PCT
`
`WORLD INTELLECTUAL PROPERTY ORGANIZATION
`International Bureau
`
`
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`WO 97/25988
`
`(11) International Publication Number:
`
`(51) International Patent Classification 6 :
`
`A61K 31/495, 31/445
`
`(43) International Publication Date:
`
`24 July 1997 (24.o7.97)
`
`(21) International Application Number:
`
`PCT/US97/00788
`
`(22) International Filing Date:
`
`17 January 1997 (17.0l.97)
`
`(30) Priority Data:
`60/010,133
`
`17 January 1996 (I7.0I.96)
`
`US
`
`(71) Applicant (for all designated States except US): ELI LILLY
`AND COMPANY [US/US]; Lilly Corporate Center, Indi-
`anapolis, IN 46285 (US).
`
`(72) Inventors; and
`IYENGAR, Smriti
`(75) Inventors/Applicants (for US only):
`[IN/US];
`I507 Redwood Drive, Carmel, IN 46032 (US).
`PI-IEBUS, Lee, A.
`[US/US];
`I744 West 1000 North,
`Fountaintown,
`IN 4130 (US). SHANNON, Harlan, E.
`[US/US]; 4229 Rolling Springs Drive, Carmel, IN 46234
`(US).
`
`(74) Agents: GAYLO, Paul, J. et al.; Eli Lilly and Company, Lilly
`Corporate Center, Indianapolis, IN 46285 (US).
`
`(81) Designated States: AL, AM, AT, AU, AZ, BA, BB, BG, BR,
`BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE,
`I-IU, IL, IS, JP, KE, KG. KP, KR, [(2, L ,LK, LR, LS, LU,
`LV, MD. MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO,
`RU, SD, SE, SG. SI, SK, TJ. TM, TR, Tl", UA, UG, US,
`UZ, ARIPO patent (KE, LS, MW, SD, SZ, UG), Eurasian
`patent (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), European
`patent (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT,
`LU, MC, NL, PT, SE), OAPI patent (BF, BJ, CF, CG, CI,
`CM, GA, GN, ML, MR, NE, SN, TD, TG).
`
`Published
`With international search report.
`Before the expiration of the time limit for amending the
`claims and to be republished in the event of the receipt of
`amendments.
`
`(54) Title: METHODS OF TREA'I'ING OR PREVENTING PAIN OR NOCICEPTION
`
`(57) Abstract
`
`This invention provides
`methods
`for
`the
`treatment
`or
`prevention
`of
`pain
`or
`nociception
`in
`a mammal
`which comprise administering
`to a mammal
`in need thereof
`an
`effective
`amount
`of
`a
`compound
`of
`fonnula
`(I), where R‘
`and R2 are
`independently selected from
`the
`group
`consisting
`of
`hydrogen, methyl, methoxy,
`chloro,
`and trifiuoromethyl,
`with
`the
`proviso
`that
`no
`more
`than one of R‘
`and
`R2 can be hydrogen;
`and
`Y is
`formula (II), N—R“, or
`CH—NR"R°, where R“, R”, and
`R0 are independently selected
`from the group consisting of
`hydrogen and C1-C5 alkyl; or
`a pharmaceutically acceptable
`salt or
`solvate
`thereof,
`in
`combination with an analgesic
`whose primary mechanism of
`action is not as a tachykinin
`receptor antagonist. This invention also provides pharmaceutical formulations comprising a compound of formula (I) in combination with
`a traditional analgesic, in combination with one or more pharmaoeutically acceptable carriers, diluents, or excipients therefor.
`
`   
`


`
`Lannett Holdings, Inc. LAN 1009
`
`
`
`

`
`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the PCT on the front pages of pamphlets publishing international
`applications under the PCT.
`Armenia
`Austria
`Australia
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`Cole d’lvoire
`Cameroon
`China
`Czechoslovakia
`Czech Republic
`Gcnnany
`Denmark
`Estonia
`Spain
`Finland
`France
`Gabon
`
`United Kingdom
`Georgia
`Guinea
`Greece
`Hungary
`Ireland
`Italy
`Japan
`Kenya
`Kyrgystan
`Democratic People's Republic
`of Korea
`Republic of Korea
`Kazalchstan
`Liechtenstein
`Sri Lanka
`Liberia
`Lithuania
`Luxembourg
`Latvia
`Monaco
`Republic of Moldova
`Madagascar
`Mali
`Mongolia
`Mauritania
`
`Malawi
`Mexico
`Niger
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Singapore
`Slovenia
`Slovakia
`Senegal
`Swaziland
`Chad
`Togo
`Tajikistan
`Trinidad and Tobago
`Ukraine
`Uganda
`United States of America
`Uzbekistan
`Viet Nam
`
`AM
`A1‘
`AU
`BB
`BE
`BF
`BC
`BJ
`BR
`BY
`CA
`CF
`CG
`CH
`CI
`CM
`CN
`CS
`CZ
`DE
`DK
`EE
`ES
`FI
`FR
`GA
`
`
`
`

`
`WO 97/25988
`
`PCTIUS97/00788
`
`-1-
`
`Iifls:
`
`METHODS OF TREATIN OR PREVENTING
`
`PAIN OR NOCICEPTION
`
`
`
`Tachykinins are a family of peptides which share a
`
`common amidated carboxy terminal sequence. Substance P was the
`
`first peptide of this family to be isolated, although its purification and the
`
`determination of its primary sequence did not occur until the early
`
`1970's.
`
`Between 1983 and 1984 several groups reported the isolation
`
`of two novel mammalian tachykinins, now termed neurokinin A (also
`
`known as substance K, neuromedin L, and neurokinin on), and
`
`neurokinin B (also known as neuromedin K and neurokinin B). Sgg, J.E.
`
`Maggie, Egp_tj_dga, 6 (Supplement 3):237-243 (1985) for a review of these
`
`discoveries.
`
`Tachykinins are widely distributed in both the central and
`
`peripheral nervous systems, are released from nerves, and exert a
`
`variety of biological actions, which, in most cases, depend upon
`
`activation of specific receptors expressed on the membrane of target
`
`cells. Tachykinins are also produced by a number of non-neural tissues.
`
`

`
`WO 97/25988
`
`PCT/US97/00788
`
`-2.
`
`The mammalian tachykinins substance P, neurokinin A,
`
`and neurokinin B act through three major receptor subtypes, denoted as
`NK-1, NK-2, and NK—3, respectively. These receptors are present in a
`
`variety of organs.
`
`Substance P is believed in1;_er_a1ia to be involved in the
`
`neurotransmission of pain sensations, including the pain associated
`
`with migraine headaches and with arthritis. These peptides have also
`
`been implicated in gastrointestinal disorders and diseases of the
`
`gastrointestinal tract such as inflammatory bowel disease. Tachykinins
`
`have also been implicated as playing a role in numerous other maladies,
`
`as discussed infra.
`
`Tachykinins play a major role in mediating the sensation
`
`and transmission of pain or nociception, especially migraine
`
`headaches.
`
`s_ee,__e,,g,, S.L. Shepheard, gt_a,L, gj
`
` , 108:11-20 (1993); S.M. Moussaoui, et_aL, E;;1'_o_p_e_an
`
` 2382421424 (1993); and W.S. Lee, _eLal__, Efifiah
`
` 112:920-924 (1994).
`
`In view of the wide number of clinical maladies associated
`
`with an excess of tachyldnins, the development of tachykinin receptor
`
`antagonists will serve to control these clinical conditions. The earliest
`
`tachykinin receptor antagonists were peptide derivatives. These
`
`antagonists proved to be of limited pharmaceutical utility because of
`
`their metabolic instability.
`
`Recent publications have described novel classes of non-
`
`peptidyl tachykinin receptor antagonists which generally have greater
`oral bioavailability and metabolic stability than the earlier classes of
`
`tachykinin receptor antagonists. Examples of such newer non-peptidyl
`
`tachykinin receptor antagonists are found in United States Patent
`
`5,328,927, issued July 12, 1994; United States Patent 5,360,820, issued
`
`November 1, 1994; United States Patent 5,344,830, issued September 6,
`
`1994; United States Patent 5,331,089, issued July 19, 1994; European
`
`Patent Publication 591,040 A1, published April 6, 1994; Patent
`
`Cooperation Treaty publication WO 94/01402, published January 20, 1994;
`Patent Cooperation Treaty publication WO 94/04494, published March 3,
`
`1994; and Patent Cooperation Treaty publication W0 93/011609, published
`
`January 21, 1993.
`
`

`
`wo 97/25988
`
`PCT/US97/00788
`
`-3-
`
`Because of the current dissatisfaction of the currently
`
`marketed treatments for pain or nociception within the affected
`
`population, there exists a need for a more eflicacious and safe
`treatment.
`
`I
`
`in
`
`This invention provides methods for the treatment or
`
`prevention of pain or nociception in a mammal which comprise
`
`administering to a mammal in need thereof an effective amount of a
`
`compound of Formula I
`
`
`
`where R1 and R2 are independently selected from the group
`consisting of hydrogen, methyl, methoxy, chloro, and trifluoromethyl,
`with the proviso that no more than one of R1 and R2 can be hydrogen;
`and
`
`Yis
`
`

`
`wo 97/259ss
`
`PCT/US97/00788
`
`-4-
`
`N-R3, or CH-NRbR°,
`
`where R3, Rb, and R“ are independently
`
`selected from the group consisting of hydrogen
`
`and C1-C5 alkyl;
`
`or a pharmaceutically acceptable salt or solvate thereof, in combination
`
`with another analgesic whose primary mechanism of action is not as a
`
`tachykinin receptor antagonist.
`
`D
`
`.1“:
`
`.|.
`
`igrf
`
`1E1 1.
`
`The terms and abbreviations used in the instant examples
`
`have their normal meanings unless otherwise designated. For example
`
`"°C" refers to degrees Celsius; "N" refers to normal or normality; "mol"
`
`refers to mole or moles; "mmol" refers to millimole or millimoles; "g"
`
`refers to gram or grams; "kg" refers to kilogram or kilograms; "L"
`
`refers to liter or liters; "ml" means milliliter or milliliters; "M" refers to
`
`molar or molarity; "MS" refers to mass spectrometry; and "NMR" refers
`
`to nuclear magnetic resonance spectroscopy.
`
`As used herein, the term "C 1-C5 alkyl" refers to straight or
`
`branched, monovalent, saturated aliphatic chains of 1 to 6 carbon atoms
`
`and includes, but is not limited to, methyl, ethyl, propyl, isopropyl, butyl,
`
`isobutyl, t-butyl, pentyl, isopentyl, and hexyl. The term "C 1-C3 alkyl"
`
`includes within its definition the term
`
`"C1-C3 alkyl".
`
`"Halo" represents chloro, fluoro, bromo or iodo.
`
`The term "haloformate" as used herein refers to an ester of
`
`a haloformic acid, this compound having the formula
`
`x—c
`
`\o— Rd
`
`wherein X is halo, and Rd is C1-C3 alkyl. Preferred haloformates are
`
`bromoformates and chloroformates. Especially preferred are
`
`

`
`W0 97/25988
`
`PCTTUS97/00788
`
`-5-
`
`chloroformates. Those haloformates wherein Rd is C3-C6 alkyl are
`
`especially preferred. Most preferred is isobutylchloroformate.
`The compounds prepared in the processes of the present
`invention have an asymmetric center. As a consequence of this chiral
`
`center, the compounds produced in the present invention may occur as
`
`racemates, mixtures of enantiomers and as individual enantiomers, as
`well as diastereomers and mixtures of diastereomers. Processes for
`
`preparing such asymmetric forms, individual isomers and
`
`combinations thereof, are within the scope of the present invention.
`
`The terms "R" and "S" are used herein as commonly used
`in organic chemistry to denote specific configuration of a chiral center.
`
`The term "R" (rectus) refers to that configuration of a chiral center with
`
`a clockwise relationship of group priorities (highest to second lowest)
`
`when viewed along the bond toward the lowest priority group. The term
`"S" (sinister) refers to that configuration of a chiral center with a
`
`counterclockwise relationship of group priorities (highest to second
`
`lowest) when viewed along the bond toward the lowest priority group.
`The priority of groups is based upon their atomic number (in order of
`
`decreasing atomic number). A partial list of priorities and a discussion
`
`of stereochemistry is contained in NOMENCLATURE OF ORGANIC
`
`COMPOUNDS: PRINCIPLES AND PRACTICE, (J .H. Fletcher, gL_a1,, eds.,
`1974) at pages 103-120.
`
`In addition to the (R)—(S) system, the older D-L system is also
`used in this document to denote absolute configuration, especially with
`reference to amino acids.
`In this system a Fischer projection formula is
`oriented so that the number 1 carbon of the main chain is at the top. The
`prefix "D" is used to represent the absolute configuration of the isomer
`in which the functional (determining) group is on the right side of the
`carbon atom at the chiral center and "L'-', that of the isomer in which it
`is on the left.
`
`Patent Cooperation Treaty Publication W0 95/140 17,
`published May 26, 1995, teaches, int_er__alj,a, a series of tachykinin
`receptor antagonists of Formula II
`
`

`
`WO 97/25988
`
`PCT/US97I00788
`
`wherein:
`
`m and n are independently O-6;
`
`Z is -(CHR4)p-(CHR5)q-, where,
`
`p is 0 or 1;
`
`qis0or 1; and
`
`R4 and R6 are independently selected from the
`
`group consisting of hydrogen and C1-C3 alkyl;
`
`Yis
`
`N ’ l
`
`N0 ,
`
`CH—N\r———> MO
`
`I
`
`I
`
`N-RH, or CH-NRbR°,
`
`where R8, Rb, and R“ are independently
`
`selected from the group consisting of hydrogen
`
`and C1-C5 alkyl; and
`
`
`
`

`
`W0 97/25988
`
`PCT/US97/00788
`
`-7-
`
`R1 and R2 are independently hydrogen, halo, C1-C3
`
`alkoxy, C1-C5 alkylthio, nitro, trifluoromethyl, or C1-
`
`C5 alkyl;
`
`or a pharmaceutically acceptable salt or solvate thereof.
`
`These compounds have been shown to be very active, specific tachykinin
`
`receptor antagonists. Particularly preferred compounds are those of
`
`Formula II in which 111 and n are both 1; R1 and R2 are independently
`hydrogen, methoxy, ethoxy, chloro, fluoro, trifluoromethyl, methyl, and
`
`ethyl; Z is methylene; and Y, when combined with the heterocyclic
`
`group to which it is attached, forms 4-(piperidin-1-yl)piperidin-1-yl, 4-
`
`(cyclohexyl)piperazin-1-yl, 4-(pheny1)piperazin-1-yl, or 4-
`
`(phenyl)piperidin-1-yl.
`
`Especially preferred is the compound (R)-3-(1H-indol-3-yl)-1-
`
`[N-(2-methoxybenzyl)acetylamino]-2-[N-(2-(4-(piperidin-1-yl)piperidin-1-
`y1)acetyl)amino]propane and the pharmaceutically acceptable salts and
`
`solvates thereof. Most especially preferred is the compound (R)-3-( 1H-
`
`indol-3-yl)-1-[N-(2-methoxybenzyl)acetylamino]-2-[N-(2-(4-(piperidin-1-
`yl)piperidin-1-yl)acetyl)amino]propane dihydrochloride trihydrate.
`
`The most preferred method of synthesizing this compound
`is depicted in Scheme I, infira. Many of the steps of this synthesis are
`
`described in Patent Cooperation Treaty Publication WO 95/14017,
`
`published May 26, 1995, and European Patent Application Publication
`
`693,489, to be published January 24, 1996.
`
`
`
`

`
`wo 97/25983
`
`PCT/US97/00788
`
`cri tyl chloride
`
`N—Me-morpholine
`01.; -———-—:-—>
`
`
`+
`
`OCH3
`
`"'?"_"
`
`(b)
`
`\
`
`N
`
`1%}! N/\£:
`
`O
`
`0:333
`
`Cm%m©—»
`NH
`Tr
`
`OCI-I3
`
`\ W:
`IYH
`Tr
`
`E
`
`OCH3
`
`OCH3
`
`VG-—» \
`
`.
`
`qgr
`
`H
`
`ACQO
`
`11:}
`
`N
`
`>=o
`
`CH3
`
`:
`
`1?};
`Tr
`
`OCH3
`
`N\
`
`H
`
`.
`
`N
`
`fin; 3:0
`
`3
`
`OCH3
`
`‘
`
`(e) N _,
`
`CH3
`
`EH
`r
`
`IT
`
`fl
`
`wherein “Tr” refers to a trityl group, and “NMM” refers to N-
`
`methylmorpholine.
`
`
`
`

`
`WO 97/25933
`
`PCT/US97/00788
`
`\
`
`5H2 >0
`
`OCH3
`
`oxalic acid
`
`E1
`
`0
`
`CH3
`
`N
`
`N/"fir’O +K
`O
`
`N
`
`-oxalate
`
`{D
`
`(f)
`
`(9)
`
`OCH3
`
`OCH 3
`
`.
`
`N
`
`,
`
`“fjfij
`CHW‘QQ CUMH1?
`H
`k0 CH3
`E;
`?O CH3
`<3
`N
`'2 HCl
`C)
`<N >
`
`—————>
`voxalate
`
`HC1, H20
`
`-31-I20
`
`

`
`WO 97125988
`
`PCT/US97l00788
`
`-10-
`
`Synthesis of (R)-2-[N-(2-((4-cyclohexyl)piperazin-1-yl)acetyl)amino]-3-(1H-
`
`indol~3-y1)- 1-[N-(2-methoxybenzyl)acetylamino]propane
`
`OCH3
`
`
`
`(a) Preparation of (R)-3—(1H-indol—3—y1)-2-(N-
`
`tripheny1methylamino)propanoic acid [N-trityltryptophan]
`
`Tritylation
`
`<
`
`O
`
`? 1 I
`/ l
`‘EH2
`
`N
`if
`
`OH
`
`-4-?»
`
`/ l
`
`N
`g
`
`O
`
`é
`EH
`
`OH
`
`'
`C r i ty 1
`
`Chlorotrimethylsilane (70.0 ml, 0.527 mol) was added at a
`
`moderate rate to a stirred slurry of D-tryptophan (100.0 g, 0.490 mol) in
`
`anhydrous methylene chloride (800 ml) under a nitrogen atmosphere.
`
`This mixture was continuously stirred for 4.25 hours. Triethylamine
`
`(147.0 ml, 1.055 mol) was added, followed by the addition of a solution of
`
`triphenylmethyl chloride (147.0 g, 0.552'mol) in methylene chloride (400
`
`ml) using an addition funnel. The mixture was stirred at room
`
`temperature, under a nitrogen atmosphere for at least 20 hours. The
`
`reaction was quenched by the addition of methanol (500 ml).
`
`The solution was concentrated on a rotary evaporator to
`
`near dryness and the mixture was redissolved in methylene chloride
`
`and ethyl acetate. An aqueous work—up involving a 5% citric acid
`
`

`
`WO 97/25988
`
`PCT/US97/00788
`
`-11-
`
`solution (2X) and brine (2X) was then performed. The organic layer was
`
`dried over anhydrous sodium sulfate, filtered, and concentrated to
`
`dryness on a rotary evaporator. The solid was dissolved in hot diethyl
`ether followed by the addition of hexanes to promote crystallization. By
`this process 173.6 g (0.389 mol) of analytically pure (R)-3-(1H-indol-3-yl)-
`2-(N-triphenylmethylamino)propanoic acid was isolated as a white solid
`
`in two crops giving a total of 79% yield.
`
`FDMS 446 (M“').
`1H NMR (DMSO-d5) 5 2.70 (m, 1H), 2.83 (m, 2H), 3.35 (m, 1H), 6.92-7.20
`
`(m, 12H), 7.30-7.41 (In, 8H), 10.83 (s, 1H), 11.73 (br s, 1H).
`Analysis for C3oH25N2O2:
`
`Theory:
`
`C, 80.69; H, 5.87; N, 6.27.
`
`Found:
`
`C, 80.47; H, 5.92; N, 6.10.
`
`(b) Preparation of (R)-3-(1H-indol-3-yl)-N-(2-methoxybenzyl)-
`2-(N-triphenylmethylamino)propanamide
`
`Coupling
`
`-Z
`1.1
`
`O
`
`—%||u.
`
`oH—————-—-—>
`
`trityl
`
`Z
`
`
`
`/‘\x,\,i,.
`
`31
`
`-2
`
`To a stirred solution of (R)-3-(1H-indol-3-yl)-2-(N-
`triphenylmethylamino)propanoic acid (179.8 g, 0.403 mol), 2-
`methoxybenzylamine (56.0 ml, 0.429 mol), and hydroxybenzotriazole
`hydrate (57.97 g, 0.429 mol) in anhydrous tetrahydrofuran (1.7 L) and
`anhydrous N,N-dimethylformamide (500 ml) under a nitrogen
`atmosphere at 0°C, were added triethylamine (60.0 ml, 0.430 mol) and 1-
`(3-dimethylaminopropyl)-3-ethoxycarbodiimide hydrochloride (82.25 g,
`0.429 mol). The mixture was allowed to warm to room temperature
`under a nitrogen atmosphere for at least 20 hours. The mixture was
`concentrated on a rotary evaporator and then redissolved in methylene .
`chloride and an aqueous work-up of 5% citric acid solution (ZX),
`saturated sodium bicarbonate solution (2X), and brine (2X) was
`
`

`
`WO 97/25988
`
`PCT/US97/00788
`
`-12-
`
`performed. The organic layer was dried over anhydrous sodium sulfate
`
`and concentrated to dryness on a rotary evaporator. The desired product
`
`was then recrystallized from hot ethyl acetate to yield 215.8 g (0.381 mol,
`
`95%) of analytically pure material.
`
`FDMS 565 (M+).
`
`1H NMR (CDC13) 5 2.19 (dd, J=6.4 Hz, Au=14.4 Hz, 1H), 2.64 (d, J=6.5 Hz,
`
`1H), 3.19 (dd, J=4.3 Hz, A1)=14.4 Hz, 1H), 3.49 (m, 1H), 3.63 (S, 3H), 3.99
`
`(dd, J=5.4 Hz, A1)=14.2 Hz, 1H), 4.25 (dd, J:7 .1 Hz, Au=14.2 Hz, 1H), 6.64
`
`(d, J=2.1 Hz, 1H), 6.80 (d, J=8.2 Hz, 1H), 6.91 (t, J=7.4 Hz, 1H), 7.06-7.38
`
`(m, 21 H), 7.49 (d, J=7.9 Hz, 1H), 7.75 (S, 1H),
`Analysis for C33H35N3O2:
`
`Theory:
`
`C, 80.68; H, 6.24; N, 7.43.
`
`Found:
`
`C, 80.65; H, 6.46; N, 7.50.
`
`(c) Preparation of (R)-3-(1H-indol-3-yl)- 1-[N-(2-
`
`methoxybenzyl )amino]-2-(N-triphenylmethylamino )propane
`
`Reduct1onofCarbonyl
`
`0
`
`1*
`,=m
`tlrityl
`
`R1
`
`|\:]
`
`R2
`
`\
`
`:
`
`
`
`H
`13,,
`I
`trityl
`
`ll
`
`R1
`
`|\]
`R2
`
`RED-AL®- [a 3.4 M, solution of sodium bis(2-
`
`methoxyethoxy)a.luminum hydride in toluene] (535 ml, 1.819 mol),
`
`dissolved in anhydrous tetrahydrofuran (400 ml) was slowly added using
`
`an addition funnel to a refluidng solution of the acylation product, (R)-3-
`
`( 1H-indol-3-yl)-N—(2-methoxybenzy1)-2-(N-
`
`triphenylmethylamino)propanamide (228.6 g, 0.404 mols) produced
`
`supra, in anhydrous tetrahydrofuran (1.0 L) under a nitrogen
`
`atmosphere. The reaction mixture became a purple solution. The
`
`reaction was quenched after at least 20 hours by the slow addition of
`
`excess saturated Rochelle's salt solution (potassium sodium tartrate
`
`tetrahydrate). The organic layer was isolated, washed with brine (2X),
`
`dried over anhydrous sodium sulfate, filtered, and concentrated to an oil
`
`

`
`wo 97/25988
`
`PCT/US97/00788
`
`-13.
`
`on a rotary evaporator. No further purification was done and the
`
`product was used directly in the next step.
`
`(d) Preparation of (R)-3-(1H-indol-3—yl)-1-[N-(2-
`
`methoxybenzyl)-acetylamino]-2-(N-triphenylmethylamino)propane
`
`AcylationofSecondaryAmine
`
`< 2/“ ]
`
`ii
`
`N
`
`/
`
`i
`
`$3
`
`trityl
`
`1
`
`R2
`
`,
`
`E
`
`\ M }o I
`
`:
`
`N
`
`3
`I
`trityl
`
`R1
`/
`
`\3
`
`R2
`
`To a stirring solution of (R)-3-(1H-indol-3-yl)-1-[N-(2-
`
`methoxybenzyl)amino]-2-(N-triphenylmethylamino)propane (0.404 mol)
`
`in anhydrous tetrahydrofuran (1.2 L) under a nitrogen atmosphere at
`
`0°C was added triethylamine (66.5 ml, 0.477 mol) and acetic anhydride
`(45.0 ml, 0.477 mol). After 4 hours, the mixture was concentrated on a
`
`rotary evaporator, redissolved in methylene chloride and ethyl acetate,
`
`washed with water (2X) and brine (2X), dried over anhydrous sodium
`
`sulfate, filtered, and concentrated to a solid on a rotary evaporator. The
`
`resulting solid was dissolved in chloroform and loaded onto silica gel 60
`(230-400 mesh) and eluted with a 1:1 mixture of ethyl acetate and
`
`hexanes. The product was then crystallized from an ethyl
`
`acetate/hexanes mixture. The resulting product of (R)-3-(1H-indol-3-yl)-
`1-[N-(2-methoxybenzyl)acetylamino]-2-(N-
`
`triphenylmethylamino)propane was crystallized and isolated over three
`
`crops giving 208.97 grams (87% yield) of analytically pure material.
`Analysis for C4oH39N3O2:
`
`Theory:
`
`C, 80.91; H, 6.62; N, 7.08.
`
`Found:
`
`C, 81.00; H, 6.69; N, 6.94.
`
`(e) Preparation of (R)-2-amino-3-( 1H-indo1-3-yl)-1-[N-(2-
`methoxybenzyl)acetylamino]propane
`
`Depmtection
`
`
`
`

`
`WO 97/25988
`
`PCT/US97/00788
`
`-14-
`
`N\
`
`H
`
`_
`
`N
`
`trityl
`
`R1
`
`/
`
`R
`
`/Nx
`
`i;
`
`=
`
`NM 1
`
`R1
`
`\,]2
`
`R
`
`Formic acid (9.0 ml, 238.540 mmol) was added to a stirring
`
`solution of (R)-3-(1H-indol-3-yl)-1-[N-(2-methoxybenzyl)acetylamino]-2-
`
`(N-triphenylmethylamino)propane (14.11 g, 23.763 mmol) in anhydrous
`
`methylene chloride under a nitrogen atmosphere at 0°C. After 4 hours,
`
`the reaction mixture was concentrated to an oil on a rotary evaporator
`
`and redissolved in diethyl ether and 1.0 N hydrochloric acid. The
`
`aqueous layer was washed twice with diethyl ether and basified with
`
`sodium hydroxide to a pH greater than 12. The product was extracted
`
`out with methylene chloride (4X). The organic extracts were combined,
`
`dried over anhydrous sodium sulfate, filtered, and concentrated on a
`
`rotary evaporator to a white foam. The compound (R)-2—amino-3-( 1H-
`
`indol-3-y1)-1-[N-(2-methoxybenzyl)acetylamino]propane (7.52 g, 21.397
`
`mmols) was isolated giving a 90% yield. No further purification was
`
`necessary.
`
`(f) Preparation of (R)-2-amino-3-(1H-indol-3-y1)-1-[N-(2-
`
`methoxybenzyl)acety1amino]propane dihydrochloride
`
`3 1?HH3C% R2
`
`R‘
`
`/
`
`i
`
`R1
`/‘
`
`5
`
`N
`
`§H;H3C R2
`
`_2 RC1
`
`3
`
`N
`
`.
`cr-tyl
`
`NH
`
`A stirring solution of (R)-3-('1H-indo1-3-yl)-1-[N-(2-
`
`methoxybenzyl)acetylamino]-2-(N-triphenylmethylamino)propane in two
`
`volumes of methylene chloride was cooled to between -40°C and -50°C.
`
`Anhydrous hydrogen chloride gas was added at such a rate that the
`
`temperature of the reaction mixture did not exceed 0°C. The reaction
`
`mixture was stirred for 30 minutes to one hour at 0-10°C.
`
`

`
`wo 97/25988
`
`PCT/US97/00788
`
`-15-
`
`To this reaction mixture was added two volumes of methyl
`t~butyl ether and the resulting mixture was allowed to stir for 30
`
`minutes to one hour at 0-10°C. The resulting crystalline solid was
`
`removed by filtration and then washed with methyl t-butyl ether. The
`
`reaction product was dried under vacuum at 50°C. (Yield >98%)
`Analysis for C21H25N3O2 ° 2 HC1:
`
`Theory:
`
`C, 59.44; H, 6.41; N, 9.90.
`
`Found:
`
`C, 60.40; H, 6.60; N, 9.99.
`
`(g) Preparation of 2-((4-cyclohexyl)piperazin-1-y1)acetic acid
`potassium salt hydrate
`
`Cyclohexylpiperazine (10.0 g, 0.059 mol) was added to ten
`
`volumes of methylene chloride at room temperature. To this mixture
`
`was added sodium hydroxide (36 ml of a 2N solution, 0.072 mol) and
`
`tetrabutylammonium bromide (1.3 g, 0.004 mol). After the addition of
`
`the sodium hydroxide and tetrabutylammonium bromide, methyl
`bromoacetate (7.0 ml, 0.073 mol) was added and the reaction mixture
`
`was stirred for four to six hours. The progress of the reaction was
`
`monitored by gas chromatography.
`
`The organic fraction was separated and the aqueous phase
`was back-extracted with methylene chloride. The organic phases were
`combined and washed twice with deionized water, once with saturated
`sodium bicarbonate solution, and then with brine. The organic phase
`was dried over magnesium sulfate and the solvents were removed in
`
`vacuo to yield methyl 2-((4-cyclohexyl)piperazin-1-yl)acetate as a
`yellowish oil.
`
`The title compound was prepared by dissolving the methyl
`2-((4-cyclohexyl)piperazin~1-yl)acetate (10.0 g, 0.042 mol) in ten volumes
`of diethyl ether. This solution was cooled to 15°C and then potassium
`trimethylsilanoate (5.9 g, 0.044) was added. This mixture was then
`stirred for four to six hours. The reaction product was removed by
`filtration, washed twice with five volumes of diethyl ether, then washed
`twice with five volumes of hexanes, and then dried in a vacuum oven for
`12-24 hours at 50°C.
`
`Analysis for C12H21KN202 ' 1.5 H20:
`
`

`
`W0 97/25988
`
`PCT/US97/00788
`
`-13-
`
`Theory:
`
`C, 49.63; H, 7.98; N, 9.65.
`
`Found:
`
`C, 49.54; H, 7.72; N, 9.11.
`
`(h) Preparation of (R)-2-[N-(2-((4-cyclohexyl)piperazin—1-
`
`yl)acetyl)amino]-3-( 1H-indol-3-yl)-1-[N-(2-
`
`methoxybenzyl)acetylamino]propane
`
`The title compound was prepared by first cooling 2-((4-
`
`cyclohexyl)piperazin-1-yl)acetic acid potassium salt to a temperature
`
`between -8°C and -15°C in 5 volumes of anhydrous methylene chloride.
`
`To this mixture was added isobutylchloroformate at a rate such that the
`
`temperature did not exceed -8°C. The resulting reaction mixture was
`
`stirred for about 1 hour, the temperature being maintained between -8°C
`
`and -15°C.
`
`To this mixture was then added (R)-2-amino-3-(1H-indol-3-
`
`yl)-1-[N-(2-methoxybenzyl)acetylamino]propane dihydrochloride at such
`
`a rate that the temperature did not exceed 0°C. Next added to this
`
`mixture was N-methyl morpholine at a rate such that the temperature
`
`did not exceed 0°C. This mixture was then stirred for about 1 hour at a
`
`temperature between -15°C and -8°C.
`
`The reaction was quenched by the addition of 5 volumes of
`
`water. The organic layer was washed once with a saturated sodium
`
`bicarbonate solution. The organic phase was then dried over anhydrous
`
`potassium carbonate and filtered to remove the drying agent. To the
`
`filtrate was then added 2 equivalents of concentrated hydrochloric acid,
`
`followed by 1 volume of isopropyl alcohol. The methylene chloride was
`
`then exchanged with isopropyl alcohol under vacuum by distillation.
`
`The final volume of isopropyl alcohol was then concentrated
`
`to three volumes by vacuum. The reaction mixture was cooled to 20°C to
`
`25°C and the product was allowed to crystallize for at least one hour.
`
`The desired product was then recovered by filtration and washed with
`
`sufficient isopropyl alcohol to give a colorless filtrate. The crystal cake
`
`was then dried under vacuum at 50°C. MS 560 (M+1*).
`
`1H NMR (CDCI3) 8 1.09-1.28 (m, 5H), 1.64 (d, J=10 Hz, 1H), 1.80-1.89 (m,
`
`4H), 2.10 (s, 3H), 2.24-2.52 (m, 9H), 2.90 (s, 2H), 2.95 (d, J=7 Hz, 1H), 3.02
`
`(d, J=7 Hz, 1H), 3.12 (dd, J:5, 14 Hz, 1H), 3.77 (s, 3H), 4.01 (dd, J=10, 14
`
`
`
`

`
`W0 9705988
`
`PCTIUS97/00788
`
`-17-
`
`Hz, 1H), 4.49 (ABq, J=17 Hz, 43 Hz, 2H), 4.56 (m, 1H), 6.79-6.87 (m, 3H),
`
`7.05-7.24 (m, 4H), 7.34-7.41 (In, 2H), 7.67 (d, J=8 Hz, 1H), 8.22 (s, 1H).
`Analysis for C33H45N5O3:
`‘
`
`Theory:
`
`C, 70.81; H, 8.10; N, 12.51.
`
`Found:
`
`C, 70.71; H, 8.21; N, 12.42.
`
`Synthesis of (R)-3-(1H-indol-3-y1)-1-[N-(2-methoxybenzy1)acety1amino]-2-
`[N-(2-(4-(piperidin-1-yl)piperidin- 1—y1)acetyl)amino]propane
`
`OCH 3
`
`
`
`(a) Preparation of 2-(4-(piperidin-1-y1)piperidin-1-yl)acetic
`acid, potassium salt
`
`4-(Piperidin-1-y1)piperidine (1.20 kg, 7.13 mol) was added to
`methylene chloride (12.0 L) under a nitrogen atmosphere.
`Tetrabutylammonium bromide (0.150 kg, 0.47 mol) and sodium
`hydroxide (1.7 L of a 5 N solution, 8.5 mol) were then added. The
`
`reaction mixture was cooled to 10-15°C and methyl bromoacetate (1.17
`kg, 7.65 mol) was added and the resulting mixture was stirred for a
`minimum of 16 hours.
`
`Deionized water (1.2 L) was then added to the mixture and
`the layers separated. The aqueous layer was back-extracted with
`
`methylene chloride (2.4 L). The organic fractions were combined and
`washed with deionized water (3 x 1.2 L), a saturated sodium bicarbonate
`solution ( 1.1 L) and a saturated sodium chloride solution ( 1.1 L). The
`
`
`
`

`
`W0 97/25988
`
`PCT/US97/00788
`
`-13-
`
`organic fraction was then dried over anhydrous magnesium sulfate and
`
`concentrated to an oil on a rotary evaporator to yield 1.613 kg (93.5%) of
`
`methyl 2-(4-(piperidin-1-yl)piperidin-1-yl)acetate.
`
`A solution of methyl 2-[4-(piperidin-1-yl)piperidin-1-
`
`yl]acetate (2.395 kg, 9.96 mol) in methanol (2.4 L) was added to a solution
`
`of potassium hydroxide (0.662 kg, 10.0 mol @ 85% purity) in methanol
`
`(10.5 L) under a nitrogen atmosphere. The reaction mixture was heated
`
`to 45-50°C for a minimum of 16 hours.
`
`A solvent exchange from methanol to acetone (15.0 L) was
`
`performed on the solution on a rotary evaporator. This solution was
`
`slowly cooled to room temperature over 16 hours. The resulting solids
`
`were filtered, rinsed with acetone (5.0 L) and then dried to yield 2.471 kg
`
`(93.8%) of 2-(4-(piperidin-1-yl)piperidin-1-yl)acetic acid, potassium salt.
`
`MS 265 (M+1)
`
`(b) Preparation of (R)-3-(1H-indol-3-yl)-1-[N-(2-
`
`methoxybenzyl)acetylamino]-2-[N-(2-(4-(piperidin-1-yl)piperidin-1-
`
`y1)acetyl)amino]propane
`
`The title compound was prepared by first admixing (R)-2-
`
`amino-3-(1H-indol-3-yl)- 1-[N-( 2-methoxybenzyl)acetylamino]propane
`
`dihydrochloride (50.0 g, 0.118 mol) with 100 ml of methylene chloride
`
`under a nitrogen atmosphere.
`
`In a second flask, under a nitrogen atmosphere, 2-(4-
`
`(piperidin-1—y1)piperidin-1-y1)acetic acid potassium salt (62.3 g, 0.236
`
`mol) was added to 600 ml of methylene chloride. This mixture was
`
`cooled to about -10°C and stirring was continued. To this mixture
`
`isobutylchloroformate (23 ml, 0.177 mol) was added dropwise such that
`
`the temperature of the 2-(4-(piperidin-1-y1)piperidin-1—yl)acetic acid
`
`potassium salt mixture never rose appreciably.
`
`This reaction mixture was stirred at about -10°C for about
`
`1.5 hours at which time the (R)-2-amino-3-(1H-indol-3-y1)-1-[N-(2-
`
`methoxybenzyl)acetylamino]propane dihydrochloride/methylene
`
`chloride mixture prepared §_u.p_r_a, was slowly added to the 2-(4-(piperidin-
`
`1-yl)piperidin—1-yl)acetic acid potassium
`
`salt/isobutylchloroformate/methylene chloride solution. The resulting
`
`
`
`

`
`W0 97/259g8
`
`PCTTUS97/00788
`
`-19-
`
`mixture was then stirred for about 1 hour at a temperature between -
`15°C and -8°C.
`
`The reaction mixture was removed from the ice bath and
`
`allowed to warm to 15-20°C and the reaction was quenched by the
`
`addition of 200 ml of water. The pH of the solution was adjusted to 2.3-2.7
`
`by the additon of 1N sulfuric acid. The layers were separated and the
`
`aqueous layer was washed with 100 ml of methylene chloride.
`
`The organic fractions were combined and washed with
`
`water (100 ml). The water wash was back extracted with methylene
`chloride (50 ml) and combined with the aqueous fraction from above.
`Methylene chloride (500 ml) was added to the combined aqueous layers
`and the mixture was stirred at room temperature for 15 minutes as
`
`basification with 2N sodium hydroidde to a final pH of 9.8 to 10.2 was
`achieved.
`
`The organic and aqueous fractions were separated. The aqueous
`fraction was washed with methylene chloride and the methylene
`chloride was added to the organic fraction. The organic fraction was
`then washed with a mixture of saturated sodium bicarbonate solution
`
`(100 ml) and water (50 ml). The bicarbonate wash was separated from
`the organic fraction and back extracted with methylene chloride (50 ml).
`The back extraction was combined with the methylene chloride fraction
`
`and the combined fractions were dried over magnesium sulfate. The
`
`magnesium sulfate was removed by filtration and the volatiles were
`
`removed by vacuum distillation to yield the title product as a foam. (72.5
`g, >93% yield). MS 559(M+1)
`NMR (DMSO-d5 3:2 mixture of amide rotamers) 8 1.25-1.70 (m, 10H),
`
`1.77-2.00 (In, 2H), 1.95 (s, 3/5-3H), 2.04 (s, 2/5-3H), 2.10-2.97 (m, 9H), 3.10-
`3.65 (m, 3H), 3.72 (s, 2/5-3H), 3.74 (s, 3/5-3H), 4.26-4.58 (m, 3H), 6.76-7.12
`(m, 6H), 7.13-7.35 (m, 2H), 7.42-7.66 (m, 2H), 10.80 (br s, 1H).
`Analysis for C33H45N5O3:
`
`Theory:
`
`Found:
`
`C, 70.81; H, 8.10; N, 12.51.
`
`C, 70.57; H, 8.05; N, 12.39.
`
`An alternative process for preparing the compounds of
`Formula I follows.
`
`

`
`wo 97/25988
`
`PCT/US97/00788
`
`.20-
`
`Preparation of (R)-3-(1H-indo1-3-y1)-2-(N-
`
`triphenylmethylamino)propanoic acid, N-methylmorpholine salt (N-
`
`trityl-D-tryptophan N-methylmopholine salt).
`
`To a one liter 4 neck flask equipped with mechanical
`
`stirrer, condensor, probe, and stopper, were added D-tryptophan (40.0 g,
`
`0.196 mol), acetonitrile (240 ml), and 1,1,1,3,3,3-hexamethyldisilazane
`
`(39.5 g, 0.245 mol). The resulting mixture was heated to 50-60°C and
`
`stirred until homogeneous. In a separate beaker trityl chloride (60.06 g,
`
`0.215 mol) and acetonitrile (120 ml) were slurried. The slurry was added
`
`to the silylated tryptophan mixture and the beaker was rinsed with 40 ml
`
`of acetonitrile. To the reaction mixture N-methylmorpholine (23.7 ml,
`
`21.8 g, 0.216 mol) was added and the resulting mixture was stirred for
`
`one hour. The progress of the reaction was monitored by
`
`chromatography.
`
`After satisfactory progress, water (240 ml) was added
`
`dropwise to the reaction mixture and the resulting mixture was cooled
`
`to less than 10°C, stirred for thirty minutes, and filtered. The residue
`
`was washed with water, and then dried to obtain 108.15 grams (>99%
`
`yield) of the desired title product.
`1H NMR (DMSO-de) 5 2.70 (In, 1H), 2.83 (In, 2H),