Patent Application: US-48974400-A

Abstract:
this invention relates to a series of substituted piperazines of formula ii , as well as enantiomers thereof these compounds are useful in the manufacture of pharmaceutical compositions .

Description:
the terms used in describing the invention are commonly used and known to those skilled in the art . however , the terms that could have other meanings are defined . “ hbss ” refers to hank &# 39 ; s balanced salt solution . “ independently ” means that when there are more than one substituent , the substitutents may be different . the term “ alkyl ” refers to straight , cyclic and branched - chain alkyl groups and “ alkoxy ” refers o - alkyl where alkyl is as defined supra . “ dmap ” refers to dimethylaminopyridine , “ tfa ” refers to trifluoroacetic acid , “ hobt ” refers to hydroxybenzotriazole hydrate , “ hatu ” refers to o -( 7 - azabenzotriazol - 1 - yl )- 1 , 1 , 3 , 3 - tetrametyluronium hexafluorophosphate , and “ edcl ” refers to 1 -( 3 - dimethylaminopropyl )- 3 - ethylcarbodiimide hydrochloride . the symbol “ ph ” refers to phenyl , and “ aryl ” includes mono and fused aromatic rings such as phenyl and naphthyl . the symbol “ cpda ” refers to 1 , 1 - cyclopentanediacetimid - 1 - yl and “ iid ” refers to 1h - isoindole 1 , 3 -( 2h ) dion - 1 - yl . the symbol “ es ” refers to electrospray and the symbol “ ms ” refers to mass spectrum . some of the compounds of formula i include a chiral carbon atom . therefore those compounds may be prepared as stereoisomers , racemic mixtures or pure enantiomers . all stereoisomers , pure enantiomers and racemic mixtures are considered to be within the scope of this invention . the compounds of the invention may be prepared by the following schemes , where some schemes produce more than one embodiment of the invention . in those cases , the choice of scheme is a matter of discretion which is within the capabilities of synthetic chemists . a compound of formula i where a , b , and e are carbon , r 1 is hydrogen , r 2 is phenyl , r 3 is hydroxy , r 4 is hydrogen , and r 5 is 3 - trifluoromethyl may be prepared using scheme 1 . the scheme assembles two halves of the desired molecule and couples them together using peptide coupling reagents . one half is prepared by treating 1 , 2 , 4 - benzenetricarboxylic anhydride , 1a , with a substituted aniline derivative , 1b , at about 130 ° c . in an acidic solvent such as glacial acetic acid for about 16 - 24 h to give the carboxy substituted phthalimido derivative 1c . the other half is prepared in two steps . first , 1 - azido - 3 -( p - toluenesulfonyloxy ) propan - 2 - ol 1d , is heated at about 100 ° c . with an appropriately substituted piperazine derivative , 1e for about 2 - 5 days to give the azide 1f . this azide is treated with pd / c and h 2 ( 50 psi ) in an inert solvent over 16 h to give the free amine 1g . this amine is treated with 1c , hobt , dmap , edcl , and n , n ′- diisopropylethylamine in methylene chloride at about room temperature for 2 - 6 h to give the desired compound of formula i . alternatively , 1c and 1g may be coupled using other peptide coupling agents such as hatu and dmap . this scheme may be used to prepare a number of compounds of formula i . for example , if compounds where a , b or e is nitrogen are desired , replace 1b with an amino pyridine derivative such as 2 - aminopyridine and follow the remaining steps of the scheme . to prepare compounds where r 1 and r 2 vary , simply replace the illustrated 1e with any known substituted piperazines . although the illustrated product was prepared from the racemic azide 1d , the pure enantiomers of this azide are known and can be used in this scheme . compounds where r 3 is carbonyl may be prepared by treating the products of scheme 1 with an oxidizing agent such as the swen &# 39 ; s reagent ( formed with oxalyl chloride and dmso ) at − 78 ° c . to room temperature over 30 min to 1 h . scheme 2 may be used to prepare compounds of formula i where a is nitrogen , r 3 is hydrogen , r 4 is hydrogen , and r 5 is hydrogen . treatment of 1 , 2 , 4 - benzenetricarboxylic anhydride , 2a , with the aniline derivative , 2b gives the phthalimide 2c . an appropriately substituted piperazine derivative α is treated with the n - boc protected 3 - bromopropylamine and cesium carbonate in acetonitrile at reflux for 16 h to give the substituted piperazine derivative 2f . this derivative is converted to the free amine , 2g , by treatment with tfa and methylene chloride at room temperature over 2 - 6 h . derivatives 2g and 2c were coupled using hobt , dmap , edcl , and n , n - diisopropylethylamine in methylene chloride at about room temperature for 2 - 6h to give the desired compound of formula i . as described in scheme 1 , scheme 2 may be modified to give all of the compounds of formula i . to produce compounds of the invention where r 4 is other than hydrogen , scheme 3 may be used . the amino group of intermediate 2g may be treated with an aldehyde 3a such as benzaldehyde to give the imine 3b . this intermediate may be reduce with nabh 4 at room temperature to give the monoamine 3c . this amine is coupled with a substituted phthalimide derivative , 2c using hatu , dmap and diisopropylethylamine in methylene chloride at about room temperature for 2 - 6 h to give the desired compound of formula i . as described in previous schemes , scheme 3 may be modified to give a number of compounds of formula i . for example , to produce a compound where r 3 is hydroxy , replace 2g with intermediate 1g and follow the remaining steps of scheme 3 . to produce compounds of the invention where r 3 is c 1 - 5 alkoxy , scheme 4 may be used . treatment of the azido derivative 1d with an appropriately substituted piperazine , such as 4a at about 100 ° c . for about 2 - 5 days gives intermediate 4b . this intermediate is treated with two equivalents of a strong organic base , such as sodium hydride in an inert solvent , such as thf , at 0 ° c . for about 1 - 5 h ; followed by treatment with an additional equivalent of base and an alkylating agent such as ethyl iodide , at 0 ° c . for about 1 - 5 h to give the ether 4c . this ether is treated with pd / c and h 2 ( ca . 50 psi ) in an inert solvent over 16 h to give the free amine 4d . this amine is coupled with a phthalimido derivative such as 4e with hatu and dmap to give the desired compounds of the invention . as discussed in schemes 1 - 3 , scheme 4 may be modified in a like manner to give all of the compounds of formula i . to produce pure enantiomers of compounds of formula i where r 3 is hydroxy , scheme 5 may be used . ( s )(+) epichlorohydrin ( 97 % ee ) may be treated with benzylamine in a suitable organic solvent such as hexane at about room temperature for about 48 - 72 hours to give hydroxy compound 5a . this intermediate may be treated with a boc reagent agent such as di - tert - butyl dicarbonate , and an organic base such as triethylamine in an inert solvent such as thf at about 0 ° c . to about room temperature over 10 to 24 h to give the n - protected derivative 5b . this intermediate may be treated with piperazine derivative , 5c , a basic reagents , such as potassium hydroxide , sodium hydroxide , or lithium hydroxide , in an alcoholic solvent such as methanol at about 0 ° c . to about room temperature over about 1 to about 3 days to give the coupled derivative 5d . this compound may be deprotected by treatment with an acidic reagents , such as tfa or 1 - 6n hcl , at about room temperature over 18 - 24 h to give free amine 5e . this amine may be debenzylated with using a reducing agents , such as palladium catalyst and ammonium formate , sodium in liquid ammonia , or palladium and hydrogen , in an alcoholic solvent such as etoh at about 45 - 60 ° c . over 20 h to give the primary amine 5f . this amine may be coupled to acids of type 5g using peptide coupling agents such as hatu to give a compound of formula i . as described in scheme i , scheme 5 may be modified to give a number of compounds of formula i . although the claimed compounds are useful as antagonists of α1 a - ar , some compounds are more active than others and are either preferred or particularly preferred . the preferred compounds of formula i include : r 5 , r 6 , and r 7 are independently selected from hydrogen , nitrile and amino , r 2 is c 1 - 6 alkyl , phenyl or substituted phenyl , r 5 , r 6 , and r 7 are independently selected from halogen , hydrogen , hydroxy , c 1 - 8 alkyl , c 1 - 5 alkoxy , and dic 1 - 5 alkylamino , r 11 is hydrogen , phenylc 1 - 5 alkyl , or c 1 - 5 alkoxy substituted phenyl . r 11 is phenylc 1 - 5 alkyl , or c 1 - 5 alkyl substituted phenyl , and the preferred basic reagent for producing a compound of formula ii is potassium hydroxide . the preferred acidic reagent for treating a compound of formula iii is trifluoroacetic acid . the preferred reducing agent for treating a compound of formula ii is ammonium formate and pd / c . as indicated by the biological activity , the compounds of formula i may be used in pharmaceutical compositions to treat patients ( humans and other primates ) with disorders related to inhibiting the activity of the α1 a adrenergic receptor . the preferred route is oral administration , however compounds may be administered by intravenous infusion . oral doses range from about 0 . 01 to about 100 mg / kg daily ; where the optimal dose range is about 0 . 1 to about 25 mg / kg / per day . infusion doses can range from about 0 . 001 - 1 mg / kg / min of inhibitor , admixed with a pharmaceutical carrier over a period ranging from several minutes to several days . the pharmaceutical compositions can be prepared using conventional pharmaceutical excipients and compounding techniques . oral dosage forms may be elixers , syrups , capsules tablets and the like . where the typical solid carrier is an inert substance such as lactose , starch , glucose , methyl cellulose , magnesium sterate , dicalcium phosphate , mannitol and the like ; and typical liquid oral excipients include ethanol , glycerol , water and the like . all excipients may be mixed as needed with disintegrants , diluents , granulating agents , lubricants , binders and the like using conventional techniques known to those skilled in the art of preparing dosage forms . parenteral dosage forms may be prepared using water or another sterile carrier . typically the compounds of formula i are isolated and used as free bases , however the compounds may be isolated and used as their pharmaceutically acceptable salts . examples of such salts include hydrobromic , hydroiodic , hydrochloric , perchloric , sulfuric , maleic , fumaric , malic , tartatic , citric , benzoic , mandelic , methanesulfonic , hydroethanesulfonic , benzenesulfonic , oxalic , pamoic , 2 - naphthalenesulfonic , p - toluenesulfonic , cyclohexanesulfamic and saccharic . in order to illustrate the invention the following examples are included . these examples do not limit the invention . they are meant only to suggest a method of practicing the invention . those skilled in the art may find other methods of practicing the invention , which are obvious to them . however those methods are deemed to be within the scope of this invention . the fumarate salt of 1 -( 2 - isopropoxyphenyl )- piperazine ( 3 . 91 g , 12 mmol ) was basified with 20 % naoh ( aq ) ( 100 ml ) and extracted with methylene chloride . the combined organic layers were dried ( na 2 so 4 ) and concentrated to give an oil ( 2 . 74 g ). a mixture of the oil and 1 - azido - 3 -( p - toluenesulfonyloxy ) propan - 2 - ol ( 3 . 25 g , 12 mmol , antonin holy , collect . czech . chem . comm . 1989 , 54 ( 2 ), 446 ) was stirred at 100 ° c . for 36 h . the cooled mixture was diluted with water and extracted with ether , dried ( na 2 so 4 ) and concentrated . the product was purified by column chromatography ( so 2 ) to yield compound 1 as ( 2 . 92 g , 76 %) as a light - brown solid : ms ( es ) m / z : 320 ( mh + ); anal . calcd for c16h25n5o2 : c , 60 . 17 ; h , 7 . 89 ; n , 21 . 93 . found : c , 60 . 45 ; h , 7 . 83 ; n , 22 . 01 . 10 % hcl ( 6 ml ) was added to a mixture of compound 1 ( 2 . 43 g , 7 . 6 mmol ) and 10 % pd / c ( 1 . 22 g ) in meoh ( 60 ml ) and the mixture was hydrogenated under h 2 ( 50 psi ) in a parr shaker for 16 h at 20 ° c . the mixture was filtered through celite and the filtrate was concentrated . the residue was basified with 20 % naoh and extracted with methylene chloride . the combined organic layers were dried ( na 2 so 4 ) and concentrated to yield compound 2 as a yellowish oil ( 2 . 2 g , 95 %): ms ( es ) m / z : 294 ( mh + ) a mixture of the 1 , 2 , 4 - benzenetricarboxylic anhydride ( 10 g , 52 mmol ) and 3 - fluoroaniline ( 5 . 77 g , 52 mmol ) in glacial acidic acid ( 200 ml ) was stirred at 130 ° c . for 16 h . the light - brown solution was cooled to 20 ° c . to give a yellow solid precipitate . the yellow solid was collected via filtration and was washed thoroughly with water to remove the trace amount of acetic acid . the product was dried at 60 ° c . for 36 h under vacuum to yield a yellow solid ( 11 . 41 g , 77 %): ms ( es ) m / z : 284 ( mh + ). a mixture of compound 2 ( 226 mg , 0 . 77 mmol ), compound 3 ( 220 mg , 0 . 77 mmol ), edcl ( 151 mg , 0 . 78 mmol ), hobt ( 105 mg , 0 . 78 mmol ), dmap ( cat .) and n , n - diisopropylethylamine ( 0 . 52 ml ) in methylene chloride ( 6 ml ) was stirred at 20 ° c . for 3 h . the mixture was concentrated , diluted with water and extracted with etoac . the combined organic layer was dried ( na 2 so 4 ), concentrated . the product was purified by column chromatography ( so 2 ) and further recrystallized from etoac / hexane to yield compound 4 ( 101 mg , 23 %) as a yellow solid : 1 h nmr ( 300 mhz , cdcl 3 ) δ 8 . 34 ( s , 1 h ), 8 . 30 ( d , j = 7 . 8 hz , 1 h ), 8 . 04 ( d , j = 7 . 8 hz , 1 h ), 7 . 48 ( m , 1 h ), 7 . 26 ( m , 1 h ), 7 . 14 ( m , 1 h ), 6 . 91 ( m , 6 h ), 4 . 59 ( m , 1 h ), 4 . 02 ( m , 1 h ), 3 . 79 ( m , 1 h ), 3 . 45 ( m , 1 h ), 3 . 13 ( m , 4 h ), 2 . 87 ( m , 2 h ), 2 . 62 ( m , 2 h ), 2 . 50 ( m , 2 h ), 1 . 34 ( d , j = 6 . 0 hz , 6 h ); ms ( es ) m / z : 561 ( mh + ). 3 - bromopropylamine hydrobromide ( 5 g , 22 . 8 mmol ) was dissolved in 10 % naoh ( 50 ml ), extracted with methylene chloride and concentrated . to the free base in methylene chloride was added ( boc ) 2 o ( 5 . 23 g , 23 . 9 mmol ) and this mixture was stirred at 20 ° c . for 4 h . the methylene chloride layer was washed with h 2 o , diluted citric acid ( 6 %), nahco 3 and sat nacl solution , dried and concentrated . the product was purified by column chromatography ( sio 2 ) to yield the protected amine ( 4 . 84 g , 89 %). the fumarate salt of 1 -( 2 - isopropoxyphenylypiperazine ( 5 . 1 g , 15 mmol ) was basified with 20 % naoh ( aq ) ( 100 ml ), extracted with methylene chloride , dried ( na 2 so 4 ) and concentrated to give a yellow oil ( 3 . 15 g ). a mixture of the oil , the protected amine ( 3 . 42 g , 14 . 3 mmol ), and cs 2 co 3 ( 4 . 66 g , 14 . 3 mmol ) in ch 3 cn ( 50 ml ) was heated at reflux overnight . solid was filtered off and the filtrate was evaporated . the product was purified by column chromatography ( sio 2 ) to yield compound 5 ( 4 . 4 g , 81 %): ms ( es ) m / z : 378 ( mh + ). compound 5 ( 3 . 97 g , 11 . 4 mmol ) was dissolved in 25 % tfa / methylene chloride ( 50 ml ). the reaction was stirred at rt for 5 h , the solvent was evaporated and solid residue was obtained . this solid was dissolved in 20 % naoh ( aq ) ( 100 ml ) and stirred for 40 min . then the free base was extracted into methylene chloride ( 3 ×). a light yellow oil was obtained ( 3 . 0 g , 95 %). a solution of this free amine ( 3 . 0 g , 10 . 8 mmol ) and diisopropylethyl amine ( 5 . 6 g , 43 . 3 mmol ) in methylene chloride ( 80 ml ) was added to a mixture containing edcl ( 2 . 08 g , 10 . 8 mmol ) hobt ( 1 . 46 g , 10 . 8 mmol ), catalytic amount of dmap and compound 3 ( 3 . 09 g , 10 . 8 mmol ). reaction was stirred overnight at 20 ° c . under n 2 . the reaction mixture was washed with water ( 3 ×). the product was purified by column chromatography ( sio 2 ) to yield compound 6 ( 1 . 34 g , 23 %): 1 h nmr ( 300 mhz , cdcl 3 ) δ 8 . 34 ( m , 2 h ), 7 . 99 ( d , j = 8 . 1 hz , 1 h ), 7 . 46 ( q , j = 8 . 0 , 6 . 4 hz , 1 h ), 7 . 18 ( m , 2 h ), 6 . 89 ( m , 4 h ), 4 . 57 ( q , j = 12 . 0 , 6 . 0 hz , 1 h ), 3 . 67 ( m , 2 h ), 3 . 09 ( brs , 4 h ), 2 . 71 ( m , 6 h ), 1 . 87 ( m , 2 h ), 1 . 33 ( d , j = 6 . 1 hz , 6 h ); ms ( es ) m / z : 545 ( mh + ). anal . calc &# 39 ; d for c 31 h 33 fn 4 o 4 : c , 68 . 37 ; h , 6 . 11 ; n , 10 . 29 . found : c , 68 . 13 ; h , 6 . 10 ; n , 10 . 17 . the fumarate salt of 1 -( 2 - isopropoxyphenyl )- piperazine ( 112 . 5 g , 345 mmol ) was basified with 20 % naoh ( aq ) ( 500 ml ) and extracted with methylene chloride ( 3 ×). the combined organic extracts were dried ( na 2 so 4 ) and concentrated to give about 70 g oil . a mixture of the oil and ( 2s )- 3 - azido - 2 - hydroxypropyl p - toluenesulfonate ( 91 g , 335 mmol , kristina juricova , collect . czech . chem . comm . 1995 , 60 , 237 ) was stirred at 100 ° c . in nmp in the presence of triethylamine ( 70 g , 690 mmol ) for 30 h . the cooled mixture was diluted with water and extracted with ether ( 3 × 500 ml ), back washed once with nacl ( sat ) ( 100 ml ), dried ( na 2 so 4 ) and concentrated . the product was purified by column chromatography ( sio 2 ) to yield compound 7 ( 70 . 6 g , 66 %) ( 98 . 8 % ee assay by chiralcel ad column ) as a off - white solid after recrystallization from methylene chloride / hexane : [ α ] d 25 − 3 . 6 ° ( c = 1 , ch 3 oh ); 1 h nmr ( 300 mhz , cdcl 3 ) δ 6 . 91 ( m , 4 h ), 4 . 59 ( m , 1 h ), 3 . 93 ( m , 1 h ), 3 . 67 ( brs , 1 h ), 3 . 42 ( dd , j = 12 . 6 , 3 . 8 hz , 1 h ), 3 . 23 ( dd , j = 12 . 6 , 5 . 4 hz , 1 h ), 3 . 12 ( m , 4 h ), 2 . 83 ( m , 2 h ), 2 . 53 ( m , 3 h ), 2 . 42 ( dd , j = 12 . 2 , 3 . 8 hz , 1 h ), 1 . 34 ( d , j = 6 . 0 hz , 6 h ); ms ( es ) m / z : 320 ( mh + ). 10 % hcl ( 6 ml ) was added to a mixture of compound 7 ( 15 g , 47 mmol ) and 10 % pd / c ( 4 g ) in meoh ( 100 ml ) and the mixture was hydrogenated under h 2 ( 50 psi ) in a parr shaker for 21 h at 20 ° c . the resulting mixture was filtered through celite and the filtrate was concentrated . the residue was basified with 20 % naoh ( aq ) ( 75 ml ) and extracted with methylene chloride ( 3 ×), dried ( na 2 so 4 ) and concentrated to yield compound 8 as a yellowish oil ( 14 g ,˜ 100 %): [ α ] d 25 + 23 . 6 ° ( c = 1 , chcl 3 ); 1 h nmr ( 300 mhz , cdcl 3 ) δ 6 . 91 ( m , 4 h ), 4 . 59 ( m , 1 h ), 3 . 76 ( m , 1 h ), 3 . 12 ( m , 4 h ), 2 . 83 ( dd , j = 12 . 7 , 3 . 7 hz , 2 h ), 2 . 82 ( m , 1 h ), 2 . 25 - 2 . 68 ( m , 8 h ), 1 . 34 ( d , j = 6 . 1 hz , 6 h ); ms ( es ) m / z : 294 ( mh + ). compound 8 ( 1 g , 3 . 41 mmol ) was dissolved in a mixture of diisopropylethyl amine ( 2 . 3 ml , 13 . 6 mmol ) and methylene chloride ( 10 ml ). to the above light - yellowish solution was added compound 3 ( 970 mg , 3 . 4 mmol ) and hatu ( 1 . 296 g , 3 . 41 mmol ) and stirred at 20 ° c . for 18 h , concentrated . 10 % k 2 co 3 ( aq ) was added and the mixture was extracted with ether ( 3 ×), dried ( na 2 so 4 ), and concentrated . the product was purified by column chromatography ( sio 2 , etoac / hexane then methylene chloride / acetone ) to give an a oily solid . the product was further recrystallized from etoac / hexane to give compound 9 as a yellow solid ( 830 mg , 43 %): [ α ] d 25 + 8 . 3 ° ( c = 1 , chcl 3 ); 1 hnmr ( 300 mhz , cdcl 3 ) δ 8 . 34 ( s , 1 h ), 8 . 30 ( d , j = 7 . 8 hz , 1 h ), 8 . 04 ( d , j = 7 . 8 hz , 1 h ), 7 . 48 ( m , 1 h ), 7 . 26 ( m , 1 h ), 7 . 14 ( m , 1 h ), 6 . 91 ( m , 6 h ), 4 . 59 ( m , 1 h ), 4 . 02 ( m , 1 h ), 3 . 79 ( m , 1 h ), 3 . 45 ( m , 1 h ), 3 . 13 ( m , 4 h ), 2 . 87 ( m , 2 h ), 2 . 62 ( m , 2 h ), 2 . 50 ( m , 2 h ), 1 . 34 ( d , j = 6 . 0 hz , 6 h ); ms ( es ) m / z : 561 ( mh + ). a mixture of the 1 , 2 , 4 - benzenetricarboxylic anhydride ( 2 g , 10 . 4 mmol ), and 3 - aminopyridine ( 0 . 98 g , 10 . 4 mmol ) in glacial acidic acid ( 40 ml ) was stirred at 130 ° c . for 16 h . the mixture was cooled and the white solid was filtered off and was washed with water . the product was dried for 24 h under vacuum to yield compound 10 as a white solid ( 2 . 55 g , 91 %) ms ( es ) m / z : 267 ( mh + ). a mixture of compound 2 ( 0 . 2 g , 0 . 68 mmol ), edcl ( 132 mg , 0 . 68 mmol ), hobt ( 94 mg , 0 . 68 mmol ), dmap ( cat . ), compound 10 ( 0 . 18 g , 0 . 68 mmol ) and n , n - diisopropylethylamine ( 0 . 46 ml , 2 . 72 mmol ) in methylene chloride ( 6 ml ) was stirred at 20 ° c . overnight . the mixture was concentrated and purified by column chromatography ( sio 2 , methylene chloride / acetone = 10 : 1 to 1 : 1 ) to yield compound 11 as a solid ( 67 mg , 18 %): ms ( es ) m / z : 544 ( mh + ). compound 1 ( 0 . 8 g , 2 . 5 mmol ) was dissolved in anhydrous thf ( 50 ml ). the solution was cooled to 0 ° c . and 60 % nah ( 0 . 2 g , 5 . 0 mmol ) was added . the solution was stirred for 10 min and ch 3 l ( 0 . 53 g , 3 . 8 mmol ) was added . the reaction mixture was stirred at 0 ° c . for 2 h , nah ( 0 . 1 g , 2 . 5 mmol ) and ch 3 l ( 0 . 15 ml ) were added and this mixture was stirred for another 2 h . the reaction was quenched with sat nh 4 cl , the solvent was evaporated and the aqueous layer was washed with methylene chloride ( 3 ×), dried ( na 2 so 4 ) and concentrated . the product was purified by column chromatography ( silica gel ) to yield compound 12 ( 0 . 69 g , 83 %): ms ( es ) m / z : 334 ( mh + ). 10 % hcl ( 0 . 3 ml ) was added to a mixture of compound 12 ( 0 . 64 g , 1 . 9 mmol ) and 10 % pd / c ( 0 . 13 g ) in meoh ( 5 ml ). this mixture was hydrogenated under h 2 ( 50 psi ) in a parr shaker overnight , filtered through celite and the filtrate was concentrated . the residue was basified with 20 % naoh and extracted with methylene chloride ( 3 ×), dried ( na 2 so 4 ) and concentrated to give a yellow oil at quantitative yield . ms ( es ) m / z : 308 ( mh + ). compound 13 ( 0 . 15 g , 0 . 49 mmol ) was dissolved in methylene chloride ( 4 ml ) and 4 eq of diisopropylethyl amine ( 0 . 25 g , 1 . 95 mmol ) was added . to this solution was added a mixture of hatu , ( 0 . 185 g , 0 . 49 mmol ) and compound 3 ( 0 . 14 g , 0 . 49 mmol ) and the reaction was stirred overnight under n 2 at rt . the solvent was evaporated and the product was purified by flash chromatography ( sio 2 , methylene chloride / acetone = 10 : 1 , 8 : 1 , 6 : 1 , 4 : 1 , 2 : 1 ). the product was recrystallized from etoacthexane to yield light yellow solid 0 . 08 g ( 29 %): 1 h nmr ( 300 mhz , cdcl 3 ) δ 8 . 36 ( m , 2 h ), 8 . 18 ( brs , 1 h ), 8 . 02 ( d , j = 7 . 69 hz , 1 h ), 7 . 47 ( m , 1 h ), 7 . 22 ( m , 3 h ), 7 . 00 ( m , 1 h ), 6 . 87 ( m , 3 h ), 4 . 57 ( m , 1 h ), 3 . 76 ( m , 3 h ), 3 . 50 ( s , 3 h ), 3 . 22 ( m , 10 h ), 1 . 35 ( d , j = 6 . 0 hz , 6 h ); ms ( es ) m / z : 575 ( mh + ). a mixture of ( s )-(+)- epichlorohydrin ( 10 g , 108 . 1 mmol , aldrich , 97 % ee ) and benzylamine ( 11 . 57 g , 108 . 1 mmol ) in hexane ( 40 ml ) were stirred at 20 ° c . for 62 h . white solid precipitated . more hexane (˜ 350 ml ) added , stirred for 20 min . and sonicated to break the big chunks of white solid . the white solid was collected by filtration and washed with hexane , dried under vacuum to give 19 . 8 g ( 92 %) white solid . the white solid was recrystallized from etoac / hexane to give 17 . 76 g ( 82 %) of 15 as a white crystalline solid ; 1 h nmr ( 300 mhz , cdcl 3 ) δ 7 . 31 ( m , 5 h ), 3 . 88 ( m , 1 h ), 3 . 79 ( m , 2 h ), 3 . 53 ( d , j = 5 . 3 hz , 2 h ), 2 . 89 ( m , 2 h ), 2 . 81 ( dd , j = 12 . 4 , 4 . 1 hz , 1 h ), 2 . 69 ( dd , j = 12 . 2 , 7 . 9 hz , 1 h ); ms ( es ): 200 ( mh + ); anal . calcd . for c 10 h 14 nocl : c , 60 . 15 ; h , 7 . 07 ; n , 7 . 01 . found : c , 60 . 10 ; h , 7 . 02 ; n , 6 . 92 . boc 2 o ( 11 g , 50 . 1 mmol ) and triethylamine ( 10 . 12 g , 100 mmol ) were dissolved in thf ( 25 ml ) and cooled to 0 ° c . the amine 15 ( 10 g , 50 . 1 mmol ) was added in portions and stirred for 20 h while the temperature was warmed up to 20 ° c . overnight . the solvent was concentrated in vacuo and water wasadded . the mixture was extracted with ether ( 3 ×), dried ( na 2 so 4 ) and concentrated . the crude residue was recrystallized from etoac / hexane to give 9 . 9 g ( 66 %) of 16 as a white crystalline solid . the filtrate was concentrated ( 3 . 1 g as oil ) and more product was purified by column chromatography ( short column , 8 cm height of sio 2 , etoac / hexane as solvent ). the oil was recrystallized from etoac / hexane to give another 2 . 78 g ( 18 %) of 16 as a white crystaline solid ; [ α ] d 25 =− 10 . 2 ° ( c = 1 , chcl 3 ); 1 h nmr ( 300 mhz , cdcl 3 ) δ 7 . 22 - 7 . 36 ( m , 5 h ), 4 . 52 ( m , 2 h ), 4 . 30 ( brs , 0 . 5 h ), 3 . 96 ( m , 1 h ), 3 . 36 - 3 . 97 ( m , 4 h ), 1 . 47 ( s , 9 h ); ms ( es ): 322 ( m + na ); anal . calcd . for c 15 h 22 no 3 cl : c , 60 . 10 ; h , 7 . 40 ; n , 4 . 67 . found : c , 60 . 26 , h , 7 . 42 ; n , 4 . 63 . koh ( 11 . 23 g , 200 . 5 mmol ) was dissolved in methanol ( 280 ml ), and the fumarate salt of 1 -( 2 - isopropoxyphenyl )- piperazine ( 10 . 9 g , 33 . 4 mmol ) was added and stirred at 20 ° c . for 20 min then cooled to 0 ° c . the boc - protected amine 16 ( 10 g , 33 . 4 mmol ) was added to the methanol solution at 0 ° c . and stirred for 20 h while the temperature was warm up to 20 ° c . overnight . the solvent was removed , water was added and the mixture was extracted with ether ( 3 ×), dried ( na 2 so 4 ) and concentrated . the product was purified by column chromatography ( short column , 8 cm height sio 2 , etoac / hexane as solvent ) to give 10 . 22 g ( 63 %) of 17 (˜ 100 % ee , chiralpak od 4 . 6 × 250 mm . 1 ml / min , 254 nm , mobile phase : 90 / 10 / 0 . 1 of hexane / ipa / 0 . 1 % diethylamine ) as a yellowish oil ; 1 h nmr ( 300 mhz , cdcl 3 ) δ 7 . 26 - 7 . 35 ( m , 5 h ), 6 . 91 ( m , 4 h ), 4 . 68 ( d , j = 15 . 6 hz , 1 h ), 4 . 59 ( m , 3 h ), 3 . 95 ( m , 1 h ), 3 . 35 ( m , 2 h ), 3 . 11 ( m , 4 h ), 2 . 75 ( m , 2 h ), 2 . 54 ( m , 2 h ), 2 . 38 ( m , 2 h ), 1 . 45 ( m , 9 h ), 1 . 34 ( d , j = 6 . 1 hz , 6 h ); ms ( es ): 484 ( mh + ). a mixture of compound 17 ( 233 mg , 0 . 48 mmol ) and 25 % tfa / methylene chloride ( 3 ml ) was stirred at 20 ° c . for 18 h . the solvent was concentrated in vacuo and the residue was basified with 20 % naoh ( aq ), extracted with methylene chloride ( 3 ×), dried ( na 2 so 4 ) and concentrated to give 174 mg (˜ 95 %) of 18 as an oil which was used directly without further purification ; ms ( es ): 384 ( mh + ). to a mixture of 18 (˜ 154 mg , 0 . 4 mmol ) and 10 % pd / c ( 154 mg ) in etoh ( 3 ml ) was added ammonium formate ( 151 mg , 2 . 4 mmol ) and stirred at 55 - 60 ° c . for 20 h . the mixture was filtered thru celite and washed with methanol . the filtrate was concentrated . the product was purified by a short column ( 5 cm height of sio 2 ) to give 63 mg ( 54 %) of 19 as a oil ; [ α ] d 25 + 23 . 6 ° ( c = 1 , chcl 3 ); 1 h nmr ( 300 mhz , cdcl 3 ) δ6 . 91 ( m , 4 h ), 4 . 59 ( m , 1 h ), 3 . 76 ( m , 1 h ), 3 . 12 ( m , 4 h ), 2 . 83 ( dd , j = 12 . 7 , 3 . 7 hz , 2 h ), 2 . 82 ( m , 1 h ), 2 . 25 - 2 . 68 ( m , 8 h ), 1 . 34 ( d , j = 6 . 1 hz , 6 h ); ms ( es ): 294 ( mh + ). a mixture of the 1 , 2 , 4 - benzenetricarboxylic anhydride ( 7 g , 36 . 4 mmol ), and n , n - dimethyl - 1 , 4 - phenylenediamine ( 4 . 96 g , 36 . 4 mmol ) in glacial acidic acid ( 120 ml ) was stirred at 130 ° c . for 16 h . the reaction solution was cooled to 20 ° c . and light brown solid precipitated out . the solid was collected thru filtration and was washed thoroughly with water to remove the trace amount of acetic acid . the product was dried at 40 ° c . for 36 h under vacuum to yield 8 . 0 g ( 71 %) of 20 as a light brown solid : 1 h nmr ( 300 mhz , dmso - d 6 ) δ8 . 40 ( d , j = 8 . 5 hz , 1 h ), 8 . 28 ( s , 1 h ), 8 . 05 ( d , j = 7 . 8 hz , 1 h ), 7 . 22 ( d , j = 8 . 9 hz , 2 h ), 6 . 82 ( d , j = 8 . 9 hz , 2 h ), 2 . 96 ( s , 6 h ); ms ( es ): 309 ( mh + ). the piperazine 19 ( 0 . 4 g , 1 . 36 mmol ) was dissolved in a mixture of diisopropylethyl amine ( 0 . 7 g , 5 . 46 mmol ) and methylene chloride ( 10 ml ). to the above solution was added compound 20 ( 420 mg , 1 . 36 mmol ) and hatu ( 0 . 52 g , 1 . 36 mmol ) and stirred at 20 ° c . for 18 h . the reaction mixture was washed with 3 % k 2 co 3 ( aq ) and the organic layer was dried ( na 2 so 4 ), and concentrated . the product was purffied by column chromatography ( sio 2 , ch 2 cl 2 / acetone = 10 : 1 , 8 : 1 , 6 : 1 , 4 : 1 , 2 : 1 ) to give 0 . 33 g ( 41 %) of cpd . 21 as a light brown solid : 1 hnmr ( 300 mhz , cdcl 3 ) δ 8 . 27 ( m , 2 h ), 8 . 00 ( d , j = 7 . 7 hz , 1 h ), 7 . 23 ( s , 1 h ), 6 . 90 ( m , 5 h ), 6 . 79 ( d , j = 8 . 9 hz , 2 h ), 4 . 59 ( m , 1 h ), 4 . 00 ( m , 1 h ), 3 . 83 ( m , 1 h ), 3 . 44 ( m , 1 h ), 3 . 12 ( brs , 4 h ), 3 . 00 ( s , 6 h ), 2 . 85 ( m , 2 h ), 2 . 52 ( m , 4 h ) 1 . 34 ( d , j = 6 . 1 hz , 6 h ); ms ( es ): 586 ( mh + ) [ α ] d 25 = 9 . 6 ° ( c = 0 . 2 , chcl 3 ). the biological activity and selectivity of the compounds of the invention was demonstrated by the following assays . the first assay tested the ability of compounds of formula i to bind to membrane bound receptors α1 a - ar , α1 b - ar and α1 d - ar . the dna sequences of the three cloned human α1 - ar subtypes have been published . furthermore , the cloned cdnas have been expressed both transiently in cos cells and stably in a variety of mammalian cell lines ( hela , lm ( tk −), cho , rat - 1 fibroblast ) and have been shown to retain radioligand binding activity and the ability to couple to phosphoinositide hydrolysis . we used published dna sequence information to design primers for use in rt - pcr amplification of each subtype to obtain cloned cdnas . human poly a + rna was obtained from commercially available sources and included hippocampus and prostate samples , sources which have been cited in the literature . for the primary screen a radioligand binding assay was used which employed membrane preparations from cells expressing the individual cloned receptor cdnas . radiolabeled ligands with binding activity on all three subtypes ( non - selective ) are commercially available ([ 125i ]- heat , [ 3h ]- prazosin ). each α1 receptor subtype was cloned from poly a + rna by the standard method of reverse transcription - polymerase chain reaction ( rt - pcr ). the following sources of polya + rna were used for the cloning of the α1 receptor subtypes : α1 d - ar , human hippocampus and prostate , α1 b - ar , human hippocampus , α1 d - ar , human hippocampus . the resulting cdnas were cloned into the pcdna3 mammalian expression vector ( invitrogen corp ., san diego calif .). each dna was sequenced for verification and to detect any possible mutations introduced during the amplification process . any deviation in sequence from the published consensus for each receptor subtype was corrected by site - directed mutagenesis . the three α1 - ar subtypes ( a , b , d ) were transfected into cos cells using a standard deae - dextran procedure with a chloroquine shock . in this procedure , each tissue culture dish ( 100 mm ) was inoculated with 3 . 5 × 10 6 cells and transfected with 10 μg of dna . approximately 72 hours post - transfection , the cells were harvested and cos membranes were prepared . transfected cos cells from 25 plates ( 100 mm ) were scraped and suspended in 15 ml of te buffer ( 50 mm tris - hcl , 5 mm edta , ph7 . 4 ). the suspension was disrupted with a homogenizer . it was then centrifuged at 1000 × g for 10 minutes at 4 ° c . the supernatant was centrifuged at 34 , 500 × g for 20 minutes at 4 ° c . the pellet was resuspended in 5 ml tne buffer ( 50 mm tris - hcl , 5 mm edta , 150 mm nacl , ph7 . 4 ). the resulting membrane preparation was aliquoted and stored at − 70 ° c . the protein concentration was determined following membrane solubilization with tritonx - 100 . the ability of each compound to bind to each of the α1 - ar subtypes was assessed in a receptor binding assay . [ 125i ]- heat , a non - selective α1 - ar ligand , was used as the radiolabeled ligand . each well of a 96 - well plate received : 140 μl tne , 25 ml [ 125i ]- heat diluted in tne ( 50 , 000 cpm ; final concentration 50 pm ), 10 μl test compound diluted in dmso ( final concentration 1 pm - 10 μm ), 25 ml cos cell membrane preparation expressing one of the three α1 - ar subtypes ( 0 . 05 - 0 . 2 mg membrane protein ). the plate was incubated for 1 hour at room temperature and the reaction mixtures were filtered through a packard gf / c unifilter filter plate . the filter plate was dried for 1 hour in a vacuum oven . scintillation fluid ( 25 ml ) was added to each well , and the filter plate was counted in a packard topcount scintillation counter . data was analyzed using graphpad prism software . tables a through d list the ic 50 values expressed in nanomolar concentration for select compounds of the invention in all receptor subtypes . the selectivity of the compounds of the invention for prostate tissues over aortic tissues was demonstrated as follows . the contractile responses of rat prostatic tissue and rat aorta tissues were examined in the presence and absence of antagonist compounds . as an indication of the selectivity of antagonism , test compound effects on vascular smooth muscle contractility ( α1 b - ar and α1 d - ar ) were compared to the effects on prostatic smooth muscle ( α1 a - ar ). strips of prostatic tissue and aortic rings were obtained from long evans derived male rats weighing 275 grams and sacrificed by cervical dislocation . the prostate tissue was placed under 1 gram tension in a 10 ml bath containing phosphate buffered saline ph 7 . 4 at 32 ° c . and isometric tension was measured with force transducers . the aortic tissue was placed under 2 grams tension in a 10 ml bath containing phosphate buffered saline ph 7 . 4 at 37 ° c . the ability of test compound to reduce the norepinephrine - induced contractile response by 50 % ( ic 50 ) was determined . compound 4 inhibited the contractile response in aortic tissue with an ic , of 63 . 2 μm and in prostate tissue with an ic 50 of 0 . 64 μm . compound 6 inhibited the contractile response in aortic tissue with an ic 50 of 2 . 8 μm and in prostate tissue with an ic 50 of 0 . 13 μm . compound 9 inhibited the contractile response in aortic tissue with an ic 50 of 6 . 5 μm and in prostate tissue with an ic 50 of 0 . 23 μm . compound 45 inhibited the contractile response in aortic tissue with an ic 50 of 3 . 3 μm and in prostate tissue with an ic 50 of 0 . 04 μm . compound 34 inhibited the contractile response in aortic tissue with an ic 50 of 42 . 5 μm and in prostate tissue with an ic 50 of 0 . 75 μm . compound 21 inhibited the contractile response in aortic tissue with an ic 50 of 22 . 4 μm and in prostate tissue with an ic 50 of 0 . 81 μm . select compounds of the invention were tested for their ability to antagonize phenylephrine ( pe ) induced increases in intraurethral pressure in dogs . the selectivity of these compounds was demonstrated by comparing their effect upon pe induced increases in mean arterial pressure ( map ) in the dog . male beagle dogs were anesthetized and catheterized to measure intraurethral pressure ( iup ) in the prostatic urethra . mean arterial pressure ( map ) was measured using a catheter placed in the femoral artery . dogs were initially administered six i . v . bolus doses ( 1 to ≦ 32 mg / kg ) of phenylephrine ( pe ) to establish a control agonist dose - response curve . iup and map were recorded following each dose until the iup returned to baseline . the dogs then were given an i . v . bolus dose of the antagonist compound , followed by i . v . pe challenges of ascending doses , as in the control agonist doseresponse curve . iup and map measurements following each pe challenge were recorded . the antagonist compound was tested over a dose range of 3 to 300 ug / kg in half - log increments . the interval between antagonist doses was at least 45 min and three experiments were performed for each test compound . fig1 and 2 illustrate the mean percentage reductions in iup and map for compounds 21 and 46 respectively . the duration of select compounds of the invention was determined by the measuring the iup and map responses to repeated pe challenges in conscious dogs over time . male beagles dogs were instrumented for the continuous measurement of arterial blood pressure by implanting a catheter containing a pressure transducer into the abdominal aorta via the femoral artery . the telemetry transmitter was positioned subcutaneously in the animal &# 39 ; s flank . iup was monitored with a catheter positioned in the prostatic urethra . prior to antagonist test compound administration , the iup and map responses to a 20 μg / kg i . v . dose of pe were determined and repeated several times to establish a baseline ( 100 % maximal ) response . an oral bolus dose of antagonist was administered , followed by a 20 μg / kg i . v . pe challenge at 0 . 5 , 1 , 1 . 5 , 2 , 4 , 6 , 12 , and 24 hours post dosing . the iup and map responses following each pe challenge were recorded . compound 21 was tested at doses of 0 . 1 , 0 . 3 , and 1 mg / kg . the iup and map responses at each time point following the pe challenge are presented in fig1 and 2 as the percent of the maximal response . m . barry & amp ; c . roehbom , management of benign prostatic hyperplasia , 48 annu . rev . med . 177 - 89 ( 1997 ), bruno j f , whiftaker j , song j , and berelowitz m . 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