(12) United States Patent
`Damon
`
`US006172081B1
`US 6,172,081 B1
`Jan. 9, 2001
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`(54) TETRAHYDROISOQUINOLINE 3
`CARBOXAMIDE DERIVATIVES
`
`(75) Inventor: Robert Damon, Randolph, NJ (US)
`
`(73) Assignee: Novartis AG, Basel (CH)
`
`( * ) Notice:
`
`Under 35 USC 154(b), the term of this
`patent shall be extended for 0 days.
`
`(21) Appl. No.: 09/339,504
`(22) Filed:
`Jun. 24, 1999
`
`(51) Int. Cl.7 ................................................... .. A61K 31/47
`(52) US. Cl. ........................................... .. 514/307; 546/146
`(58) Field Of Search ............................ .. 514/307; 546/146
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`5,430,023
`5,491,164
`5,714,485
`
`7/1995 Gesellchen et al. ................. .. 514/18
`2/1996 deSolms et al.
`514/423
`2/1998 Lumma et al. .................... .. 514/247
`
`Kaspari, et al. Biochirnica et Biophysica., vol. 1293, pp.
`147—153 (1996).
`Li, et al. Archives of Biochemistry and Biophysics, vol.
`323(1), pp. 148—154 (1995).
`Li, et al. J. of Neurochemistry, vol. 66, pp. 2105—2112
`(1996).
`Yamada, et al. Bulletin of the Chemical Society of Japan,
`vol. 50(7), pp. 1827—1830 (1977).
`Yamada, et al. Bulletin of the Chemical Society of Japan,
`vol. 51(3), pp. 878—883 (1978).
`
`Primary Examiner—Amelia OWens
`(74) Attorney, Agent, or Firm—Joseph J. Borovian
`(57)
`ABSTRACT
`
`Tetrahydroisoquinoline 3-carboXamide derivatives of for
`mula
`
`NH
`
`FOREIGN PATENT DOCUMENTS
`
`R1
`
`1581 09
`296 075 A5
`555 824 A1
`WO 90/12005
`WO 91/16339
`WO 93/08259
`W0 95/11689
`W0 95/13069
`W0 95/15309
`W0 95/29190
`W0 95/29691
`W0 95/34538
`
`12/1982 (DE).
`11/1991 (DE) .
`8/1993 (EP) .
`10/1990 (W0).
`10/1991 (WO) .
`4/1993 (W0).
`5/1995 (W0).
`5/1995 (W0).
`6/1995 (W0).
`11/1995 (W0).
`11/1995 (W0).
`12/1995 (W0).
`
`OTHER PUBLICATIONS
`
`AshWorth, et al., Bioorganic and Medicinal Chemistry Let
`ters, vol. 6 (10), pp. 1163—1166 (1996).
`AshWorth, et al., Bioorganic and Medicinal Chemistry Let
`ters, vol. 6 (22), pp. 2745—2748 (1996).
`Augustyns, et al., Eur.J.Med.Chem., vol. 32; pp. 301—309
`(1997).
`DerWent Abstract 84—177689.
`DerWent Abstract 95—302548.
`Coutts, et al. J.Med.Chem., vol. 39, pp. 2087—2094 (1996).
`Deacon, et al. Diabetes, vol. 44, pp. 1126—1131 (1996).
`
`and pharmaceutically acceptable salts thereof Wherein:
`X is
`(a) CH2;
`(b) 5
`(c) O; or
`(d) C(CH3)2;
`R1 and R2 are independently
`(a) hydrogen;
`(b) hydroXy;
`(c) alkyl;
`(d) alkoXy;
`(e) aralkoXy; or
`(f) halogen.
`
`Compounds of formula I inhibit DPP-IV (dipeptidyl-pepti
`dase-IV) activity. They are therefore useful in the treatment
`of conditions mediated by DPP-IV, such as non-insulin
`dependent diabetes mellitus, arthritis, obesity, osteoporosis
`and further conditions of impaired glucose tolerance.
`
`8 Claims, N0 Drawings
`
`AstraZeneca Exhibit 2156
`Mylan v. AstraZeneca
`IPR2015-01340
`
`Page 1 of 12
`
`

`
`US 6,172,081 B1
`
`1
`TETRAHYDROISOQUINOLINE 3
`CARBOXAMIDE DERIVATIVES
`
`FIELD OF THE INVENTION
`
`The present invention relates to the area of dipeptidyl
`peptidase-IV (DPP-IV) inhibition. DPP-IV is a serine pro
`tease Which cleaves N-terminal dipeptides from a peptide
`chain containing, preferably, a proline residue in the penul
`timate position. Although the biological role of DPP-IV in
`mammalian systems has not been completely established, it
`is believed to play an important role in neuropeptide
`metabolism, T-cell activation, attachment of cancer cells to
`the endothelium and the entry of HIV into lymphoid cells.
`More recently, it Was discovered that DPP-IV is respon
`sible for inactivating glucagon-like peptide-1 (GLP-l) More
`particularly, DPP-IV cleaves the amino-terminal His-Ala
`dipeptide of GLP-1. generating a GLP-1 receptor antagonist,
`and thereby shortens the physiological response to GLP-1.
`Since the half-life for DPP-IV cleavage is much shorter than
`the half-life for removal of GLP-l from circulation, a sig
`ni?cant increase in GLP-1 bioactivity (5- to 10-fold) is
`anticipated from DPP-IV inhibition. Since GLP-1 is a major
`stimulator of pancreatic insulin secretion and has direct
`bene?cial effects on glucose disposal, DPP-IV inhibition
`appears to represent an attractive approach for treating
`non-insulin-dependent diabetes mellitus (NIDDM).
`
`10
`
`15
`
`25
`
`SUMMARY OF THE INVENTION
`
`The instant invention relates to novel tetrahydroisoquino
`line 3-carboXamide derivatives of formula I
`
`R2
`
`R1
`
`NH
`
`and pharmaceutically acceptable salts thereof. As used in
`formula I, and throughout the speci?cation, the symbols
`have the folloWing meanings:
`X is
`(a) CH2;
`(b) S;
`(c) O; or
`(d) C(CH3)2;
`R1 and R2 are independently
`(a) hydrogen;
`(b) hydroXy;
`(C) alkyl;
`(d) alkoXy;
`(e) aralkoXy; or
`(f) halogen.
`Compounds of formula I are DPP-IV inhibitors Which are
`effective in treating conditions mediated by DPP-IV.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`The present invention provides for compounds of formula
`I, pharmaceutical compositions employing such compounds
`and for methods of using such compounds. Listed beloW are
`
`2
`de?nitions of various terms used to describe the compounds
`of the instant invention. These de?nitions apply to the terms
`as they are used throughout the speci?cation (unless they are
`otherWise limited in speci?c instances either individually or
`as part of a larger group).
`The term “alkyl” refers to optionally substituted straight
`or branched chain hydrocarbon groups having 1 to 8 carbon
`atoms, preferably 1 to 5 carbons. Exemplary unsubstituted
`alkyl groups include methyl, ethyl, propyl, butyl, pentyl,
`heXyl, heptyl, octyl, the various branched chain isomers
`thereof, such as isopropyl, t-butyl, isobutyl, isoheXyl, 4,4
`dimethylpentyl, 2,2,4-trimethylpentyl and the like. Substi
`tuted alkyl groups include said alkyl groups substituted by
`one or more substituents selected from halogen, alkoXy,
`cycloalkyl, hydroXy, carboXy, —CONR3R4, —NR3R4
`(Where R3 and R4 are independently hydrogen or alkyl),
`nitro, cyano or thiol.
`The term “alkoXy” refers to any of the above alkyl groups
`linked to an oXygen atom.
`The term “cycloalkyl” refers to saturated cyclic hydro
`carbon groups containing 3 to 7 ring carbons With
`cyclopropyl, cyclopentyl and cycloheXyl being preferred.
`The term “halogen” or “halo” refers to chlorine, bromine
`and ?uorine.
`The term “aryl” refers to monocyclic or bicyclic aromatic
`hydrocarbon groups having 6 to 12 carbon atoms in the ring
`portion, such as phenyl, naphthyl, tetrahydronaphthyl or
`biphenyl groups, each of Which may optionally be substi
`tuted by one to four substituents such as alkyl, halo,
`hydroXy, alkoXy, amino, thiol, nitro, cyano, carboXy and the
`like.
`
`The term “aralkoXy” refers to an aryl group bonded to an
`alkoXy group.
`The compounds of formula I can eXist in free form or in
`acid addition salt form. Salt forms may be recovered from
`the free form in knoWn manner and vice-versa. Acid addition
`salts may eg be those of pharmaceutically acceptable
`organic or inorganic acids. Although the preferred acid
`addition salts are the tri?uoroacetate, the hydrochloric, lactic
`or acetic acid may also be utiliZed.
`
`45
`
`The compounds of the invention may eXist in the form of
`optically active isomers or diastereoisomers and can be
`separated and recovered by conventional techniques, such as
`chromatography.
`A preferred group of compounds of the invention is the
`compounds of formula I Wherein.
`
`55
`
`X is CH2; and
`R1 and R2 are independently hydrogen, hydroXy, or
`alkoXy.
`More preferred compounds of the invention are those
`compounds of formula I Wherein
`X is CH2;
`R1 is alkoXy; and
`R2 is hydrogen.
`The compounds of formula I may be prepared as illus
`trated for the compounds of formula I Where X is CH2 and
`one of R1 or R2 is hydroXy or alkoXy according to scheme
`1 beloW:
`
`Page 2 of 12
`
`

`
`US
`6,172,081 B1
`
`Scheme 1
`
`COZH
`
`—>
`
`N-Boc
`
`COZY
`
`HN
`
`7 (2A)
`
`N-Boc
`
`—>
`
`HO
`
`TBDMSO
`
`(1)
`
`(2)
`
`O
`
`SCONHZ
`
`I:
`
`—>
`
`N
`
`TBDMSO
`
`(3)
`
`N-Boc
`
`TBDMSO
`
`/
`
`O
`
`SCN
`N-Boc O
`
`N
`
`—>
`
`HO
`
`(6)
`
`R0
`
`45
`
`The Boc amino acid derivative (1) is silylated using a
`silating agent such as t-butyl dimethyl chlorosilane to form
`compounds of formula (2), Where Y is H or a protecting
`group such as trialkylsilyl, arylalkylsilyl, arylsilyl or t-butyl
`ester, The silyl derivative (2) is condensed With prolineam
`ide (2A; commercially available) mediated by an activating
`agent such as EDCI and HOAt in a solvent such as DMF.
`The resulting amide (3) is dehydrated to the nitrile (4) using
`a dehydrating agent such as phosphorus oXychloride. The
`nitrile (4) is then desilylated and alkylated using an alky
`lating agent such as an alkyl halide of the formula RaX
`(Where Ra is an alkyl or arylalkyl group such as methyl or
`benZyl and X is a halogen such as iodine, bromine or
`chlorine) Without isolation of the phenol, to form the ether
`(5). Alternatively, compound (5) can be prepared by alky
`lating the nitrile (4) With an alcohol subsequent to desily
`lation via a Mitsunobu-type reaction (via intermediates
`In all cases, the ?nal step is the removal of the Boo group
`using an acid such as tri?uoroacetic acid in an organic
`solvent such as acetonitrile, preferably in the presence of a
`scavenger such as 1,3-dimethoXybenZene to give compound
`(7) Which are compounds of formula I Where R2 is hydrogen
`and R1 is alkoXy.
`For compounds of formula I Where R2 is other than
`hydroXy condensation With a prolineamide is carried out
`using the Boo amino acid derivative (1) directly.
`The Boc amino acid derivative(1) is commercially avail
`able or can be derived using knoWn methods.
`Compounds of formula I Where X is other than CH2 can
`be prepared in a similar fashion using the appropriate analog
`65
`of proline as a starting material. Proline analogs Where X=S
`or O are commercially available and can be used With
`
`55
`
`O
`
`N .
`
`N-Boc
`
`(4)
`
`standard methods of converting the carboXylic acid func
`tionality to a nitrile via the primary amide. In the case Where
`X represents —C(CH3)2, the requisite proline analog may be
`prepared as described in either of tWo literature references:
`J. EZquerra, C. Pedregal,A. Rubio, and J. B. Deeter, Journal
`of Organic Chemistry 1994, 59,4327 or F. Soucy, D. Wernic
`and P. Beaulieu, JCS Perkin I, 1991, 2885.
`The compounds of the invention may be isolated from the
`reaction mixture and puri?ed in conventional manner, eg
`by chromatography.
`Insofar as its preparation is not particularly described
`herein, a compound used as starting material is knoWn or
`may be prepared from knoWn compounds in knoWn manner
`or analogously to knoWn methods or analogously to methods
`described in the Examples.
`The instant invention also includes pharmaceutical com
`positions useful in inhibiting DPP-IV comprising a pharma
`ceutically acceptable carrier or diluent and a therapeutically
`effective amount of a compound of formula I, or a pharma
`ceutically acceptable acid addition salt thereof
`In still another embodiment, the instant invention pro
`vides a method of inhibiting DPP-IV comprising adminis
`tering to a mammal in need of such treatment a therapeuti
`cally effective amount of a compound of formula I, or a
`pharmaceutically acceptable acid addition salt thereof.
`In a further embodiment, the instant invention provides a
`method of treating conditions mediated by DPP-IV inhibi
`tion comprising administering to a mammal in need of such
`treatment a therapeutically effective amount of a compound
`of formula I above, or a pharmaceutically acceptable acid
`addition salt thereof.
`As indicated above, all of the compounds of formula I,
`and their corresponding pharmaceutically acceptable acid
`
`Page 3 of 12
`
`

`
`US 6,172,081 B1
`
`5
`addition salts, are useful in inhibiting DPP-IV. The ability of
`the compounds of formula I, and their corresponding phar
`maceutically acceptable acid addition salts, to inhibit DPP
`IV may be demonstrated employing the Caco-2 DPP-IV
`Assay Which measures the ability of test compounds to
`inhibit DPP-IV activity from human colonic carcinoma cell
`extracts. The human colonic carcinoma cell line Caco-2 Was
`obtained from the American Type Culture Collection (ATCC
`HTB 37). Differentiation of the cells to induce DPP-IV
`expression Was accomplished as described by Reisher, et al.
`in an article entitled “Increased expression of .
`.
`. intestinal
`cell line Caco-2” in Proc. Natl. Acad. Sci., Vol. 90, pgs.
`5757—5761 (1993). Cell extract is prepared from cells solu
`biliZed in 10 mM Tris-HCl, 0.15 M NaCl, 0.04 t.i.u.
`aprotinin, 0.5% nonidet-P40, pH 8.0, Which is centrifuged at
`35,000 g for 30 min. at 4° C. to remove cell debris. The assay
`is conducted by adding 20 mg solubiliZed Caco-2 protein,
`diluted to a ?nal volume of 125 mL in assay buffer (25 mM
`Tris-HCl pH 7.4, 140 mM NaCl, 10 mM KCl, 1% bovine
`serum albumin) to microtiter plate Wells. The reaction is
`initiated by adding 25 mL of 1 mM substrate (H-Alanine
`Proline-pNA; pNA is p-nitroaniline). The reaction is run at
`room temperature for 10 minutes after Which time a 19 mL
`volume of 25% glacial acetic acid is added to stop the
`reaction. Test compounds are typically added as 30 mL
`25
`additions and the assay buffer volume is reduced to 95 mL.
`A standard curve of free p-nitroaniline is generated using
`0—500 mM solutions of free pNA in assay buffer. The curve
`generated is linear and is used for interpolation of substrate
`consumption (catalytic activity in nmoles substrate cleaved/
`min). The endpoint is determined by measuring absorbance
`at 405 nm in a Molecular Devices UV Max microtiter plate
`reader. The potency of the test compounds as DPP-IV
`inhibitors, expressed as ICSO, is calculated from 8-point,
`dose-response curves using a 4-parameter logistic function.
`The folloWing ICSOs Were obtained:
`
`10
`
`15
`
`20
`
`30
`
`35
`
`
`
`Compound Ex. 1
`
`
`
`Caco-2 DPP-IV 0.0076
`
`Ex. 2
`Ex. 3
`Ex. 4
`Ex. 5
`Ex. 6
`Ex. 7
`Ex. 8
`Ex. 9
`Ex. 10
`Ex. 11
`
`0.004
`0.014
`0.009
`0.008
`>10
`0.013
`0.01
`0.01
`0.016
`0.01
`
`The ability of the compounds of formula I, and their
`corresponding pharmaceutically acceptable acid addition
`salts, to inhibit DPP-IV may also be demonstrated by
`measuring the effects of test compounds on DPP-IV activity
`in human and rat plasma employing a modi?ed version of
`the assay described by Kubota, et al. in an article entitled
`“Involvement of dipeptidylpeptidase IV in an in vivo
`immune response” in Clin. Exp. Immunol., Vol. 89, pgs.
`192—197 (1992). Brie?y, ?ve mL of plasma are added to
`96-well ?at-bottom mictotiter plates (Falcon), folloWed by
`the addition of 5 mL of 80 mM MgCl2 in incubation buffer
`(25 mM HEPES, 140 mM NaCl, 1% RIA-grade BSA, pH
`7.8). After a 5 min. incubation at room temperature, the
`reaction is initiated by the addition of 10 mL of incubation
`buffer containing 0.1 mM substrate (H-Glycine-Proline
`AMC; AMC is 7-amino-4-methylcoumarin). The plates are
`covered With aluminum foil (or kept in the dark,) and
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`6
`incubated at room temperature for 20 min. After the 20 min.
`reaction, ?uorescence is measured using a CytoFluor 2350
`?uorimeter (Excitation 380 nm Emission 460 nm; sensitivity
`setting 4). Test compounds are typically added as 2 mL
`additions and the assay buffer volume is reduced to 13 mL.
`A ?uorescence-concentration curve of free AMC is gener
`ated using 0—50 mM solutions of AMC in assay buffer. The
`curve generated is linear and is used for interpolation of
`substrate consumption (catalytic activity in nmoles substrate
`cleaved/min). As With the previous assay, the potency of the
`test compounds as DPP-IV inhibitors, expressed as ICSO, is
`calculated from 8-point, dose-response curves using a 4
`parameter logistic function.
`The folloWing ICSOs Were obtained:
`
`
`
`Compound Ex. 1
`
`
`
`human plasma DPP-IV 0.041
`
`
`
`rat plasma DPP-IV 0.79
`
`Ex. 3
`Ex. 4
`Ex. 5
`Ex. 7
`Ex. 10
`
`0.004
`0.167
`0.049
`0.012
`0.005
`
`0.016
`1.3
`0.315
`0.078
`0.012
`
`In vieW of their ability to inhibit DPP-IV, the compounds
`of formula I, and their corresponding pharmaceutically
`acceptable acid addition salts, are useful in treating condi
`tions mediated by DPP-IV inhibition. Based on the above
`and ?ndings in the literature, it is expected that the com
`pounds disclosed herein are useful in the treatment of
`conditions such as non-insulin-dependent diabetes mellitus,
`arthritis, obesity, allograft transplantation, and calcitonin
`osteoporosis. More speci?cally, for example, the compounds
`of formula I, and their corresponding pharmaceutically
`acceptable acid addition salts, improve early insulin
`response to an oral glucose challenge and, therefore, are
`useful in treating non-insulin-dependent diabetes mellitus.
`The precise dosage of the compounds of formula I, and
`their corresponding pharmaceutically acceptable acid addi
`tion salts, to be employed for treating conditions mediated
`by DPP-IV inhibition depends upon several factors, includ
`ing the host, the nature and the severity of the condition
`being treated, the mode of administration and the particular
`compound employed. HoWever, in general, conditions medi
`ated by DPP-IV inhibition are effectively treated When a
`compound of formula I, or a corresponding pharmaceuti
`cally acceptable acid addition salt, is administered enterally,
`e.g., orally, or parenterally, e.g., intravenously, preferably
`orally, at a daily dosage of 0.002—5, preferably 0.02—2.5
`mg/kg body Weight or, for most larger primates, a daily
`dosage of 0.1—250, preferably 1—100 mg. A typical oral
`dosage unit is 0.01—0.75 mg/kg, one to three times a day.
`Usually, a small dose is administered initially and the
`dosage is gradually increased until the optimal dosage for
`the host under treatment is determined. The upper limit of
`dosage is that imposed by side effects and can be determined
`by trial for the host being treated.
`The compounds of formula I, and their corresponding
`pharmaceutically acceptable acid addition salts, may be
`combined With one or more pharmaceutically acceptable
`carriers and, optionally, one or more other conventional
`pharmaceutical adjuvants and administered enterally, e.g.,
`orally, in the form of tablets, capsules, caplets, etc. or
`parenterally, e.g., intravenously, in the form of sterile inject
`able solutions or suspensions. The enteral and parenteral
`compositions may be prepared by conventional means.
`The compounds of formula I, and their corresponding
`pharmaceutically acceptable acid addition salts, may be
`
`Page 4 of 12
`
`

`
`US 6,172,081 B1
`
`7
`formulated into enteral and parenteral pharmaceutical com
`positions containing an amount of the active substance that
`is effective for treating conditions mediated by DPP-IV
`inhibition, such compositions in unit dosage form and such
`compositions comprising a pharmaceutically acceptable car
`rier.
`The compounds of formula I (including those of each of
`the subscopes thereof and each of the examples) may be
`administered in enantiomerically pure form (e.g., ee 98%,
`preferably 99%) or together With the R enantiomer, e.g., in
`racemic form. The above dosage ranges are based on the
`compounds of formula I (excluding the amount of the R
`enantiomer).
`The folloWing examples shoW representative compounds
`encompassed by this invention and their synthesis.
`HoWever, it should be clearly understood that they are for
`purposes of illustration only.
`Abbreviations:
`EDCI: 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide
`hydrochloride
`HOAt: 1-Hydroxy-7-aZabenZotriaZole
`DMF: Dimethylformamide
`THF: Tetrahydrofuran
`TBAF: Tetrabutylammonium ?uoride
`
`EXAMPLE 1
`[S-(R* ,R*)]- 1-(1,2,3,4-tetrahydro-3-isoquinolinyl)
`carbonyl-2-pyrrolidinecarbonitrile tri?uoroacetate
`
`10
`
`15
`
`20
`
`25
`
`30
`
`o
`
`gc
`
`N
`
`N
`
`NH
`CF3CO2H
`
`A. [S-(R*,R*)]-3-(2-aminocarbonyl-1-pyrrolidinyl)
`carbonyl-3,4-dihydro-2(1H) isoquinolinecarboxylic acid
`1,1-dimethylethyl ester
`HOAt (450 mg, 3.6 mmol), EDCI (690 mg, 3.6 mmol)
`and L-prolinamide (411 mg, 3.6 mmol) Were added sequen
`tially to a solution of (S)-3,4-dihydro-2,3(1H)
`isoquinolinedicarboxylic acid 2-(1,1-dimethylethyl) ester
`(1.0 g, 3.6 mmol) in 25 mL of dimethyl formamide. The
`resulting solution Was stirred at room temperature for 20 h.
`The reaction mixture Was diluted With 40 mL of Water and
`extracted With methylene chloride. The organic solution Was
`Washed With 2N HCl, 10% aqueous sodium bicarbonate and
`brine, dried over sodium sulfate, and concentrated under
`vacuum to give 1.34 g of crude product as a White solid.
`B. [S-(R*,R*)]-3-(2-cyano-1-pyrrolidinyl)carbonyl-3,4
`dihydro-2(1H)-isoquinolinecarboxylic acid 1,1 -
`dimethylethyl ester
`Phosphorus oxychloride (1.07 g, 0.65 mL, 6.97 mmol)
`Was added to a solution of the amide (1.0 g, 2.68 mmol) and
`imidaZole (237 mg, 3.48 mmol) in pyridine (22 mL) at room
`temperature. The reaction (Which Was exothermic) Was
`stirred at room temperature for 1.25 h, then concentrated
`under vacuum to provide the crude product as a dark broWn
`mushy solid. Flash chromatography on silica gel using ethyl
`acetate-hexane (60:40) gave 758 mg of product as a
`yelloWish-White solid. This material Was rechromatographed
`on silica gel using 1:1 ethyl acetatezhexane as the eluent to
`give 675 mg (71%) of the pure product.
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`8
`C. [S-(R*,R*)]-1-(1,2,3,4-tetrahydro-3-isoquinolinyl)
`carbonyl-2-pyrrolidinecarbonitrile tri?uoroacetate
`Tri?uoroacetic acid (0.2 mL; 2.6 mmol) Was added to a
`solution of 36 mg (0.1 mmol) of the nitrile in 3 mL of
`acetonitrile at room temperature. The reaction Was stirred 21
`h., diluted With toluene (1 mL) and concentrated under
`vacuum. Addition of toluene and concentration under
`vacuum Was repeated three more times. The White solid
`residue Was partitioned betWeen ethyl acetate and Water. The
`aqueous phase Was concentrated under vacuum and toluene
`Was again added and removed under vacuum three more
`times to give 26 mg (70%) of product as a White solid, mp.
`145—150° C. (dec).. MS: Base peak - 256 (MH+ for free
`amine). 1H NMR (CH3OD; 300 MHZ): 7.1—7.4 (m, 4H),
`4.85 (m, 1H), 4.6 (dd, 1H), 3.7 (m, 2H), 3.5 (dd, 1H), 3.15
`(dd, 1H), 2.1—2.4 (m, 4H). 13C NMR (CH3OD): 119.2 (CN).
`
`EXAMPLE 2
`[S-(R* ,R*)]- 1-(1 ,2,3,4-tetrahydro-7-hydroxy-3
`isoquinolinyl)carbonyl-2-Pyrrolidinecarbonitrile tri?uoro
`acetate
`
`0
`
`N
`
`SCN
`
`HO
`
`NH
`CF3CO2H
`
`A. (S)-3-(dimethyl)(1,1-dimethylethyl)silyl-ester-7
`[(dimethyl)(1,1-dimethylethyl)silyl]oxy-3,4-dihydro-2,3
`(1H)-Isoquinolinedicarboxylic acid 2-(1,1-dimethylethyl)
`ester
`g; 45.54 mmol) and
`ImidaZole (3.1
`t-butyldimethylchlorosilane (6.86 g, 45 .54 mmol) Were
`added to a solution of (S)-3,4-dihydro-7-hydroxy-2,3(1H)
`isoquinolinedicarboxylic acid 2-(1,1-dimethylethyl) ester (6
`g, 18.2 mmol) in dimethyl formamide (50 mL) at room
`temperature. The mixture Was stirred at room temperature
`overnight, then quenched With Water and extracted With
`methyl t-butyl ether. The organic solution Was Washed With
`brine, dried (sodium sulfate) and concentrated to give 11.97
`g of the title compound as a colorless oil.
`B. [S-(R*,R*)]-3-(2-aminocarbonyl-1-pyrrolidinyl)
`carbonyl-3,4-dihydro-7-[(dimethyl)(1,1-dimethylethyl)
`silyl]oxy-2(1H)-Isoquinolinecarboxylic acid 1,1
`dimethylethyl ester
`To a solution of the crude title A compound, (S)-3
`(dimethyl)(1,1-dimethylethyl)silyl-ester 7-[(dimethyl)(1,1
`dimethylethyl)silyl]oxy-3,4-dihydro-2,3(1H)
`isoquinolinedicarboxylic acid 2-(1,1-dimethylethyl) ester
`(9.49 g, 18.22 mmol) in 120 mL of DMF Was added EDCI
`(4.1 g, 21.9 mmol) and HOAt (2.97 g, 21.0 mmol). After
`stirring for 10 minutes, triethyl amine (2.21 g, 3.05 mL, 21.9
`mmol) Was added, After an additional 10 minutes,
`L-prolinamide (2.5 g, 21.9 mmol) Was added to the cloudy
`yelloW mixture. The reaction Was stirred overnight at room
`temperature, 1 hour at 50° C., and overnight again at room
`temperature, and then partitioned betWeen ethyl acetate and
`Water. The ethyl acetate solution Was Washed With 1N HCl,
`saturated aq. sodium bicarbonate, and brine, ?ltered, dried
`(sodium sulfate), and concentrated to give product as 9.2 g
`of a White foam. Puri?cation of the crude product by ?ash
`chromatography on silica gel using 2% methanol in meth
`ylene chloride as the eluent gave 5.7 g of the title compound
`as a White foam, 91.3% pure by HPLC.
`
`Page 5 of 12
`
`

`
`US 6,172,081 B1
`
`9
`C. [S-(R*,R*)]-3-2-cyano-1-pyrrolidinyl)carbonyl-7
`[(dimethyl)(1,1-dimethylethyl)silyl]oxy-3,4-dihydro-2(1H)
`Isoquinolinecarboxylic acid 1,1-dimethylethyl ester
`Phosphorus oxychloride (2 mL, 3.24 g, 21.2 mmol) Was
`added slowly to a solution of the title B compound, [S-(R*,
`R*)]-3-(2-aminocarbonyl- -pyrrolidinyl)carbonyl-3,4
`dihydro-7-[(dimethyl)(1,1-dimethylethyl)silyl]oxy-2(1H)
`isoquinolinecarboxylic acid 1,1-dimethylethyl ester (4.1 g.
`8.15 mmol) in 40 mL of pyridine at —46° C. Stirring Was
`continued at —46° C. for 1.5 hours after Which the tempera
`ture Was raised to —12° C. over 2 hours. The mixture Was
`alloWed to Warm to room temperature, diluted With hexane,
`and concentrated under vacuum to remove the solvents. The
`residue Was chromatographed on silica gel using 20% ethyl
`acetate/80% hexane as the eluent to give 2.2 g of the title
`compound as a White foam.
`D. [S-(R*,R*)]-3-(2-cyano-1-pyrrolidinyl)carbonyl-3,4
`dihydro-7-hydroxy-2(1H)—Isoquinolinecarboxylic acid 1,1
`dimethylethyl ester
`A solution of tetrabutyl ammonium ?uoride in THF (2
`mL, 2 mmol) Was added to a solution of the title C
`compound, [S-(R* ,R*)]-3-(2-cyano-1-pyrrolidinyl)
`carbonyl-7-[(dimethyl)(1,1-dimethylethyl)silyl]oxy-3,4
`dihydro-2(1H)-isoquinolinecarboxylic acid 1,1 -
`dimethylethyl ester (0.8 g, 1.65 mmol) in 2 mL of THF at
`room temperature. The reaction Was stirred for 1 hour after
`Which it Was concentrated to remove the solvent. The
`residue Was partitioned betWeen ethyl acetate and aqueous
`ammonium chloride. The organic solution Was dried
`(sodium sulfate) and concentrated to give product as a White
`solid. The crude product Was chromatographed on silica gel
`using 5% methanol in methylene chloride as the eluent to
`give 0.45 g of the title compound as a White solid, mp.
`92—95° C.
`E. [S-(R*,R*)]-1-(1,2,3,4-tetrahydro-7-hydroxy-3
`isoquinolinyl)carbonyl-2-Pyrrolidinecarbonitrile tri?uoro
`acetate
`Tri?uoroacetic acid (1 mL, 1.48 g, 13 mmol) Was added
`to a solution of the title D compound, [S-(R*,R*)]-3-(2
`cyano-1-pyrrolidinyl)carbonyl-3,4-dihydro-7-hydroxy-2
`(1H)-isoquinolinecarboxylic acid 1,1-dimethylethyl ester
`(0.3 g, 0.83 mmol) in 5 mL of acetonitrile at room tempera
`ture. Stirring Was continued for 1.5 hours, after Which
`solvent Was removed under vacuum. The residue Was tritu
`rated With methyl tert-butyl ether to give the title compound
`as a White solid Which Was collected by ?ltration (mp. 1520
`C.). MS: 272 (MH+ for free amine). 1H NMR (CH3OD; 300
`MHZ): 7.12 (d, 1H), 6.75 (d, 1H), 6.67 (s, 1H), 4.85 (m, 1H),
`4.5 (dd, 1H), 4.42 (s, 2H). 3.7 (m, 2H), 3.4 (dd, 1H), 3.1 (dd,
`1H), 2.1—2.4 (m, 4H).
`EXAMPLE 3
`[S-(R* ,R*)]-1-(1,2,3,4-tetrahydro-7-hydroxy-3
`isoquinolinyl)carbonyl-2-Pyrrolidinecarbonitrile tri?uoro
`acetate
`
`0
`
`N
`
`SCN
`
`CH3O
`
`NH
`CF3CO2H
`
`A. [S-(R*,R*)]-3-(2-cyano-1-pyrrolidinyl)carbonyl-3,4
`dihydro-7-methoxy-2(1H)—Isoquinolinecarboxylic acid 1,1
`dimethylethyl ester.
`Methyl iodide (528 mg, 3.72 mmol) Was added to a THF
`solution of the title C compound of Example 2, [S-(R*,R*)]
`
`10
`3-(2-cyano-1-pyrrolidinyl)carbonyl-7-[(dimethyl)(1,1
`dimethylethyl)silyl]oxy-3,4-dihydro-2(1H)
`isoquinolinecarboxylic acid 1,1-dimethylethyl ester (600
`mg, 1.24 mmol) at room temperature. A 1M solution of
`tetrabutyl ammonium ?uoride (1.36 mL, 1.36 mmol) Was
`added sloWly during 1 minute. After stirring 2 hours at room
`temperature, the reaction Was quenched With aqueous
`ammonium chloride. The mixture Was then extracted With
`ethyl acetate. The combined organic extracts Were dried
`(sodium sulfate) and concentrated to give crude product
`Which Was puri?ed by ?ash chromatography on silica gel
`using a gradient of methanol (1% to 2%) in methylene
`chloride to give 314 mg of the title compound as a White
`solid.
`B. [S-(R* ,R*)]-1-(1,2,3,4-tetrahydro-7-methoxy-3
`isoquinolinyl)carbonyl-2-Pyrrolidinecarbonitrile tri?uoro
`acetate.
`Tri?uoroacetic acid (16.6 mL, 24.56 g, 215.45 mmol) Was
`added to a solution of the title A compound, [S-(R*,R*)]
`3-(2-cyano-1-pyrrolidinyl)carbonyl-3,4-dihydro-7
`methoxy-2(1H)-isoquinolinecarboxylic acid 1,1
`dimethylethyl ester (2.37 g, 6.16 mmol) and 1,3-dimethoxy
`benZene (4 mL, 4.25 g, 30.78 mmol) in 50 mL of acetonitrile
`at room temperature. Stirring Was continued at room tem
`perature overnight. Excess tri?uoroacetic acid Was removed
`under vacuum. Hexane Was added and the mixture concen
`trated under vacuum again, This addition and removal of
`hexane under vacuum (to remove residual tri?uoroacetic
`acid) Was repeated a total of three times. The resulting
`semi-solid material Was triturated With ether and ?ltered to
`give 1.96 g. of the title compound, mp. 1500 C. (dec.). 1H
`NMR (DMSO; 250 MHZ): 7.15 (d, 1H), 6.9 (d, 1H), 6.8 (s,
`1H), 4.85 (dd, 1H), 4.55 (dd, 1H), 4.25 (s, 2H), 3.7 (s, 3H),
`3.65 (m, 2H), 3.3 (dd, 1H), 2.85 (dd, 1H), 1.95—2.3 (m, 4H).
`13C NMR: 118.6 (CN). MS: 286 (MH+ for free amine).
`EXAMPLE 4
`[S-(R* ,R*)]-1-(1,2,3,4-tetrahydro-7-phenylmethoxy-3
`isoquinolinyl)carbonyl-2-Pyrrolidinecarbonitrile tri?uoro
`acetate
`
`0
`
`N
`
`$CN
`
`PhCHZO
`
`NH
`CF3CO2H
`
`A. [S-(R*,R*)]-3-(2-cyano-1-pyrrolidinyl)carbonyl-3,4
`dihydro-7-phenylmethoxy-2(1H)—Isoquinolinecarboxylic
`acid 1,1-dimethylethyl ester
`Tetrabutyl ammonium ?uoride in THF (2 mL, 2 mmol)
`Was added to a solution of the title C compound of Example
`2, [S-(R*,R*)]-3-(2-cyano-1-pyrrolidinyl)carbonyl-7
`[(dimethyl)(,1,1-dimethylethyl)silyl]oxy-3,4-dihydro-2
`(1H)-isoquinolinecarboxylic acid 1,1-dimethylethyl ester
`(700 mg, 1.4 mmol) and benZyl bromide (431 mg, 2.52
`mmol) in THF at room temperature. Stirring Was continued
`for 1.5 hours. Solvent Was removed under vacuum and the
`residue Was partitioned betWeen ethyl acetate and aqueous
`ammonium chloride, The organic solution Was dried
`(sodium sulfate) and concentrated to give the crude product
`as 410 mg of a White solid, mp. 580 C.
`B. [S-(R*,R*)]-1-(1,2,3,4-tetrahydro-7-phenylmethoxy-3
`isoquinolinyl)carbonyl-2-Pyrrolidinecarbonitrile tri?uoro
`acetate.
`Tri?uoroacetic acid (1 mL, 13 mmol) Was added to a
`solution of the title A compound [S-(R*,R*)]-3-(2-cyano-1
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`Page 6 of 12
`
`

`
`US 6,172,081 B1
`
`11
`pyrrolidinyl)carbonyl-3,4-dihydro-7-phenylmethoxy-2
`(1H)-isoquinolinecarboxylic acid 1,1-dimethylethyl ester
`(300 mg, 0.65 mmol) in 5 mL of acetonitrile at room
`temperature. Stirring Was continued for 3 hours after Which
`excess solvent Was removed under vacuum. Toluene Was
`added and stripped off under vacuum to facilitate the
`removal of residual tri?uoroacetic acid. The residue Was
`triturated With methyl tert-butyl ether to give 213 mg of the
`title compound as a White solid, mp. 162° C. 1H NMR
`(DMSO; 300 MHZ): 7.3—7.5 (m, 5H), 7.2 (s, 1H), 7.0 (d,
`10
`1H), 6.95 (s, 1H), 5.1 (s, 2H), 4.85 (dd, 1H), 4.55 (dd, 1H),
`4.3 (s, 2H), 3.65 (m, 2H), 3.35 (dd, 1H), 2.9 (dd, 1H),
`1.95—2.35 (m, 4H). MS: 362 (MH+ for free amine).
`
`EXAMPLE 5
`[S-(R* ,R*)]-1-(1,2,3,4-tetrahydro-7-propoxy-3
`isoquinolinyl)carbonyl-2-Pyrrolidinecarbonitrile tri?uoro
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`A. [S-(R*,R*)]-3-(2-cyano-1-pyrrolidinyl)carbonyl-3,4
`dihydro-7-propoxy-2(1H)-Isoquinolinecarboxylic acid 1,1
`dimethylethyl ester
`Tetrabutyl ammonium ?uoride in THF (0.68 mL, 0.68
`mmol) Was added sloWly to a solution of the title C com
`pound of Example 2, [S-(R*,R*)]-3-(2-cyano-1
`pyrrolidinyl)carbonyl-7-[(dimethyl)(1,1-dimethylethyl)
`silyl]oxy-3,4.dihydro-2(1H)-isoquinolinecarboxylic acid
`1,1-dimethylethyl ester (300 mg, 0.62 mmol) and
`1-iodopropane (72 pL, 126 mg, 0.74 mmol) in 5 mL of THF
`at room temperature. The reaction Was stirred at room
`temperature for 4 hours and then quenched With ca. 1 mL of
`saturated aqueous ammonium chloride. Water Was added to
`dissolve the salts and the mixture Was extracted With ethyl
`acetate. The combined organic solution Was Washed With
`brine, dried (sodium sulfate) and concentrated under
`vacuum to give product as 409 mg of a yelloW, sticky
`residue. This material Was puri?ed by ?ash chromatography
`on silica gel using 1.5% methanol in methylene chloride as
`the eluent. Product Was isolated in 38% yield as a White
`solid.
`B. [S-(