CA1280112C - Prostaglandin i2 analogue and pharmaceutical containing the same - Google Patents

Abstract

Abstract:

There are disclosed a prostaglandin I2 analogue represented by the formula:

wherein R1 represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms or a phenyl group, A
represents a cyclohexyl group, 1-methyl-3-hexynyl group, 2-methyl-3-hexynyl group, 1-methylhexyl group, 2-phenethyl group, 1,1-dimethylpentyl group, 2-methylpentyl group, 1-cyclohexylethyl group or a 2-methylhexyl group, the double bond between the carbon atoms at 4- and 5-positiohs is E or Z or a mixture thereof, the asymmetric center in the substituent represented by A is R-configuration or S-configuration or a mixture thereof, and a pharmaceutical having circulation ameliorating effect and antiulcer effect containing the same.

Description

ADDRESSES OF INVENTORS CONTINUED

(5) 3707-2, Aza Ohtakebashi, Oaza Ami, Ami-machi, Inashiki-gun, Ibaraki-ken, Japan;
(6) 1-174, Tagu, Ushiku-machi, Inashiki-gun, Ibaraki-ken, Japan;
(7) 11-6-405, Chuo l-chome, Ami-machi, Inashiki-gun, Ibaraki-ken, Japan.

~80~ FP-1522 Prostaglandin I2 analogue and pharmaceutical containing the same BACKGROUND OF THE INVENTION

This invention relates to novel prostaglandin I2 S analogues and uses thereof for circulation ameliorating pharmaceuticals for blood flow amelioration, antithrombus etc. or antiulcer pharmaceuticals.

Prostaglandin I2 (hereinater written as PGI2) has been known as a natural physiologically active substance and has the structure shown by the following formula:

4, ~ 3 _7 (II) ,2 OH OHH

Its chemical name is (5Z,13E)-(9a,11a,15S)-6,9-epoxy-11, 15-dihydroxyprost-5,13-dienic acid. PGI2 exists within 1280~1Z

the arterial walls and has a potent platelet aggregation inhibiting effect as well as a powerful effect for relaxing smooth muscles of a peripheral artery [Nature, 263, 663 (1976)].

PGI2 exhibiting such properties is useful for prophylaxis and therapy of cerebral thrombosis, myocardial infarction and acute stenocardia induced by exasperation of platelet aggregation and further increase of thrombotic tendency, expected to be appicable for prophylaxis and therapy of arteriosclerotic diseases and desired to be developed as the so-called circulation ameliorating or antithrombotic pharmaceuticals.

Also, prostaglandins containing PGI2 are known to have gastric mucosa protective effect and blood flow increasing effect within gastric mucosa ['83 Inflammation Seminar "Prostaglandin" Pretext page 50 (spon~ored b~
Society o In1ammation of ~apan~], and PGI2 having such effects can be expected to be applicable for prophylaxis and therapy of gastrointestinal ulcers, typically stomach ulcer.

Howev~r, PGI2 is remarkably unstable and this has been an obstacle against practical application as pharmaceuticals.

In order to overcome such an obstacle, studies have been made about stable analogues in which the oxygen atom between the carbon atoms at the 6- and 9-positions in PGI2 is replaced with carbon atom. The carbacycline type compounds [Japanese Provisional Patént Publication No.
130543/1979] of the formula (III) as represented by oP-41483 [Japanese Provisional Patent Publication No.
130543/1979] and 9(0)-~6-PGIl of the chemical formula (IV) ~JapaneSe Provisional Patent Publication No, 1280~2.

32436/1981] are all chemically stable PGI2 analogues.
Also, 9(0)-methano-~6(9~)-prostaglandin Il (isocarba-cyclin, chemical formula (V)) in which the 5-position double bond in 9(0)-methano-prostacyclin (carbacyclin) is transferred to the 6(9a) position is also chemically sufficiently stable and has been reported as a PGI2 analogue having potent physiological activities [Japanese Provisional Patent Publication No. 137445/1984].
<~

(III) 0~ ~
[OP-41483 A = cyclopentyl]

H~OC ~

~ ~ (IV) OH ~H

~OOC

~ (v) 0~ OH

SUMMARY OF THE INVENTION

The present inventors have made extensive studies in order to provide prostaglandin I2 analogues which are stable, substantially free from decomposition at room temperature and have excellent pharmacological properties, and consequently created novel prostaglandin I2 analogues and found that said analogues have potent platelet aggregation inhibiting effect, hypotensive effect, vasodilative effect and antiulcer effect, and are 1~ also low in toxicity, to accomplish the present invention.

Thus, the present invention provides a prostaglandin I2 analogue represented by the formula (I) and a pharmaceutical containing the same as the effective ingredient:

~UlC~12 CH2 ~OR' J ~I) 9~ -8 o~A
~ ~3 ' OH

wherein Rl represents a hydrogen atom, an alkyl group having l to 12 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms or a phenyl group, A represents a cyclohexyl group, a l-methyl-3-hexynyl group, a 2-methyl-3-hexynyl group, a l-methylhexyl group, a 2-phenethyl group, a 1,1-dimethylpentyl group, a 2-methylpentyl group, a l-cyclohexylethyl group or a 2-methylhexyl group, the double bond between the carbon ~280~2 atoms at 4- and 5-positions is E or Z or a mixture thereof, the asymmetric center in the substituent represented by A is R-configuration or S-configuration or a mixture thereof.

PREFERRED EMBODIMENTS OF THE INVENTION

The compound of the present invention was found to exhibit potent platelet aggregation inhibiting effect, hypotensive effect, vasodilative effect and antiulcer effect in animal experiments. Such platelet aggregation inhibiting effect and vasodilative effect suggest that the present compound is an excellent blood flow ameliorating agent or an antithrombotic drug for prophylaxis or therapy for human against cerebral thrombosis, myocardial infarction, acute stenocardia, various circulation disorders such as peripheral circulation disorders, etc. caused by platelet aggregation exasperation or arterio~clerosis. ~urther, the antiulcer effect suggests that the present compound is an excellent antiulcer drug for prophylaxis or therapy for human against gastrointestinal ulcers, typically stomach ulcer.

In the animal experiments, the compound of the present invention proved to be low in toxicity, and this fact suggests that it is an excellent pharmaceutical with high safety.

tThe compounds of the present invention) In the compounds of the present invention represented by the above formula (I), Rl represents a hydrogen atom, an alkyl group having l to 12 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms or a phenyl group. The alkyl group having 1 to 12 carbon atoms may include ~280~12 straight or branched alkyl groups such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, iso-amyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl and the like. The cyclo-alkyl group having 4 to 7 carbon atoms may be exemplifiedby cyclobutyl, l-propylcyclobutyl, cyclopentyl, 2-pentyl-cyclopentyl, cyclohexyl, 3-ethylcyclohexyl, cycloheptyl and the like.

Specific examples of the prostaglandin I2 analogues provided by the present invention may include 3-(4'-carboxy-3'-cyclohexyl-trans-1'-propenyl)-7(R)-hydroxy-(lS, 5S)-cis-bicyclo[3.3.0}oct-2-ene (Compound A) and its ethyl ester (Compound A'), 3-(4'-carboxy-1'-butenyl)-6(S)-(3'(S)-hydroxy-4'(RS)-methyl-trans-l'-nonen-6'-ynyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo[3.3.0]oct-2-ene (Compound B) and its ethyl ester (Compound B'), 3-(4'-carboxy~ butenyl)-6(S)-(3'(S)-hydroxy-5'(R)-methyl-trans-l'-nonen-6'-ynyl)-7(R)~hydroxy-(lS,5S)-cis-bicyclo-13.3.0~oct-2-ene (Compound C) and its ethyl ester (Compound C'), 3-(4'-carboxy-1'-butenyl)-6~S)-(3'(S)-hydroxy-4'(RS)-methyl-trans-l'-nonenyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo[3.3.0]oct-2-ene (Compound D) and its ethyl e5ter (Compound D'), 3-(4'-carboxy-1'-butenyl)-6(S)-(3'(S)-hydroxy-5'-phenyl-trans-1'-pentenyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo~3.3.0~oct-2-ene (Compound E) and its ethyl ester (Compound E'), 3-(4'-carboxy-1'-butenyl)-6(S)-(3'(S)-hydroxy-4',4'-dimethyl-trans-1'-octenyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo[3.3.0]oct-2-ene (Compound F) and its ethyl ester (Compound F'), 3-(4'-carboxy-1'-butenyl)-6(S)-(3'(S)-hydroxy-5'(RS)-methyl-trans-l'-octenyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo[3.3.0]-oct-2-ene (Compound G) and its ethyl ester ~Compound G'), 3-(4'-butenyl-1'-butenyl)-6(S)-(3'(S)-hydroxy-4'(RS)-cyclohexyl-trans-l'-pentenyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo[3.3.0]oct-2-ene (Compound H) and its ethyl ester lZ~2 (Compound H'), 3-(4'-carboxy-l'-butenyl)-6(S)-~3'(S)-hydroxy-5'(RS)-methyl-trans-l'-nonenyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo[3.3.0]-oct-2-ene (Compound I) and its ethyl ester (Compound I'), and further inclusion compounds of these compounds and cyclodextrin.

(Pharmaceuticals) In application of the compounds of the present invention for clinical uses as the blood flow ameliorator, anti-thrombotic, antihypertensive and antiulcer, the effective administration may be either oral or parenteral, and they are desired to be administered at a dose of 0.1 ~g to 100 mg per one administration, preferably at a daily dose of l ~g to l mg in one or several divided doses. However, the accurate dosage depends on the age, body weight, severity of disease of the patient, the administration route and the number of administrations.

The solid preparation5 for oral administration may include tablets, pills, powders and granules. In such solid preparations, one or more active substances may be mixed with at least one inert diluent such as half-digestable starch, potato starch, alginic acid, mannitol or sucrose. The preparation may also contain additives other than diluents, for example, lubricants such as magnesium stearate, according to a conventional manner.
The liquid preparations for oral administraton may contain pharmaceutically acceptable emulsifiers, - solvents, suspending agents or elexirs, and may also contain, in addition to inert diluents used in general, auxiliary agents such as wetting agents, suspension aids, sweetners, flavors, aromatics-or preservatives. As other preparations for oral administration, there may also be included capsules of absorbable materials such as gelatin containing one or more active substance together with or 1280~12 without diluents or excipients.

As the solid preparation for rectal administration, there may be included suppositories comprising one or more active substance and at least one inert base such as S cacao butter, macrogol, Witepsol, and which can be treated according to the method known per se. Further, as the preparation for topical application, ointments, etc. may be employed.

The product for parenteral administration contains sterile aqueous or non-aqueous solvents, suspending agents or emulsifiers. Non-aqueous solvents or suspending agents may include propylene glycol, polyethylene glycol, vegetable oils such as olive oil, injectable organic acid esters such as ethyl oleate.
Such preparations can also contain auxiliary agents such as preservatives, wetting agents, emulsifiers and dispersants. They can be sterilized by filtration through a bacteria retaining filter, formulation with a sterilizer or by irradiation. It is also possible to prepare sterile solid preparations which are to be dissolved in a sterile solvent for injection immediately before use.

(Synthetic method) The compounds of the present invention represented by the formula (I) can be produced according to, for example, the route shown below by using as a starting material the known compound (VI) as disclosed together with its synthetic method in [Collected Gists of Lectures, pp. 51 - 54, the 45th Symposium on the synthetic organic chemistry (sponsored by The Society of Synthetic Organic Chemistry, JAPAN)].

~80i~

~&1~2~ .2 O~OSii~ Wittig reaction - =
O~HP ~OS i~-Ol'HP
(VI ¦ (VII ) ~C~12CH2~0~2 F~ oxidization 0~" 2 } (neO~ 2PC~C-A

0~ ' O ~:

(VI I I ) ~C~2~2~ 2 ~/~ re~luction~ ~CH2CH2COOR2 (~A
O~HP ~yA
O~P 0~
(IX) (X) ~2 ~H2 CO~R2 de~roteGti~n ,~A hydrolysi~i (I l ) 1280~1Z

~C~C~2~2~
_ ~A
~H C)H

( I 11 ) wherein A is the same as defined above; R2 represents an alkyl group having 1 to 12 carbon atoms, a cycloaklyl group having 4 to 7 carbon atoms or a phenyl group; Si-+ represents t-butyldimethyl-silyl group; and THP represents tetrahydro-2-pyranyl group, The compound (VII) can be prepared by allowing the compound (VI~ to react with the Wittig reagent obtained by the treatment of ~33P~CH2CH2CH2C02R2X [wherein R2 i8 1~ the same as defined above; R3 i8 an alkyl group having 1 to 4 carbon atoms or a phenyl group; X is a halogen atom such as chlorine, bromine, etc.] with a base. As the base, sodium hydride, potassium hydride or potassium tert-butoxide may preferably be employed. The amount of the Wittig reagent may be 1 to 10 equivalents, preferably 1 to 5 equivalents, relative to the starting compound.
The reaction solvent may preferably be dimethyl sulfoxide or ethers such as tetrahydrofuran, dimethoxyethane, etc.
The reaction temperature may be - 78 C to 50 C, ~ preferably - 20 C to 30 C.

The compound (VIII) can be obtained by treating the compound (VII) with 1 to 10 equivalents, preferably 1 to 3 equivalents of a fluorine compound such as tetra-n-butylammonium fluoride or cesium fluoride. The reaction may be carried out generally in an ether such as 12801~2 tetrahydrofuran, ethyl ether, etc. at a reaction temperature of 0 to 30 C for about 10 minutes to 3 days.

The compound (IX) can be obtained by oxidizing the hydroxymethyl group in the compound ~VIII) to convert it to an aldehyde, and then allowing the aldehyde to react with the Wittig reagent obtained by the treatment of ~R4o)2p~o)cH2c~o)-A [wherein A is the same as defined above, R4 is an alkyl group having 1 to 3 carbon atoms]
with a base. In oxidation of the hydroxymethyl group, it is particularly preferred to employ the oxidation method in which a system of amine/pyridine-sulfur trioxide complex/dimethyl sulfoxide for oxidizing a primary alcohol to aldehyde is employed. The reaction is carried out generally at 10 C to 40 C for about 1 minute to 2 hours. The amount of the oxidizing agent used may preferably be in an excess, namely about 2 to 100 equivalents relative to the starting compound (VIII).
The aldehyde thus obtained Qhould preferably be subjected as such without purification to the subsequent Wittig reaction. The base to be used in the Wittig reaction should preferably be sodium hydride, potassium hydride or potassium tert-butoxide. The amount of the reagent employed may be 1 to 10 equivalents, preferably 1 to 5 equivalents, relative to the aldehyde. The reaction solvent may preferably be an ether such as tetrahydro-furan, dimethoxyethane, etc., and the reaction may be carried out at a temperature from - 20 C to 50 C for about 5 minutes to 24 hours. These compounds (VII) to (IX) can be purified according to conventional purification means such as column chromatography, thin layer chromatography, liquid chromatography, etc.

The compound (X) can be obtained by reduction of the compound (IX). As the reducing agent, those which can not reduce COOR2 are preferred. For example, there may 128U1~2 be included sodium borohydride, zinc borohydride, diphenyl tin hydride, lithium trialkylborohydride such as lithium tri-sec-butylborohydride, di-isobutylaluminum hydride modified with 2,6-di-tert-butyl-4-methylphenol, or lithium aluminumhydride modified with 1,1'-bi-2-naphthol and a lower alcohol such as ethanoI and so on.
The reaction solvent may include lower alcohols such as methanol, ethanol and the like, ethers such as diethyl ether, tetrahydrofuran and dioxane, or aromatic hydro-carbons such as benzene and toluene. The amount of thereducing agent used may preferably be 0.5 to 30 equiva-lents, particularly preferably 1 to 10 equivalents, relative to the starting compound, the ~,~-unsaturated compound. The reaction temperature may be - 150 C to 80 C, preferably - 100 C to 30 C. The reaction mixture thus obtained may be treated according to the post-treatments as usual.

For example, the reaction mixture may be poured into dil.
hydrochloric acid, dil. sulfuric acid or an aqueous saturated ammonium chloride solution, extracted with an organia solvent poorly soluble in water such as hexane, pentane, petroleum ether, ethyl ether, benzene or toluene, the extracts obtained are washed with an aqueous sodium chloride solution, dried over a drying agent such as anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous potassium carbonate, etc., and the organic solvent is evaporated under reduced pressure to give a crude product. The crude product can be purified according to purification means such as column chromatography, thin layer chromatography, liquid chromatography, etc., if desired. The product thus obtained may further be subjected to the deprotection reaction, separation of diastereomers, hydrolysis reaction and salt forming reaction, if necessary ~280~12 Removal of the protective group on hydroxyl group may be practiced preferably with the use of acetic acid, pyridinium salt of p-toluenesulfonic acid or a cation exchange resin as the catalyst in a solvent such as water, tetrahydrofuran, ethyl ether, dioxane, acetone, acetonitrile, etc. The reaction may be carried out generally at - 78 C to 80 C for about 10 minutes to 3 days. The product thus obtained may be further subjected to separation of diastereomers based on the 15-position lU hydroxyl group formed by the reduction reaction by purification according to the purification means such as column chromatography, thin layer chromatography, liquid chromatography, etc.

The hydrolysis reaction of the carboxylic acid ester may lS be conducted in water, methanol or ethanol alone or a mixture thereof containing caustic soda or caustic potash at a temperature ranging from - 10 C to 100 C for one minute to 24 hours, or alternatively by u~e of an enzyme such as lipase in water or a solution containing water at a temperature ranging from - 10 C to 60 C for one minute to 24 hours. The product after the hydrolysis reaction can be purified according to the same purification means as mentioned above.

The present invention is described in more detail by 2~ referring to the following Examples.

tSynthesis of the compound) Example 1 C~PD ~ ~ C~2c~2~

~ ~ os ~

(1) (2) ~280112 Under argon gas atmosphere, 216 mg (9.0 mmol~ of sodium hydride was suspended in 10 ml of dimethyl sulfoxide and stirred at 50 C for 30 minutes to prepare a solution, followed by cooling to 20 C. To this solution was added dropwise a solution of 4.11 g (9.0 mmol) of (3-ethoxy-carbonyl)propyltriphenylphosphonium bromide in dimethyl sulfoxide ~7 ml). After sti~ring for 30 minutes, a solution of 1.14 g (3.0 mmol) of 3-formyl-6(R)-tert-butyldimethylsiloxy-7(R)-tetrahydropyranyloxy-bicyclo-[3.3.0]oct-2-ene (1) in dimethyl sulfoxide (10 ml) was added, followed by stirring at room temperature for one hour. The reaction mixture was poured into water, extracted with ether, dried over MgSO4, and concentrated under reduced pressure to obtain a crude product. This 15 was purified by column chromatography (ethyl ether/hexane = 3/2) to obtain 1.37 g of 3-(4'-ethoxycarbonyl-1'-butenyl)-6 (R)-tert-butyldimethylsiloxy-7(R)-tetrahydro-pyranyloxy-bicyclo~3.3.0]oct-2-ene (Compound 2). Yield:
97 %.

20IR (neat): 1735, 1135, 1020, 835 cm~1.
NMR ~ ~CDC13): 5.90 (d, J=llHz, O.9H), 5.4 - 5.6 (m, 1H?, 4 9 - 5.4 ~m, lH), 4.4 - 4.7 (m, lH), 4.05 (q, J=7Hz, 2H), 1.20 (t, J=7Hz, 3H), 0.89 (s, 9H), 0.05 (S, 6H).

Example 2 ~HC~2(~2C02Et ~1(~2~2C02Et a~si~ O~
~P ~P

(2) (3) 280~12 To a solution of 1.30 g (2.7 mmol) of the Compound (2) dissolved in 30 ml of tetrahydrofuran was added under room temperature 4 ml (40 mmol) of a tetrahydrofuran solution of tetrabutylammonium fluoride (lM). After stirring at room temperature for 5 hours and at 0 C
overnight, the reaction mixture was poured into an aqueous NaHCO3 solution, followed by extraction with ethyl ether. The extract was dried over MgSO4, concen-trated under reduced pressure, and the crude product obtained was purified by column chromatography (ethyl ether/hexane = 2/1) to obtain 936 mg of 3-(4'-ethoxy-carbonyl-l'-butenyl)-6(R)-hydroxy-7(R)-tetrapyranyloxy-bicyclo~3.3.0]oct-2-ene (Compound 3). Yield: 95 ~.

IR (neat): 3450, 1730, 1370, 1350, 810 cm 1.
NMR ~ (CDC13): 5.83 (d, J=llHz, O.9H), 5.5 - 5.7 (m, lH), 5.0 - 5.5 (m, lH), 4.11 (q, J=7Hz, 2H), 1.28 (t, J=7Hz, 3H).

Example 3 ~ C~C~2C~12C2E~ ~-- CHC~2~H2CO2Et -- ~ _ ~

~C~H y_c~O
o~P
O~P
(3) (4 ~CHCH ~C~H2C02Et ~ Q~
~p O
(5) 12801~2 Under argon gas atmosphere, 60 mg (0.16 mmol) of the alcohol derivative (3) was dissolved in 0.8 ml of triethylamine and 0.5 ml of dimethyl sulfoxide and to the resultant solution was added dropwise under room 5 temperature a solution of 534 mg of SO3 - pyridine complex in dimethyl sulfoxide (2 ml). After stirring for 30 minutes, the reaction mixture was poured into ice-cold water, extracted with ethyl ether, dried over MsSO4 and concentrated to obtain a crude aldehyde (4).

Under argon gas atmosphere, 13 mg (60 %, 0.32 mmol) of sodium hydride was suspended in tetrahydrofuran and a solution of 82 mg (0.35 mmol) of dimethyl(2-cyclohexyl-2-oxoethyl)phosphonate was added under room temperature.
After stirring for 30 minutes, a solution of the above lS crude aldehyde (4) in tetrahydrofuran (2 ml) was added, followed further by stirring for one hour. The reaction mixture was poured into ice-cold water, extracted with ethyl ether, dried over MgSO4 and the solvent was evaporated to give a crude product. This was purified by thin layer chromatography (hexane/ethyl ether = 1/1) to obtain 66 mg of an a,B-unsaturated carbonyl compound ~Compound 5). Yield: 86 %.

IR ~neat): 1735, 1680, 1665, 1625 cm 1 NMR ~ (CDC13): 6.0 - 7.1 (m, 2H), 5.81 (d, J=llHz, O.9H), 5.5 - 5.7 (m, lH), 5.0 - 5.5 (m, lH), 4.4 -4.7 (m, lH), 4.08 (q, J=7Hz, 2H), 1.25 (t, J=7Hz, 3H).

Example 4 According to the same procedure as in Example 3, the following compounds were synthesized. In Table 1, yields and spectra data are shown.

28011.2 ~Q~2~2~2~t A
O~P O

1;280~2 `

Table 1 Yield dpectrum IR (neat): 173~, 1688, 1668, 1625 cm~1 CH NMR ~ (CDC13): 5.9 - 7.1 ~,~CH3 35 (m, 2H), 5.88 (d, J=llHz, O.9H), 5.0 - 5.7 (m, 2H), 4.4 - 4.7 (m, lH), 4.08 (q, J=7Hz, 2H), 0.9 - 1.4 (m, 9H).
IR (neat): 1730, 1675, 1615 cm~l.
CH NMR ~ (CDC13): 5.9 - 6.8 3 73 ~m, 2H), 5.88 (d, J=llHz, 1 O.9H), 5.0 - 5.7 (m, 2H), CH3 4.4 - 4.7 (m, lH), 4.05 (q, J=7Hz, 2H), 0.9 - 1.4 __ (m, 9H).
IR (neat): 1735, 1690, 1683, 1622 cm~1.
C~3 NMR ~ ~CDC13): 6.0 - 7.1 100 (m, 2H), 5.82 td, J=llHz, C 3 O.9H), 5.5 - 5.7 (m, lH), 5.0 - 5.5 ~m, lH), 4.4 -4.7 (m, lH), 4.04 (q, J=
7Hz, 2H), 0.8 - 1.5 (m, _ IR (neat): 1730, 1670, 1620 cm~1.
MMR ~ (CDC13): 7.20 (s, lll 5H), 6.0 - 6.9 (m, 2H), ,~ " 79 5.95 (d, J=llHz, 0.9H), 5.0 - 5.7 (m, 2H), 4.4 -4.7 (m, lH), 4.10 (q, J=7Hz, 2H), 1.25 (t, J=
_ 7Hz, 3H).
IR (neat): 1730, 1690, 1685, 1625 cm~l.
CH NMR ~ (CDC13): 5.9 - 6.9 CH3 ~ C~3 100 (m, 2H), 5.96 (d, J=llHz, O.9H), 5.0 - 5.7 (m, 2H), 4.4 - 4.7 (m, lH), 4.1 (q, J=7Hz, 2H), 1.30 (~

1280~i2 Table 1 (Contd.) _ .
A Yield Spectrum t%) data ._ _ ._ IR (neat): 1735, 1690, 1665, 1625 cm~l.
C~3 NMR ~ (CDC13): 5.95 - 6.
C~ 73 (m, 2H), 5.85 (d, J=llHz, 3 O.9H), 5.0 - 5.7 (m, 2H), 4.4 - 4.7 (m, lH), 4.05 IR (neat) -1-735 ---1692 CH~ 1665, 1623 cm~l.
NMR ~ (CDC13): 6.0 - 7.0 1 ~ ¦ 86 (m, 2H), 5.88 (d, J=llHz, ~" O.9H), 5.0 - 5.7 (m, 2H), 4.4 - 4.7 (m, lH), 4.05 (q, J=7Hz, 2H).
CH3 IR (neat): 2950, 1730, 1688, 1664, 1624 cm~l.
C~ 88 Mass m/z; 388, 370, 327, 3 ~ _ _ _ 257, 211, 169, 85, _3.

Example 5 ,~C~C~2~H2 C2~ t ~HC~2CH2Co2~t (~3 (~
OT~lP ---- OH
(5) (6) ~t r~ ~
~u 0~ v~.
(7) To a solution of 60 mg (0.13 mmol) of the a,~-unsaturated ketone (Compound 5) dissolved in 5 ml of methanol, a solution of 6.0 mg of sodium borohydride in methanol (1 ml) was added at - 78 C. After one hour, the reaction 5 mixture was elevated in temperature to ~ 20 C, at which the mixture was further stirred ~or one hour. The reaction was stopped by addition of acetone, and the reaction mixture was poured into aqueous saturated ammonium chloride, extracted with ethyl ether and concentrated under reduced pressure to give a crude alcohol (6). The crude alcohol was dissolved in aqueous 65 % acetic acid and the solution was stirred under heating at 50 C for 2 hours. After cooling of the reaction mixture, it was poured into an aqueous NaHCO3 solution, extracted with ethyl acetate, dried over MgSO4, followed by evaporation of the solvent, to give a crude product. This was purified by thin layer chromatography to obtain 29 mg of a 15a-diol derivative ~7) as high polar component. Yield 59 %.

IR (neat): 3450, 1730 cm l.
NMR ~ ~CDC13): 5.90 (d, J=llHz, O.9H), 4.9 - 5.8 (m, 4H), 4.5 - 4.8 ~m, lH), 4.07 (q, J=7Hz, 2H), 1.25 (t, J=7Hz, 3H).

Example 6 According to the same procedure as in Example 5, the following compounds were synthesized. In Table 2, yields and spectra data are shown.

CHCH2 CH2 C2 E t A
OH OH

~280~2 Table 2 Yield ¦ data C~ IR (neat): 3360, 1730 ,~--~CH cm~l .
54 234, 117 841' 382, 271, IR (neat): 3350, 1735 ~l.
23 NMR ~ (CDC13) 5.91 (d, CH J=llHz, 0.9H), 5.0 - 5.7 3 (m, 4H), 4.07 (q, J=7Hz, 2H), 1.23 (t, J=7Hz, 3H).
IR (neat): 3380, 1735 CH3 Cm_l .
NMR ~ (CDC13): 5.89 (d, " "~'~`~'~` C~3 48 J=llHz, 0.9H), 5.0 - 5.6 (m, 4H), 4.05 (q, J=7Hz, 2H), 0 7 -_1.0 (m 9H).
IR (neat): 3360, ~730 ~l, ~ NMR ~ (CDC13): 7.16 (s, ,~ 33 5H), 5.92 (d, J=llHz, O.9H), 5.0 - 5.7 lm, 4H), 4.04 (q, J=7Hz, 2H), 1.2 __ ~ 3H).
C~13C~3 IR (neat): 3400, 1730 ; ~CH3 52 Mass m/z: 386, 368, 311, 287, 192, 143, 91.
~CH3 IR (neat): 3350, 1735 C~3 46 (neat-): 33;0, 1;35 C~ IR
3 39 cm-l.
297, 192, 81.

280~i2 Table 2 (Contd.) Yleld Spectrum _ IR ~neat): 33S~, 2960, 2925, 2870, 1735, 1155, 970 cm~l.
CH3 NMR ~ (CDC13): 6.27 (d, 47 J=15Hz, O.lH), 5.99 (d, C~l J=llHz, O.9H), 5.3 - 5.7 3 (m, 4H), 4.16 (m, lH), 4.13 (q, J=7.3Hz, 2H), 3 8 (m, lH), 3.08 ~m, _ 234.

Example 7 ~c~c~l2c~H2cv2~ ~C~C~2C~zC02H

OH 0~ OH OH

(7) (A) To a solution of 29 mg (0.075 mmol) of the 15a-diol (Compound 7) dissolved in 2 ml of ethanol, 1 ml of an aqueous 5 % sodium hydroxide solution was added under room temperature, followed by stirring for one hour.
After completion of the reaction, the reaction mixture was carefully neutralized with a 5N hydrochloric acid finally to pH 4 to 3. This was extracted with ethyl acetate, dried over MgSO4 and the solvent evaporated to give a crude product. This was purified through a 1~80~12 neutral silica gel capillary column to obtain 23 mg of a carboxylic acid (A). Yield: 85 %.

IR (neat): 3350, 1700 cm 1, NMR ~ (CDC13) 6.29 (d, J=158z, O.lH), 6.10 (d, J=llHz, O.9H), 5.4 - 5.7 (m, 3H), 5.3 - 5.4 (m, lH), 3.7 -3.9 (m, 2H), 3.0 - 3.2 (m, lH).
Mass m/z: 342, 324.

Example 8 According to the same procedure as in Example 7, the following compounds were synthesized. In Table 3, yields and spectra data are shown.

Fc~l~2c~2c~2H

~=~
~H 0~

i2~30112 - 2~ -Table 3 Com- Yield Spectrum pound __ (~ data _ NMR ~ (CDC13): 6.28 (d, J=15Hz, O.lH), 6.01 (d, I ~ ~ J=llHz, 0.9H), 5.2 - 5.7 B ~ ~ C~ 2 (m, 4H), 3.7 - 4.2 (m, 3 5 2H), 3.1 (m, lH), 0.9 -3.0 (m, 23H).
Mass m/z: 354, 336, 259, 177, 91, 81 IR (neat): 3320, 1700 cm~l ~ ~ C NMR ~ (DMSO-d6): 6.23 (d, C ~ 3 59 J=15Hz, O.lH), 5.97 (d, J=llHz, 0.9H), 5.2 - 5.7 (m, 4H), 3.9 - 4.2 (m, lH), 0.9 - 1.2 (m, 6H).
IR (neat): 3350, 1705 cm~l .
NMR ~ (CDC13): 6.28 (d, D ~ 96 J=15Hz, O.lH), 6.01 (d, CH J=llHz, O.9H), 5~4 - 5.7 3 (m, 3H), 3.9 - 4.1 (m, lH~, 3.7 - 0.9 ~m, lH), 0.8 - 1.0 (m, 6H).
_ ~ Mass m/z: 358, 340.
_ IR (neat): 3340, 1700 ,, , Cm~l NMR ~ (CDC13): 7.1 - 7.5 ~ (m, 5H), 6.29 (d, J=15H
E ~ 89 0 lH), 6.01 (d, J=llHz, ' O.9H), 5.5 - 5.8 (m, 3H), 5.3 - 5.5 (m, lH), 4.1 -4.2 (m, lH), 3.7 - 3.9 (m, lH).
Mass m/z: 364, 346.
NMR ~ (CDC13): 6.28 (d, J=15Hz, O.lH), 6.01 (d, r~ J=llHz, 0.9H), 5.3 - 5.8 ~'~3 CH3 (m, 4H), 3.83 ~m, 2H), F ~ CH 52 3.10 (m, lH), 1.1 - 2.8 ~_-~,- 3 (m, 20H), 0.89 (s, 3H), 0.85 (s, 3H).
Mass m/z: 358, 340, 314, 259, 206, 164, 95, 57.

- 2~ _ Table 3 (Contd.) Com- Yield Spectrum ~ound (%) data _ NMR ~ (CDC13): 6.28 (d, J=15Hz, O.lH), 6.01 (d, J=llHz, 0.9H), 5.3 - 5.7 ~ (m, 4H), 4.19 (m, lH), G CH ~ 3 63 3.78 (m, lH), 1.0 - 3.2 3 (m, 25H), 0.89 - 0.93 (two d, 3H).
Mass m/z: 358, 340, 314, 259, 206, 164, 117, 57 _ _ _ NMR ~ (CDC13): 6.28 (d;

J=15Hz, O.lH), 6.01 (d, CH3 J=llHz~ 0.9H), 5.2 - 5.7 l (m, 4H), 4.05 (m, lH), H ~ 91 3.80 (m, lH), 0.8 - 3.5 (m, 25H), 0.76 (d, J=7.3 Mass m/z: 370, 352, 326, 259, 206, 164, 81, 55.
. IR (neat): 3350, 2950, 2860, 1700 cm~l.
CH NMR ~ (CDC13): 6.28 ~d, ~'"_' 3 Jz15Hz, O.lH), 6.00 (d, l J=llHz, 0.9H), 5.2 - 5.7.
CH (m, 4H), 4.20 (m, lH), I 3 73 3.80 (dd, J=16, 9.5Hz, lH)i, 3.06 ~m, lH).
Mass m/z: 344, 326, 300, (Preparation of pharmaceutical) Example 9 5 mg of 3-( 4'-carbonyl-1'-butenyl)-6~S)-(3'(S)-hydroxy-3'-cyclohexyl-trans-1'-propenyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo[3.3.0]oct-2-ene (Compound A) dissolved in 5 ml of ethanol, 0. 2 g of carboxymethyl cellulose calcium, 20 mg of silicon dioxide, 0.2 g of magnesium stearate and 5 g of mannitol were mixed and dried according to a conventional method. The mixture was made up to 10 g ~280~12 with addition of mannitol and then mixed sufficiently until it became uniform. The resultant mixture was directly punched by use of a mortar and a pounder according to a conventional manner to obtain 100 tablets containing 50 ~g of the active substance in one tablet.

Example 10 For Compound A', Compound B, Compound B', Compound C, Compound C', Compound D, Compound D', Compound E, Compound E', Compound F, Compound F', Compound G, Compound G', Compound H, Compound H', Compound I and Compound I', according to the same procedure as in Example 9, 100 tablets containing 50 ~g of the active substance in one tablet were obtained.

Example 11 70 mg [content of Compound A': 5 mg] of ~-cyclodextrin inclusion compound o 3-(4'-ethoxycarbonyl-1'-butenyl)-6(S)-(3'(S)-hydroxy-3'-cyclohexyl-trans-1'-propenyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo[3.3.0]oct-2-ene (Compound A ", 0.2 g of carboxymethyl cellulose calcium, 20 mg of silicon dioxide, 0.2 g o~ magnesium stearate and the dried mannitol were added to make up 10 g and then mixed sufficiently until it became uniform, and directly punched according to a conventional manner to obtain 100 tablets containing 50 ~g of the active substance in one ~5 tablet.

Example 12 70 mg [content of Compound B: 5 mg] of ~-cyclodextrin inclusion compound of 3-(4'-carboxy-1-butenyl)-6(S)-(3'(S)-hydroxy-4'(RS)-methyl-trans-l'-nonen-6'-ynyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo[3.3.0]oct-2-ene (Compound B), 0.23 g of magnesium stearate and lactose were added to 1280~2 make up 23 g, and then mixed sufficiently until it became uniform and filled in No. 3 gelatin capsules according to a conventional manner to obtain lO0 capsules containing 50 ~g of the active substance in one capsule.

Example 13 A solution of 14 mg [content of Compound C': 5 mg] of ~-cyclodextrin inclusion compound of 3'-(4'-ethoxy-carbonyl-l'-butenyl)-6(S)-(3'-(S)-hydroxy-5'(RS)-methyl-trans-1'-nonen-6'-ynyl)-7(R)-hydroxy-(lS,5S)-cis-bicyclo-~3.3.0]oct-2-ene (Compound C') dissolved in lO0 ml of distilled water was sterilized according to a conventional manner, and l ml of the solution were injected into ampoules of 5 ml capacity to obtain lO0 injection preparations containing 10 g of the active substance in one ampoule.

~Ph~siolo~ical activities) Experiment 1 Platelet ag~regation inhi~iting effect (Method) Bloods were sampled from healthy male adults (22 - 23 years old) with no administration of drug for 2 weeks or more early in the morning when they were hungry. By use of an injector filled with 3.8 % sodium citrate solution, 50 ml of blood was sampled, immediately stirred by ~5 turning upside down and centrifuged at 200xg for 15 minutes. The supernatant was separated as the PRP
(platelet rich plasma) and the residue further subjected to centrifugation at 2000xg for 15 minutes, followed by recovery of the supernatant as PPP (poor platelet plasma) which was provided for use in the experiment. PRP ~250 128(~12 ~1) was placed in a cuvette, 5 ~1 of an 1 % ethanol solution of the compound of the present invention or an 1 % ethanol solution was added, and incubation was carried out at 37 C for one minute. Then, an aggregation inducing agent (ADP) was added and the process of aggregation wa5 recorded by Aggregometer ~Sienco Co.).
As the concentration of ADP, the minimum concentrations of ADP t2 - 10 ~M) to give the maximum aggregation for respective platelets were employed. The inhibition percentage of platelet aggregation was calculated by the following formula:

Inhibition percentage = (A - B)/A x 100 A: Maximum aggregation ratio during addition of solvent (1 ~ ethanol solution) B: Maximum aggregation ratio during addition of the compound of the present invention.

The platelet aggregation inhibiting effects of the compounds of the present invention are shown in terms of IC50 values in Table 4.

~0~12 Table 4 Human platelet aggregation inhibiting effect (in vitro) , Platelet aggregation Compound No. inhibiting rat1o (IC50) Compound A 5 x 10 9 M
Compound B 4 x 10 9 M
Compound C 6 x 10-l M
Compound D 8 x 10 9 M
Compound E 8 x 10 8 M
Compound F 2 x 10 7 M
Compound G 2 x 10 9 M
Compound H 3 x 10 7 M
Compound I 4 x 10 9 M
oP-41483 9 x 10 9 M

Experiment 2 Antiulcer effect "
(Method) Male wistar strain rats (weighing 250 - 280 g) were fasted for 18 hours and then subjected to peritoneotomy under ether anesthesia for ligature of pylorus, and after 4 hours under abstinence from food and water, gastric juice was sampled. The gastric juice was centrifuged at 3000 rpm for 10 minutes, and then the amount, pH and acidity of the gastric juice were measured. The acidity was measured by titration by means of an automatic titrating device (Toa Denpa Kogyo) with a 0.lN NaOH to pH

7.0 and calculating according to the following formula:

~8M12 - 3 "

Titration amount ~0.lN NaOH) required for l_ml sample 0 l required for l ml 0.lN HCl The gastric acid secretion inhibition percentage was calculated according to the following formula:

Inhibition = A,__B x 100 percentage A

A: Amount of gastric acid secreted in Control group B: Amount of gastric acid secreted in Drug group The drugs to be tested were administered subcutaneously immediately after pylorus ligature. The results are shown in Table 5.

Table 5 Rat gastric acid secretion inhibitinq effect _ ....... __ .
_ Amount of Compound No. Dose gastric,acid Inh,ibition (%) " , . , , ~g/kg secreted , , ,s.c.) (mE~/l) ' Solvent , _ 73.6 . Compound A 100 28.7 61.0 Compound B 100 13.4 81.8 Compound C 100 25.3 65.6 Compound D 100 7.4 89.9 Compound E 100 19.5 73.5 Compound F 100 60.3 18.1 Compound G 100 21.7 70.5 Compound H 100 46.5 36.8 Compound I 100 19.5 73.5

Claims (4)

1. A prostaglandin I2 analogue represented by the formula:

wherein R1 represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms or a phenyl group, A
represents a cyclohexyl group, 1-methyl-3-hexynyl group, 2-methyl-3-hexynyl group, 1-methylhexyl group,

2-phenethyl group, 1,1-dimethylpentyl group, 2-methylpentyl group, 1-cyclohexylethyl group or a 2-methylhexyl group, the double bond between the carbon atoms at 4- and 5-positions is E or Z or a mixture thereof, the asymmetric center in the substituent represented by A is R-configuration or S-configuration or a mixture thereof 2. A prostaglandin I2 analogue according to Claim 1, wherein said prostaglandin I2 analogue is prepared by the following reaction schemes:

wherein A is the same as defined in Claim 1; R2 represents an alkyl group having 1 to 12 carbon atoms, a cycloaklyl group having 4 to 7 carbon atoms or a phenyl group; represents t-butyldimethyl-silyl group; and THP represents tetrahydro-2-pyranyl group.

3. A pharmaceutical having circulation ameliorating effect and antiulcer effect containing a prostaglandin I2 analogue represented by the formula or a non-toxic salt of its acid or a cyclodextrin inclusion compound thereof as the effective ingredient:

wherein R1 represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 4 to 7 carbon atoms or a phenyl group, A
represents a cyclohexyl group, 1-methyl-3-hexynyl group, 2-methyl-3-hexynyl group, 1-methylhexyl group, 2-phenethyl group, 1,1-dimethylpentyl group, 2-methylpentyl group, 1-cyclohexylethyl group or a 2-methylhexyl group, the double bond between the carbon atoms at 4- and 5-positions is E or Z or a mixture thereof, the asymmetric center in the substituent represented by A is R-configuration or S-configuration or a mixture thereof.

4. A pharmaceutical according to Claim 3, wherein said prostaglandin I2 analogue is prepared by the following reaction schemes:

wherein A is the same as defined in Claim 3; R2 represents an alkyl group having 1 to 12 carbon atoms, a cycloaklyl group having 4 to 7 carbon atoms or a phenyl group; represents t-butyldimethyl-silyl group; and THP represents tetrahydro-2-pyranyl group.