the invention provides novel crystalline forms of compound a , an inhibitor of weel kinase . compound a , also known as mk - 1775 , is 2 - allyl - 1 -[ 6 -( 1 - hydroxy - 1 - methylethyl ) pyridin - 2 - yl ]- 6 -{[ 4 -( 4 - methylpiperazin - 1 - yl ) phenyl ] amino }- 1 , 2 - dihydro - 3h - pyrazolo [ 3 , 4 - d ] pyrimidin - 3 - one , of structural formula : which can be prepared by procedures described in international publications wo2007 / 126128 and wo2007 / 126122 , both of which published on nov . 8 , 2007 to merck & amp ; co ., inc . other crystalline forms and salts of compound a , including the monohydrate form g and anhydrate form b , are described in international publication wo2008 / 133866 , which published on nov . 6 , 2008 , to merck & amp ; co ., inc ., which is hereby incorporated by reference in its entirety . the novel crystalline forms of compound a or a salt thereof , especially the hemihydrates described herein , can be provided stably and constantly from the standpoint of the manufacturing process , and are useful in the treatment of cancer . the crystalline hemihydrate form i described herein is more stable thermodynamically than other known forms at temperatures up to 44 ° c . and relative humidity range of 14 - 93 % ( herein abbreviated as “ rh ”). the crystalline hemihydrate form ii described herein is more stable thermodynamically than other known forms at temperatures equal or higher than 48 ° c . and relative humidity range of 19 - 93 %. the relative stability of the hemihydrates and monohydrate form g at relative humidity higher than 93 % has been difficult to establish , because the solubility of the three crystalline forms are very close ( difference & lt ; 1 mg / ml ) and the conversion is very slow . also , the hemihydrate form ii can be synthesized using a crystallization process that is more efficient and results in improved particle size and morphology control when compared to other forms the novel crystalline hemihydrate forms of compound a , or a salt thereof , as well as compound a per se , have a kinase - inhibitory effect , especially a weel kinase - inhibitory effect , and are therefore useful as pharmaceutical agents for the treatment of various cancers such as brain cancer , cervicocerebral cancer , esophageal cancer , thyroid cancer , small cell cancer , non - small cell cancer , breast cancer , lung cancer , stomach cancer , gallbladder / bile duct cancer , liver cancer , pancreatic cancer , colon cancer , rectal cancer , ovarian cancer , choriocarcinoma , uterus body cancer , uterocervical cancer , renal pelvis / ureter cancer , bladder cancer , prostate cancer , penis cancer , testicles cancer , fetal cancer , wilms &# 39 ; cancer , skin cancer , malignant melanoma , neuroblastoma , osteosarcoma , ewing &# 39 ; s tumor , soft part sarcoma , acute leukemia , chronic lymphatic leukemia , chronic myelocytic leukemia , hodgkin &# 39 ; s lymphoma . in particular , the novel crystalline forms of compound a or a salt thereof , as well as compound a per se , are useful as pharmaceutical agents , for example , for the treatment of breast cancer , lung cancer , pancreatic cancer , colon cancer , ovarian cancer , acute leukemia , chronic lymphatic leukemia , chronic myelocytic leukemia , hodgkin &# 39 ; s lymphoma . the term “ compound a ” as referred to herein means a compound of the above - described chemical structural formula and includes any amorphous form , polymorphic crystalline forms , hydrate , solvate and the mixture thereof . x - ray powder diffraction studies are widely used to characterize molecular structures , crystallinity , and polymorphism . the x - ray powder diffraction pattern of the hemihydrate was generated on a philips analytical x &# 39 ; pert pro x - ray diffraction system with pw3040 / 60 console . a pw3373 / 00 ceramic cu lef x - ray tube k - alpha radiation was used as the source . the x - ray powder diffraction pattern of the hemihydrate form ii of compound a is shown in fig1 . the hemihydrate form ii of compound a , also known as “ the hemihydrate form ii ” or “ the crystalline hemihydrate form ii of compound a ,” exhibits characteristic diffraction peaks corresponding to d - spacings of 13 . 81 , 11 . 16 , and 3 . 34 angstroms . the hemihydrate is further characterized by the d - spacings of 6 . 92 , 6 . 74 , and 6 . 53 angstroms . the hemihydrate is even further characterized by the d - spacings of 18 . 17 and 4 . 30 angstroms . the x - ray powder diffraction pattern of the hemihydrate form i of compound a is shown in fig6 . the hemihydrate form i of compound a , also known as “ the hemihydrate form 1 ” or “ the crystalline hemihydrate form i of compound a ,” exhibits characteristic diffraction peaks corresponding to d - spacings of 10 . 66 , 5 . 30 , and 4 . 18 angstroms . the hemihydrate is further characterized by the d - spacings of 9 . 11 , 8 . 80 and 3 . 54 angstroms . the hemihydrate is even further characterized by the d - spacings of 18 . 22 , 3 . 09 and 3 . 02 angstroms . in addition to the x - ray powder diffraction patterns described above , the hemihydrates were further characterized by solid - state carbon - 13 nuclear magnetic resonance ( nmr ) spectra . the solid - state carbon - 13 nmr spectra were obtained on a bruker dsx 400wb nmr system using a bruker 4 mm h / x cpmas probe . the carbon - 13 nmr spectra utilized proton / carbon - 13 cross - polarization magic - angle spinning with variable - amplitude cross polarization , and tppm decoupling at 80 khz . the samples were spun at 10 . 0 khz , and a total of 1024 scans were collected with a recycle delay of 5 seconds . a line broadening of 10 hz was applied to the spectra before ft was performed . chemical shifts are reported on the tms scale using the carbonyl carbon of glycine ( 176 . 70 p . p . m .) as a secondary reference . the solid - state carbon - 13 cpmas nmr spectrum for the crystalline hemihydrate form ii of compound a is shown in fig2 . it is characterized by a solid - state carbon - 13 cpmas nuclear magnetic resonance spectrum showing signals at 28 . 6 , 55 . 8 and 132 . 3 p . p . m . the spectrum is further characterized by signals at 123 . 2 , 118 . 2 , and 72 . 3 p . p . m . the solid - state carbon - 13 cpmas nmr spectrum for the crystalline hemihydrate form i of compound a is shown in fig5 . crystalline hemihydrate form i is characterized by a solid - state carbon - 13 cpmas nuclear magnetic resonance spectrum showing signals at 116 . 6 , 52 . 4 , 55 . 0 and 31 . 7 p . p . m . the spectrum is further characterized by signals at 145 . 0 , 154 . 8 , 160 . 1 and 169 . 4 p . p . m . dsc data are acquired using ta instruments dsc 2910 or equivalent instrumentation . between 1 and 7 mg sample are weighed into an open pan . this pan is then placed at the sample position in the calorimeter cell . an empty open pan is placed at the reference position . the calorimeter cell is closed and a flow of nitrogen was passed through the cell . the heating program is set to heat the sample at a heating rate of 10 ° c ./ min to a temperature of approximately 260 ° c . the heating program is started . when the run is completed , the data are analyzed using the dsc analysis program contained in the system software . the observed endotherms and exotherms are integrated between baseline temperature points that are above and below the temperature range over which these endotherms and exotherms are observed . the data reported are the onset temperature , peak temperature and enthalpy . the differential calorimetry scan for the crystalline hemihydrate form ii of compound a is shown in fig3 . the dsc curve is characterized by two endotherms and one exotherm . the first endotherm with an extrapolated onset temperature of 134 . 63 ° c ., a peak temperature of 139 . 47 ° c . and enthalpy of 97 . 54 j / g is associated with the loss of water from the crystal lattice . the loss of water leads to a formation of amorphous phase , which re - crystallizes as the anhydrate form b of compound a . the re - crystallization is observed in the dsc curve as an exotherm with an extrapolated onset temperature of 151 . 32 ° c ., a peak temperature of 163 . 52 ° c . and enthalpy of 30 . 22 j / g . the second endotherm , with an extrapolated onset temperature of 179 . 74 ° c ., a peak temperature of 182 . 55 ° c . and enthalpy of 31 . 8 j / g is due to the melting of the anhydrate form b of compound a . the differential calorimetry scan for the crystalline hemihydrate form i of compound a is shown in fig8 . the dsc curve is characterized by two endotherms and one exotherm . the first endotherm with an extrapolated onset temperature of 106 . 1 ° c . and a peak temperature of 117 . 9 ° c . is associated with the loss of water from the crystal lattice . the loss of water leads to a formation of amorphous phase , which re - crystallizes as the anhydrate form b of compound a . the re - crystallization is observed in the dsc curve as an exotherm with an extrapolated peak temperature of 125 . 1 ° c . the second endotherm , with an extrapolated onset temperature of 181 . 3 ° c ., a peak temperature of 182 . 9 ° c . and enthalpy of 82 . 33 j / g is due to the melting of the anhydrate form b of compound a . the compounds of the present invention can be prepared according to the following specific examples . those skilled in the art will readily understand that known variations of the conditions and processes of the following preparative procedures can be used to prepare these compounds . all temperatures are degrees celsius unless otherwise noted . to a 500 ml jacketed vessel with overhead agitation is charged 32 g compound a monohydrate form g and 106 . 7 ml n - methyl - 2 - pyrrolidone ( nmp ). the mixture is stirred and heated to 50 ° c . to this solution is added 35 . 7 ml h 2 o . the batch is then seeded with 0 . 64 g compound a hemihydrate form ii . the batch is aged for 15 minutes . to this slurry is then added 91 ml h 2 o over 7 hours via syringe pump , followed by 193 ml over 5 hrs . the batch is then cooled from 50 ° c . to 20 ° c . over three hours . after the cooldown , the batch is ika milled (˜ 30 turnovers ). the batch is then filtered , washed with 64 ml 1 : 3 ( v : v ) nmp : diw and then 64 ml 2 : 5 ( v : v ) etoh : diw . the batch is dried in a vacuum oven at 35 ° c . compound a hemihydrate form h (˜ 30 . 5 g ) was obtained as a yellow solid in a yield of approximately 95 %. raw material name mw charge amount ( kg ) moles eq / vol compound a ipa solvate 500 . 95 37 . 8 1 . 00 eq (~ 17 . 5 wt % ipa , free - base used as basis ) butylated hydroxytoluene 220 . 4 0 . 0143 0 . 064 150 ppm in ( bht ) nmp n - methyl - 2 - pyrrolidone 99 . 13 95 . 31 3 . 0 l / kg ( nmp ) freebase deionized water ( diw ) 18 215 . 3 7 l / kg freebase 3 : 1 diw : nmp ~ 70 l 2 . 25 l / kg freebase 9 : 1 diw etoh ~ 150 l 4 . 5 l / kg freebase 9 : 1 diw etoh ~ 150 l 4 . 5 l / kg freebase compound a hemihydrate 500 . 95 ~ 0 . 62 2 % seed ( form ii ) seed (~ 1 . 8 % water ) load n - methyl - 2 - pyrrolidone ( nmp ) with 150 ppm bht ( 2 . 0 l / kg ) and compound a ipa solvate ( 1 . 0 eq .) are charged to the reaction vessel . after all solids have dissolved , nmp with 150 ppm bht ( 1 . 0 l / kg ) is charged to rinse down the vessels / equipment . the vessel is heated to 60 c . and diw is charged slowly to the solution until diw content is 32 vol % diw (˜ 1 . 3 l / kg , 32 vol % relative to nmp ). the seed (˜ 2 wt %) is charged . the seed port is rinsed with 50 vol % nmp in diw . the seed bed is aged for 1 hour . once seed bed is established , diw is charged slowly and the water content is brought to 50 vol % over at least 2 hours (˜ 1 . 7 l / kg ). the remaining diw is charged slowly to the batch over 2 hours . the final water concentration should be 70 vol % (˜ 3 . 98 l / kg , total water addition ˜ 7 l / kg ). terminal ika milling at t & gt ; 50 ° c . for ˜ 30 turnovers is used to reduce particle size . if a significant number of fine particles are generated , a heat - cool cycle is performed . the heat cool cycle consists of heating the batch to 80 ° c . over 4 hours , holding at 80 ° c . for 4 hours , and cooling to 50 ° c . over 4 hours . the batch is filtered at temperature equal or higher than 50 ° ( t ≧ 50 ° c .). displacement wash was performed on the batch with hot ( t ≧ 50 ° c .) 75 % diw : 25 % nmp ( v : v ) ( 2 . 0 l / kg freebase ). the displacement wash is filtered . slurry wash of the batch is performed with hot ( t ≧ 50 ° c .) 90 % diw : 10 : etoh ( v : v ) ( 2 . 0 l / kg freebase ) and the slurry is filtered . the washing procedure was repeated with the same amount of hot 90 % diw : 10 : etoh ( v : v ). to avoid cake dehydration , the batch is humid dried at 65 ° c . to a 2 l rb flask with overhead agitation is charged 60 g compound a hemihydrate form ii and 180 ml n - methyl - 2 - pyrrolidone ( nmp ). the mixture is stirred and heated to 45 ° c . to dissolve . the batch is cooled to 40 ° c . to this solution is added 60 ml h 2 o over 30 min . the batch is then seeded with 1 . 2 g compound a hemihydrate form i . to this slurry is then added 114 ml h 2 o over 2 . 5 hours , followed by 306 ml over 2 . 5 hrs . the batch is then cooled from 40 ° c . to 20 ° c . after the cooldown , the batch is high shear rotor - stator wetmilled to reduce the particle size . the batch is then filtered , washed with ˜ 350 ml 2 : 5 ( v : v ) etoh : diw . the batch is dried with vacuum and n 2 stream at room temperature (˜ 20 ° c .). compound a hemihydrate form i ( 53 . 1 g ) was obtained as a light yellow solid in a yield of approximately 90 %. in addition to a mixture of hemihydrates , any other crystalline form of compound a free base can be used as a starting material for preparation of hemihydrate form i .
the instant invention relates to crystalline forms of mk - 1775 , an inhibitor of weel kinase . specifically , the instant invention relates to hemihydrates of mk - 1775 .