AU602083B2 - Pyrimidine derivatives - Google Patents

Description

I

S F Ref: 55438 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION 1~.

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9 1tI

(ORIGINAL)

FOR OFFICE USE: Class Int Class Complete Specification Lodged; Accepted: Published: Priority, 11hk dOCunIDInt C01ltdII1 I' I Sk Oon -14) atid is CMr~T 0I Related Art: of Applicant: Address for Service: F Hoffmann-La Roche Co Aktiengesell3chaft Grenzacherstrasse 124-184 4002 Basle SWlITZERLAND Spruson Ferguson, Patront Attorneys Level 33 St Mar-tins Tower, 31 Market Street Sydney, New South Wales, 2000, Australila Complete Specification for the Invention entitled,, Pyrimidine Derivatives The following statement is a full description of this Invention, including the best method of performing it known to me/us 5845 I--~-LWWIIIIII~ni--UI:~

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RAN 4430/24 Abstract Compounds of the formula

NH,

.2 wherein R 1 represents hydroxy or esterified hydroxy and amides and Schiff's bases thereof possess antiviral activity and are useful in the treatment or prophylaxis of viral infections, particularly retroviral infections such as visna and hLV infections.

S'

RAN 4430/24 The present invention relates to pyrimidine derivatives of the formula

NH

2

ICI

1 N

F

wherein R is hydroxy or esterified hydroxy, and amides and Schiff's bases thereof.

These compounds possess valuable pharmacological properties. In particular, they possess antiviral activity and are useful in the treatment or prophylaxis of viLal fections, particularly of retroviral infections, such as v, na, HIV and like infections.

Objects of the present invention are the compounds defined above per se and for use as therapeutically active substances; a process for the manufacture of said compounds; medicaments containing said compounds and the use of said compounds in the control or prevention of illnesses, especially in the treatment or prophylaxis of viral infections, or for the manufacture of medicaments for the treatment or prophylaxis of viral infections.

Me/10.3.88 2 The esterified hydroxy group denoted by R in formula I can be any conventional esterified hydroxy group, e.g. an alkanoyloxy group, such as acetoxy, propionyloxy or butyryloxy; an aroyloxy group, such as benzoyloxy or substituted-benzoyloxy, e.g. p-toluoyloxy or p-chlorobenzoyloxy. Amides of the compounds of formula I are formed at the 4-amino group with any conventional acyl group, such as an alkanoyl group, e.g. acetyl, propionyl, butyryl or pivaloyl; an aroyl group, e.g. benzoyl; or an acyl group derived from an amino acid, e.g. glycyl, alanyl or lysyl. Schiff's bases of the compounds of formula I are formed at the 4-amino group with any conventional aldehyde or ketone, such as benzaldehyde, or with a dimethylformamide acetal.

l-(2',3'-Dideoxy-2'-fluoro- -D-arabinofuranosyl)cytosine (hereinafter DFAC) is a particularly preferr.I compound of formula I.

According to the process provided by the present invention, the compounds aforesaid are manufactured by removing the 3'-hydroxy group from a compound of the formula

NH

2

N

30 0 3 1in 3 wherein R10 is an esterified hydroxy group, and, if desired, converting the esterified hydroxy group R in the product obtained into a hydroxy group, or for the manufacture of a compound of formula I in which R is esterified hydroxy, esterifying a compound of formula I, in which R is hydroxy, or for the manufacture of an amide or a Schiff's base of a compound of formula I, converting a compound of formula I into an amide or into a Schiff's base.

The removal of the 3'-hydroxy group from a compound of formula II in accordance with embodiment of the process can be carried out by firstly converting such a compound of tormula II into the corresponding sulphonic acid ester, such as the mesylate, by treatment with a sulphonic acid halide, such as methanesulphonyl chloride, conveniently in the presence of an acid-binding agent, especiallr, a tertiary amine, such as pyridine, and at a low temperature, e.g. 0-5 0 C. The thus-obtained sulphonic acid ester can then be converted into the 3'-iodide in a known manner, e.g. by treatment with an alkali metal iodide, such as sodium iodide, in a suitable medium, such as an aliphatic ketone, e.g. acetone or 2-butanone, at an elevated temperature, preferably at reflux temperature of the mixture. The resulting 3'-iodide can subsequently be converted into a desired compound of formula I, in which R is esterified hydroxy by hydrogenation in the 30 presence of a palladium catalyst. Alternatively, an aforementioned 3'-iodide can be treated with tributyl tin iydride in the presence of a free radical initiator, e.g.

azobisisobutyronitrile, conveniently in an inert organic solvent, such as an aromatic hydrocarbon, e.g. benzene or toluene, and at an elevated temperature, e.g. about 606-90 0 C, to give a desired compound of formula I, in which R is esterified hydroxy.

4 A further method for the removal of the 3'-hydroxy group from a compound of formula II comprises firstly reacting such a compound with phenyl thionochloroformate, conveniently in an inert organic solvent, such as acetonitrile, in the presence of an acid-binding agent, such as a tertiary amine, e.g. pyridine or 4-dimethylaminopyridine, and at about room temperature, to give a corresponding 3'-0-phenoxythiocarbonyl compound. Such a compound can then be converted into a desired compound of formula I, in which R 1 is esterified hydroxy, by treatment with tributyltin hydride in the presence of a free radical initiator in a manner analogous to that described earlier. In a preferred embodiment of this method, the compound of formula II is acylated at the 4-amino group prior to the reaction with phenyl thionochloroformate. In this embodiment the product obtained after the treatment with tributyltin hydride is a corresponding amide of a compound of formula I, in which R is esterified hydroxy.

The conversion of the esterified hydroxy group in the product into a hydroxy group can be carried out in a manner known per se, e.g. by treatment with a saturated solution of ammonia in an alkanol, e.g. methanol. When the product carries an acylamino group in the 4-position, this group can be concomitantly converted into an amino group.

A compound of formula I, in which R 1 4 hydroxy. can be esterified in accordance with embodiment of the process to give a compound of formula I in which R is esterified hydroxy. This esterification can be carried out in a manner known per se, e.g. by treating the hydrochloride salt of a compound of formula I with an appropriate acid halide in an inert organic solvent, such as dimethylformamide.

5 The conversion of a compound of formula I into an amide or into a Schiff's base in accordance with enibodiment of the process can also be carried out in a manner known per se by treatment with, respectively, an appropriate acylating agent or an appropriate aldehyde, ketone or dimethylformamide acetal.

The starting materials of formula II can be prepared, e.g. by converting the 3'-acyloxy group in a compound of the formula

NH,

N

0AN

IIII

R2 wherein R 10 has the significance given earlier and 2 R is an acyl group, into a 3'-hydroxy group.

This conversion can be carried out in a known manner, such as by treatment with ammonia or an appropriate amine, such as methylAmine, ethylamine, n-propylamine or ,0 triethylamine, il, a lower alkanol, such as methanol, conveniently at about room temperature. It will be appreciated that the reagent used to effect the conversion and the reaction conditions should be chosen so as not to bring about concomitant conversion of the esterified hydroxy group R into hydroxy.

6 The compounds of formula III above are known compounds or analogues of known compounds which can be prepared in a similar manner to the known compounds.

The in vitro antiviral activity of the pyrimidine derivatives provided by the present invention can be demonstrated in the assays described hereinafter.

Activity against sheep lentivirus: This assay uses sheep lentivirus (strain WLC-1) grown in sheep choroid plexus (SCP) cells using a medium which contains 10% foetal bovine serum. The compounds are tested in 96 well microculture plates. Each well contains 10 4 SCP cells which have been incubated for 48 hours.

Test compounds, dissolved in dimethyl sulphoxide, are added to give a final concentration of 1% dimethyl sulphoxide together with a virus innoculum calclated to produce 100% cytopathic effect in 12 days. After incubation at 37 0 C for 12 days the plates are fixed and stained with ceystal violet. The protection in wells containing test compounds is assessed visually relative to wells containing virus alone and uninfected wells. The activity (MPC) is expressed as the lowest concentration of test compound which produces 100% protection of the infected wells. In this assay, DFAC has a MPC of Activity against HIV: This assay uses HTLV-III (strain RF) grown in C8166 cells (a human CD4 T lymphoblastoid line) using RPM1 1640 medium with bicarbonate buffer, antibiotics and foetal bovine serum. A suspension of cells is infected with ten times the TCD50 of virus and adsorption allwed to proceed 'or 90 minutes at 37°C. The cells are washed with medium. The test is carried out in 6 ml tissue culture tubes, each tube containing 2 X 105 infected 7 cells in 1.5 ml of medium. Test compounds are dissolved in either aqueous medium or dimethyl sulphoxide, according to solubility, and a 15 il solution of the substance added.

The cultures are incubated at 37 0 C for 72 hours in a humidified atmosphere containing 5% carbon dioxide in air.

The cultures are then centrifuged and an aliquot of the supernatant is solubilized and subjected to an antigen capture assay which uses a primary antiserum with particular reactivity against the viral protein 24 and a horseradish peroxidase detection system. Colour generation is measured spectrophotometrically and plotted against the concentration of test substance. The concentration that produces 50% protection is determined (IC 50 In the assay described above, DFAC exhibits an IC 50 of I.M.

The pyrimidine derivatives provided by the present invention can be used as medicaments in the form of pharmaceutical preparations which contain them in association with a compatible pharmaceutical carrier material.

These preparations can be administered orally, e.g. in the form of tablets, dragees, hard gelatine capsules, soft gelatine capsules, solutions, emulsions or suspensions; or parenterally, e.g. in the form of injection solutions.

The above mentioned carrier material can be a pharmaceutically inert, inorganic or organic carrier.

Examples of such carriers which can be used for tablets, dragees and hard gelatine capsules are lactose, maize starch or derivatives thereof, talc, otearic acid or its salts Examples of suitable carriers for soft gelatine capsules are vegetable oils, waxes, fats, semi-solid and liquid polyols. Suitable carriers for the production of solutions and syrups include, e.g. water, polyols, saccharose, invert sugar and glucose. Suitable carriers for injection solutions are, e.g. water, alcohols, 8 polyols, glycerine and vegetable oils.

The pharmaceutical preparations can also contain conventional pharmaceutical adjuvants, such as preserving, solubilizing, stabilizing, wetting, emulsifying, sweetening, colouring or flavouring agents, salts for varying the osmotic pressuru, buffers, coating agents or antioxidants. The pharmaceutical preparations can contain other therapeutically valuable substances.

The dosage in which the pyrimidine derivatives provided by the present invention can be administered will vary according to the potency of the particular derivative in question, the condition being treated and the requirements of the patient as determined by the attending physician. In general, the pyrimidine derivatives can be administered in a daily dosage of about 0.1 to preferably about 0.2 to 15 and particularly about 0.4 to mg/kg body weight, although it will be appreciated that these dosage ranges are given by way of example only and may be varied upwards or downwards.

The pyrimidine derivatives aforesaid can be administered in a single dosage or, preferably, in several sub- -dosages, e.g. up to six, divided over the day. A suitable unit dosage form for this administration can contain, e.g.

from about 0.5 to 300, preferably about 1.0 to 300 and particularly about 2.0 to about 200 mg of pyrimidi,.e derivatives.

The pharmaceutical preparations can be produced by mixing an aforemention-, pyrimidine derivative and, if desired, one or more other therapeutically valuable substances 2ith a compatible pharmaceutical ca,:rier material and, if desired, a pharmaceutical adjuvant and bringing thi mixture into a desired administration form. The production of the pharmaceutical preparations can be 9 carried out in a manner known per se.

The following Examples illustrates the process provided by the present invention: Example 1 a) A solution containing 0.94 g of 1-(3'-0-acetyl-5'-0- -benzoyl-2'-deoxy-2'-fluoro-B-D -arabinofuranusyl)cytosine in 4.9 ml of a 2M solution of ammonia in methanol was stirred for 2 hours. The solution was evaporated to dryness and the residue was recrystallized from ethyl acetate to give 0.64 g of 1-(5'-O-benzoyl-2'-deoxy- -2 -fluoro-B-D -arabinofuranosyl)cytosine, m.p. 135-140 0

C.

b) A solution containing 0.4 g of the product of Example la) in 5.6 ml of dry pyridine was stirred at 0 C while 0.26 g of methanesulphonyl chloride was added dropwise.

The mixture was stirred at 0-5OC for 20 hours and then treated with 0.1 ml of water. After stirring for I hour the mixture was poured into 20 ml of ice/water and extracted with ethyl acetate. The ethyl acetate extracts were washed with saturated sodium chloride solution, dried over magnesium sulphate and evaporated to give 05 g of 1-(5 '-0benzoyl-2 .deoxy-2 -3 -D-arabinofuranosyl)cytosine, c) A solution of 0,5 g of the product of Example Ib) and 0.9 g of sodium iodide in 12 ml of dry 2-butanone was stirred and boiled under reflux for 16 hours. The resulting suspension was evaporated to dryness and the residue was partitioned between 20 ml of water and 12 ml of ethyl acetate. The layers were separated and the aqueous layer was extracted with ethyl acetate. The ethyl acetate solutions were dried ov L >.agnediUm sulphate and evaporated. The residue was chromatograph ed on silica gel with methanol/dichloromethane There was obtained .4 -1 10 0.2 g of 1-(5,-O-benzoyl-2,3'-dideoxy-2'-fluoro-3'- -iodo-B-D -arabinofuranosyl)cytosine.

d) A solution of 0.2 g of the product of Example lc) in 8 ml of ethanol was treated with a solution of 0.04 g of sodium bicarbonate in 2 ml of water and then hydrogenated in the presence of 0.06 g of 10% palladium-on-carbon catalyst for 24 hours. The catalyst was removed by filtration and the filtrate was evaporated to dryness, The residue was partitioned between water and ethyl acetate.

The aqueous phase was separated and back-extracted with ethyl acetate. The ethyl acetate solutions were dried over magnesium sulphate and evaporated. There was obtained 0,14 g of 1-(5'-O-benzoyl-2',3' -dideoxy-2'-fluoro-3-D- -arabinofuranosyl)cytosine, e) 0.0Q5 of the product of Example 1d) Was dissolved in 2 ml of a saturated solution of ammonia in methanol. The solution was left to stand for 3 days and was then evaporated to dryness. The residue was dissolved in 2 ml of water and the solution was washed with ethyl acetate.

The aqueous solution was lyophilized for 24 hours to give 0.02 g of DFAC, MS m/e 229 151, 112.

Example 2 a) A solution containing 11.8 g of the product of Example la) in 1180 ml of methanol was stirred and heated to boiling under reflux, The solution was treated with 12 ml

S

0 of acetic anhydride and then at hourly intervals fot a further 4 hours with 12 ml of acetic anhydride each time.

After 6 hours the solution was evaporated to dryness and the residue was co-evaporated twice with 300 Ll of toluene each time, then redissolved in 1 litre of methanol and treated at hourly intervals over a period of 3 hours with 12 ml of acetic ahydride each time. The solution was evaporated to dryness and the residue was dissolved in dichioronethane. The solution was washed with water, saturated sodium hydrogen carbonate "*on and water, then dried over sodium sulphate and a ted. The residue was dried in vacuo to give 12,b q of N-acetyl-l- (5 1 -O-benzoyl-2 I -deoxy-2 I-f luoro-13-D -arabinof uraposyl) cytosime.

b A solution containing 10O.7 g of the product of Example 2a) and 29.7 q of 4-(dimethylamino)pyridine in 295 ml of acetonitrlle was stirred under argon and cooled at SPC while 5.61 g of phenyl chJloro thionocar bona to were added dropWise, The mixture was stirred at 56C for a further minutes and then at room temperature for 3 hours. The resulting solution was evaporated to dryness and the residue was dissolved in dichloromethane. The solution was washed with loe-oold water, IM hydrochloric acid, Water, saturated sodium hydrogen carbonate solution and saturated sodium chloride solution, then dried over sodium sulphate and evaporated, The residue was dried in vaouo to give 14.2 g of N-vtll(I0bnoy-Idoy2-loo Opeocticroy-Daal~aoy~y~ie c)A solution containing 14,1 q of the product of Example 2b) and g of azobioloobutyronitrile in $20 ml of -iry toluene was stirred while argon was bubbled throuigh the solution for 10 minutes, 112 g of tributyltin iirido were added and the introduction Qf argon was colt u or a further 30 minutes, The mixture was then heated at under argon for 3 hours, The solution was, evaporated to dryness and the residue was tritUrated with hexano, The product was filtered off and purified by chromatography on silica gel with methanol/di-hloromethane There wore obtained 6,95 g of N-acetyl-l-(51-O-bonzoyl-2',31 -did eoxy-2' -fluoo-3-D-a tab Inoturanosyl) cytos ine. iu.p.

191-1l93.511C, after recrystalliZation from toluene.

12 d) A solution containing 0.5 g of the product of Example 2c) in 50 m: methanol, which had previously been saturated with ammonia at 0 0 C, was stirred, or 3 days. The solution was evaporated to dryness and the residue was dissolved in 30 ml of water. The aqueous solution was wasted with ethyl acetate and then evaporated to dryness.

The residue was recrystallized from ethanol to give 0.18 g of DFAC, m.p. 204-207 0 C. The mother liquors from the reotystallization were evaporated and the iesidue was disoolved in distilled water. The aqueous solution was lyophilized and the residue was recrystallized from ethanol to give a second crop of 0.06 g of DFAC, m.p.

199-203 0

C.

The following Examples illustrate typical pharmaceutical preparations containing the pyrimidine derivatives provided by the present invention as the active ingredient: Example A Tablets containing the following ingredients can be p:epared in a conventional manner; Ingredients Per tablet Active ingredient 10 mg Lactose 20 mg StaLth 4 mg Polyvinylpyrrolidone 0.5 mg Magnesium stearate 0o5 mg Tablet weight 13 Exam~le B Ingredients Per capsule Active ingredient 25 mg Lactose 15 mg sodium starch glyoollate 2.5 mg Magnesium stearate 0 .5 mgr Capsule fill weight 43 mg 4;

Claims (6)

1. Compounds of the general formula wherein R 1 represents hydroxy or esterified hydroxy, and amides and Schiff's bases thereof.

2. 1-(2',3'-Dideoxy-2'-fluoro-B-D-arabinofuranoyl)cytosine.

3. A pyrimidine derivative substantially as hereinbefore described with reference to Example 1 or Example 2.

4. A process for the manufacture of ile pyrimidine derivatives claimed in claim 1, which process comprises removing the 3'-hydroxy group from a compound of the general formula wherein R 10 represents an esterified hydroxy group, and, if desired, converting the esterified hydroxy group R10 in the product obtained into a hydroxy group, or /945c 15 for the manufacture of a compound of formula I in which R 1 represents esterified hydroxy, esterifying a compound of formula I in which R represents hydroxy, or for the manufacture of an amide or a Schiff's base of a compound of formula I, converting a compound of formula I into an amide or into a Schiff's base. A medicament, for the treatment or prophylaxis of viral infections, containing a pyrimidine derivative set forth in any one of claims 1 to 3 and a compatible pharmaceutical carrier material. 6, A medicament, substantially as hereinbefore described with reference to Example A or Example B.

7. A method of treatment or prophylaxis of viral infections in a patient requiring said treatment or prophylaxis, which method comprises administering to said patient an effective aiwount of a compound according to any one of claims 1 to 3 or a medicament accFr'-g claim 5 or 6. 8, The method of claim 7 wherein the viral innfction is caused by a retrovirus. 9, 'he method of claim 8 wherein the virus is HIV, A process of the manufacture of a pyrimidine derivative, substantially as hereinbefore described with reference to Example I or Example 2.

11. A process of preparing a medicament according to claim comprising mixing a compound as defined In any one of claims 1 to 3 with a compatible pharmaceutical carrier material. DATED this THIRD day of JULY 1990 F, Hoffmann-La Roche Co. Aktiengesellschaft Patent Attorneys for the Applicant SPRUSON FERGUSON