IL42730A - D-6-methyl-2,8-disubstituted ergolines,their preparation and pharmaceutical compositions containing them - Google Patents

Description

nnayn D'-inma-n a' a'-naTN-V'na-e- oniK o' 'aan nmpn 'T'wDm oman ,8-1 D-6-sieth l-2 ,8-disubstituted ergolines , their preparation and pharmaceutical compositions containing them ELI LILLY AND COMPANY This invention provides novel Ό-&-methyl-2,8-di- substituted ergolines wherein the substituents in the 2 and 8 position are ' different as represented b the following formula I: wherein X is halo, methyl, or cyano and R is CHg-CN or CHg-C-NHg and their salts formed with pharmaceutically- 0 acceptable acids.

Compounds according to the above formula in which X is halogen are prepared by the action of N-bromo- succinimide, N-chlorosuccinimide or other positive halo- genating agent on D-6-methyl-8-cyanomethylergoline or D- 6-methyl-8-carbamoylmethylergoline—prepared by the methods' of Semonsky and co-workers (Coll. Czech. Chem. Commun.. ;55. 577 (1968)). Alternatively, the compounds in which R is CI^-CN can be prepared by the reaction of a positive halogenatin agent on a D-6-methyl-8-halomethylergoline followed by replacement of the halogen atom of the halomethyl group with a cyano group, using sodium cyanide or like reagent to effect the displacement. Conversion of the cyano group to a carbamoyl group can be carried out by procedures well known in the art, Similar halogenation of D-6-meth l-8-mesyloxymethyl yields an intermediate which will react with sodium cy- \ anide or other like inorganic cyanide in an inert solvent to yield compounds -coming within the .scope of:_the^above- formula. Compounds in which X is methyl are prepared by reacting D-6-methyl-8-cyanomethyl (or 8-carbamoylmethyl) j ergoline with methyl formate and ethanedithiol to yield the dithioethylene acetal of a D-2-formyl-6-methyl-8-substituted ergoline. Desulfurization of the resulting di-thioacetal yields the desired 2-methyl derivative. ^F. Stutz and D.A. Stadler, Helv. Chem. Acta. 55. 75. (1972J7 Again, alternatively, a 6-methyl-8-bromomethylergoline can be formylated in the 2-position in the presence of ethanedithiol to yield the dithioacetal of the 2-formyl derivative. Desulfurization of the dithioacetal to yield the 2-methyl derivative followed by reaction of the bromo-methyl group with sodium cyanide provides compounds of the desired structure. Finally, those compounds in which X is cyano are prepared by reaction of a 2-unsubstituted ergoline with chlorosulfonyl^socyanate and triethylamine VorbrSggen, Tetrahedron Letters, I63I (1968_)7.

The prefix "D" in the naming of the compounds of the above structure indicates that the stereochemistry of the ergoline derivative is identical. to that of D-lysergic acid—the naturally-occurring form.

Salts of the ergolines represented by the above formula can be formed with both organic and inorganic pharmaceutically-acceptable acids. Such salts include sulfates, such as sulfate, pyrosulfate, and bisulfatej sulfites, such as sulfite and bisulfite nitrate; phos-phates, such as phosphate, monohydrogenphosphate, dihydro- genphosphate, metaphosphate and pyrophosphate; halides, such as chloride, bromide, iodide and fluoride; aliphatic carboxylases, such as^acetate, propionate, decanoate, caprylate, acrylate, formate, isobutyrate, caprate, heptanoate and propiolate; C^-C^ aliphatic dicarboxylates, such as oxalate, malonate, succinate, suberate'L sebacate, fumarate, maleate, butyne-l, -dioate and hexyne-l^o-dioate; benzoates, such as benzoate, chlorobenzoate, methylbenzoate, dinitrobe zoate, hydroxy-benzoate and methoxybenzoate; phthalates, such as phthalate and terephthalate; arylsulfonates, such as toluenesulfonate, benzenesulfonate, naphthalenesulfonate, p_-chlorobenzenesulfonate and xylenesulfonate; citrate; C~-Cc a-hydroxyalkanoates, such as lactate, β-hydroxy-butyrate and glycollate; ¾-Cg a-hydroxyalkanedic"ar^boxylates, such as malate and tartrate; and C^-C^ alkylsulfonates, such as methanesulfonate and propanesulfonate.

Lysergic and isolysergic acid are 8-carboxy-6- 9 methyl-Δ -ergolines. The amides of lysergic acid, many of which have valuable and unique pharmacologic properties, include the naturally occurring oxytocic alkaloids -ergocornine, ergokryptine, ergonovine, ergocristine, ergosine, ergotamine etc. - and synthetic oxytocics such as methergine as well as the synthetic hallucinogen -lysergic -acid diethylamide^ or^LSD.1 The amides of 6-methyl-8-carboxyergoline, known generically as dihydro-ergot alkaloids, are oxytocic agents of lower potency and also lower toxicity than the ergot alkaloids themselves. Ergotamine, a Δ^-ergoline, has been used in the treatment of migraine and recently, both ergocornine and 2-bromo-a-ergokryptine have been shown to be inhibitors of prolactin and of dimethylbenzanthracene (DMBA) induced tumors in rats, according to Nagasana and Meites, Proc. Soc. Exp't'l. Biol. Med. 135s 69 (1970) and to Heuson et al, Europ. J. Cancer, 353 (1970) .

D-6-methyl-8-cyanomethyl ergoline was first reported by Semonsky and co-workers in Coll. Czech. Chem. Commun. , 33* 577 (1968), and its use in preventing pregnancy in rats was published by the same group in Nature, 221, 666 (1969) . The compound was thought to interfere with the secretion of hypophysial leuteotropic hormone and the hypophysial gonadotropins. It was also suggested that the compound inhibited the secretion of prolactin. See Seda et al, J. Re rod. Fert. , 24, 3 (1971) and Mantle and Finn, id, 44ΐ7· Semonsky and co-workers, Coll. Czech. Chem. Comm., 3, 2200 (1971) , described the preparation of D-6-methyl-8-efgolinylacetamide, a compound which is stated to have antifertility and ariti-lactating effects on rats. The effect of these compounds in neoplastic disease , is unknown.

This invention is further illustrated^ by the following specific examples.

Example 1 Preparation of D-2-chloro-6-methyl-8-cyanomethylergoline 400 Mg. of N-chlorosuccinimide were dissolved in 30 ml. of dioxane and the solution added in dropwise fashion at a temperature of about 6o°C. to a stirred suspension of 535 mg. of D-6-methyl-8-cyanomethylergoline dissolved in 25 ml. of dioxane. After the addition. had been completed, the reaction mixture was heated under a nitrogen atmosphere in the range 60-65°C. for a period of about 4.5 hours. The reaction mixture was then cooled, and diluted-with- ater.—isolid sodium-bicarbonate was added to the mixture which was then extracted with chloroform. The chloroform layer was separated and dried, and the chloroform removed by evaporation in vacuo. The resulting crude residue showed the presence of 2 spots on thin-layer chromatography. The residue was therefore dissolved in chloroform and chromatographed over "lorisil. Thin-layer chromatography carried out on each of the chloroform eluate fractions indicated that fractions 7-12 had the largest amounts of a new component, (not starting material). The fractions showing a relatively large amount of this new component by thin-layer chromatography were combined and the chloroform evaporated therefrom.

The resulting residue, on recrystallization from ether, yielded 165 mg. of D-2-chloro-6-methyl-8-cyanomethyl-ergoline melting at 270-3°C.

Following the above procedure, D-6-methyl-8-cyanomethylergoline was brominated with N-bromosuccin-imide to yield D-2-bromo-6-methyl-8*cyanomethylergbline melting at about 244-7°C with decomposition after recrystallization from ethanol.

Analysis : . Calc : C, 59.31* H, 5.27; N, 12.21j Br, 23.21.

Found. C, 59.33; H, 5.37; W, U.96; Br, 23.39 Following the above procedure, D-6-methyl-8-cyanomethylergoline was reacted with N-iodosuccinimide to yield D-2-iodo-6-methyl-8-cyanomethylergoline melting at about 211-213°C. ith decomposition after recrystalliza-tion from ether.

Analysis: Calc: C 52.19* H, .64 N, 10.74; I, 32.44 .Found: C, 51. 0 H, 4.51; N, 10.58j I, 32.17 Example 2 Preparation of D-2-cyano-6-metnyl-8-cyanomethylergoline Following the procedure of H. Vorbruggen, Tetrahedron Letters, 1631 (1968), 32 mg. of D-6-methyl-8-carbomethoxyergoline were dissolved in 40 ml. of acet-onitrile. A solution containing 310 mg. of chlorosulfon-yljLsocyanate in 10 ml. of acetonitrile was added rapidly in dropwis fashion to the original solution. The reaction mixture was stirred at room temperature under a nitrogen atmosphere for about 68 hours. Thin layer chromatography on an aliquot of the reaction indicated the presence of a material less polar than starting material. About 3 ml. of triethylamine were added and the resulting mixture stirred for about 3 hours. The reaction mixture was then poured into saturated aqueous sodium bicarbonate and the resulting mixture extracted with ethyl acetate. The ethyl acetate layer was separated, washed several times with an equal volume of water, washed once with an equal volume of saturated aqueous, sodium chloride, separated and then dried. Evaporation of the solvent therefrom yielded a residue which was dissolved in chloroform, and the resulting solution chromatographed over 20 g. of Florisil. Development of the chromatogram with chloroform containing 2 percent ethanol yielded two fractions of about 150 ml. each which contained D-2-cyano-6-methyl-8-carbomethoxyergoline synthesized in the above reaction. The solvents were evaporated from the combined fractions and the residue recrystallized from a mixture of ether and hexane. D-2-cyajo-6-methyl-8-carbomethoxyergoline thus prepared melted at about 210-11° C. with decomposition.

Analysis: Calc: C, 69. 885 H, 6.195 N, 13- 58 Pound: C, 70. 165 H, - 6. 365 N, 13. 77 Reduction of the above carbomethoxy derivative with sodium borohydride readily yields the corresponding D-2-cyano-6-methyl-8-hydroxymethylergoline„ Reaction of the hydroxy group with methanesulfonyljchloride by a procedure set forth hereinafter in Example 6 readily yields the mesylate derivative of the 8-hydroxymethyl group.

Reaction of the mesylate with sodium cyanide as set forth in Example 7 for the reaction between an 8-bromomethyl compound and sodium cyanide readily yields D-2-cyano-6-methyl-8-cyanomethylergoline„ Example 3 Preparation of D-2, 6-dimethyl -8-cyanomethylergoline About 2. 6 g. of D-6-methyl-8-cyanomethylergo-line were dissolved in 100 ml. of chloroform to which had been added 50 ml. of methyl formate. 1.84 G. of ethanedithiol were next added. A solution of 4.4 ml. of titanium tetrachloride in 50 ml. of chloroform was added in a slow stream to the previously prepared solution.

The resulting mixture was stirred under a nitrogen atmosphere at room temperature for about 63 hours, and was then cooled to about 0°C. Twenty-five ml. of methanol were added. The reaction mixture was made basic with 15 aqueous ammonium hydroxide. The organic layer was separated, washed with saturated aqueous sodium bicarbonate, again separated and dried. Evaporation of the solvent in vacuo left as a residue the ethylenedithioacetal formed with the aldehyde group on the 2-position of the ergoline ring, namely D-2-(l,3-dithiolan-2-yl)-6-methyl-8-eyanomethylergoline formed in the above reaction.

Chromatography over Plorisil using a 19:1 chloroform-ethanol solvent mixture as eluant yielded fraction in which on thi -layer chromatography a spot other than the spdt attributable to starting material predominated.

These fractions were combined, the solvents removed by evaporation in vacuo, and' the resulting residue „recrys-tallized from ether to yield DT-2-(1.3-dithiolan- 2 -yl)-6-methyl-8-cyanomethylergoline melting at about 239-242° C. with decomposition.

Analysis: Calc: C, 65.00; H, 6.27; N, 11.37; S, 17.35 Found: C, 64.73; H, 6.02; N, 11.12; S, 17.38 An aqueous suspension of -6 Raney nickel was washed with ethanol until the water had been displaced by ethanol. A 19 ml. aliquot of this ethanol suspension was itself suspended in a mixture of l6 ml. each of dimethyl-formamide (DMF) and of acetone. To this solution was added a solution of 1.7 g. of D-2- (l,3-dithiolan-2-yl)- 6-methyl-8-cyanomethylergoline in 70 ml. of acetone and 70 ml. of DMF. The mixture was stirred at room temperature for about 1.5 hours. The Raney nickel catalyst was separated by filtration, and the filter cake washed several times with acetone. The filtrate was then diluted with water and with aqueous sodium bicarbonate.

The filtrate was next extracted with chloroform, the chloroform layer separated and dried, and the chloroform evaporated therefrom in vacuo. The resulting residue was diluted with water to ield a e solved in ethyl acetate. The ethyl acetate solution was separated, washed successively with water and saturated γ aqueous sodium chlorides-dried. The ethyl. acetate was removed by evaporation in vacuo to yield a residue containing D-2, 6-dimethyl-8-cyanomethylergoline. Crystallization of the residue from ethanol yielded unreacted starting material. A chloroform solution of the solid from the filtrate was chromatographed over IPLorisil using chloroform and a 19 1 chloroform tethanol solvent mixture as eluants. The more polar eluates yielded D-2, 6-dimethyl-8-cyano- methylergoline which melted at 285°C. with decomposition after recrystallization from benzene.

Analysis: Calc; C, 77.38; H, 7. 58; N, 15.04 Found: C, 77. 65; H, 7. 36; N, 15. o6 Example Preparation of D-2-bromo-6-methyl-8-carbamoyimethyl- ergoline A solution containing 240 mg. of D-6-methyl-8- carbamoylmethylergoline and 25 'ml. of dioxane was pre- pared at a temperature in the range 65-70°C. under a nitrogen atmosphere. A solution containing 180 mg,. of N- bromosuccinimide in 20 ml. of dioxane was added in dropwise fashion. The resulting mixture was heated at the same temperature range with stirring for about one-half hour and was then poured over saturated aqueous tartaric acid.

The resulting mixture was extracted with chloroform, and the chloroform layer discarded. The aqueous layer was filtered and then made basic with dilute ammonium hydroxide. D-2-bromo-6-methyl-8- . ^arbambyXmethylergoline formed in the above reaction was insoluble in the aqueous alkaline solution and separated. The separated compound was dis-solved in chloroform. The chloroform layer was separated and dried. Evaporation of the solvents in vacuo yielded D-2-bromo-6-methyl-8- carbamoylmethylergoline which melted at about 238-241°C. with decomposition after crystallization from ether.

Example 5 Preparation of D-6-methyl-8-bromomethylergoline A solution of 5.2 g. of triphenylphosphine dis-solved in 100 ml. of acetonitrile was placed, under a nitrogen atmosphere and stirring initiated. 1.0 Ml. of bromine was added in dropwise fashion to the triphenylphosphine solution. After the addition had been completed slight warming yielded a clear, colorless solution indicating completion of the reaction. 505 Mg. of D-6-methyl-8-hydroxymethylergoline was added all at once to the tri- solution. The reaction mixture was stirred for about 6.5 hours at room temperature protected by a calcium chloride drying tube. The solution was then poured into saturated aqueous sodium bicarbonate and the organic material extracted with chloroform. The chloroform iLayer was then contacted with saturated aqueous tartaric acid, thereby forming water-soluble tartrate salts of the ergoline bases present. The water layer was separated, the chloroform layer being discarded. The water layer was then made basic with solid sodium bicarbonate. The ergoline base, bein insoluble in the aqueous alkaline solution, separated and were dissolved in chloroform. The chloroform layer was separated and dried. Evaporation of the chloroform in vacuo yielded a residue comprising D-6-methyl -8-bromomethylergoline formed in the above reaction.

Analysis? Calci C, 60. 20; H, 6. 00 ; N, 8.785 Br, 25. 03 Found: C, 60. 11 ; H, 6. 06; N, 8. 59; Br, 25- 35 Example 6 Preparation of D-6-methyl-8-cyanomethylergoline A suspension of 10 g. of D-6-methyl-8-hydroxy-methylergoline in 200 ml. of pyridine was prepared. To this suspension was added slowly a solution containing 6. 0 ml. of methanesulfonyl chloride and 200 ml. of pyridine. The resulting mixture was stirred at room tempera- I ture under a nitrogen atmosphere for about one half hour and was then poured into 2. 1. of saturated aqueous sodium bicarbonate. The alkaline aqueous layer was diluted to 6 liters with water and the diluted layer allowed to stand at room temperature. D-6-methyl-8-mesyloxymethyl-ergoline formed in the above reaction crystallized. The solution was chilled to about 0°C. in order to cause more of the desired material to precipitate. The solution was then filtered and the filter cake recrystallized from ethanol. A further quantity of D-6-methyl-8-mesyloxy-methylergoline was obtained by extracting the filtrate with ethyl acetate, separating the ethyl acetate layer and removing the ethyl acetate by evaporation in vacuo. Recrystallization of D-6-methyl-8-mesyloxymethylergoline prepared as above from ethanol yielded material melting at about 192-4° C. with decomposition.

Analysis: Calcs C, 61, 05; H, 6.63; N, 8. 38; S, 9. 9 Found: C, 60. 85; H, 6.46¼ N, 8. 45; S, 9. 30 prepared as above was heated with 12 g. of sodium cyanide in -the* presence of 350 ml. of DMSO at 100-105°C. under a nitrogen atmosphere for 45 minutes. The reaction mixture was poured into 2 1. of saturated aqueous sodium chloride and the resulting mixture filtered. The solid material thus obtained Was slurried in warm water and refiltered to give about 8.4 g. of D-6-methyl-8-cyanomethylergoline.

Example 7 Alternate preparation of D~2-bromo-6-methyl-8-cyanomethylergoline A solution of 955 mg. of D-6-methyl-8-bromo-methylergoline, prepared by the procedure of Example 5* in 50 ml. of dioxane was heated to 6o-65°C. under a nitrogen atmosphere. A solution of 600 mg. of N-bromosuccinimide in 70 ml. of dio-sane was added in dropwise fashion. The reaction mixture was heated at 60-65°C. for an additional half hour after all the N-bromosuccinimide had been added. The reaction mixture was then cooled and aqueous tartaric acid added thus forming water-soluble tartrate salts of the ergoline bases present. The resulting mixture was extracted with chloroform, and the chloroform layer discarded. The aqueous layer was filtered and theji made basic by the addition of solid sodium bicarbonate in which the ergoline bases were insoluble. The aqueous layer was extracted with chloroform and the chloroform layer separated and dried, and the chloroform removed by evaporation in vacuo. Chromatography of the resulting residue over Florisil using chloroform at the eluant yielded fractions containing, as a predominant spot on thin-layer chromat-ography, a material other than starting material. These fractions were combined, the solvent removed by evaporation in vacuo, and the resulting residue recrystallized from ether to yield D-2-bromo-6-methyl-8-bromomethylergo-line produced in the above reaction. The compound melted at about 215° C. with decomposition.

Analysis: Calcs C, 48.27; H, .565 N, 7.04; Br, 40.l4 Found: C, 48.01; H, 4.66; N, 7. 16; Br, 4θ.38 0 Mg. of D- 2- romo -6-methyl-8-bromomethylergo-line prepared as above were dissolved in 10 ml. of di-methy-jsulfoxide (DMSO), 100 Mg. of sodium cyanide were added and the resulting mixture heated at 105°C. under a nitrogen atmosphere for about 5 minutes. The reaction mixture was cooled, diluted with water and filtered. The filter cake was dissolved in an ethanol-chloroform solvent mixture, and the solvents removed by evaporation in vacuo. Recrystallization of the residue from ether yielded^ D-2-bromo-6-methyl-8-cyanomethylergoline prepared in the above reaction. The compound melted at about 240-3°C„ with decomposition.

Following the above procedure, D-6-methyl-8-mesyloxymethylergoline (from Example 6) can be halogenated in the 2-position by the procedure of Example 1 to yield D-2-chloro-6-methyl-8-mesyloxymethylergoline, D-2-bromo-6-methyl -8— mesyloxymethylergoline or D-2-iodo-6-methyl-8-mesyloxymethylergoline, each of which can in turn be converted to the 8-cyanomethyl derivative by reaction with sodium cyanide as above.

The 8-tosyloxymethyl derivatives, prepared by substituting p_-toluenesulfonyl chloride for methane sulfonyl chloride in the procedure of Example 6, can b halogenated In the 2-position and the 2-halo derivative reacted with sodium cyanide to yield the same compounds.

Salts of the compounds of this invention (Formula I; above) with pharmaceutically-acceptable acids can be prepared by dissolving a quantity of the particular ergoline base in ether and adding an equivalent of the pharmaceutically-acceptable acid, also dissolved in ether,, The salts thus prepared are in general insoluble in ether and can be isolated by filtration and purified by recrys-tallization. Alternatively, the ergoline base can be dissolved in ethanol and the pharmaceutically-acceptable acid added in an equivalent amount also in ethanol solution. In this instance, the salts are soluble and are recovered by removal of the solvent by evaporation in vacuo. The resulting residue, if not crystalline, can be readily crystallized from ethanol or other suitable solvents, Preparation of Salts A solution containing 56Ο mg. of D-2-bromo-6-methyl -8-cyanomethylergoline in about θ ml. of tetra-hydrofuran (THF) was prepared. About 10 ml. of a solution prepared by dissolving 1 g. of maleic acid In 50 ml. of THF were added with stirring to the solution of the ergoline base. About 200 ml. of ether were added, and the resulting precipitate separated by filtration. D-2-bromo-6-methyl-8-cyanomethylergoline acid maleate thus prepared melted at about 207-209°C. with decomposition.

Following the above procedure D-2-chloro-6-methyl-8-cyanomethylergoline acid maleate was prepared melting at about 204-206°C. with decomposition.

Following the above procedure, 320 mg. of D-2-chloro-6-methyl-8-cyanomethylergoline were dissolved in 15 ml. of THF. To this solution was added a solution of methanesulfonic acid in THF, 1 drop at a time, until the addition of a drop gave no further precipitate. The THF solution was diluted with ether, and the resulting mixture filtered to yield the methanesulfonic acid salt of D-2-chloro-6-methyl-8-cyanomethylergoline melting at about 295° C. with decomposition after recrystallization from ethanol-ether solvent mixture.

Analysis: Calc: C, 4.6lj H, 5, 60j N, 10. 61 CI, 8.95; S, 8.10 Found: C, 54.43; H, 5.79; N, 10.86; CI, 9.22; Following the above procedure, 220 mg. of D-2-chloro-6-methyl-8-cyahOmethylergoline were dissolved in 15 ml. of THF. An excess of a saturated solution of d-tartaric acid in THF was added. A gelatinous precipitate resulted which slowly crystallized. The mixture was di-luted with ether and filtered to yield the tartrate salt of D-2-chloro-6-methyl-8-cyanomethylergoline melting at about 247-9°C. after recrystallization from an ethanol-ether solvent mixture.

Analysis: Calc: C, 60.88; H, 5. 65; N, 11.21; CI, 9.46 Found: C, 60.66; H, 5.4l; N, 11.41; Cl, 9.49 The compounds of this invention are useful as gonadatropin inhibitors. As such they inhibit lactation and are specifically prolactin inhibitors. The compounds are useful in the treatment of inappropriate lactation such as postpartum lactation and galactorrhea. In addi- tion, the compounds can be used to treat prolactin-de- pendent adenocarcinomas and prolactin-secreting pituitary- tumors as well as the following disorders: Forbes -A,lbright syndrome, Chiari - Frommel syndrome, gynecomastia itself and gynecomastia occurring as a result of estrogenic steroid administration for prostatic hypertrophy, fibrocystic disease of the breast (benign nodules), prophylactic treatment of breast cancer, and breast development resulting from the administration of psychotropic drugs, for example, thorazine.

In carrying out our novel control method, using the compounds of this invention to inhibit prolactin, a 2, 8-disubstituted-6-methylergoline according to Formula I. or a salt thereof with a pharmaceutically-acceptable acid is suspended in corn oil and injected parenterally or fed to a female mammal in amounts varying frem .01 to 10 mg/kg/day of mammalian weight. Oral administration is preferred. If parenteral administration is used, the injection is preferably by the subcutaneous route although other modes of parenteral administration such as intraperitoneal, intramuscular, or intravenous routes are equally effective. For these other routes of parenteral administration, as is well understood in the art, other vehicles than corn oil must be used. In particular, with intravenous or intramuscular administration, a soluble pharmaceutically-acceptable salt of D-6-methyl-8rcyano-methylergoline is customarily employed. For oral administration, a compound according to Formula or a salt can also be mixed with' standard pharmaceutical excipients and loaded into empty telescoping gelatin capsules or pressed into tablets.

The inhibition of prolactin secretion by the compounds of this invention is evidenced by the following experiment: Groups of lactating postpartum female rats were administered drug at to 8 days post partum (delivery equals day 0). A control group receive only 0.2 ml. of corn oil daily, and other groups received D-2-bromo-6-methyl-8-cyanomethylergoline or the corresponding chloro compound at different dose levels. At the begin-ning of treatment, the rat litters were reduced to six pups each and the total weight of each litter recorded.

Both litters and lactating females were weighed on days 4, 6, and 8, On day 8 the lactating females were taken from their suckling litters and immediately decapitated. The blood was collected and the resulting serum assayed by a radioimmunoassay for prolactin content. The table which follows records results of this experiment. In the Table column 1 gives the treatment administered, column 2 the number of rats in the treated group, column 3 the average weight changes of the reduced litter, column 4 the average body weight change of the lactating female, and column 5 the average serum prolactin levels on day 8.

Table 1 Treatment No. of Avg. Weight Change Avg. Body (Day - Day 8 Rats of Reduced Litter Change, of L post partum) (Day 4 - Day 8) Female - Con rol Corn oil + +43.8 + 1.9 +11. 3 3. 2 (0, 2 ml/da) 2-Bromo -6-methyl-ergoline-8p-aceto- 11 + +24.9 4.2*gm +18. 5 + 5.1 nitrile ( 0. 6 mg/da) 2-Bromo-6-methyl-ergoline-8p-aceto- 10 +14.8 + 2.0*gm + 3o 9 + 4.0 nitrile (1.0 mg/da) * Significantly different from controls P .001 NS Not significantly different a This value based on 5 animals As can be seen from the above table, the two compounds coming within the scope of Formula I above greatly decreased the prolactin levels and thus the prolactin secretion in the lactating female rats.

Experiments designed to show the activity of compounds of this invention in suppressing the growth of adenocarcinomas in female mammals is demonstrated by the following experiment in which, for illustrative purposes only, rats were used as exemplary of adenocarcinoma-susceptible female mammals. The determination was carried out as follows; Mammary tumors were induced in rats by a single oral feeding of 20 mg. of 7* 12-dimethylbenzanthracene (DMBA). The mammary glands were palpated for tumors at weekly intervals. Rats were selected for experimentation when they had at least one measurable tumor about 0.5 cm. in diameter. The animals with tumors were divided into groups of 5 and treated daily with various doses of D-2-halo-6-methyl-8-cyanomethylergoline suspended in corn oil. One group of control rats was treated with corn oil only. The results are given in Table 2. In the table, column 1 gives the name of the compound under test, column 2 gives the dose employed, column 3 gives the route of administration, column 4 the original tumor diameter, column 5 the tumor diameter after 12 days of treatment, and column 6 gives the percent change.

Tumor diameter after 12 days Name of of treatment Percent Compound D-2-bromo- • 5 s.c* 6.7 2.8 -58 6-methyl-8- cyahomethyl- 7 s.c. 7.T 5. -27 ergbline % P.O.** 7.1 3.1 -56 .O. 7.7 4.5 -42 Control, 0.2 ml corn oil - P.O. ,7.0 8.9 .+27 vehicle · D-2-chloro- 5 s.c. 7.5 5.3 -29 6-methylr8- cyanomethyl- 7 s.c. 6,3 4.8 -24 ergoline , .O. 7.1 4. -37 P.O. 7.2 4.5 -38 *S. C. = Subcutaneous **P.O. = by mouth The compounds of this invention produce a significant regression of mammary tumors after either subcutaneous or oral administration as indicated in the above experiment.

The compounds of this invention have a greatl decreased toxicity as compared with those compounds for the prior art in which the 2-position is unsubstituted.

For example, acute toxicity studies in mice^ indicate^ that the D-2-halo-6-methyl-8-cyanomethyl (or 8-carbamoylmethyl) ergolines have an LD^Q in the neighbourhood of 1,000 mg/kg. however, the 2-halo substituted compounds of ~this invention were equally potent to the unsubstituted D-6-methyl-8- cyanomethyl (or 8-carbamoylmethyl)ergolines of the prior

Claims (6)

42730/2 CLAIMS:

1. A D-6-methyl-2, 8-disubstituted ergoline compound of the formulas wherein X is halo, methyl, or cyano and R is CHg-CN or CHp-C- H and their salts formed with pharmaceutically- acceptable acids.

2. The compound of claim 1 wherein the compound is D-2-chloro-6-methyl-8-cyanomethylergoline.

3. The compound of claim 1 wherein the compound is D-2-bromo-6-methyl-8-cyanomethylergoline.

4. The compound of claim 1 wherein the compound is D-2-bromo-6-methyl-8-carbamoylmetbylergoline .

5. A process for preparing an ergoline compound of the formula: wherein X' is CI, Br or I, which comprises reacting a compound of the formula: wherein R1 is CI, Br, -tolyl; with a positive halogenating agent containing positive chlorine, < bromine or iodine; to yield a compound of the formula wherein R1 and X' have the same meaning as hereinabove, and then reacting said compound with an inorganic cyanide 42730/2 in an inert solvent.

6. A pharmaceutical composition for inhibiting the secretion of prolactin in mammals comprising / as an active ingredient an ergoline compound as defined in any one of claims 1 to 4. ,ND