~ Pergamon
`
`Bioorganic & Medicinal Chemistry Letters, Vol. 5, No.8, pp. 853-856, 1995
`Copyright © 1995 Elsevier Science Ltd
`Printed in Great Britain. All rights reserved
`0960-894X/95 $9.50+0.00
`
`0960-894X(95)00127-1
`
`DESIGN, SYNTHESIS, AND STRUCTURE-ACTIVITY
`RELATIONSHIPS OF
`2-SUBSTITUTED-2-AMIN0-1,3-PROPANEDIOLS: DISCOVERY OF
`A NOVEL IMMUNOSUPPRESSANT, FTY720.
`
`Kunitomo Adachi*, Toshiyuki Kohara, Noriyoshi Nakao, Masafumi Arita, Kenji Chiba,
`Tadashi Mishina, Shigeo Sasaki', and Tetsuro Fujita*b
`
`Research Laboratories, Yoshitomi Pharmaceutical Industries, Ltd., 7-25 Koyata 3-chome,
`Jruma-shi, Saitama 358, Japan
`• Research Laboratory, Taito Co., Ltd., 1-26 Higashi Shiriike-shinmachi, Nagata-ku, Kobe 653,
`Japan
`b Faculty of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-01, Japan
`
`Abstract: FTY720 (2-amino-2-(2-( 4-octylphenyl)ethyl]-1, 3-propanediol hydrochloride), a novel
`synthetic immunosuppressant led by modification of IS P-I (myriocin, thermozymocidin) displayed
`potent immunosuppressive activity both in vitro and in vivo.
`
`As reported in the preceding communication\ simplification of the structure of ISP-1 including
`removal of the side chain functionalities as well as elimination of chiral centers led to
`2-alkyl-2-amino-1,3-propanediols such as la-c (Figure 1). Some of them displayed more potent
`immunosuppressive activity than ciclosporin, which is currently used clinically. In addition to that,
`the toxicity of ISP-1 was reduced to a considerable extent although it was still insufficient. Here,
`we displaced a part of the alkyl chain of la-c with sterically equivalent 1,4-phenylene group in
`expectation of modifying their physicochemical, pharmacological, toxicological, or pharmaco(cid:173)
`kinetical property. In this communication, we descnbe the design, synthesis, and structure-activity
`relationships of thus modified compounds.
`
`Figure 1
`
`R=
`a: C14H29
`b: C1sH31
`c: c16H33
`
`>
`
`853
`
`APOTEX - EXHIBIT 1017
`
`

`

`854
`
`K. ADACin et al.
`
`Design: Each of 2-amino-1,3-propanediols (la-c) consists of both a hydrophilic part (amino
`alcohol) and a lipophilic part (hydrocarbon chain). The amphiphilicity should be one of the most
`important features of these compounds. The lipophilic side chain contains a number of rotatable
`bonds. The activity would be improved if conformation of the compound can be properly
`restricted. We planned to introduce a phenyl ring, which was considered an effective template for
`restricting the conformation of molecules2
`into the lipophilic side chain of 1 maintaining the total
`,
`amphiphilicity of the molecule. We chose 1a as a lead compound because la had proved less toxic
`than 1 b3
`• We prepared a series of compounds possessing a phenyl ring on a variety of positions
`within the side chain keeping the chain length constant (m+n=lO) (Figure 1).
`
`Synthesis: Compounds 2b-h 4 were synthesized by a similar route to that described in the
`preceding paper but (4-alkylphenyl)alkyl halides (3b-h: X=Br or I) were used instead of the
`simple alkyl bromides (Scheme 1). Compound 2a was prepared in a totally different way (Scheme
`2). 4-Decylbenzyl bromide ( 4) was nitrated with silver nitrate to give nitro compound, which was
`bishydroxymethylated using formalin and sodium hydroxide in ethanol5 followed by reduction with
`Raney-nickel to afford the desired compound 2a.
`
`Scheme 1. Synthesis of 2b-h.
`
`CfOOEt
`AcHN _LCOOEt
`
`1 ) ~ ~
`HO
`X, ---~b-h H2N
`NaH I DMF
`CnH2n+1
`or
`NaOEt I EtOH
`
`2) LlAIH4
`3) Ac2 0 I py
`4) aq. LIOH
`
`b: m=1, n=9
`c: m=2, n=B
`d: m=3, n=7
`e: m=4, n=6
`
`f: m=6, n=4
`g: m=B, n=2
`h: m=10,n=O
`
`Scheme 2. Synthesis of 2a.
`
`1) AgN0 2
`2) HCHO I NaOH
`
`3) H 2 I Raney-NI
`
`

`

`2-Substituted-2-amino-1 ,3-propanediols
`
`855
`
`Results and discussion: Compounds 2a-h were evaluated for their ability to inhibit mouse
`allogeneic MLR (IC50 ) in vitro (Table 1t.
`
`Table 1. Effect of 2a-h on mouse allogeneic MLR
`
`2b
`
`70
`
`2c
`
`6.1
`
`2d
`
`350
`
`2e
`
`19
`
`2f
`100
`
`2g
`
`32
`
`2h
`
`54
`
`2a
`IC50 (nM) 13
`-------------------------------------
`
`All the compounds displayed moderate to potent inhibitory activity. Compound 2c (FTY720)
`was most potent among them and demonstrated comparable activity to the lead compound la7
`(IC~= 5. 9nM). Moving the phenyl ring of 2c toward each direction by only one carbon
`(compounds 2b and 2d) resulted in a great loss in potency, suggesting that it is of critical
`importance for the potent activity where the phenyl ring is positioned within the side chain. Some
`"even-odd effect" was observed concerning the compounds 2a-2e. The compounds 2a, 2c, and
`2e, the number of whose methylene units between the aminopropanediol terminus and the phenyl
`ring is even, were much more potent than the others (2b and 2d: odd number).
`Compounds la and 2c were evaluated in rat skin allograft in combination with I.EW donor and
`F344 recipient in vivo (Figure 2t. FfY720 (2c) displayed remarkable immunosuppressive activity
`in vivo and prolonged rat skin allograft survival in a dose dependent manner. It was approximately
`3-fold more potent than la.
`
`Figure 2. Effect of 1a and 2c on rat skin allograft
`
`~r-------------------------------------------------~~------------------------------,
`•
`0.111181k8 (ip)
`•
`0.311181k8 (ip)
`•
`111181k8 (ip)
`fj2J
`311181k8 (ip)
`
`Vehicle
`
`la
`
`2c(FfY720)
`
`Compound 2c also displayed excellent immunosuppressive activity in other administration
`routes in vivo (mean survival time: 24.8days/0.1mg!kg, 46.3days/3mg!kg, and 53.5days/10mg!kg,
`iv; 19.3daystO.lmg!kg, 4l.Odays!.3mg!kg and 57.8days/.30mg!kg, po). Moreover, 2c was not
`toxic in the rat skin allograft up to a dose of lOmg!kg, iv, while compounds 1a and lb were
`toxiC' at a dose of 10 and 3mg!kg, iv, respectively. Our preliminary data show that the mechanism
`
`

`

`856
`
`K. ADACID et al.
`
`of action of 2c is different from that of ciclosporin and FK50610
`• Although 2c did not inhibit the
`•
`production of interleukin-2 unlike ciclosporin and FK506,
`it inhibited immune responces by
`selective depletion of mature T-cells probably caused by lymphocyte migration and apotosis (data
`not shown here12
`}.
`
`11
`
`Conclusion: We inco~porated a phenyl ring into the side chain of the lead compound la to
`obtain a novel immunosuppressant, FTY720 (2c), which displayed remarkable immuno(cid:173)
`suppressive activity both in vitro and in vivo as well as significant improvement in side effects.
`F1Y720 (2c) is expected as a powerful candidate for safer immunosuppressant13 for organ
`transplantations and for the treatment of autoimmune diseases.
`
`References and Notes:
`
`1. Fujita, T.; Yoneta, M.; Hirose, R.; Sasaki, S.; Inoue, K.; Kiuchi, M.; Hirase, S.; Adachi, K.;
`Arita, M.; Chiba, K. BioMed. Chern. Lett., preceding communication of this issue.
`2. Moore, G.J. TiPS. 1994, 15, 124.
`3. When intraperitoneally administrated in the rat skin allograft, lb displayed intenser local
`irritation than la.
`4. All new compounds in this communication gave satisfactory analytical and spectroscopic data
`in full accord with their assigned structures.
`5. Feuer, H.; Nielsen, A. T.; Colwell, C. E. Tetrahedron 1963, 19, Suppl. 1, 57.
`6. The effect of the compounds on mouse allogeneic MLR was examined by the method
`described in our previous paper: Fujita, T.; Inoue, K.; Yamamoto, S.; Ikumoto, T.; Sasaki,
`S.; Toyama, R.; Chiba, K.; Hoshino, Y.; Okumoto, T. J. Antibiotics 1994, 47, 208.
`7. We also prepared 2-amino-2-[2-( 4-nonylphenyl)ethyl]-1,3-propanediol (IC50=8.5nM)
`corresponding to lb. It exhibited a slight decrease in potency compared with lb (IC50=2.9
`nM).
`8. The effect of the compounds on rat skin allograft was examined by the method described in
`the preceding paper.
`9. The term "toxic" used here means that animals die at indicated doses.
`10. Mechanism of action: (a) Schreiber, S. L. Science 1991, 251, 283. (b) Liu, J.; Farmer,
`Jr.,J. D.; Lane, W. S.; Friedman, J.; Weissmann, 1.; Schreiber, S.L. Cell 1991, 66, 807.
`(c) Schreiber, S. L. Cell 1992, 70, 365.
`11. FK506: (a) Tanaka, H.; Kuroda, A.; Marusawa, H.; Hatanaka, H.; Kino, T.; Goto,T.;
`Hashimoto, M.; Taga, T. J. Am. Chem. Soc. 1987, 109, 5031. (b) Kino,T.; Hatanaka,
`H.; Hashimoto, M.; Nishiyama, M.; Goto, T.; Okuhara, M.; Kohsaka, M.; Aoki, H.;
`Imanaka, H. J. Antibiotics 1987, 40, 1249.
`12. Our study on mechanism of action of FTY720 (2c) will be reported in due course.
`13. Ciclosporin and FK506 possess several adverse effects such as nephrotoxicity and neuro(cid:173)
`toxicity: (a) The U.S. Multicenter FK506 liver study group, The New England Journal of
`Medicine 1994, 331, 1110. (b) Japanese FK506 Study Group, Transplantation Proceedings
`1993, 25, 649. (c) Japanese FK506 Study Group, Transplantation Proceedings 1991, 23,
`3071.
`
`(Received in Japan 20 February 1995; accepted 6 March 1995)
`
`