Note: Descriptions are shown in the official language in which they were submitted.
- A521
~hls lnv~ntion re1ates to a prostaglal1c~ derlvatlve~
the synthesis thereof 9 ~ormulation~ containing lt anct
its use in medIclne.
The applicants r~cently described ~S Moncada et al 9
Nature, ~ , 663, (197~ ~ the discovery and isolation of
a new proslaglandin derivative having~ inter alia~ potent
an-ti-aggre~atory activity on blood platelets.
Further investigation ~Johnson et al, Prostaglandins,
1976, 12, 915-978~ has sho~n that the prosta~l~ndin, now
known as prostacyclin or PGI2, is (5Z)-didehydro-9-
deoxy-6, 9~-epoxyprostaglandin ~ as shown in formula
(I) (R is hydrogen) below:
R02C -- ~
\ (I)
<
r~
OH OH
Prostacyclin is unstable at room temperature in
aqueous medium, having a half-life of approximately 10
minutes~ but is more stable in aqueous alkali.
The applicants have now discovered a process for the
preparation of salts of prostacyclin (i.e. conlpounds of
formula (I) above wherein R is an appropriate cation~
I~articularly the alkali metal salts~ more particulaIly
the so~ium salt. Such salts, which may be obtained in
B
crystalline form, are stable at room t~ll~Ld~Ul~.
In accordance with the invention ~here is provided a process
for yl~kling a crystAll;n~ salt of (5Z)-5,6-didehy~ro-9-d00Ky-
6, 9~ xy~lv~ An~;n Fl~ cY~prising:
a) dehydrohalvgenation of a c~ l of fon~
s COY
/ ~
~ (III)
'
ozl ~z2
(wherein X is bromide or iodine, Y is OH, NHRl ox OR , R beingaIkyl of 1 to 4 carbon atoms, and Z and z2 are selected frcm
hydxogen and hydxoxy blocking groups) with a base, ~ollowed, as
n~ y, by hydrolysis of any NHRl or ORl group and by removal
of any hydroxy blocking group(s) Z and~or Z , and -formation of a
crystAll;n~ salt, other ~han a sodium.salt o~ (5~)-5,6-didehydro-9-
deoxy-6,9~ -~U~y~L~stA~l An~ i n Fla;
b) dehydroh~Alo~nAting a ~ v -Kl of formula (III), as ~Pf;ne~
abcve, with a base, where.Ln in said ~ILU~ X is bromine,
Y is OH, NHRl or ORl' Rl being alkyl of 1 ~o 4 OE bon atoms and Z
and z2 are hy~rogen or hydLu~ blocking groups, followed, as
n~e~sAry, by hydrolysis o~ any NHRl or ORl group an~ by remcval
o any Hydluxy blocking group in zl and z2 , and ormation o a
crys~ll;nP salt of (5Z)-5,6-didehydro-9-deoxy-6,9~-~L~xy~Lusta-
glAn~;n Fl~ ; or
c) dehy~luhalogenating a ~'"L'~ 1 Of fon~llA (III), as
~,.
defin~d above~ with a base, wherein in said ormr~lln~ (III), X is
brcmine or iodine, Y is OR , R being alkyl of 2 to 4 carbon atoms
and zl and 22 are hydrogen or hydroxy blocking groups, followed,
as necessary, by hydrolysis of an~ NHRl or oRl group and by
removal of any hydroxy blocking group in Zl and z2, and formation
of a crys~llinP salt of (5Z)-5,6-dideh~dro-9-deoxy-6,9~ epoxy-
prostagl~n~; n F~ ;
or
d) dehydrohalogenating a compound of f~n~ III), as
~PfinP~ akove, with an aIkali metal alkoxide, wherein in said
~ y~d (III), X is bromine or iod m e, Y is OH or NHR , R being
alkyl of 1 to 4 carbon atoms and Z and Z are hydrogen or hydroxy
blocking yroups, followed, as nP~Pss~ry~ by hydrolysis of any NHR
group and by removal of any hydroxy blocking group in zl and z2,
; and formation of a cryst~llinP. salt of ~5Z)-5,6-didehydro-9_deoxy-
6,9 ~-e~u~y~u~ n~;n Flo~; or
e) hydrolysing the methyl ester group in a f~..q~~ l of formula:
~C~,
e~ ~
~,
`~ ~
in the ~Les~ ~e of a base other than sodium hydroxide an~ formation
~0 of the sodi~m salt of formula:
~ o~
~o ~
or
f) hydrolysing the ester group in a cnmrolln~ of fonmll~
. ~ioo~
~A
~herein R is alkyl of 2 to 4 carbcn atoms, and formation o the
sodium salt of formula:
~ ~
0~ 0~
In another aspect of the invention there is provided crystAll;n~
salts of (SZ)-5,6-didehydro-9-deoxy-6,9~ -epoxypros~agl~n~;n Flo_
'~.
~ 5
produced in accordance with the processes of the invention.
In a particular Pmho~;mpnt the salts of prostacyclin may be
synthP~ l fro~ a comFound o formula (II) as shx~n in the reaction
scheme kelow wherein Z and z2 are select0d from hydrogen an~
hy~roxy blw king group~, for ~x~rlP, acyl, or trialkylsilyl
(for ~mrle, trImethylsilyl)~ Oxidative attack, for example by
iodine or pOt~`~S;l~n tr;in~;de in the ~l~s~lce of a metal bicarb-
onate~ at~the 5,6-do~ible kond of a ~nmrOlln~ of form~la ~II) with
simult~n~lls or ~lhse~Pnt cyclisation involving the 9-hydroxy
group produces a cnm~olm~ o f~n~lla (III) as shcwn below. Upon
LL~L~ L with a suitable kase, for example an organic base or a
metal alkoxide, the ~nm~olln~ of fon~ (III) may then be dehydro-
halogenatedl resulting in the introduction of a 5,6~double bond.
This reaction seguence is illustration in the following reaction
scheme:- l====~ COY
OH I ~
~r ~ (II 3
\f~ ~
02 H Z
/coy
<~
~-,
-- 6 --
YoC- '
3 (IV)
OZ 1 oz2
~herein Y, X and Z are as ~f;n~ above.
When Z and/or Z in fon~llA~ (II), (III) and ~IV) are
blockin~ sroups, these klocking groups may be l~WV~d at _ny
desired point in the synthesis, e.g. by methods kncwn in the art,
for ~x~m~e, base hydrolysis.
In another particular fmhC~ nt the prostacyclin salts may
be ~L~CL~d by treating an ester thereof (formula (I): R is alkyl,
for I ~le the meth~l ester), with a strong base, in a suitable
solvent and ly~ph;1;c;n~ the resulting reaction nLixture. Gne
suitable kase is sodium hydroxide. By way of example the sodi~m
s31t may be preFared by the reaction of 5-halo-9-deoxy-6,9~-
~J~y~Lost~ n~;n Fl~ methyl ester, where halo is brcmo or icdo,
with scdium ~ ^~h~)x;~ and then reacting the so obta med prosta-
glAn~;n ester with a sodium base. PreferA~ly the 5-halo-prDsta-
gl ~n~; n is either (5R,6R)-5-iodo-9-deoKy-6,9~ -epoxyprost~gl~n~; n
Fla or a muxture thereof with the (5S,6S) isomer.
When the sodium salt of prostac~clin is isolated in crystal-
line form, it is a*vantageously pro~ided with a cc~t;n~ of sodium
c~rhnnate formed, by ~x~mrle by l~qhlng the sodium salt with
sodium hydroxide ~ollowed b~ air drying-
The reaction may be carried out at or below ~mh;~nt t~mrPr~ture.
-- 7 --
r~he dehydrohalogenation reaction is preferably carri~d out under
~n inert atmosphere.
Prostacyclin c~nd its salts are useul as ;~nm~;ateS in the
synth~ of prostAgl_ndi~ analogues, _nd exhibit a potent anti-
ayyl~y~Lory action on blood platelets, and th~l~L.~l~ have a
particuk~r utility in the LLea~e~lLan~/or prophylaxis of mAmm
as anti-thrombotic agents.
'mey are also useful in mAmm~l~, including ~an, to reduce
an~ control ~essive gastric secretion, thereby r~ ;n~ or
av~idiny- gastrointestinal ulcer fonmation, and A~c~l~rating the
h~Alin~ of such ulcers and les;~n~ already presen~ in the gastro-
intestinal tract.
Prostacyclin and its salts further exhibit v~o~;latory action
on blood vessels and thtL~ e have a pqIticular utility as anti-
hypertensives for the L~ L of high blood pressure in mAmm~
;n~ ;ng man. Platelets cA~ be A~;m;lAte~ into the vA~ Ar
endothPl;l~ or even in~vly~.~Led into endoth~ l cells.
~;nrh~m;r~l co-operation hethe^~ platelets and VAq~llAr endoth~l;
in the generation of Prostacyclin contrihutes to the repair of
vAc~llAr endo~hPl;l~m and Prostacyclin and its salts have a ~urther
utility in the pramotion of w~und ~PAl;n~ in mAmm~ls, inrlll~;nq
man.
Prostacyclin and its salts may be used whenever it is desir0d
to ;nh;h;t platelet ayyL~ydLion, to reduce the adhesive character
of platelets, and to treat or ~u~v~lL the fonmation of thramLhi in
mA~mAl~, inrll~;n~ man. For ~Am~le~ they may be used in the treat-
ment and ~v~lLion of myocardial infarcts, in the ~ ~L~ L of
peripheral~ llAr ~;~eA~e to treat and ~l~v~lL post operative
_ r
8 --
~hrambo$is, -to promote F~ate~cy o v~q~ll~r grafts ~ollowing
surgery/ and to treat c*mplications of arteriosclerosis and
conditions such as atheroscler~sis, blood clotting defects due to
l;~Fm;~, and o-ther cl;~;r~l conditions in which the underlying
etiology is ~q~ocl~ted with lipid lmh~1~n~e or hyper 1i~id~m;~.
They may also be used as additives to blood, blood products,
blood substitutes, and other fluids which are use~ in ar~if;~
extra-corporeal circulation and perfusion of isolated bcdy portions,
e.g., limbs and organs, ~h~h~r attached to the original body,
detache~ and being preserved or ~ ~d for tr~nqrl~nt, or attached
to a new body. During these circulations and perfusions, ayyLtydted
platelets tend to block the blood vessels and portions of the
circulation d~dLdL~S. miS blocking is avoided by the presence of
Prostacyclin. For this purpose, Prostacyclin or its salts may be
added graduall~ or in single or multiple portions to the circulating
blood, to the blood of the donor animal, to the perfused body portion,
at~ or ~t~hf~ to the r~c;p;~ntl or to two or all of those
at a total steady state dose of.001 to 10 mg., per liter of
circulating fluid. It is e.q~P~;~lly useful to use Prost~cyclin Ln
lab~Ld~ly ~nim~l~, e.g., cats, dogs,rabbits, monkeys and rats, for these
purposes in order to develop new methods and ~e~hn;~l~q fox organ
and limb ~r~n~ ntq.
The amount of prostacyclin or a s~lt thereof required (herein-
after referred to as the active ingredients) for th~Ld~ ic effect
will vary with the route of ~m;n;qtration In ger.eral a suitable
dose for a m~mmal will lie in the range of 0.01 to 200 mg. per
kilogram bcdyweight, conv~n;~ntly 0.01 to 10 mg per kilogram.
~hile it is possible for the active ingredient to be admin-
''. ~
~L!92~
~ 9 _
istered as th~ raw chPmlr~l it is preferable to prevent it as a
ph~rn~ tical for~ulation. Such formulations c~re preferably non-
~lPo~l~ c~nd non-hydrQYylic in nature, but alkaline ~lfoll~
solutions ma~ b2 used. Unit doses of a formulation contain between
0.5 m~ an~ 1.5 g of the active ingredient.
Such formulations, both for veterLnary and for human ~F~
use, of the present invention con~rise the active in3redient, as
above ~Fin~, together with one or more acceptable carriers
therefor and opt;on~lly other therapeutic ingredients. The
carrier(s) must be "acceptable" in the sense of being compatible
with the other in~redients of the for~ll~tion and not deleterious
to the recipient thereof.
The formulations ;n~ those suitable for parenteral
(;n~ in~ sub~uL~le~us, intr~ r and inLl~v~ ~us) ~m;n;~tration
which must of course be sterile.
The f~n~ tions may convF~;Fntly be p~F~ntp~ in unit dosage
form and may be yL~dlffd by any of the m~h~ well-known in the
art of ph~rm~ry. All ~ethn~ include the step of bringing into
~oc;ation the active ingredient with the carrier which constit-
utes one or more ~rcP~q~ry ingrF~;~nt~. In general the fon~ tions
are ~L~dl~d by uniformly and intimateLy bring mg into association
the actlve in~redient with liquid carriers or finely divided solid
carriers or both, and then, if nP~F~ ry~ ~h~;ng the product into
the desired formulation.
~ronr~;ng to the present invention there are thtL~ p~ovided:
(a) cryst~llin~ ph~rm~rolr~;r~lly acceptable salts of (5Z)-
5,6-didehydro-9-deoxy-6,9~ -~y~lost~7l~n~in FloL;
(b) the ~ rdLion of such salts;
'~;.
-- 10 --
(c) FhArn~c~tical formulations ~on~A i n; n~ ~uch salts;
~d) -the pxeparation of ~ h~rmAret~;r~l formulations;
(e) method for ~he LL~a~ .L or prophylaxis of thrnmh~
in a ma~n~ or m~ n ~ es, ;n~lnrli ~ Ir.an, c~
prising ~te ~m;n;~tration of a non-toxic, prophylactic
anti-tl~,~o~ic amot~tt of a salt as defin0d in (a) akove.
(f) methDd ~or ;n~l7~in~ vasodilation in a mammal, in~ ;n~
~m~n~ ~omprising the ~Am;n;~tration of a non-toxic,
vA~s~;lAttory _motmt of a salt as def;nPd .in (a) above.
(g) method ~or the prophylaxis or L~ "~ of gastric
~ n~ in a ~ammal, ;n~ln~;n~ m~n, comprising t~te
A~min;~tration of a ~ton-toxic, prophylactic or thera-
peutic amcQ~tt of a salt as ~Pf;n~ m ~a~ above.
(h) method for the prcm~tion of wound hPAl;n~ i~ a nE~al,
;n~ ;n~ man, comprising the ~m;n;~tration of a non-
toxic w wnd-L eGLLL~ amDunt of a salt as ~Pf;nPd in (a)
akove.
The following ~mrlP.~ are prcvided by way of an
illustration of the present invention and should in no way be
construed as constituting a limitation thereof:
EXAr~E 1
A stirred solution o~ PGF2a methyl ester (50 mg) in ~ther
(1 ml) was treated with sodium h;~?~"~Le (115.0 n~; 10 m~le~ r
e~uivalents3 an~ water (1 ml) and then dropwise during 2 hours
with a~l~Dll~ potA~s;~n tr;;~i~e (0.7 molar; 0.261 ~1). After
stirring cvP~ h~, the reaction mixture was shaken with ether and
aqueous sodium ~h;nS~ hAte; the etheral phase was sL-~cL~Led~ washed
with water, dried with mA~nP.~;lTm sulphate, and ~vd~JLdL~ to leave
2!9~
a ye_low ~um oE 5~ ~iodo-9-deoxy-6~,9~_-epo~ypros~;rJl~nrl;n Flo_
mRthyl ester.
A solution of 5~~iodo-9--deoxy-6~,9~ -epQxyprost~glAn~7;n Flo~
methyl ester (100 mg) in mpt~h~n~l;c sodium methoxide ~.~yc~ frGm
sodium (46 mg) and dry mP~h~n~l (0.70 ml) was set aside under dry
nitrogen or 5 hours, then freed fram solvent in high vacuum.
me rPc;rl~ S solid was washed with hPn7PnP, set aside
in the air ovPrn;rJht, and stirred with N ar~foll~ sodium hy~roxide
(0.5 m_) to give a ~l~pPn~;~n of coiourless fine nr~r77P~ m e
crystals wexe collected, washed with a few drops of N Ar~leou~
sodium hydroxide, an~ dried in the air to give the sodium salt of
9-deoxv-6,9~ -epoxy- ~ 5-prostAgl~nr7;n Fl~ . The inhibition of
ar~h;~n;~ acid-induced ayyL~ydLian of human plate7ets at a
~",r~ Lion of 0.2 ng~ml by this salt and its instability in
water at acid pH, together with further evidence, is compatible
with ~s;gn~tion of the c~nf;~-ration (5Z)-5,6-did~hydro-9-deoxy-
6,9~-~J~y~L~st~qlAn~7;n Fl~ .
m e high-resolution 13C n.m.r. spectrum of a solution of the
crystals in dimethyl ~ h~ -d6 showed the expect~d 20 reson-
ances whose ch~m;r~l shifts were entir~ly consistent with the
~h~m;c~l structure est~hl;~h~ for Prostacyclin. No impurity p~aks
were d~L~Led.
EXAMPLE 2
5~ -iodo,9-deoxy-6~,9~-~J~y~l~st~gl ~nrl; n Fl methyl es~er
(500 ml) was stirred with mrth~n~ NaQMe ~L~dled frcm Na (0.23g,
10 equivs.) and Meca (3.5 ml) un~er N2 at room t~l,~eL~LuL~ over
night; lN aq. NaOH (2.5 ml) was added to the yellow reaction
solution to bring about hydrolysis of the ester moiety and, after
'~
- 12 -
tw~ hours, -the methanol was evaporated in vao~o at room temperature.
m e re~;~n~ OU~ solution gave rise ~o~ eously tc a mass
of colourless fine nPP~l~s of ~he desired sodium salt (f~r~~
R-Na) which was cooled (0), collected, washed sparingly with lN
aq. NaOH, air-dried, and stored in a ~J~el~d tube; this salt
(383 mg) had~max (KBr disc~ 1692 cm 1 (O-C=C) and twenty 13C
r~n~n~es only were obse~ve~ at 18~.7 (C-l), 158.2 (C-6), 140.0
and 134.3 (C-13,14), 100.7 (C-5), 87.5 ~C-15), 80.6 and 75.5 (C
-9,11), 58.0(C-12), 49.0, 45.8, 42.4, 41.9, 37.5, 35.8 (C-18),
31~6, 29.9, 29,3, 26.7 (C-l9~, 18.4 (C-20) ppm fro~ IMS in DMSO-d6).
The product sodium (5Z)-5,6-dldehydro-9-deoxy-6,9Q-epoxyprosta-
~l~n~;n Fl~ (s~n. sodium prostacyclin), thus obtained cnmrlet~ly
inhibited ~r~h;~n;o acid-;n~n~Pd platelet a~y~y~l~ion (human
platelet-rich plasma) at 1 ng/~l and its profile of biological
activity on the rakbit aorta, rabbit ~oPl;~ æ tery, rat s~omach
strip an~ rat colon ~vll~vr~ wi~h that of sodium prostacyclin
ob~ain~d by bio-synthesis. After air-drying, the salt has a
surface coating of sodium c~ Le (ca. 3.5 % ~hy weight) which
protects the vinyl ether moiety against ~ P catalysed
hydrolysis.
EXAMPLE 3
5~-io~o-9-deQxy-6~9~-eFoxypros~ n~; n Fl~ methyl ester was
Ll~1Led with 1,5-diazabicyclo-5-nvnene (DBN) at roam t~m~r~L
in the AhsPn~e of a solvent for a few hours. The ~BN and hydro-
gen iodide were cvnv~niently ~I~V~d by adsorption on to a column
of SiO2, prepared from a sll~pPn~;~n of SiO2 in Etc~c/Et3N 50:1,
and the vinyl ether was eluted with the same sol~ent system.
I. R. spectroscopy (thin film, ~ ma~ 1738 (C02Me) and 1696 cm 1
,~
~'
~9Z~
- 13 -
(-0- ~ )), H n.m-r- m C6D6-Et3N, 19~ 4,?2, triplet of
triplPtsl2, J6.9 a~ 1.0 ~ ~C-5 vinyl probon)), and 13C n.m.r.
in C D Et N, 19:1 (distinctive features were ll~cr~n,,~ s at 159.8
(C-l), 155.8 ~C-l), 155.8 (C-6), 137.2 and 130.6(C-13,14), 95.3
(C-~ 4.1(C-15) 77.3 and 72.2(C-9,11) an~ 51.1. (M~ ester) pFm
from 'LMS).
The vinyl ether (5Z)-5,6-dLidehydro-9-deoxy-6,9a -epoxy-
prost~ n~;n me~hyl ester, was h~rolys0d with ~lfOll~ scdium
prostacyclin (fon~ 5I): R=sodiuml).
EXAMPLE 4
(SR,6R)-5-Iodo-PGIl methyl ester (13.375 g, o~t~;n;n~ ca.
2% 5S,6S isomer~ was taken up in methanolic scdium meth~ [from
Na (6.23 g) and MeOH (94 ml)] at rocm l~ Lule under N2 and
set aside at r w m temperature ovPrn;ght. The resulting yellow
sollltinn was treated with IN ~lfml~ NaCH (70 ml~, filtered
from .s~;m~nt, set aside at roam temp~L~LuLe for 2 h~urs, and
freed from MeOH on a Buchi ~vd~oLdLoL in ~acuo at rcam t~nr~.~Lule.
m e r~ syrup was treated with H20 (25 ml) and with ~ore lN
~q~ NdOH (80 ml), cryst~ Ation t~king place ~ ly
to give a mass of felted crystals. After cooling to ~l the solid
was collected, washed with ice-cold lN ,l~le~u~ NaOH ~caO 40 ml)
until the ~ch;n~q were colourless, and dried in the air (2 days)
to ~v.~L~L weight, affording 10.15 g, m.p. 164-166 ~following
drying at 100) of oolourless prostacyclin sodium salt.
~r;~;f;r~t;on of the ~ ml.~ liquors with ~qllR~ Cl yielded
1.84 g of cxude 6-Qxo-PGFl~which was purified e~her ~ h;n~,
column ~ ~l~LoyLd~ly (SiO2,AIX) to give 0.955 g of pure 6-oxo-EGF ~.
~.
