the compound of formula i used to practice this invention can be synthesized by conventional methods . in general , the compounds of the formulae described herein are conveniently obtained via standard organic chemistry synthesis methods , including those methods illustrated in the schemes and the examples ( e . g ., example 1 ) herein . as can be appreciated by the skilled artisan , the synthetic schemes herein are not intended to constitute a comprehensive list of all means by which the compounds described and claimed in this application can be synthesized . further methods will be evident to those of ordinary skill in the art . additionally , the various synthetic steps described above can be performed in an alternate sequence or order to give the desired compounds . synthetic chemistry transformations and protecting group methodologies ( protection and deprotection ) useful in synthesizing the compounds described herein are known in the art and include , for example , those such as described in r . larock , comprehensive organic transformations , vch publishers ( 1989 ); t . w . greene and p . g . m . wuts , protective groups in organic synthesis , 2nd . ed ., john wiley and sons ( 1991 ); l . fieser and m . fieser , fieser and fieser &# 39 ; s reagents for organic synthesis , john wiley and sons ( 1994 ); and l . paquette , ed ., encyclopedia of reagents for organic synthesis , john wiley and sons ( 1995 ); and subsequent editions thereof . as an example , the compounds used to practice this invention are prepared according to the synthetic scheme shown below . variables and groups in the chemical structural formulas in the methods below are defined as delineated herein for any of the formulae , including formula i . a solution of indolyl compound starting material in solvent ( e . g ., tetrahydrofuran , isopropanol , dichloromethane , dioxane , dimethyl formamide , dimethyl sulfoxide , or toluene ) is reacted with a base ( e . g ., sodium hydride , potassium hydroxide , or potassium tert - butoxide ) and a compound of the formula xch 2 r 3 ( where x is a leaving group ). the resulting intermediate is reacted with an oxalyl derivative and an amine of the formula mnr 1 r 2 ( where m is h or metal cation , e . g ., k , li , na ), to give compounds of the formulae delineated herein . the desired compounds or intermediates can be isolated and purified using standard synthetic techniques or can be reacted further ( i . e ., “ one - pot synthesis ”) without isolation or purification . alternatively , the compounds used to practice this invention are prepared according to the following synthetic scheme shown below : the indolyl starting material is dissolved in solvent ( e . g ., diethyl ether , tetrahydrofuran , or dichloromethane ) and reacted with an oxalyl derivative ( e . g ., oxalyl chloride ) and an amine of the formula mnr 1 r 2 ( where m is h or metal cation , e . g ., k , li , na ). the intermediate compound is reacted with a compound of the formula xch 2 r 3 ( where x is a leaving group ) to give compounds of the formulae herein . the desired compounds or intermediates can be isolated ( and optionally purified ) or can be reacted further ( i . e ., “ one - pot synthesis ” without isolation or purification ). the compound thus synthesized can be further purified by flash column chromatography , high performance liquid chromatography , crystallization , or any other suitable methods . to prepare the formulation of this invention , one can simply mix the compound of formula i , the tpgs , the transcutol , and optionally the peg at the desired ratio in any sequence . for example , one can mix a predetermined amount of the compound with transcutol and optionally peg at a predetermined concentration , and then add tpgs . mixing can be achieved by shaking , agitation , or swirling and is controlled to reconstitute the active ingredient ( s ) ( e . g ., the compound of formula i ) into the inactive ingredient ( s ) ( e . g ., tpgs , transcutol , and peg ). the formulation may be prepared at room temperature or heated at a temperature between 40 and 80 ° c . to facilitate the mixing process . at any stage of the preparation , sterilization , e . g ., by an autoclave , may be applied . the formulation of this invention may further contain one or more solid excipients minimize leakage of the liquid mixture from the capsule . the solid excipients can be included in the formulation at any stage of its preparation . the suitable concentration of a solid excipient in the formulation for conferring the intended effect , as recognized by those skilled in the art , can be assayed using conventional methods . the formulation of this invention , when administered orally to a subject in need thereof , is preferably encapsulated in a capsule ( e . g ., a soft or hard - shell capsule ). the capsule can be formed of a material that is well recognized by one skilled in the art , for example , porcine collagen , bovine collagen material , gelatin ( e . g ., porcine gelatin ), gum arabic , pectin , poly ( ethylene - co - maleic anhydride ), poly ( vinylmethylether - co - maleic anhydride ), carrageenan , and agar - agar . one can employ the formulation of this invention to treat cancer by administering orally to a subject in need of the treatment an effective amount of the formulation . as used herein , the term “ treating ” or “ treatment ” is defined as the administration of an effective amount of the formulation to a subject , who has cancer , a symptom of the cancer , a disease or disorder secondary to the cancer , or a predisposition toward the cancer , with the purpose to cure , alleviate , relieve , remedy , or ameliorate the cancer , the symptom of , the disease or disorder secondary to , or the predisposition toward the cancer . the term “ an effective amount ” refers to an amount of a compound of formula i in the formulation or an amount of the formulation which confers a therapeutic effect on the treated subject . the therapeutic effect may be objective ( i . e ., measurable by some test or marker ) or subjective ( i . e ., subject gives an indication of or feels and effect ). an effective amount of the compound described above may range from about 0 . 1 mg / kg to about 500 mg / kg body weight per day , alternatively from about 1 to about 50 mg / kg body weight per day . the formulation of this invention may be administered from 1 to 6 times per day ( e . g ., at 0 . 1 mg - 100 mg / dose ). the amount of active ingredient that can be combined with the carrier materials to produce a single dosage form may vary depending upon the host treated . a typical formulation of this invention will contain from 0 . 5 % to 20 % of an active compound ( w / w ). without further elaboration , it is believed that the above description has adequately enabled the present invention . the following examples are , therefore , to be construed as merely illustrative , and not limitative of the remainder of the disclosure in any way whatsoever . all of the publications cited herein are hereby incorporated by reference in their entirety . a solution of indole ( 1 . 17 g , 10 mmol ) in 10 ml tetrahydrofuran was added dropwise to a suspension of potassium tert - butoxide ( 1 . 34 g , 12 mmol ) in 10 ml tetrahydrofuran . the reaction mixture was stirred at room temperature for 2 hours , then 5 -( chloromethyl )- 3 - methylisoxazole ( 1 . 32 g , 10 mmol ) in 5 ml tetrahydrofuran was added dropwise . the solution was allowed stand for 4 hours and then 10 ml saturated ammonium chloride was added with stirring . the mixture was extracted three times with a total of 60 ml of ether , the organic phase was dried using anhydrous magnesium sulfate and filtered , and the filtrate was concentrated in vacuum and purified by flash chromatography on silica gel . the eluent used was a mixture of n - hexane and ethyl acetate in the ratio 8 : 1 ( vol / vol ). yield : 1 . 61 g , 76 %. a solution of 5 -( 1h - 1 - indolylmethyl )- 3 - methylisoxazole ( 212 mg , 1 . 0 mmol ) in 10 ml diethyl ether was added to oxalyl chloride ( 254 mg , 2 . 0 mmol ) dropwise at 0 ° c . the reaction mixture was stirred at 0 ° c . for 3 hours and then the reaction solvent was evaporated . the residue was dissolved in 5 ml tetrahydrofuran and then the 3 - methyl - 5 - isothiazolamine ( 114 mg , 1 . 0 mmol ) and triethylamine ( 1 ml ) in 10 ml tetrahydrofuran was added dropwise . the mixture was stirred for 10 hours and then 1 n naoh ( 4 ml ) was added to the reaction flask dropwise . the mixture was extracted three times with a total of 60 ml of tetrahydrofuran , the organic phase was dried using anhydrous magnesium sulfate and filtered , and the filtrate was concentrated in vacuum . the residue was crystallized from methanol . yield : 0 . 27 g , 71 %. nmr : 10 . 33 ( s , 1h ), 9 . 15 ( s , 1h ), 8 . 44 ( d , j = 6 . 3 hz , 1h ), 7 . 45 - 7 . 38 ( m , 3h ), 6 . 82 ( s , 1h ), 5 . 96 ( s , 1h ), 5 . 48 ( s , 2h ), 2 . 49 ( s , 3h ), 2 . 52 ( s , 3h ). bpr0c261 ( 5 mg ) was first dissolved in transcutol ( 99 mg ). then peg 400 ( 330 mg ) was added to the solution . tpgs ( 105 mg ) was heated at 60 - 70 ° c . until it was molten . the molten tpgs was then added to the transcutol / peg solution with constant stirring to form a homogenous solution . the solution was further stirred at 40 ° c . until it became a clear solution . the solubility of bpr0c261 in different drug carriers or mixed carriers was evaluated . the solubility is defined as the maximum amount of a compound dissolved in a carrier or mixed carrier at room temperature . the results are shown in table 1 below . b all of the percentages listed in this table were calculated based on a ratio of the initial volume of each individual carrier component to the sum of initial volumes of all components . the oral bioavailability of bpr0c261 was assessed by comparing the pharmacokinetic (“ pk ”) profiles obtained from orally administered (“ po ”) bpr0c261 in various oral formulation described herein with the pk profile obtained from intravenously administered (“ iv ”) bpr0c261 . an intravenous formulation of bpr0c261 ( carriers : 5 % dmso , 25 % cremophor el , and 70 % water , v / v / v ) was administered intravenously by a bolus injection to a group of three mice each via the tail vein , in a single dose of 2 mg / kg body weight . a blood sample ( 0 . 15 ml ) was drawn at different points ( pre - dose , 2 min , 5 min , 15 min , 30 min . 1 hr , 2 hr , 4 hr , 6 hr , 8 hr , and 24 hr after dosing ) from each animal via the cardiac puncture and stored in ice ( 0 - 5 ° c .). an oral formulation of bpr0c261 ( i . e ., the just - described formulation containing dmso , cremophor el , and water , or a formulation containing tpgs , transcutol , and optionally peg 400 ), was orally administered in various doses to groups of three mice by gavage . a blood sample ( 0 . 15 ml ) was drawn at different points ( pre - dose , 15 min , 30 min . 1 hr , 2 hr , 4 hr , 6 hr , 8 hr , and 24 hr after dosing ) from each animal via the cardiac puncture and stored in ice ( 0 - 5 ° c .). plasma was separated from the blood sample by centrifugation at 15 , 000 g for 15 min at 4 ° c . the separated plasma was then stored in a freezer (− 20 ° c .). all plasma samples were analyzed for the bpr0c261 concentrations by hplc - tandem mass spectrometry . bpr0c261 plasma concentration data were used to obtain the pk profile for the iv or po administration , i . e ., a plasma - concentration vs . time curve . the area under the curve (“ auc ”) was then calculated . oral bioavailability ( f %) was determined by comparing the dose - normalized area under the curve for the oral formulation (“ auc po / dose po ”) with that for the intravenous formulation (“ auc iv / dose iv ”), i . e ., f %=[ auc po / dose po ]/[ auc iv / dose iv ]. the oral bioavailability of bpr0c261 in the formulation containing 5 % dmso , 25 % cremophor el , and 70 % water ( v / v / v ) was determined to be 18 % in mouse . unexpectedly , the oral bioavailability of bpr0c261 in formulations containing tpgs , transcutol , and optionally peg 400 was determined to be in a range of 25 % to 80 %. all of the features disclosed in this specification may be combined in any combination . an alternative feature serving the same , equivalent , or similar purpose may replace each feature disclosed in this specification . thus , unless expressly stated otherwise , each feature disclosed is only an example of a generic series of equivalent or similar features . from the above description , one skilled in the art can easily ascertain the essential characteristics of the present invention , and without departing from the spirit and scope thereof , can make various changes and modifications of the invention to adapt it to various usages and conditions . thus , other embodiments are also within the scope of the following claims .
this invention relates to an oral formulation containing an effective amount of the compound of the following formula i : d - alpha - tocopheryl polyethylene glycol 1000 succinate ; and 2 - ethanol . r 1 through r 4 and n are defined herein . also disclosed is a method of treating cancer by administering this formula to a subject orally .