Bioorganic & Medicinal Chemistry Ltrers. Vol. 4, No. 21. pp. 2631-2634. 1994 Copyright 0 1994 Elsevier Science Ltd Printed in Great Britain. All rights resewed G960-894x/94 $7.ooto.00
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`096C-894X(94)00390-4
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`SYNTHESIS AND BIOLOGICAL ACTIVITY OF 3’-ALKYL- AND 3’-ALKENYL-3’-DEPHENYLDOCETAXELS Iwao Ojimat*, Olivier Duclost, Scott D. Kudukt, Chung-Ming Sun?, John C. Slatert, Fraqois Lavellet, Jean M. Veiths, and Ralph J. Bernacki* TDepartment of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400. ~Rhhe-Poulenc Rarer, Centre a’e Recherches a’e Vitry-Alfortvilk, 94403 Vitry sur Seine, France. *Department of Eqerimental Therapeutics, Grace Cancer Drug Center, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, New York 14263 Abstract. 3’-Alkyl- and 3’-alkenyL3’-dephenyldocetaxels am syntbesixed from BJ-deacetylbaccatin III based on the &lactam synthon method in good yields. The cytotoxicity of the new taxoids ate evaluated against different human tumor cell lines and their ability to inhibit the microtubules disassembly examined. The 3’-isobutenyl, 3’- crotyl, and 3’-isobutyl analogs possess very strong cytotoxicity as well as antitumor activity in vivo. 3’- Isobutenyl- as well as 3’-crotyl-3’-dephenyl- lo-acetyldocetaxel shows ca. 20 times stronger activity against an adriamycin-resistant human breast cancer cell line (MCF7-R) than those of docetaxel and paclitaxel. Taxol* (paclitaxel) is currently considered the most exciting lead in cancer chemotherapy.1-3 Taxotere@ (docetaxel), a semisynthetic analog, is also exceptionally promising.4 Paclitaxel and docetaxel possess strong antitumor activity against different cancers which have not been effectively treated by existing antitumor drugs.5*6 Paclitaxel has been approved by FDA for the treatment of advanced ovarian cancer (December, 1992) and breast cancer (April, 1994), and is currently in phase II and III clinical trials for lung, neck and other cancers2 Docetaxel is currently in phase II and III clinical trials for breast, lung and other cancers in the United States, Europe, and Japan and expected to be on the market shortly.6 Recent reports on clinical trials of paclitaxel and docetaxel, however, have disclosed that these highly effective drugs have a number of undesired side effects and are inactive against certain tumor types. ?‘a Therefore, it is very important to develop new anticancer drugs which have less undesirable side effects and activity spectra against various tumor types different from those of these two drugs. Pa&axe1 and docetaxel are, for example, inactive against colon cancer and renal cell carcinoma.7s which are originated from tissues that express constitutively the MDRl gene.Tb Thus, the observed lack of activity against these tumors could be partly due to the fact that these two drugs are subjected to multi-drug resistance (MDR)yC. Accordingly, it would be worthwhile to develop new taxoids that are not or minimally recognized by cancer cells expressing the MDR phenotype. In the course of our structure-activity relationship (SAR) study of paclitaxel and docetaxel.8 we synthesized a series of 3’-cyclohexyl and/or 2-hexahydro analogs and found the fact that 3’-phenyl is not essential for the biological activity of paclitaxel and docetaxel at least in vitro. 9 This discovery prompted us to synthesll a series of 3’-alkyl and 3’alkenyl analogs of do&axe1 and look at their structure-activity relationsbips.to The new 3’-alkyl and 3’-alkenyl analogs of docetaxel were synthesized from Wdeacetylbaccatin III (DAB) based on the p-Lactam Synthon Method using 1-tBOC-(3R,4S)-4-alkyl-3-hydroxyazetidin-2-ones
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`(1a.b)
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`(2a,b,c),
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`respectively, as the key precursors of the C- 2631
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`Sanofi Exh. 2006
`Neptune v. Aventis
`IPR2019-00136
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`and l-rSOC-(3R,4S)-4-alkenyl-3-hydroxyaxe.tidin-2-ones
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`2632 I. OJIMA et al. 13 side chains.12 These 4-alkyl- and 4-alkenyl-j,%lactarns were readily obtained through efficient chiral ester enolate - imine cyclocondensation in the same manner as reported previously from these laboratories. 1 t The couplings of 8-lactams
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`1
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`and 2 with 7,10-ditroc-DAB and ‘I-TES-baccatin Ill were carried out based on our protocolt2 using NaHMDS as the base followed by deprotection to give the corresponding 3’-alkyl- and 3’-alkenyl-3’-dephenyldocetaxels in good overall yields (Chart 1). 13 We also synthesized 3’-isobutenyl-3’- dephenylpaclitaxel (RAH-l)lo in a similar manner for comparison purpose. TIPSO,, o .p+ ““s’-’ ‘“Opp~~T~PSO..=< T~W!!~.+J ’ NyOBu’ o \OBu’ o NyOB~t o VBu’ o NyOBut la O lb 0 200 2b0 2c 0 Chart
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`1
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`Microtubule Disassembly Inhibitory Activity and Cytotoxicity of the 3’-Alkyl and 3’-Alkenyl
`Analogs.
`Biological activities of four 3’-alkyl and 3’alkenyl analogs of docetaxel were evaluated in three assay systems, i.e., inhibition of microtubule disassembly and cytotoxicity against murine P388 leukemia cell line as
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`3’-Alkyl- and 3’-alkenyl-3’-dephenyldocetaxels 2633 well as doxorubicin-resistant leukemia cell line (P388iDox) which is a MDR expressing cell line cross resistant to paclitaxel and docetaxel.14 Results are listed in Table l.l2 As Table 1 shows, the 3’-isobutyl analog
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`SB-T-
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`SB-T-1211
`1101
`possess excellent activities comparable to docetaxel. It is also obvious that the activity is very sensitive to the bulkiness of the 3’-substituents.
`Table 1. Microtubule Disassembly Inhibitory Activity and
`Cytotoxicity of
`3’-Alkyl and 3’-Alkenyl Analogs
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`*
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`ICso represents the concentration of an agent leading to 50% inhibition of the rate of microtubule disassembly. IC~u@aclitaxel) is the ICso value of paclitaxel in the same assay. In the same assay, the ICso of paclitaxel is 0.015 mM. h IQ0 represents the concentration that inhibits 50% of cell proliferation. The cytotoxicity of 3’-alkyl and 3’-alkenyl analogs of docetaxel and a 3’-alkenyl paclitaxel analog
`evaluated against human ovarian (A121), human non-small cell lung (A549). human colon (HT-29). and human breast (MCF7) cancer cell lines. In addition to these cell lines, the activity against an adriamycin-resistant human breast cancer cell line (MCF7-R) was also examined. Results are summarized in Table 2.13 As Table 2 shows, 3’-isobutenyl, 3’-crotyl, and 3’-isobutyl analogs, especially the 3’-isobutenyl and 3’-crotyl analogs,
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`were
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`T-1212
`T-1302
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`SB-T-1302,
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`RAIL1
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`SB-
`SB-T-1102, SB-T-1212, SB-
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`show one order of magnitude better activity than paclitaxel and docetaxel against MCP7-R. This finding may provide significant information for the development of newer antitumor agents effective against tumors expressing the MDR phenotype.
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`Table 2. Cytotoxicities (IC50 nM)a of 3’.Alkyl and 3’.Alkenyl Analogs
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`a See the footnote of Table 1. b MCF7-R = mammary carcinoma cells 180 fold resistant to adriamycin.
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`and the 3’-isobutenyl analog
`in vitro
`and
`exhibit excellent cytotoxicity. It is noteworthy that
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`2634 I.
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`OJIMA et al.
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`Antitumor Activity of the 3’-Alkyl and 3’-Alkenyl Analogs
`in vivo. The in vivo antitumor activity of
`SB-T-1101
`SB-T-1211
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`was evaluated against B16 melanoma in B6D2Fl mice. Taxoids (0.4 &mouse) were administered intra-venously (iv.) on days of $7, and 9 (see Ref. 9 for details). Results are as follows: SB-T-1101, T/C = 5% (20 mg/Kg/day), time for median tumor to reach 1,000 mg (days) = 26.03, log10 cell kill = 1.97; SB-T-1211, T/C = 8% (12.4 mg/Kg/day), time for median tumor to reach 1,000 mg (days) = 27.54, log10 cell kill = 2.25. The results clearly indicate that both analogs are very active in vivo, and their activities are equivalent to that of docetaxel in the same assay. Consequently, it appears that 3’-alkyl and 3’-alkenyl analogs of docetaxel and paclitaxel have opened a new avenue for the development of newer and potent taxoid antitumor agents.
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`Acknowledgments.
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`References
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`and Notes
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`1992.19.
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`This research was supported by grants from Rhone-Poulenc Rorer, the National Institutes of He&h (GM417980). the Center for Biotechnology at Stony Brook which is sponsored by the New York State Science & Technology Foundation, and the National Cancer Institute (CA13038). The authors would like to thank Dr. M.-C. Bissery, Dr. C. Combeau, Dr. J.-F. Riou, and Dr. P. Vrignard of Rhone-Poulenc Rorer for their excellent collaboration in bioassay. 1. 2. :* 5: 6. 7. 8. 9. 10. 11. 12. 13. 14.
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`646-662. Suffness,‘&l. In Annual ieodrts in M~dic&ziChemi&; J. A. Bristol, Ed.; Acade& Press: S& Diego, 1993; Vol. 28; pp Chapter 32.30.5-314. Kingston. D. G. I. Pharmac. Ther.
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`1991.52.
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`l-34 and references cited therein. Gu&rd,‘D.; GuCritte-Vogelein, F.; Potikr, P. Ace. Chem. Res. 1993,26, 160-167. Seidman, A. D. Stony Brook Symposium on Tax01 and TaxoGre, May 14-15, 1993, Stony Brook, M: Abstracts pp 14-16. Ravdin, P. M. Stony Brook Symposium on Tax01 and TaxoGre, May 14-15, 1993, Stony Brook, Ivr, Abstracts p 18. (a) Verweij, J.; Clavel, M.; Chevalier, B. Ann. Oncol. 1994,.5,495-505. (b) Sikic B. I. J. Clin. Oncol. 1993,11, 1629-1635. (c) Horwitz, S. B. Stony Brook Symposium on Tax01 and Taxodre, May 14-15, 1993, Stony Brook, NY, Abstracts pp 23-24. (a) Ojima, I.; Park, Y. H.; Sun, C. M.; Fenoglio, I.; Appendino, G.; Pera, P.; Bemacki, R. J. J. Med. Chem. 1994,37, 1408-1410. (b) Ojima, I.; Fenoglio, I.; Park, Y. H.; Pera, P.; Bemacki, R. J. Bioorg. Med. Chem. Len., 1994,4, 1571-1574. (c) Ojima, I.; Fenoglio, I.; Park, Y. H.; Sun, C. M.; Appendino, G.; Pera, P.; Bemacki, R. J. J. Org. Chem. 1994,59 , 5 15-5 17. Ojima, I.; Duclos, 0.; Zucco, M.; Bissery, M.-C.; Combeau, C.; Vrignaud, P.; Riou, J. F.; Lavelle, F. J. Med. Chem. 1994,37,2602-2608. The results were presented at the 207th American Chemical Society National Meeting, San Diego, March 13-17, 1994; Duclos, 0.; Zucco, M.; Ojima, I.; Bissery, M.-C.; Lavelle, F. Abstracts MEDI 86. At the same meeting, Professor Gunda I. Georg presented similar results on the cyclohexyl analogs of paclitaxel and docetaxel; Georg, G. I. Abstracts MEDI 146. For 2- (hexahydro)paclitaxel, see also Chen, S-H.; Farina, V.; Wei, J.-M.; Long, B.; Fairchild, C.; Mamber, S. W.; Kadow, J. F.; Vyas, D.; Doyle, T. W. Bioorg. Med. Chem. Lett. 1994,4, 479-482. (a) A recent patent claims that 3’-isobutenyl analog of paclitaxel
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`@AH-l
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`in this paper) shows excellent in vitro cytotoxicity: Holton, R. A.; Nadizadeh, H. U. S. Parent 1994, 5,284,864. (b) For 3’-alkyl-9- dihydro analogs of paclitaxel and docetaxel, see (b) Li, L.; Rbomas, S. A., Klein, L. L.; Yeung, C. M.; Maring, C. J.; Grampovnik, D. J.; Lartey, P. A.; Plattner, J. J. J. Med. Chem. 1994.37, 2655-2663. Ojima, I.; Park, Y. H.; Sun, C. M.; Zhao, M.; Brigaud, T. Tetrahedron Lett. 1992,33, 5739-5742. (a) Ojima, I.; Habus, I.; Zhao, M.; Zucco, M.; Park, Y. H.; Sun, C. M.; Brigaud, T. Tetrahedron 1992, 48,6985-7012. (b) Ojima, I.; Sun, C. M.; Zucco, M.; Park, Y. H.; Duclos, 0.; Kuduk, S. D. Tetrahedron Lett. 1993,34, 4149-4152. (c) Ojima, I.; Zucco, M.; Duclos, 0.; Kuduk, S. D.; Sun, C. M.; Park, Y. H. Bioorg. Med. Chem. L&t. 1993,3, 2479-2482. See also, e.g., Holton, R. A. Eur. Pat. Appl. EP 400,971, 1990; Georg, G. I.; Cheruvallath, Z. S. J. Med. Chem.
`4230-4237. A preliminary results were presented at the 208th American Chemical Society National Meeting, Washington, August 21-25. 1994. Duclos. 0.: Kuduk. S. D.: Sun. C. M.: Oiima. I.: Pera. P.: Veith. J. M.: Bemacki. R. J. 2bsrracts bDI57. d ’ ’ ’ Riou, J. F.; Naudin, A.; Favelle, F. Biochem. Biophys. Res. Commun. 1992, 187, 164-170. (Received in USA 7 September 1994; accepted 4 October 1994)
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`1992,35,
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`and
`Rowinskv. E. K.: Onetto. N.: Canetta. R. M.: Arbuck. S. G. Seminars in Oncolopv
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