PH26909A

PH26909A - Pyrimidine derivatives

Info

Publication number: PH26909A
Application number: PH36945A
Authority: PH
Inventors: Peter James Machin; Joseph Armstrong Martin; Gareth John Thomas
Original assignee: Hoffmann La Roche
Priority date: 1987-05-22
Filing date: 1988-05-18
Publication date: 1992-12-03
Also published as: YU93288A; PT87550B; MC1934A1; EP0292023A2; ZA883447B; DK227388A; PT87550A; JPS63303992A; DK165985C; HUT47127A; NZ224638A; NO171065C; AU1631788A; HU199868B; IS3344A7; NO882233D0; NO882233L; CN88103089A; KR880013927A; DK165985B

Description

’ Le] 1 .

The present invention relates to pyrimidine deriv- atives of the formula

Ni, wn?

A

0 N . 1 rR} 0

EF

. 1. Pa 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 viral o5 infections, particularly of retroviral infections, such as visna, 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 15 for the treatment or prophylaxis of viral infections.

Duet] . - 2 -

The esterified hydroxy group denoted by rl 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 dimethyl- formamide acetal. 1-(2',3'-Dideoxy 2'-fluoro-f -D-arabinofuranosyl)- cytosine (hereinafter DFAC) is a particularly preferred compound of formula I.

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

NH,

CO)

A

. 30 10 11

R 0

FE

HO

Spor] ~- 3 wherein gO is an esterified hydroxy group. and, if desired, converting the esterified hydroxy group gO in the product obtained into a hydroxy group, or (b) for the manufacture of a compound of formula 1 in which r! ig esterified hydroxy, esterifying a compound of formula I, in which r' is hydroxy. or (c) 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 (a) of the

Process can be carried out by firstly converting such a compound of formula 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, og especially a tertiary amine, such as pyridine, and at a low temperature, e.g. 0-5°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 jodide, 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 3j'_-jiodide can subsequently be converted into a desired compound of formula I, in which

Rr} igs esterified hydroxy by hydrogenation in the a0 presence of a palladium catalyst. Alternatively, an afore- mentioned 3'-iodide can be treated with tributyl tin hydride 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 60°-90°C, to give a desired compound of formula I, in which RE is esterified hydroxy.

LC Gee } - 4 -

A further method for the removal of the 3'-hydroxy group from a compound of formula 11 comprises firstly reacting such a compound with phenyl thionochloro- formate, 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-dimethyl- aminopyridine, and at about room temperature, to give a corresponding 3'-O-phenoxythiocarbonyl compound. Such a compound can then be converted into a desired compound of 19 formula I, in which r! 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 a 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 formila I, in which r! is hydroxy, can be esterified in accordance with embodiment (b) of the process to give a compound of formula 1 in which r' is esterified hydroxy. This esterification can be carried out in a manner known per se, e.g. by treating the hydro- chloride salt of a compound of formula I with an appropriate acid halide in an inert organic solvent, such as dimethylformamide. .

. Safe \ . ~ 5

The conversion of a compound of formula I into an amide or into a Schiff's base in accordance with embodi- ment (c) 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 Il can be prepared. e.g. by converting the 3'-acyloxy group in a compound of the formula

NH,

NZ

; 1 0 N ’ IIL 10

R 0

F

R20 . 10 Co wherein R has the significance grven earlier and 2 08 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 triethylamine, in 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 a5 bring about concomitant conversion of the esterified 10 , : hydroxy group R into hydroxy.

Ye ¢} of . - 6 -

The compounds of formula Ill 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. (A) 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%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 calculated to produce 100% cytopathic effect in 12 days. After incubation at 37°C for 12 days the plates are fixed and stained with crystal 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 2.5uM. (B) Activity against HIV:

This assay uses HTLV-I1I11 (strain RF) grown in C8166 : cells (a human cpa’ T lymphoblastoid line) using RPM1 1640 medium with bicarbonate buffer, antibiotics and 10% foetal bovine serum. A suspension of cells is infected with ten times the TCD of virus and adsorption allowed to proceed for 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 10° infected

Jefe) 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 nl solution of the substance added.

The cultures are incubated at 37°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 4) -

In the assay described above, DFAC exhibits an ICcq of 1uM.

The pyrimidine derivatives provided by the present invention can be used as medicaments in the form of pharmaceutical preparations which contain them in associ- ation 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 og 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. stearic 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 a5 solutions and syrups include, e.g. water, polyols, saccharose, invert sugar and glucose. suitable carriers for injection solutions are, e.g. water, alcohols,

Sed) i - 8 - polyols, glycerine and vegetable oils.

The pharmaceutical preparations can also contain conventional pharmaceutical adjuvants, such as preserving, solubilizing, stabilizing, wetting, emulsifying,

Ea sweetening, colouring or flavouring agents, salts for varying the osmotic pressure, buffers. coating agents or antioxidants. The pharmaceutical preparations can contain other therapeutically valuable substances.

The dosage in which the pyrimidine derivatives pro- vided 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 require- ments 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 20, preferably about 0.2 to 15 and particularly about 0.4 to 10 mg/kg body weight, although it will be appreciated that 50 these dosage ranges are given by way of example only and may be varied upwards or downwards.

The pyrimidine derivatives aforesaid can be admini- stered in a single dosage or, preferably, in several sub- : 25 -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 pyrimidine derivatives.

The pharmaceutical preparations can be produced by mixing an aforementioned pyrimidine derivative and, if desired, one or more other therapeutically valuable sub- stances with a compatible pharmaceutical carrier material and, if desired, a pharmaceutical adjuvant and bringing the mixture into a desired administration form. The production of the pharmaceutical preparations can be

Sq) _ 9 - carried out in a manner known per se.

The following Examples illustrates the process provided by the present invention:

Example 1 a) NA solution containing 0.94 g of 1-(3'-0-acetyl-5'-0- _benzoyl-2'-deoxy-2'-fluoro-8-D _arabinofuranosyl)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' >-benzoyl-2'-deoxy- -2'-fluoro-3-D _arabinofuranosyl)cytosine, m.p. 135-140°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 0-5°C for 20 hours and then og treated with 0.1 ml of water. Nfter stirring for 1 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 0.5 ¢ of 1-(5'_O-benzoyl-2'-deoxy-2'-fluoro-3'-O-methylsulphonyl- _B -D-arabinofuranosyl)cytosine. ¢) A solution of 0.5 ¢ of the product of Example 1b) 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 over magnesium sulphate and evaporated. The residue was chromatographed on silica gel with methanol/dichloromethane (1:9). There was obtained

Lequ 10 - 0.2 g of 1-(5'-O-benzoyl-2',3'-dideoxy-2'-fluoro-3"- -iodo-f-D _arabinofuranosyl)cytosine. d) A solution of 0.2 ¢g of the product of Example 1c) 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 regsidué 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-8-D- _arabinofuranosyl)cytosine. e) 0.05 g 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 (EI): m/e 229 mm’, 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 of acetic anhydride and then at hourly jntervals for 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 ml of toluene each time, then redissolved in 1 litre of methanol and a5 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

Llp] 11 -

dichloromethane.

The solution was washed with water, saturated sodium hydrogen carbonate solution and water, then dried over sodium sulphate and evaporated.

The residue was dried in vacuo to give 12.5 g of N-acetyl-1-

-(5'-O-benzoyl-2'.deoxy-2'-fluoro-f-D-arabinofuranosyl)-

cytosine.

b) A solution containing 10.7 g of the product of Example 2a) and 29.7 ¢g of 4-(dimethylamino)pyridine in 295 ml of

40 acetonitrile was stirred under argon and cooled at 5°C while 5.61 g of phenyl chlorothionocarbonate were added dropwise.

The mixture was stirred at 5°C 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 ice-cold water, 1M 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 vacuo to give og 14.2 g of N-acetyl-1-(5'-0O-benzoyl-2'-deoxy-2'-fluoro- _3'-0-phenoxythiocarbonyl-B-D-arabinofuranosyl)cytosine. c) A solution containing 14.1 g¢ of the product of Example 2b) and 0.5 g of azobisisobutyronitrile in 520 ml of dry

55 toluene was stirred while argon was bubbled through the solution for 10 minutes. 11.28 g of tributyltin hydride were added and the introduction of argon was continued for a further 30 minutes.

The mixture was then heated at 75°C under argon for 3 hours.

The solution was evaporated to dryness and the residue was triturated with hexane.

The

: product was filtered off and purified by chromatography on silica gel with methanol/dichloromethane (1:9). There were obtained 6.95 g of N-acetyl-1-(5'-O-benzoyl-2',63' —-dideoxy-2'-fluoro-f-D-arabinofuranosyl)cytosine, m.p.

191-193.5°C, after recrystallization from toluene.

Je) - 12 -- d) NA solution containing 0.5 g of the product of Example 2c) in 50 ml of methanol, which had previously been saturated with ammonia at 0°C, was stirred for 3 days. The solution was evaporated to dryness and the residue was dissolved in 30 ml of water. The aqueous solution was washed 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°C. The mother liquors from the recrystallization were evaporated and the residue was dissolved 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°C.

The following Examples illustrate typical pharma- ceutical preparations containing the pyrimidine deriva- tives provided by the present invention as the active ingredient:

Example A

Tablets containing the following ingredients can be prepared in a conventional manner:

Ingredients Per tablet

Active ingredient 10 mg

Lactose 20 mg starch 4 mg pPolyvinylpyrrolidone 0.5 mg

Magnesium stearate 0.5 mg

Tablet weight 35 mg as ,

-~ 13 -

Example B

Ingredients Per capsule

NActive ingredient 25 mg

Lactose 15 mg

Sodium starch glycollate 2.95 mg

Claims

Do — 14 — CLAIMS: . 1. Compound of the general formula: PN ne?’ J A 1 pl Pa Ci wherein R* represents hydroxy, acetoxy or benzoyloxy and amides formed at the 4-amino group with an acetyl or benzoyl group.
2. 1-(2',3'-Dideoxy-2'—fluoro-B-D-arabino- furanosyl)cytosine.
3. A method for treating viral infections which comprises administering to a host in need of such treatment an effective amount of a compound according to claim 1.
4. A pharmaceutical composition containing a pyrimidine derivative set forth in claim 1 and a pharmaceutically acceptable carrier material. PETER JAMES MACHIN JOSEPH ARMSTRONG MARTIN GARETH JOHN THOMAS (Inventors)