111111
`
`1111111111111111111111111111111111111111111111111111111111111
`US007326708B2
`
`c12) United States Patent
`Cypes et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,326,708 B2
`Feb.5,2008
`
`(54) PHOSPHORIC ACID SALT OF A
`DIPEPTIDYL PEPTIDASE-IV INHIBITOR
`
`(75)
`
`Inventors: Stephen Howard Cypes, Santa Clara,
`CA (US); Alex Minhua Chen,
`Metuchen, NJ (US); Russell R. Ferlita,
`Westfield, NJ (US); Karl Hansen,
`Atlantic Highlands, NJ (US); Ivan Lee,
`Piscataway, NJ (US); Vicky K. Vydra,
`Fair Lawn, NJ (US); Robert M.
`Wenslow, Jr., East Windsor, NJ (US)
`
`(73) Assignee: Merck & Co., Inc., Rahway, NJ (US)
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 657 days.
`
`(21) Appl. No.: 10/874,992
`
`(22) Filed:
`
`Jun. 23, 2004
`
`(56)
`
`wo
`wo
`
`References Cited
`U.S. PATENT DOCUMENTS
`6,479,692 B1 *
`11/2002 Ekwuribe eta!. ........... 558/413
`3/2004 Edmondson et a!.
`6,699,871 B2
`2003/0100563 A1
`5/2003 Edmondson et a!.
`2006/0287528 A1 *
`12/2006 Wenslow et a!.
`........... 544/350
`2007/0021430 A1 *
`112007 Chen et a!.
`................. 514/249
`FOREIGN PATENT DOCUMENTS
`WO 2005/072530 A1
`8/2005
`WO 2006/033848 A1
`3/2006
`OTHER PUBLICATIONS
`Edmondson, S.D., Drug Data Report, vol. 25, No. 3, pp. 245-246
`(2003).
`Database Prous DDR Online-Database Accession No. 2003: 3561.
`* cited by examiner
`Primary Examiner-James 0. Wilson
`Assistant Examiner-Ebenezer Sackey
`(74) Attorney, Agent, or Firm-Philippe L. Durette;
`Catherine D. Fitch
`
`(65)
`
`Prior Publication Data
`US 2005/0032804 Al
`Feb. 10, 2005
`
`Related U.S. Application Data
`(60) Provisional application No. 60/482,161, filed on Jun.
`24, 2003.
`
`(51)
`
`Int. Cl.
`(2006.01)
`A61K 311495
`(2006.01)
`C07D 471104
`(52) U.S. Cl. ....................................... 514/249; 544/350
`(58) Field of Classification Search ................ 514/249;
`544/350
`See application file for complete search history.
`
`ABSTRACT
`(57)
`The dihydrogenphosphate salt of 4-oxo-4-[3-(trifluorom-
`ethyl)-5,6-dihydro [1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl]-
`l-(2,4,5-trifluorophenyl)butan-2-amine is a potent inhibitor
`of dipeptidyl peptidase-IV and is useful for the prevention
`and/or treatment of non-insulin dependent diabetes mellitus,
`also referred to as type 2 diabetes. The invention also relates
`to a crystalline monohydrate of the dihydrogenphosphate
`salt as well as a process for its preparation, pharmaceutical
`compositions containing this novel form and methods of use
`for the treatment of diabetes, obesity, and high blood pres-
`sure.
`
`24 Claims, 5 Drawing Sheets
`
` Ex. 1001, p. 001
`
`DRL
`
`

`

`U.S. Patent
`
`Feb.5,2008
`
`Sheet 1 of 5
`
`US 7,326,708 B2
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`

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`U.S. Patent
`U.S. Patent
`
`Feb.5,2008
`Feb. 5, 2008
`
`Sheet 2 of 5
`Sheet 2 0f 5
`
`US 7,326,708 B2
`US 7,326,708 B2
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`
`

`

`U.S. Patent
`U.S. Patent
`
`Feb.5,2008
`Feb. 5,2008
`
`Sheet 3 of 5
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`US 7,326,708 B2
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`U.S. Patent
`
`Feb.5,2008
`
`Sheet 4 of 5
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`US 7,326,708 B2
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`

`

`U.S. Patent
`
`Feb.5,2008
`
`Sheet 5 of 5
`
`US 7,326,708 B2
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`
`DRL
`
`

`

`US 7,326,708 B2
`
`1
`PHOSPHORIC ACID SALT OF A
`DIPEPTIDYL PEPTIDASE-IV INHIBITOR
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`The present invention is related to U.S. provisional appli-
`cation Ser. No. 60/482,161, filed Jun. 24, 2003, the contents
`of which are hereby incorporated by reference.
`
`FIELD OF THE INVENTION
`
`2
`4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro[ 1 ,2,4]
`inhibitor
`triazolo[ 4,3-a ]pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)
`butan-2-amine and crystalline hydrates thereof, in particular
`a crystalline monohydrate. The dihydrogenphosphate salt
`5 and crystalline hydrates of the present invention have advan-
`tages in the preparation of pharmaceutical compositions of
`4-oxo-4-[3 -( trifluoromethy I )-5, 6-dihydro [ 1 ,2,4]triazolo [ 4,
`3-a ]pyrazin-7 (8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-
`amine, such as ease of processing, handling, and dosing. In
`10 particular, they exhibit improved physical and chemical
`stability, such as stability to stress, high temperatures and
`humidity, as well as improved physicochemical properties,
`such as solubility and rate of solution, rendering them
`particularly suitable for the manufacture of various pharma-
`15 ceutical dosage forms. The invention also concerns pharma-
`ceutical compositions containing the novel salt and hydrates
`as well as methods for using them as DP-IV inhibitors, in
`particular for the prevention or treatment of Type 2 diabetes,
`obesity, and high blood pressure.
`
`The present invention relates to a particular salt of a
`dipeptidyl peptidase-IV inhibitor. More particularly, the
`invention relates to a dihydrogenphosphate salt of 4-oxo-4-
`[3-(trifluoromethyl)-5,6-dihydro[ 1 ,2,4]triazolo[ 4,3-a]
`pyrazin-7(8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine,
`which is a potent inhibitor of dipeptidyl peptidase-IV. This
`novel salt and crystalline hydrates thereof are useful for the
`treatment and prevention of diseases and conditions for 20
`which an inhibitor of dipeptidyl peptidase-IV is indicated, in
`particular Type 2 diabetes, obesity, and high blood pressure.
`The invention further concerns pharmaceutical composi-
`tions comprising the dihydrogenphosphate salt and crystal-
`line hydrates thereof useful to treat Type 2 diabetes, obesity,
`and high blood pressure as well as processes for preparing
`the dihydrogenphosphate salt and crystalline hydrates
`thereof and their pharmaceutical compositions.
`
`BACKGROUND OF THE INVENTION
`
`30
`
`FIG. 1 is a characteristic X-ray diffraction pattern of the
`crystalline monohydrate of the dihydrogenphosphate salt of
`25 structural formula II.
`FIG. 2 is a carbon-13 cross-polarization magic-angle
`spinning (CPMAS) nuclear magnetic resonance (NMR)
`spectrum of the crystalline monohydrate of the dihydrogen-
`phosphate salt of structural formula II.
`FIG. 3 is a fluorine-19 magic-angle spinning (MAS)
`nuclear magnetic resonance (NMR) spectrum of the crys-
`talline monohydrate of the dihydrogenphosphate salt of
`structural formula II.
`FIG. 4 is a typical thermogravimetric analysis (TGA)
`35 curve of the crystalline monohydrate dihydrogenphosphate
`salt of structural formula II.
`FIG. 5 is a typical differential scanning calorimetry (DSC)
`curve of the crystalline monohydrate of the dihydrogenphos-
`phate salt of structural formula II.
`
`BRIEF DESCRIPTION OF THE FIGURES
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`
`This invention provides a new monobasic dihydrogen-
`phosphate salt of 4-oxo-4-[3-(trifluoromethyl)-5,6-dihy-
`dro[1 ,2,4]triazolo[ 4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluo-
`rophenyl) butan-2-amine of the following structural formula
`I:
`
`F
`
`F
`
`(I)
`
`Inhibition of dipeptidyl peptidase-IV (DP-IV), an enzyme
`that inactivates both glucose-dependent insulinotropic pep-
`tide (GIP) and glucagon-like peptide 1 (GLP-1), represents
`a novel approach to the treatment and prevention of Type 2
`diabetes, also known as non-insulin dependent diabetes
`mellitus (NIDDM). The therapeutic potential of DP-IV
`inhibitors for the treatment of Type 2 diabetes has been
`reviewed: C. F. Deacon and J. J. Holst, "Dipeptidyl pepti-
`dase IV inhibition as an approach to the treatment and 40
`prevention of Type 2 diabetes: a historical perspective,"
`Biochem. Biophys. Res. Commun., 294: 1-4 (2000); K.
`Augustyns, eta!., "Dipeptidyl peptidase IV inhibitors as new
`therapeutic agents for the treatment of Type 2 diabetes,"
`Expert. Opin. Ther. Patents, 13: 499-510 (2003); and D. J. 45
`Drucker, "Therapeutic potential of dipeptidyl peptidase IV
`inhibitors for the treatment of Type 2 diabetes," Expert Opin.
`Investig. Drugs, 12: 87-100 (2003).
`WO 03/004498 (published 16 Jan. 2003), assigned to
`Merck & Co., describes a class of beta-amino tetrahydrot- 50
`riazolo[4,3-a]pyrazines, which are potent inhibitors of DP-
`IV and therefore useful for the treatment of Type 2 diabetes.
`Specifically disclosed in WO 03/004498 is 4-oxo-4-[3-
`(trifluoromethyl)-5,6-dihydro[1 ,2,4]triazolo[ 4,3-a ]pyrazin-
`7 (8H)-yl]-1-(2,4,5-trifluorophenyl)butan-2-amine. Pharma- 55
`ceutically acceptable salts of this compound are generically
`encompassed within the scope of WO 03/004498.
`However, there is no specific disclosure in the above
`reference of the newly discovered monobasic dihydrogen-
`phosphate salt of 4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro 60
`[ 1 ,2,4]triazolo[ 4,3-a ]pyrazin-7(8H)-yl]-1-(2,4,5-trifluo-
`rophenyl)butan-2-amine of structural formula I below.
`
`SUMMARY OF THE INVENTION
`
`The present invention is concerned with a novel dihydro-
`genphosphate salt of the dipeptidyl peptidase-IV (DP-IV)
`
`or a crystalline hydrate thereof. In particular, the instant
`invention provides a crystalline monohydrate of the dihy-
`65 drogenphosphate salt of formula I.
`The dihydrogenphosphate salt of the present invention has
`a center of asymmetry at the stereogenic carbon atom
`
` Ex. 1001, p. 007
`
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`

`US 7,326,708 B2
`
`3
`indicated with an * and can thus occur as a racemate,
`racemic mixture, and single enantiomers, with all isomeric
`forms being included in the present invention. The separate
`enantiomers, substantially free of the other, are included
`within the scope of the invention, as well as mixtures of the 5
`two enantiomers.
`One embodiment of the present invention provides the
`dihydrogenphosphate salt of (2R)-4-oxo-4-[3-(trifluorom-
`ethyl)-5,6-dihydro[ 1 ,2,4]triazolo[ 4,3-a ]pyrazin-7 (SH)-yl]-
`1-(2,4,5-triflorophenyl) butan-2-amine of structural formula
`II:
`
`4
`solid state Fourier-transform infrared spectroscopy, and
`Raman spectroscopy. In a class of this embodiment, about
`5% to about 100% by weight of the crystalline monohydrate
`is present in the drug substance. In a second class of this
`embodiment, about 10% to about 100% by weight of the
`crystalline monohydrate is present in the drug substance. In
`a third class of this embodiment, about 25% to about 100%
`by weight of the crystalline monohydrate is present in the
`drug substance. In a fourth class of this embodiment, about
`10 50% to about 100% by weight of the crystalline monohy-
`drate is present in the drug substance. In a fifth class of this
`embodiment, about 75% to about 100% by weight of the
`crystalline monohydrate is present in the drug substance. In
`a sixth class of this embodiment, substantially all of the
`15 dihydrogenphosphate salt drug substance is the crystalline
`monohydrate of the present invention, i.e., the dihydrogen-
`phosphate salt drug substance is substantially phase pure
`monohydrate.
`The crystalline dihydrogenphosphate salt of the present
`20 invention exhibits pharmaceutic advantages over the free
`base and the previously disclosed hydrochloride salt (WO
`03/004498) in the preparation of a pharmaceutical drug
`product containing the pharmacologically active ingredient.
`In particular, the enhanced chemical and physical stability of
`25 the crystalline dihydrogenphosphate salt monohydrate con-
`stitute advantageous properties in the preparation of solid
`pharmaceutical dosage forms containing the pharmacologi-
`cally active ingredient.
`The dihydrogenphosphate salt of the present invention,
`30 which exhibits potent DP-IV inhibitory properties, is par-
`ticularly useful for the prevention or treatment of Type 2
`diabetes, obesity, and high blood pressure.
`Another aspect of the present invention provides a method
`for the prevention or treatment of clinical conditions for
`which an inhibitor of DP-IV is indicated, which method
`comprises administering to a patient in need of such pre-
`vention or treatment a prophylactically or therapeutically
`effective amount of the dihydrogenphosphate salt of struc-
`tural formula I or a hydrate thereof, in particular the crys-
`talline monohydrate
`thereof. Such clinical conditions
`include diabetes, in particular Type 2 diabetes, hyperglyce-
`mia, insulin resistance, and obesity.
`The present invention also provides the use of the dihy-
`drogenphosphate salt of structural formula I or a hydrate
`thereof, in particular the crystalline monohydrate, for the
`manufacture of a medicament for the prevention or treat-
`ment of clinical conditions for which an inhibitor of DP-IV
`is indicated.
`The present invention also provides pharmaceutical com-
`50 positions comprising the dihydrogenphosphate salt of struc-
`tural formula I or a hydrate thereof, in particular the crys-
`talline monohydrate, in association with one or more
`pharmaceutically acceptable carriers or excipients. In one
`embodiment the pharmaceutical composition comprise a
`therapeutically effective amount of the active pharmaceuti-
`cal ingredient in admixture with pharmaceutically accept-
`able excipients wherein the active pharmaceutical ingredient
`comprises a detectable amount of the crystalline monohy-
`drate of the present invention. In a second embodiment the
`pharmaceutical composition comprise a therapeutically
`effective amount of the active pharmaceutical ingredient in
`admixture with pharmaceutically acceptable excipients
`wherein the active pharmaceutical ingredient comprises
`about 5% to about 100% by weight of the crystalline
`monohydrate of the present invention. In a class of this
`second embodiment, the active pharmaceutical ingredient in
`such compositions comprises about 10% to about 100% by
`
`F
`
`F
`
`(II)
`
`or a crystalline hydrate thereof.
`A second embodiment of the present invention provides
`the dihydrogenphosphate salt of (2S)-4-oxo-4-[3-(trifluo-
`romethyl)-5,6-dihydro[1 ,2,4]triazolo[ 4,3-a ]pyrazin-7 (SH)-
`yl]-1-(2,4,5-trifluorophenyl) butan-2-amine of structural for-
`mula III:
`
`F
`
`F
`
`F
`
`(III)
`
`N~N\
`~N-<N
`
`CF3
`
`35
`
`40
`
`45
`
`or a crystalline hydrate thereof.
`More specifically, the dihydrogenphosphate salt of the
`present invention is comprised of one molar equivalent of
`mono-protonated 4-oxo-4-[3-(trifluoromethyl)-5,6-dihydro
`[ 1 ,2,4]triazolo[ 4,3-a ]pyrazin-7(8H)-yl]-1-(2,4,5-trifluo-
`rophenyl)butan-2-amine cation and one molar equivalent of
`dihydrogenphosphate (biphosphate) anion.
`In a further embodiment of the present invention, the
`dihydrogenphosphate salt of structural formulae I-III is a
`crystalline hydrate. In one class of this embodiment, the 55
`crystalline hydrate is a crystalline monohydrate.
`A further embodiment of the present invention provides
`the dihydrogenphosphate salt drug substance of structural
`formulae I-III that comprises the crystalline monohydrate
`present in a detectable amount. By "drug substance" is 60
`meant the active pharmaceutical ingredient ("API"). The
`amount of crystalline monohydrate in the drug substance can
`be quantified by the use of physical methods such as X -ray
`powder diffraction, solid-state fluorine-19 magic-angle spin-
`ning (MAS) nuclear magnetic resonance spectroscopy, 65
`solid-state carbon-13 cross-polarization magic-angle spin-
`ning (CPMAS) nuclear magnetic resonance spectroscopy,
`
` Ex. 1001, p. 008
`
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`US 7,326,708 B2
`
`6
`For instance, for oral administration in the form of a tablet
`or capsule, the active pharmaceutical ingredient can be
`combined with an oral, non-toxic, pharmaceutically accept-
`able, inert carrier such as lactose, starch, sucrose, glucose,
`methyl cellulose, magnesium stearate, dicalcium phosphate,
`calcium sulfate, maunitol, sorbitol and the like; for oral
`administration in liquid form, the active pharmaceutical
`ingredient can be combined with any oral, non-toxic, phar-
`maceutically acceptable inert carrier such as ethanol, glyc-
`erol, water and the like. Moreover, when desired or neces-
`sary, suitable binders, lubricants, disintegrating agents and
`coloring agents can also be incorporated into the mixture.
`Suitable binders include starch, gelatin, natural sugars such
`as glucose or beta-lactose, corn sweeteners, natural and
`synthetic gums such as acacia, tragacanth or sodium algi-
`nate, carboxymethylcellulose, polyethylene glycol, waxes
`and the like. Lubricants used in these dosage forms include
`sodium oleate, sodium stearate, magnesium stearate, sodium
`benzoate, sodium acetate, sodium chloride and the like.
`Disintegrators include, without limitation, starch, methyl
`20 cellulose, agar, bentonite, xanthan gum and the like.
`The dihydrogenphosphate salt of structural formula I and
`the crystalline monohydrate have been found to possess a
`high solubility in water, rendering it especially amenable to
`the preparation of formulations, in particular intranasal and
`25 intravenous formulations, which require relatively concen-
`trated aqueous solutions of active ingredient. The solubility
`of the crystalline dihydrogenphosphate salt monohydrate of
`formula I in water has been found to be about 72 mg/mL.
`According to a further aspect, the present invention pro-
`vides a process for the preparation of the dihydrogenphos-
`phate salt of formula I, which process comprises reacting
`4-oxo-4-[3 -( trifluoromethy I )-5, 6-dihydro [ 1 ,2,4]triazolo [ 4,
`3-a ]pyrazin-7 (SH)-yl]-1-(2,4,5-trifluoromethyl)butan-2-
`amine of structural formula IV below:
`
`5
`weight of the crystalline monohydrate. In a second class of
`this embodiment, the active pharmaceutical ingredient in
`such compositions comprises about 25% to about 100% by
`weight of the crystalline monohydrate. In a third class of this
`embodiment, the active pharmaceutical ingredient in such
`compositions comprises about 50% to about 100% by
`weight of the crystalline monohydrate. In a fourth class of
`this embodiment, the active pharmaceutical ingredient in
`such compositions comprises about 75% to about 100% by
`weight of the crystalline monohydrate. In a fifth class of this 10
`embodiment, substantially all of the active pharmaceutical
`ingredient is the crystalline dihydrogenphosphate salt mono-
`hydrate of the present invention, i.e., the active pharmaceu-
`tical ingredient is substantially phase pure dihydrogenphos- 15
`phate salt monohydrate.
`The compositions in accordance with the invention are
`suitably in unit dosage forms such as tablets, pills, capsules,
`powders, granules, sterile solutions or suspensions, metered
`aerosol or liquid sprays, drops, ampoules, auto-injector
`devices or suppositories. The compositions are intended for
`oral, parenteral, intranasal, sublingual, or rectal administra-
`tion, or for administration by inhalation or insufflation.
`Formulation of the compositions according to the invention
`can conveniently be effected by methods known from the
`art, for example, as described in Remington's Pharmaceu-
`tical Sciences, 17'h ed., 1995.
`The dosage regimen is selected in accordance with a
`variety of factors including type, species, age, weight, sex
`and medical condition of the patient; the severity of the 30
`condition to be treated; the route of administration; and the
`renal and hepatic function of the patient. An ordinarily
`skilled physician, veterinarian, or clinician can readily deter-
`mine and prescribe the effective amount of the drug required
`to prevent, counter or arrest the progress of the condition.
`Oral dosages of the present invention, when used for the 35
`indicated effects, will range between about 0.01 mg per kg
`of body weight per day (mg/kg/day) to about 100 mg/kg/day,
`preferably 0.01 to 10 mg/kg/day, and most preferably 0.1 to
`5.0 mg/kg/day. For oral administration, the compositions are
`preferably provided in the form of tablets containing 0.01, 40
`0.05, 0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 15.0, 25.0, 50.0, 100, 200,
`and 500 milligrams of the active ingredient for the symp-
`tomatic adjustment of the dosage to the patient to be treated.
`A medicament typically contains from about 0.01 mg to
`about 500 mg of the active ingredient, preferably, from about 45
`1 mg to about 200 mg of active ingredient. Intravenously, the
`most preferred doses will range from about 0.1 to about 10
`mg/kg/minute during a constant rate infusion. Advanta-
`geously, the crystalline forms of the present invention may
`be administered in a single daily dose, or the total daily 50
`dosage may be administered in divided doses of two, three
`or four times daily. Furthermore, the crystalline forms of the
`present invention can be administered in intranasal form via
`topical use of suitable intranasal vehicles, or via transdermal
`routes, using those forms of transdermal skin patches well
`known to those of ordinary skill in the art. To be adminis- 55
`tered in the form of a transdermal delivery system, the
`dosage administration will, of course, be continuous rather
`than intermittent throughout the dosage regimen.
`In the methods of the present invention, the dihydrogen-
`phosphate salt and crystalline hydrates herein described in 60
`detail can form the active pharmaceutical ingredient, and are
`typically administered in admixture with suitable pharma-
`ceutical diluents, excipients or carriers (collectively referred
`to herein as 'carrier' materials) suitably selected with respect
`to the intended form of administration, that is, oral tablets, 65
`capsules, elixirs, syrups and the like, and consistent with
`conventional pharmaceutical practices.
`
`F
`
`F
`
`(IV)
`
`with approximately one equivalent of phosphoric acid in a
`suitable C 1 -C5 alkanol, such as methanol, ethanol, isopropyl
`alcohol (IPA), and isoamyl alcohol (IAA) or aqueous C 1-C5
`alkanol. The reaction is carried out at a temperature range of
`about 25 o C. to about 80 o C. The phosphoric acid solution
`can be added to a solution of the amine, or the addition can
`be performed in the reverse direction. The crystalline dihy-
`drogenphosphate salt monohydrate is obtained by crystalli-
`zation from an aqueous C 1-C5 alkanol solution of the dihy-
`drogenphosphate salt as described below.
`
`General Methods for Crystallizing the Monohydrate
`of the Dihydrogenphosphate Salt of Structural
`Formula I
`
`(a) In Ethanol/Water System at 25° C.:
`(1) crystallization from a mixture of compound I in ethanol
`and water, such that the water concentration is above 31
`weight percent,
`(2) recovering the resultant solid phase, and
`(3) removing the solvent therefrom.
`
` Ex. 1001, p. 009
`
`DRL
`
`

`

`US 7,326,708 B2
`
`8
`EXAMPLE
`
`7
`(b) In Isoamyl Alcohol (IAA)/Water System at 25° C.:
`(1) crystallization from a mixture of compound I in IAA and
`water, such that the water concentration is above 2.9
`weight percent;
`(2) recovering the resultant solid phase; and
`(3) removing the solvent therefrom.
`(c) In IAA/Water System at 40° C.:
`(1) crystallization from a mixture of compound I in IAA and
`water, such that the water concentration is above 3.6 10
`weight percent;
`(2) recovering the resultant solid phase; and
`(3) removing the solvent therefrom
`(d) In IAA/Water System at 60° C.:
`(1) crystallization from a mixture of compound I in IAA and
`water, such that the water concentration is above 4.5
`weight percent;
`(2) recovering the resultant solid phase; and
`(3) removing the solvent therefrom.
`(e) In Isopropyl Alcohol (IPA)/Water System at 25° C.:
`(1) crystallization from a mixture of compound I in IPA and
`water, such that the water concentration is above 7.0
`weight percent;
`(2) recovering the resultant solid phase; and
`(3) removing the solvent therefrom
`(f) In IPA/Water System at 40° C.:
`(1) crystallization from a mixture of compound I in EPA and
`water, such that the water concentration is above 8.1
`weight percent;
`(2) recovering the resultant solid phase; and
`(3) removing the solvent therefrom.
`
`15
`
`20
`
`25
`
`30
`
`35
`
`F
`
`F
`
`(2R )-4-oxo-4-[3 -( trifluoromethy 1)-5 ,6-dihydro [ 1 ,2,4]
`triazolo[ 4,3-a]pyrazin-7(8H)-yl]-1-(2,4,5-trifluo-
`rophenyl)butan-2-amine dihydrogenphosphate
`monohydrate
`
`Preparation of 3-(trifluoromethyl)-5,6, 7,8-tetrahydro[1 ,2,
`41]triazolo[ 4,3-a ]pyrazine hydrochloride (1-4)
`
`1. CF3COOEt, CH3CN
`2. ClCOCH2Cl, NaOH
`0
`
`)l )~ycH2c1
`
`F3C
`
`~
`
`0
`
`1-1
`N-N
`
`F3C-(0 )-_CH2Cl
`1-2
`
`MeOH
`
`0
`
`HN~N'-N)lCF
`~~H H
`
`3
`
`MeOH, HCl, 55° C.
`
`1-3
`
`HCl
`
`1-4
`
`40
`
`45
`
`(g) In IPA/Water System at 75° C.:
`(1) crystallization from a mixture of compound I in IPA and
`water, such that the water concentration is above about 20
`weight percent;
`(2) recovering the resultant solid phase; and
`(3) removing the solvent therefrom.
`The starting compound of structural formula IV can be
`prepared by the procedures detailed in Schemes 1-3 and
`Example 1 below.
`In a still further aspect, the present invention provides a
`method for the treatment and/or prevention of clinical con-
`ditions for which a DP-IV inhibitor is indicated, which
`method comprises administering to a patient in need of such
`prevention or treatment a prophylactically or therapeutically 50
`effective amount of the salt of Formula I as defined above or
`a crystalline hydrate thereof.
`The following non-limiting Examples are intended to
`illustrate the present invention and should not be construed 55
`as being limitations on the scope or spirit of the instant
`invention.
`Compounds described herein may exist as tautomers such
`as keto-enol tautomers. The individual tautomers as well as
`mixtures thereof are encompassed with compounds of struc- 60
`tural formula I.
`The term "% enantiomeric excess" (abbreviated "ee")
`shall mean the % major enantiomer less the % minor
`enantiomer. Thus, a 70% enantiomeric excess corresponds
`to formation of 85% of one enantiomer and 15% of the other.
`The term "enantiomeric excess" is synonymous with the
`term "optical purity."
`
`Step A: Preparation of bishydrazide (1-1)
`Hydrazine (20.1 g, 35 wt% in water, 0.22 mol) was mixed
`with 310 mL of acetonitrile. 31.5 g of ethyl trifluoroacetate
`(0.22 mol) was added over 60 min. The internal temperature
`was increased to 25° C. from 14° C. The resulting solution
`was aged at 22-25° C. for 60 min. The was cooled to 7° C.
`17.9 g of 50 wt% aqueous NaOH (0.22 mol) and 25.3 g of
`65 chloroacetyl chloride (0.22 mol) were added simultaneously
`over 130 min at a temperature below 16° C. When the
`reaction was complete, the mixture was vacuum distilled to
`
` Ex. 1001, p. 010
`
`DRL
`
`

`

`9
`remove water and ethanol at 27-30° C. and under 26 -27 in
`Hg vacuum. During the distillation, 720 mL of acetonitrile
`was added slowly to maintain constant volume (approxi-
`mately 500 mL). The slurry was filtered to remove sodium
`chloride. The cake was rinsed with about 100 mL of aceta-
`nitrile. Removal of the solvent afforded his-hydrazide 1-1
`(43.2 g, 96.5% yield, 94.4 area% pure by HPLC assay).
`1H-NMR (400 MHz, DMSO-d6): o 4.2 (s, 2H), 10.7 (s,
`lH), and 11.6 (s, lH) ppm. 13C-NMR (100 MHz, DMSO-
`d6): o 41.0, 116.1 (q, 1=362 Hz), 155.8 (q, 1=50 Hz), and 10 F
`165.4 ppm.
`Step B: Preparation of 5-(trifluoromethyl)-2-(chlorom-
`ethyl)-1.3.4-oxadiazole (1-2)
`Bishydrazide 1-1 from Step A (43.2 g, 0.21 mol) inACN 15
`(82 mL) was cooled to so C. Phosphorus oxychloride (32.2
`g, 0.21 mol) was added, maintaining the temperature below
`1 oo C. The mixture was heated to 80° C. and aged at this
`temperature for 24 h until HPLC showed less than 2 area %
`of 1-1. In a separate vessel, 260 mL of IPAc and 250 mL of 20
`water were mixed and cooled to oo C. The reaction slurry
`was charged to the quench keeping the internal temperature
`below 10° C. After the addition, the mixture was agitated
`vigorously for 30 min, the temperature was increased to
`room temperature and the aqueous layer was cut. The 25
`organic layer was then washed with 215 mL of water, 215
`mL of 5 wt% aqueous sodium bicarbonate and finally 215
`mL of 20 wt % aqueous brine solution. HPLC assay yield
`after work up was 86-92%. Volatiles were removed by
`distillation at 75-80 mm Hg, 55° C. to afford an oil which 30
`could be used directly in Step C without further purification.
`Otherwise the product can be purified by distillation to
`afford 1-2 in 70-80% yield.
`1H-NMR (400 MHz, CDC13 ): o 4.8 (s, 2H) ppm. 13C-
`NMR (100 MHz, CDC13 ): o32.1, 115.8 (q, 1=337 Hz), 156.2 35
`(q, 1=50 Hz), and 164.4 ppm.
`Step C: Preparation of N-[(2Z)-piperazin-2-ylidene]trifluo-
`roacetohydrazide (1-3)
`To a solution of ethylenediamine (33.1 g, 0.55 mol) in
`methanol (150 mL) cooled at -20° C. was added distilled 40
`oxadiazole 1-2 from Step B (29.8 g, 0.16 mol) while keeping
`the internal temperature at -20° C. After the addition was
`complete, the resulting slurry was aged at -20° C. for 1 h.
`Ethanol (225 mL) was then charged and the slurry slowly
`warmed to -5° C. After 60 min at -5° C., the slurry was 45
`filtered and washed with ethanol (60 mL) at -5° C. Amidine
`1-3 was obtained as a white solid in 72% yield (24.4 g, 99.5
`area wt % pure by HPLC).
`1H-NMR (400 MHz, DMSO-d6): o2.9 (t, 2H), 3.2 (t, 2H),
`3.6 (s, 2H), and 8.3 (b, lH) ppm. 13C-NMR (100 MHz, 50
`DMSO-d6): o 40.8, 42.0,43.3, 119.3 (q, 1=350 Hz), 154.2,
`and 156.2 (q, 1=38 Hz) ppm.
`Step D: Preparation of 3-(trifluoromethyl)-5,6,7,8-tetrahy-
`dro[1 ,2,4]triazolo[ 4.3-a]pyrazine hydrochloride (1-4)
`A suspension ofamidine 1-3 (27.3 g, 0.13 mol) in 110 mL
`of methanol was warmed to 55° C. 37% Hydrochloric acid
`(11.2 mL, 0.14 mol) was added over 15 min at this tem-
`perature. During the addition, all solids dissolved resulting
`in a clear solution. The reaction was aged for 30 min. The 60
`solution was cooled down to 20° C. and aged at this
`temperature until a seed bed formed (1 0 min to 1 h). 300 mL
`of MTBE was charged at 20° C. over 1 h. The resulting
`slurry was cooled to 2° C., aged for 30 min and filtered.
`Solids were washed with 50 mL of ethanol:MTBE (1:3) and 65
`dried under vacuum at 45° C. Yield oftriazole 1-4 was 26.7
`g (99.5 area wt % pure by HPLC).
`
`F
`
`F
`
`5
`
`55
`
`US 7,326,708 B2
`
`10
`1H-NMR(400MHz, DMSO-d6): o3.6 (t, 2H), 4.4 (t, 2H),
`4.6 (s, 2H), and 10.6 (b, 2H) ppm; 13C-NMR (100 MHz,
`DMSO-d6): o: 39.4, 39.6, 41.0, 118.6 (q, 1=325 Hz), 142.9
`(q, 1=50 Hz), and 148.8 ppm.
`
`F
`
`F
`
`F
`
`2-1
`
`F
`
`F
`
`0
`
`2-2
`
`OH
`
`2-3
`
`2-4
`
`F
`
`F
`
`tBuCOCl, iPr2NEt,
`DMAP,DMAc
`HCl
`HN~N\.
`~N-{N
`
`0
`
`CF3
`
`1-4
`
`N~OAc
`MeOH
`
`[Rh( cod)Clh,
`R, S- t-Bu Josiphos,
`H2, MeOH, 200 psi, 50' C.
`
`2-5
`
`Step A: Preparation of 4-oxo-4-[3-(trifluoromethyl)-5,6-di-
`hydro[1,2,4]triazolo[ 4,3-a ]pyrazin-7(8H)-yl]-1-(2,4,5-trif-
`luorophenyl)butan-2-one (2-3)
`2,4,5-Trifluorophenylacetic acid (2-1 (150 g, 0.789 mol),
`Meldrum's acid (125 g, 0.868 mol), and 4-(dimethylamino)
`pyridine (DMAP) (7.7 g, 0063 mol) were charged into a 5
`L three-neck flask. N,N-Dimethylacetamide (DMAc) (525
`mL) was added in one portion at room temperature to
`
` Ex. 1001, p. 011
`
`DRL
`
`

`

`US 7,326,708 B2
`
`11
`dissolve the solids. N,N-diisopropylethylamine (282 mL,
`1.62 mol) was added in one portion at room temperature
`while maintaining the temperature below 40° C. Pivaloyl
`chloride (107 mL, 0.868 mol) was added dropwise over 1 to
`2 h while maintaining the temperature between 0 and so C. 5
`The reaction mixture was aged at so C. for 1 h. Triazole
`hydrochloride 14 (180 g, 0.789 mol) was added in one
`portion at 40-S0° C. The reaction solution was aged at 70°
`C. for several h. S% Aqueous sodium hydrogencarbonate
`solution (62S mL) was then added dropwise at 20-4S° C. 10
`The batch was seeded and aged at 20-30° C. for 1-2 h. Then
`an additional S2S mL of S% aqueous sodium hydrogencar-
`bonate solution was added dropwise over 2-3 h. After aging
`several hat room temperature, the slurry was cooled to O-S 0
`C. and aged 1 h before filtering the solid. The wet cake was
`displacement-washed with 20% aqueous DMAc (300 mL),
`followed by an additional two batches of 20% aqueous
`DMAc (400 mL), and finally water (400 mL). The cake was
`suction-dried at room te