this invention comprises , as one embodiment , a new class of k cat or suicide enzyme inhibitors , which are organic sulfoxides of formula : ## str4 ## or a pharmaceutically acceptable salt thereof , wherein x is hydrogen , fluoro , chloro , bromo , iodo , c 2 - 4 alkanoyloxy , toluenesulfonyloxy , benzenesulfonyloxy , c 1 - 3 alkanesulfonyloxy , p - nitrobenzoyloxy , or the like , or ## str5 ## y is hydrogen or ## str6 ## and z is fluoro , chloro , bromo , iodo , c 2 - 4 alkanoyloxy , toluenesulfonyloxy , benzenesulfonyloxy , c 1 - 3 alkanesulfonyloxy , p - nitrobenzoyloxy , or the like , or ## str7 ## or y and z taken together form ═ ch 2 ; with the proviso that one and only one of x , y and z is a sulfoxide group , and one and only one of x and z is fluoro , chloro , bromo , iodo , c 2 - 4 alkanoyloxy , toluenesulfonyloxy , benzenesulfonyloxy , c 1 - 3 alkanesulfonyloxy , p - nitrobenzoyloxy , or the like ; wherein many disease states of mammals , including humans , are known to depend for their progress on the activity or hyperactivity of particular enzymes and treatment of many of these diseases have been devised around inhibitors of these enzymes . accordingly , the novel enzyme inhibitors of this invention have utility in the study of certain disease states and in their treatment . generally the novel enzyme inhibitors of this invention produce the desired effect when administered at from 0 . 1 to about 500 mg / kg body weight , preferably at from 1 to about 50 mg / kg of body weight . the preferred form of delivery of the instant compounds to domestic animals is by solution in drinking water or by inclusion in preformulated feedstuffs . for human and animal administration , any of the usual pharmaceutical oral forms may be employed such as tablets elixirs , aqueous suspensions or the like comprising from about 0 . 1 to about 500 mg of the compounds of this invention . sterile solutions ( representatively given for human treatment ) for injection comprising from about 0 . 1 to about 500 mg of the compounds of this invention given two to four times daily are also suitable means of delivery . representative specific members of the new class of suicide enzyme inhibitors are shown in table i along with the enzyme to be inhibited and the pharmacological or medical effect to be elicited . in each case , r represents o - or p - nitrophenyl , o - or p - cyanophenyl , o or p - methoxycarbonylphenyl , o - or p - methylsulfonylphenyl , o , p - di ( trifluoromethyl ) phenyl , trifluoromethyl , trichloromethyl , 2 - pyrimidinyl , 2 - pyridyl , 2 - imidazolyl , 2 - thienyl , 2 - thiazolyl , 2 - oxazolyl , o - methylphenyl , o - ethylphenyl , o - propylphenyl , o , o - di ( methyl ) phenyl , o , o - di ( ethyl ) phenyl , or o , o - di ( propyl ) phenyl . table i__________________________________________________________________________ use , pharmacological orinhibitor enzyme inhibited medical effect__________________________________________________________________________ ## str8 ## ## str9 ## histidine decarboxylase antihistamine ## str10 ## ## str11 ## histidine decarboxylase antihistamine ## str12 ## ## str13 ## dopa decarboxylase antihypertensive antiparkinson when administered with l - dopa ## str14 ## ## str15 ## dopa decarboxylase antihypertensive antiparkinson when administered with l - dopa ## str16 ## ## str17 ## ornithine decarboxylase anti - psoriasis anti - arthritis anti - canc er ## str18 ## ## str19 ## ornithine decarboxylase anti - psoriasis anti - arthritis anti - canc er ## str20 ## ## str21 ## ## str22 ## tryptophan decarboxylase antiserotonin ## str23 ## ## str24 ## tryptophan decarboxylase antiserotonin ## str25 ## ## str26 ## tyrosine hydroxylase antihypertensive ## str27 ## ## str28 ## tyrosine hydroxylase antihypertensive__________________________________________________________________________ the novel process for preparing the novel compounds of this invention comprises oxidation of an aromatic thio compound of structure : ## str29 ## wherein x 1 is hydrogen , fluoro , chloro , bromo , iodo , c 2 - 4 alkanoyloxy , toluenesulfonyloxy , benzenesulfonyloxy , c 1 - 3 alkanesulfonyloxy , p - nitrobenzoyloxy , or the like , or ## str30 ## y 1 is hydrogen or ## str31 ## and z 1 is fluoro , chloro , bromo , iodo , c 2 - 4 alkanoyloxy , toluenesulfonyloxy , benzenesulfonyloxy , c 1 - 3 alkanesulfonyloxy , p - nitrobenzoyloxy , or the like , or ## str32 ## or y and x taken together form ═ ch 2 ; with the proviso that one and only one of x , y and z is a thio group , and one and only one of x and z is fluoro , chloro , bromo , iodo , c 2 - 4 alkanoyloxy , toluenesulfonyloxy , benzenesulfonyloxy , c 1 - 3 alkanesulfonyloxy , p - nitrobenzoyloxy , or the like ; and r , and r 1 are as previously defined with the exception that any of the substituents which are sensitive to the conditions of oxidation of sulfide to sulfoxide carry protective groups . the oxidizing agent is such as 1 - chlorobenzotriazole , h 2 o 2 / v 2 o 5 , so 2 cl 2 / h 2 o / silica gel , cl 2 , br 2 , naio 4 , acetyl nitrile , tl ( no 3 ) 3 , or a peracid such as m - chloroperbenzoic acid , preferably the latter . the oxidation with a peracid is conducted at temperatures from - 70 ° c . to about 30 ° c ., preferably at about 0 °- 25 ° c ., in an organic solvent such as an aromatic solvent , for example benzene , toluene or the like ; or a chlorinated hydrocarbon such as tetrachloroethylene , chloroform , methylene chloride or the like , for times of a few minutes to about 4 hours . after the oxidation is substantially complete , any protective groups present are removed by standard procedures such as treatment with a strong organic acid such as trifluoroacetic acid to remove t - butyloxycarbonyl groups from amines and to cause deesterification ; strong mineral acids to remove trityl groups from amines ; and strong bases such as sodium hydroxide or potassium hydroxide to saponify esters . 2 - fluoromethyl histidine methyl ester , 2 . 01 g ( 10 mmoles ) and 1 . 48 g of phthalic anhydride ( 10 mmoles ) are ground together in a mortar and then heated together 2 hours at 150 ° c . to form compound 1 . i . step b : preparation of n im - trityl - n . sub . α - phthaloyl - 2 - fluoromethylhistidine methyl ester ( 1 . ii ) ## str34 ## compound 1 . i , 331 mg ( 1 mmole ), is treated with 278 . 5 mg ( 1 mmole ) of trityl chloride in 25 ml of dmf containing 139 μl of triethylamine ( 1 mmole ) overnight . the dmf is pumped off in vacuo and the residue is taken up in benzene , is washed with dilute aqueous sodium bicarbonate three times , then brine , then dried over k 2 co 3 . filtration and evaporation of the solvent affords 1 . ii . step c : preparation of n im - trityl - n . sub . α - phthaloyl - 2 - fluoromethyl - 2 &# 39 ;- trimethylsilyl histidine methyl ester ( 1 . iii ) ## str35 ## lithium 2 , 2 , 6 , 6 - tetramethyl piperidide ( litmp ) ( 1 mmole ) is prepared as follows : to 141 mg of tmp ( 1 mmole ) in 10 ml of thf at - 18 ° c . under n 2 is added 1 mmole of n - butyllithium . the solution is then aged 15 minutes at 0 ° c . to it is then added a solution of compound 1 . ii , 573 mg ( 1 mmole ), in 10 ml of thf at - 78 ° under n 2 . the reaction mixture is aged 30 minutes at - 78 ° c . and 10 minutes at 0 ° c . and then treated at - 78 ° c . with a solution of 127 μl ( 1 mmole ) of trimethyl silyl chloride in 2 ml of thf . the reaction is allowed to warm to room temperature over 30 minutes . the solution of 1 . iii thus obtained is used directly in the next step . step d : preparation of n im - trityl - n . sub . α - phthaloyl - 2 - fluoromethyl - 3 -( p - nitrophenyl )- 2 &# 39 ;- trimethylsilylhistidine methyl ester ( 1 . iv ) ## str36 ## the solution of 1 . iii from step c is treated with a second mmole of litmp as before . then at - 78 ° c . this is added to a suspension of 308 mg ( 1 mmole ) of very finely ground bis -( p - nitrophenyl ) disulfide in 25 ml of thf . with vigorous stirring , this reaction mixture is allowed to warm to room temperature over 20 minutes , and then refluxed for 30 minutes . the solvent is evaporated , and the residue is taken up in 30 ml of benzene , washed twice with 1n aqueous naoh , then with dilute aqueous hcl , then with brine . after drying over mgso 4 , filtration and evaporation of the solvent , there is obtained compound 1 . iv . step e : preparation of n im - trityl - n . sub . α - phthaloyl - 2 - fluoromethyl - 3 -( p - nitrophenylsulfinyl )- 2 &# 39 ;- trimethylsilylhistidine methyl ester ( 1 . v ) ## str37 ## to 798 mg of compound 1 . iv ( 1 mmole ) in 25 ml of ch 2 cl 2 is added dropwise over 1 hour a solution of 203 mg of 85 % pure mcpba ( net 172 . 6 mg ; 1 mmole ) in 20 ml of ch 2 cl 2 . the solution is aged 30 minutes at 25 ° c . and washed successively with aqueous nahco 3 and brine . evaporation gives compound 1 . v . step f : preparation of n im - trityl - n . sub . α - phthaloyl - 2 - fluoromethyl - 3 -( p - nitrophenylsulfinyl ) histidine ( 1 . vi ) ## str38 ## compound 1 . v , 814 mg ( 1 mmole ), is heated 2 hours at 50 ° c . with 30 ml of 2n naoh in 3 : 2 ( v / v ) h 2 o - meoh with stirring . water , 50 ml , is then added , the ph is adjusted to 2 . 0 with aqueous hcl , and the product is extracted with 3 × 30 ml of ch 2 cl 2 . the organic extracts are combined , washed with brine , dried with mgso 4 , filtered and evaporated to provide compound 1 . vi . the phthaloyl group is removed by refluxing 728 mg of compound 1 . vi ( 1 mmole ) with 96 mg of hydrazine hydrate ( 3 mmoles ) in 20 ml of etoh for 2 hours . aqueous naoh , 1 mmole , is added , and the reaction mixture is pumped to dryness at 0 . 1 torr . toluene is added and pumped off at 0 . 1 torr to remove traces of hydrazine . the product is separated from phthaloyl hydrazide by taking it up in aqueous nahco 3 and washing with ch 2 cl 2 . evaporation of the water affords compound 1 . vii as the sodium salt . compound 1 . vii , 598 mg ( 620 mg as the na salt ) ( 1 mmole ), is refluxed 3 hours with 25 ml of 6n ncl in meoh containing 5 % by volume of water to remove the trityl group . the reaction mixture is evaporated to dryness in vacuo , triturated with ether , taken up in ethanol , filtered and evaporated to afford compound 1 . viii . histidine methyl ester , 185 mg ( 1 mmole ), is treated with 1 . 06 g ( 1 mmole ) of benzaldehyde in 25 ml of chcl 3 for 3 hours . mgso 4 , 0 . 2 g , is added for the last hour . the mixture is filtered and the solvent is evaporated , to leaving compound 2 . i as a residue . step b : preparation of n im - trityl - n . sub . α - benzylidene histidine methyl ester ( 2 . ii ) ## str42 ## compound 2 . i , 273 mg ( 1 mmole ) is treated with 278 . 5 mg ( 1 mmole ) of trityl chloride in 25 ml of dmf containing 139 μl of triethylamine ( 1 mmole ) overnight . the dmf is pumped off in vacuo and the residue , taken up in benzene , is washed with dilute aqueous sodium bicarbonate three times , then brine , then dried with k 2 co 3 . filtration and evaporation of the solvent afford compound 2 . ii . step c : preparation of n im - trityl - n . sub . α - benzylidene - 2 -( 1 - hydroxyethyl ) histidine methyl ester ( 2 . iii ) ## str43 ## compound 2 . ii , 516 mg ( 1 mmole ), in 20 ml thf under n 2 at - 78 ° c ., is treated with 1 mmole of phenyllithium for 1 minute , forming the anion . acetaldehyde , 44 mg ( 1 mmole ) in 1 ml of thf is then added , and the mixture is allowed to warm slowly to room temperature . after evaporation of the solvent and replacement with chcl 3 , the sample is washed with water , then brine , then dried with k 2 co 3 and filtered . the filtrate is used directly in the next step . step d : preparation of n im - trityl - n . sub . α - benzylidene - 2 -( 1 - tosyloxyethyl ) histidine methyl ester ( 2 . iv ) ## str44 ## to the solution of compound 2 . iii from step c is added 0 . 5 ml of pyridine and then 190 . 5 mg ( 1 mmole ) of tosyl chloride . after 30 minutes at 25 ° c . the solution is washed three times with water , once with brine , and dried with k 2 co 3 and filtered . the filtrate is used directly in the next step . step e : preparation of n im - trityl - n . sub . α - benzylidene - 2 - vinyl histidine methyl ester ( 2 . v ) ## str45 ## the solution of compound 2 . iv from step d is evaporated , taken up in benzene and refluxed 3 hours with 124 mg ( 1 mmole ) of diazabicyclononane ( dbn ). the solution is washed twice with water , once with brine , and dried with k 2 co 3 . filtration and evaporation afford compound 2 . v . step f : preparation of n im - trityl - 2 - vinylhistidinemethyl ester ( 2 . vi ) ## str46 ## compound 2 . v from step e is taken up in anhydrous ether and added dropwise over 10 minutes to a solution of 190 mg of p - tsa . h 2 o ( 1 mmole ) in 20 ml of ether . the toslyate salt of 2 . vi precipitates out . it is collected by decantation , and stirred with ether and aqueous sodium bicarbonate . the ether phase is separated from the aqueous layer , washed with brine , dried with k 2 co 3 , filtered and evaporated to yield compound 2 . vi . step g : preparation of n im - trityl - 2 - vinyl - n . sub . α - boc - histidine methyl ester ( 2 . vii ) ## str47 ## compound 2 . vi , 454 mg ( 1 mmole ), is stirred with 218 mg of ( boc ) 2 o in 30 ml of ch 2 cl 2 for 3 hours at 25 ° c . and then washed successively with water and brine , and dried with k 2 co 3 . filtration and evaporation provides compound 2 . vii . step h : preparation of n im - trityl - 2 -([ 1 - chloro - 2 - p - nitrophenylthio ] ethyl )- n . sub . α - boc - histidine methyl ester ( 2 . viii ) ## str48 ## to 554 mg ( 1 mmole ) of compound 2 . vii in 25 ml of ch 2 cl 2 at - 18 ° c . is added dropwise over 30 minutes a solution of 190 mg ( 1 mmole ) of p - nitrophenylsulfenyl chloride in 10 ml of ch 2 cl 2 . the reaction is aged 30 minutes at room temperature and evaporated to afford compound 2 . viii . step i : preparation of n im - trityl - 2 -([ 1 - fluoro - 2 - p - nitrophenylthio ] ethyl )- n . sub . α - boc - histidine methyl ester ( 2 . ix ) ## str49 ## compound 2 . viii , 744 mg ( 1 mmole ), is stirred overnight in 30 ml of dry acetonitrile with 127 mg ( 1 mmole ) of silver fluoride . the precipitated silver chloride is separated by centrifugation and the solvent is evaporated to afford compound 2 . ix . step j : preparation of n im - trityl - 2 -([ 1 - fluoro - 2 - p - nitrophenylsulfinyl ] ethyl )- n . sub . α - boc - histidine methyl ester ( 2 . x ) ## str50 ## to 727 mg of compound 2 . ix ( 1 mmole ) in 25 ml of ch 2 cl 2 at 0 ° c . is added dropwise over 1 hour a solution of 172 . 6 mg ( 1 mmole ; actually 203 mg of 85 % pure ) of mcpba in 20 ml of ch 2 cl 2 . the solution is aged 30 minutes at 25 ° c . and washed successively with aqueous nahco 3 and brine . evaporation gives compound 2 . x . compound 2 . x , 745 mg , is treated with 60 mg of koh ( 1 . 05 mmole ) in 5 ml of meoh for 2 hours at 45 ° c . to saponify the methyl ester . then 25 ml 6n hcl in meoh containing 5 % by volume of water is added and the mixture is refluxed 3 hours to remove the trityl group . the reaction mixture is evaporated to dryness in vacuo , triturated with ether to remove trityl alcohol , and then taken up in 10 ml of ethanol . the kcl is filtered and the filtrate evaporated to afford compound 2ξ step a : preparation of n im - trityl imidazole - 4 - carboxaldehyde ( 3 . i ) ## str52 ## imidazole 4 - carboxaldehyde , 96 mg ( 1 mmole ), is treated with 278 . 5 mg ( 1 mmole ) of trityl chloride in 25 ml of dmf containing 139 μl of triethylamine ( 1 mmole ) overnight . the dmf is pumped off in vacuo and the residue , taken up in benzene , is washed with dilute aqueous nahco 3 three times , then brine , then dried with k 2 co 3 , filtered and evaporated to afford compound 3 . i . cysteine n - boc methyl ester , 235 mg ( 1 mmole ), is treated with 24 mg of nah ( 1 mmole ) in dioxane with 20 mg of 15 - crown - 5 , and then with 158 mg of p - chloronitrobenzene ( 1 mmole ) at 100 ° c . for five hours . the dioxane is evaporated in vacuo , leaving crude 3 . ii . crude ii from step b is taken up in 2 ml anisole and then treated at 0 ° c . for 11 minutes with 10 ml of tfa . the tfa and anisole are pumped off at 0 . 1 torr at 30 ° c . and the residue partitioned between chloroform and aqueous 1n hcl . the aqueous layer is made to ph 9 . 0 with naoh and extracted with ch 2 cl 2 , providing a solution of compound 3 . iii . step d : preparation of n - benzylidene s - p - nitrophenyl cysteine methyl ester ( 3 . iv ) ## str55 ## compound 3 . iii , 256 mg ( 1 mmole ), in 10 ml of ch 2 cl 2 , is treated with 106 mg of benzaldehyde ( 1 mmole ) for two hours at 25 ° c ., then for a third hour with added mgso 4 ( 100 mg ). the solution is filtered and evaporated , affording compound 3 . iv . step e : prepaation of n im - trityl n . sub . α - benzylidene 2 -( p - nitrophenylthio )- 3 - hydroxy histidine methyl ester ( 3 . v ) ## str56 ## compound 3 . iv , 344 mg ( 1 mmole ), is treated at - 78 ° in 10 ml of thf with one equivalent of phli . after one minute , compound 3 . i , 338 mg ( 1 mmole ), is added , and the reaction allowed to warm to room temperature over 30 minutes . the solvent is evaporated and the residue is taken up in ether , washed with water and brine , dried with k 2 co 3 , filtered and evaporated to afford compound 3 . v . step f : preparation of n im - trityl n . sub . α - boc 2 -( p - nitrophenylthio )- 3 - hydroxy histidine methyl ester ( 3 . vi ) ## str57 ## compound 3 . v , 682 mg ( 1 mmole ), in 5 ml of anhydrous ether is added dropwise over 10 minutes to a solution of 190 mg of p - tsa . h 2 o ( 1 mmole ) in 20 ml of ether . the tosylate salt of the free n . sub . α amine is collected by decantation , stirred with ch 2 cl 2 and aqueous nahco 3 . the organic layer is dried over k 2 co 3 . the solution is filtered and treated with 218 mg of boc 2 o for three hours at 25 ° c . and then washed successively with water and brine , and dried with k 2 co 3 . after filtration and evaporation , compound 3 . vi is obtained . step g : preparation of n im - trityl n . sub . α - boc 2 -( p - nitrophenylthio )- 3 - chloro histidine methyl ester ( 3 . vii ) ## str58 ## compound 3 . vi , 694 mg ( 1 mmole ), is treated with 5 ml of pure socl 2 for one hour and then pumped in vacuo , affording compound 3 . vii . step h : preparation of n im - trityl n . sub . α - boc 2 -( p - nitrophenylsulfinyl )- 3 - chloro histidine methyl ester ( 3 . viii ) ## str59 ## to 713 mg of compound 3 . vii ( 1 mmole ) in 25 ml of ch 2 cl 2 at 0 ° c . is added dropwise over one hour a solution of 172 . 6 mg ( 1 mmole ; actually 203 mg of 85 % pure ) of mcpba in 20 ml of ch 2 cl 2 . the solution is aged 30 minutes at 25 ° c . and washed successively with aqueous nahco 3 and brine to afford , after evaporation , compound 3 . viii . step i : preparation of n im - trityl n . sub . α - boc 2 -( p - nitrophenylsulfinyl )- 3 - chloro histidine ( 3 . ix ) ## str60 ## compound 3 . viii , 729 mg ( 1 mmole ), is treated with 60 mg of koh in 5 ml of meoh for two hours at 45 ° c . to saponify the methyl ester , affording compound 3 . ix in solution . to the solution of compound 3 . ix from step i is added 25 ml of 6n hcl in methanol + 5 % water . the mixture is refluxed three hours to remove the trityl and boc groups . the product 3 . x is isolated by evaporating the methanol , triturating with ether , taking it up in 10 ml of ethanol , filtration and evaporation . the pharmaceutical formulations of this invention are illustrated in the following examples which are meant to be illustrative only and not limiting with respect to type of formulation , nature of pharmaceutical carrier or proportions of ingredients . ______________________________________ tablet per tablet , mg . ______________________________________levodopa 2502 - fluoromethyl - 3 -( 4 - nitro - 25phenylsulfinyl )- 3 -( 3 , 4 - dihydroxyphenyl ) alaninelactose 79 . 0starch , corn 65 . 0hydroxypropyl cellulose 8 . 0 ( as 2 % in ethanol ) add : starch , corn 55 . 0guar gum 55 . 0magnesium stearate 4 . 0______________________________________ the first four components are reduced to a fine powder by milling and remxing . the mixture is granulated with the hydroxypropyl cellulose solution . the wetted mass is passed through a no . 10 stainless steel screen and dried in the dark at 100 ° f . the dried granules are passed through a no . 20 stainless steel screen , and the additional quantity of corn starch , guar gum and magnesium stearate added . the mixture is compressed using a 1 / 2 &# 34 ; standard curvature punch into tablets and the tablet may be coated with a conventional protective film containing various types of cellulose polymers , dyes and opacifying agents .
organic sulfoxides having a latent allyl group bound to the sulfur are enzyme inhibitors of the suicide or k cat type .