayes, J. P. Pete, C. Portella, and D. Scholler, “Photolysis of carboxylic esters: conversion of alcohols into alkanes,” Journal of the Chemical Society, Chemical Communications, no. 11, pp. 439–440, 1975. View at Publisher · View at Google Scholar · View at Scopus
  173. R. K. Crossland and K. L. Servis, “A facile synthesis of methanesulfonate esters,” The Journal of Organic Chemistry, vol. 35, no. 9, pp. 3195–3196, 1970. View at Scopus
  174. R. O. Hutchins, D. Kandasamy, C. A. Maryanoff, D. Masilamani, and B. E. Maryanoff, “Selective reductive displacement of alkyl halides and sulfonate esters with cyanoborohydride reagents in hexamethylphosphoramide,” The Journal of Organic Chemistry, vol. 42, no. 1, pp. 82–91, 1977. View at Scopus
  175. J. March, Advanced Organic Chemistry, John Wiley & Sons, New York, NY, USA, 3rd edition, 1985.
  176. H. O. House, Modern Synthetic Reactions, W. A. Benjamin, Menlo Park, California, USA, 2nd edition, 1972.
  177. J. C. F. Alves would like to explain that the incorrectness previously committed in the writing of works about chemical transformations of eremanthine [150, 166–167] were, whenever possible, corrected and revised in works published on this decade [168–170].