Note: Descriptions are shown in the official language in which they were submitted.
8-THIOMETHYLERGOLINES
Compounds based on the ergoline ring system,
formula (I),
71
--H-
~'
H-N 1 2
have a surprising variety of pharmaceutical activities. For
example, lysergic and isolysergic acid are 8-carboxy-6-methyl-
~9-ergolines (9,10-didehydroergolines). The amides of
lysergic acid, many of which have valuable and unique pharma-
cologic properties, include the naturally occurring oxytocic
alkaloids - ergocornine, ergokryptine, ergonovine, ergo-
; cristine, ergosine, ergotamine etc. - and-synthetia oxytocics
such as methergine as well as the synthetic hallucinogen---
lysergic acid diethylamide or LSD. The amides of 6-methyl-8-
carboxyergoline, known generically as dihydroergot alkaloids,
are oxytocic agents of lower potency and also lower toxicity
than the ergot alkaloids themselves. Ergotamine, a ~9-ergo-
line, has been used in the treatment o~ migraine and recently
both ergocornine and 2-bromo-a-ergokryptine have been shown
to be inhibitors of prolactin and of dimethylbenzan~hracene
(DMBA)-induced tumors in rats, accordin~ to Nagasawa and
Meites, Proc. Soc. ExE~tl. Biol. Med. 135, 469 (1970~ and to
Heuson et al., Europ. J. Cancer, 353 (1970). (See also U.S.
Patents 3,752,8B8 and 3,752,81~).
D-6-methyl-8-cyanomethylergoline was first pre-
X-4228 Z
~ .
. .
~: . -, .. , . :
pared by Semonsky and co-workers, 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).
(See also U.S. Patent 3,732,231) The compound was thought to
interfere with the secretion of hypophysial leuteotropic
hormone and the hypophysial gonadotropins. It was also sug-
gested that the compound inhibited the secretion of pro-
lactin. [See Seda et al., Reprod. Fert., 24, 263 (1971)
and Mantle and Finn, id. 441)]. Semonsky and co-workers
C _ , Czech. Chem. Comm., 36, 220 (1971), described the prep-_
aration of D-6-methyl-8-ergolinylacetamide, a compound which
is stated to have anti-fertility and anti-lactating effects
on rats. The effect of these compounds in neoplastic disease
is unknown. Ergolines with a thiomethyl substituent or a
derivative thereof have not previously been prepared.
This invention provides 8-thiomethylergolines of
the formula:
CH --S--R
~
CH
HN-- R
wherein R is H, ~-alk, phenyl, or alk;
~1 is H, Cl, or Br;
alk is Cl-C3 alkyl; and
the dotted line represent5 the optional presence
of a double bond, or
X-4228 3
., .
1~7~ii23
a non-toxi~, pharmaceutically-acceptable acid
addition salt thereof.
The term alk in the above formula, comprehending
as it does Cl-C3 alkyl groups, includes the following radicals:
methyl, ethyl, _-propyl and isopropyl. In formula tII),
when the ~9,10 bond is saturated, the compounds are generically
denominated as D-6-methyl-8-thiométhyl (or mercaptomethyl)
ergolines. When the ~9,10 hond is unsaturated, the resulting
compounds are known generically as D-6-methyl-8-thiomethyl
or mercaptomethyl-9,10-didehydroergolines. Compounds
illustrative of the scope of the above formula include the
following:
D-2-chloro-6-methyl-8-propionylthiomethylergoline
D-2-chloro-6-methyl-8-butyrylthiomethyl-9,10-didehydro-
ergoline
D-2-chloro-6-methyl-8-phenylmercaptomethyl-9,10-didehydro-
ergoline
D-2-bromo-6-methyl-8-phenylmercaptomethyl-9,10-didehydro-
ergoline
D-2-chloro-6-methyl-8-ethylmercaptomethyl-9,10-didehydro-
ergoline
D-6-methyl-8-n-propylmercaptomethylergoline
D-6-methyl-8-isopropylmercaptomethylergoline.
The compounds of formula (II) are prepared by
reacting a compound of the formula
X-4228 4
.: , ' :,
6~3
C~12OR
1~
N-CH
(III)
.: ,1 11 .
wherein Rl and the dotted line are defined as before; and R2
is a methanesulfonyl or p-toluenesulfonate group,
with a nucleophilic reagent of the formula
- O HSR (IV)
wherein R3 is C-alk, phenyl, or alk, followed by
O
Il
hydrolysis when R3 is C-alk and the compounds of formula
~II) wherein R is H are desired. However, compounds in
which R is other than H are particularly preferred.
The compounds of this invention in which R is
other than H are prepared by reacting via nucleophilic dis-
placement an ester of a D-6~methyl-8-hydroxymethylergoline or
of a 9,10-didehydroergoline, optionally substituted at C-2
with chlorine or bromine, with salts of thio-
phenol, a thioalkanoic acid (alk-COSH) or an alkylthiol
talk-SH). Esters useful as starting materials in the above
synthetic procedure include the mesyl (methanesulfonyl),
the ~-toluenesulfonyl (~-tosyl) and the like esters formed
with the hydroxy group of 8-hydroxymethyl-6-methylergoline,
8-hydroxymethyl-6-methyl-9,10-didehydroergoline or of a 2-halo
derivative of either of the ~9 compounds of formula II. These
mesyloxy and p-tosyloxy derivatives are either known compounds
or can be prepared from the corresponding hydroxy derivativ~s
by processes available in the art. In carrying out reactions
X-4228 5
.~ ,,. I .
with thiophenol or with an alkyl thiol, the sodium salt of
the mercaptan group is usually formed, using sodium methylate
or sodium hydride.
The nucleophilic displacement reaction is carried out in an
inert solvent such as dimethyl formamide (DMF), or dimethyl-
sulfoxide (DMSO). Ordinarily, the reaction is carried out
at room temperature or if desired ~y heating to a temperature
in the range from room temperature to 100C. The products
of the reaction are customarily isolated by standard tech-
niques and purified b~ chromatography, preferably over
"Florisil"*. The compounds of this invention in which R is H
are prepared by hydrolysis in base of the corresponding com-
; l
pound in which R is C-alk. '¦
The compounds of this invention are white crystal-
line solids and form pharmaceutically acceptable salts with
nontoxic acids. These pharmaceutically acceptable salts
are included within the scope of ~his invention. Nontoxic
acids useful in forming the salt3 of this invention include
such inorganic acids as hydrochloric acid, nitric acid, phos-
phoric acid, sulfuric acid, hydrobromic acid, hydriodic
acid, nitrous acid, phosphorus acid and the like, as well
as non-toxic organic acids including aliphatic mono and di-
carboxylic acids, phenyl-substituted alkanoic acids, hydroxy
alkanoic and alkandioic acids, arvmatic acids, and aliphatic
and aromatic sulfonic acids. Such pharmaceutically-
acceptable salts thus include sulfate, pyrosulfate, bisulfate,
sulfite, bisulfite, nitrate, phosphate~ monohydrogenphosphate~
dihydrogenpho5phate, metaphosphate, pyrophosphate, chloride,
bromide, iodide, iluoride, acetate, propionate, decanoat~,
X-4228 6
*Trademark for a highly selective adsorbent oE hard granular
or powdered magnesium silicate.
. . ,~
.
caprylate, acrylate, formate, isobutyrate, caprate, heptanoate,
propiolate, oxalate, malonate, succinate, suberate, sebacate,
fumarate, maleate, butyne-1,4-dioate, hexyne-1,6-dioate, ben-
zoate, chlorobenzoate, methylbenzoate, dinitrobenzoate,
hydroxybenzoate, methoxybenzoate, phthalate, terephthalate,
benzenesulfonates, toluenesulfonate, chlorobenzenesulfonate,
xylenesulfonate, phenylacetate, phenylpropionate, phenyl-
butyrate, citrate, lactate, ~-hydroxybutyrate, glycollate,
malate, tartrate, methanesulfonate, propanesulfonates,
naphthalene-l-sulfonate and naphthalene-2-sulfonate.
The compounds of this invention are useful as
prolactin inhibitors. The inhibition of prolactin secretion
by the compounds of this invention is evidenced by the fol-
lowing experiment: Adult male rats of the Spraque-Dawley
strain weighing about 200 g. were used. All rats were
housed in an air-conditioned room with controlled lighting
(lights on 6 a.m. - 8 p.m.) and fed lab chow and water ad
libi~um.
In each experiment the rats were killed by de-
20 capitation, and 150 ~1 aliquots of serum were assayed forprolactin. Each male rat received an intraperitoneal in-
jection of 2.0 mg of reserpine in aqueous suspension 18 hours
before administration of the ergoline derivative. The pur-
pose of the reserpine was to keep prolactin levels uniformly
elevated. The derivatives were dissolved in 10% ethanol at
a concentration of 10 ~g/ml, and were injected intraperi-
toneally at a standard dose of 50 ~g/kg. Each compound was
administered to a group of 10 rats, and a control group of 10
intact males received an equivalent arnount of 10 percent
30 ethanol. One hour after treatment all rats were killed by
; X-4228 7
.
~ 7~ 3
decapitation, and the serum was collected and assayed for pro-
lactin as previousl~ described. The results were evaluated
statistically using Student's "t" test (a mathematical
comparison between means) to calculate the level of
significance, "p."
The difference between the prolactin level oE the
treated rats and prolactin level of the control rats, divided
by the prolactin level of the control rats gives the percent
inhibition of prolactin secretion attributable to the com-
10 pounds of this invention. The table which follows gives pro-
lactin inhibition percentages for a series of compounds coming
within the scope of formula (II) above. In the table, column
1 gives the name of the compound; column 2, the dose level of
the compound in the prolactin inhibition test; column 3, the
percent prolactin inhibition; and column 4, the level of sig-
nificance.
Being prolactin inhibitors, the compounds of this
invention are also potentially useful for suppressing the
growth of breast adenocarcinomas in female mammals.
This invention is further illustrated by Examples 1-6
which follow.
..',..~ ~
1~77~Z;3
o o o ~
~ oo o o o o o
: ~ V V V V V V V
..
.,, o
.,,
t, ~
,,
O~ O ~ ~ ~D
O-rl U~
~;
H :
dP
O OO O O O O
a) ~ ~~ _l ~ ~,
E~ I I
Orl O-rl
~ o ~ o a) .
e
h a) ~ E~
a) o ~ o ~ o a) co
:: k ~1~ ~ ~ ~ E3 1 rl ~-~
0~ ~ >~ >1 0 ~ O
o ~ ~~ ~ o a) ~ ~ ~ o Q) ,,
~-r~ O ,,
I ~I ~ I I I ~: I ~ I h
O I OI O I I I ~1 1 IJ I
--
j h O O .1
U ~ I
o I o l .~ l O
a ~ Q aJ
X-4228 g
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Example 1
A reaction mixture was prepared from 2 g~ of
D-6-methyl-8-~-toluenesulfonyloxymethylergoline, 2 g. of sodium
thiocyanate and 100 ml. of dimethylsulfoxide (DMSO) . The
mixture was heated in the range 100 110C. for 4.5 hour~. The
reaction mixture was then cooled and poured over an ice water
mixture. 6-Methyl-8-thiocyanomethylergoline was in~oluble in
water and precipitated. The solid was collected by filtration
and melted at about 181-3C. with decomposition after re-
10 crystallization from an ether-hexane olvent mixture.
Analysis: Calc.: C, 68.65; H, 6.44; N, 14.13; S, 10.78;
Found: C, 68.31; H, 6.66; N, 13.99; S, 10.48.
Example 2
A suspension of 10 g. of D-6-m~thyl-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 r~-
sulting mixture was stirred at room temperature under a
nitrogen atmosphere for about one half hour and was then poured
20 into 2.5 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-mesyloxymethylergoline ormed in the above
reaction slowly crystallized. The ~olution was chilled to
about 0C. in order to cause more of the compound to precipi-
tate. The solution was then filtered, and the filter cake
recrystallized from ethanol. A furthex quantity of D-6-methyl- -
8-mesyloxymethylergoline was obtained by extracting the fil
trate with ethyl acetate, separating the ethyl acetate layer
; 30 and removing the ethyl acetate therefrom by evaporation in
X-~228 10
.
' . ~ ., ' ' . : . ' ' ,
vacuo. Recrystallization of D-6-methyl-8-mesyloxymethylergO~
line prepared as above from ethanol yielded material ~nelting
at about 192-4C. with decomposition.
Analysis: Calc.: C, 61.05; H, 6.63; N, 8.38; S, 9.59;
Found: C, 60.85; N, 6.46; N, 8.45; S, 9.30.
A solution of 2.5 ml. of thiophenol in 25 ml. of
DMSO was prepared. 1.1 g. of sodium me~hylate were a~ded.
Next a solution of 700 mg. of D-6-methyl-8-mesyloxymethylergo-
line in 50 ml. of DMSO was added in drop-wise fashion to the
10 sodium thiophenate solution. After the addition had been
completed, the reaction mixture was stirred at room temperature
under a nitrogen atmosphere for about 2 hours, and was ~en
poured into a saturated aqueous tartaric acid solution. The
acidic layer was extracted wi~h chloroform. The chloroform
extract was separated and discarded. The acidic layer was
then made basic with the excess of 14N ammonium hydroxide,
and the resulting alkaline layer extracted with chloroform.
The chloroform extract was separated and dried. Evaporation
of ~he chloroform left a residue which was dissolved in ethyl
20 acetate. The ethyl acetate solution was thoroughly washed
with water followed by a wash with saturated aqueou~ sodium
chloride solution. The e~hyl acetate layer was dried. Removal
of the ethyl acetate by evaporation in vacuo yielded a residue
comprising D-6-methyl-8-phenylmercaptome~hylergoline which
was recrystallized from ethanol and melted at 194-5C. with
dec~mposition. The compound was ~hen dissolved in chloroform
and chromatographed over "Florisil" (25g.). The chromatogram
was developed with a chloxoform-methanol (19:1) solvent mixture~
Fractions containing D-6-methyl-8-phenylmercaptomethylergoline
30 as determined by ~hin layer chromatography were combined.
X-4~8 ll
Evaporation of the solvent from the comblned fraction~ and
recrystallization of the resulting residue from an ether-
hexane solvent mixture yielded D-6-methyl-8-phenylmercapto-
methylergoline; MP=195-6C. with decomposition.
~nalysis: Calc.: C, 75.82; H, 6.95; N, 8.04; S, 9.20;
Found: C, 75.85; H, 6.69; N, 7.97; S, 9.19.
Following the above procedure D-6-methyl-8-mesyloxy-
methyl-9,10-didehydroergoline was reacted with thiophenol to
yield D-6-methyl-8-phenylmercaptomethyl-9,10-didehydroergoline
10 which melted at about 200-3C. with decomposition after re-
crystallization from methanol.
Analysis: Calc.: C, 76.26; H, 6.40; N, 8.08; S, 9.25;
Found; C, 76.02i H, 6.42i N, 7.99; S, 9.02.
- The corresponding 3,10-didehydro maleate salt was
prepared by dissolving the compound in tetrahydrofuran and
adding an equivalent amount of maleic acid also in tetra-
hydrofuran. The maleate salt melted at 188-9C. after
recrystallization from methanol.
; Analysis: Calc.: C, 67.51; H, 5.67; N, 6.06i S, 6.93;
Found: C, 67.29; H, 5.89; N, 5.79; S, 6.71.
Exam~le 3
Ten milliliters of dimethyl formamide (DMF) were
cool~d to about 0C. 1 ml. of methanethiol was added followed
by 1.0 g. of sodium hydride as a 50 percent suspension in
mineral oil in portio~s. The resulting mixture was stirred for
about 1 hour and then allowed to warm to room temperature.
Then, following the procedure of Example 2, a solution of 1 g.
of D-6-methyl-8-mesyloxymethylergoline in 50 ml. of DMF was
added in drop-wise fashion to the sodium salt of methanethiol.
30 The resulting product was i~olated and purified by the pxo-
X-4228 12
Z3
cedure of Example 2 to yield D-6~methyl-8-methylmercapto-
methylergoline melting at about 153-5C. Recrystallization
of the compound thus obtained (omitting the chromatographic
purificatiOn step of Example 2) from an ether-hexane solvent
mixture yielded ~-6-methyl-8-methylmercaptomethylergoline,
MP = 153-4C.
Analysis: Calc.: C, 71.2~; H, 7.74; N, 9.78; S, 11.19;
Found: C, 71.08; H, 7.59; N~ 9.83; S, 10.99.
Following the above procedure D-6-methyl-8-methyl-
10 mercaptomethyl-9,10-didehydroergoline was prepared from the
corresponding 8-mesyloxymethyl derivative by reaction with
methylmercaptan. The compound melted at 181-3C. with de-
composition after recrystallization from ether-hexane sol-
vent mixture.
~'"Analysis: Calc.: C, 71.79; H, 7.0g; N, 9.85; S, 11.27;
Found: C, 72.01; H~ 6.84; N~ 9.62; S, 11.270
The-corresponding 9,10-didehydro maleate salt was
prepared by dissolving the compound in ether and adding an
; equivalent amount of maleic acid al~o in ether. Maleate salt
20 melted at 159-160C. with decomposition.
Analysis: Calc.: C, 62.98; ~, 6.07; M, 6.99; S, 8.01;
Found: C, 62.99; H, 6.13; N, 6.787 S, 7.~6.
Example 4
Following the procedure of Example 2, thioacetic acid
(as the sodium salt) was rPacted wi~h D-6-methyl-8-mesyloxy-
methylergoline in DMF solution to yield D-6-methyl-8-acetyl-
mercaptomethylergoline which was isolated and purified by ~he
procedure of that example. Chromatography of the cruae
product over "Florisil" using chlorofonm containing 2 percent
30 ethanol as eluent yielded purified D-6-methyl-8-acetylmer-
X-42~8 13
,~
. . .
~'7~6~3
captomethylergoline MP=153-5C. wlth decomposition.
Analysis: Calc.: C, 68.75; H, 7.05; N, 8.91; S, 10.20;
- Found: C, 68.70; il, 7.22; N, 8.62; S, 10.47.
Following the above procedure, D-6-methyl-8~acetyl-
mercaptomethyl-9,10-didehydroergollne was prepared from the
corresponding 8-mesyloxymethyl compound. The purified com-
pound thus prepared melted in the range 165-7C. with de-
composition after recrystallization from an ether-hexane
solvent mixture.
Analysis: Calc.: C, 69.20; H, 6.45; N, 8.97; S, 10,26;
Found: C, 69.48; H, 6.71; N, 9.00; S, 10.56.
The corresponding 9,10-didehydro maleate salt wa~
prepared by dissolving the base in ether and adding an
equivalent amount of maleic acid in ether. The maleate salt
melted at 178-9C. with decomposition.
Analysis: Calc.: C, 61.67; H, 5.65; N, 6.54; S, 7.48;
Found: C, 61.95; H, 5.50; N, 6.84; S, 7.63.
D~2-chloro-6-methyl-8-acetylmercaptomethylergoline
was also prepared by the above procedure. Recrystallization
20 of the residue remaining after combining fractions from
chromatography shown to contain D-2-chloro-6~methyl-8-acetyl-
mercaptomethylergoline by thin layer chromatography, using a
solvent mixture of ether and hexane for recrystallization
yielded purified material melting at 140-1C.
Analysis: Calc.: C, 61.97; H, 6.07; N, 8.03; S, 9.19;
Cl, 10.16;
Found: C, 61.75; H, 5.78; N, 7.75; S, 9.41;
Cl, 10.32.
Example 5
A reaction mixture containing 1.0 g. of D-6-methyl-
- X-4228 14
. . ~. ' . '
8-acetylmercaptomethyler~oline (from Example 4), 100 ml. of
ethanol and 100 ml. of 4N aqueous hydrochloric acid was re-
fluxed under a nitrogen atmosphere ~or fi~e and one~half
hours. The reaction mixture was cooled and made basic with
an excess of 14N ammonium hydroxide. The aqueous alkaline
layer was extracted with chloroform, and the chloroform yielded
a residue comprising D-6-methyl-8-mercaptomethylergoline formed
in the above reaction. The residue was chromatographed over
75 g, of "Florisil" using chloroform containing 5 percent ethanol
10 as the eluant. D-6-methyl-8-mercaptome~hylergoline was
identified in chromatographic fractions by thin layer chroma-
tograph~ as a more polar, and therefore more slowly moving,
material than starting material. Fractions containing D-6-
methyl-8-mercaptomethylergoline were combined and recrystallized
from ethanol. The compound thus purified melted at 255-7C.
with decomposition.
Analysis: Calc.: C, 70.55; H, 7.40; N, l0.?8; s, 11.77;
Found: C, 70.31; H, 7.65; N, 10.-04; S, 12.00.
The above procedure was repeated except that methyl-
20 mercaptan wa~ used in place of thioacetic acid for reaction
wlth D-2-chloro-6-methyl-8-mesyloxymethylergoline to form
D-2-chloro-6-methyl-8-methylmercaptomekhylergoline. Chroma-
tography over "Florisil" of the residue obtained by combiningchromatographic fractions 5hown to contain the desired material
u~ing an ether-hexane mixture for recry~tallization yielded
purified D-2-chloro-6-methyl~8-me~hylmercaptomethylergoline
melting at 194-5C.
X-4228 15
' ,: ' ' , '. '
~07~ 3
Analysis: Calc.: C, 63.63; }I, 6.60i N, 8.73; S, 9.99;
Cl, 11.05;
; Found: C, 63.42; H, 6.55; N, 8.47; S, 10.12;
Cl, 11 . 35 .
16
~, '.
, . . ' . . .
