CA1336088C - 1-(3'-substitued-2', 3'-dideoxy-d-ribofuranosyl) thymine and uracil - Google Patents

Abstract

A compound of the formula wherein the radicals A, X, R1, R2, and R3 are defined as follows:

A : (a) or (b) X : (a) O
(b) S
(c) CH2 R1: H; alkyl containing 1-3 carbon atoms;
-CH=CH2; -CH=CH-CH3; -CH2-CH=CH2;
; -C?CH

R2: H; or R2 constitutes together with R3 a carbon - carbon bond R3: H; F; Cl; Br; I; N3; CN; C?CH; OH; OCH3; CH2OH; and when R3 is F;
Cl, Br; I; N3 ; CN; C?CH; OH; OCH3 or CH2OH it may have either the cis-configuration or trans-configuration relative to the hydroxymetyl function at position 4', or R3 constitutes together with R2 a carbon -carbon bond, and therapeutically acceptable salts thereof, for use in therapy, in particular for the treatment of HIV virus infections.

Description

A 888-7 ~33 ~088 Novel Medic~nal Co~pounds Field of the invention The present invention relates to the use of chemical compounds and physiologically acceptable salts thereof for the therapheutic and prophylactic control and treatment of the Acquired Immuno Deficiency Syndrome (AIDS), infections by Human Immunodeficiency Virus, hepatitis B
virus infections and retrovirus infec-tions and method for such control and treatment in animal and man.

Background of the invention In the late seventies a new disease was reported, which subsequently was referred to as Acquired Immuno Deficiency Syndrome (AIDS). It is now generally accepted that a retrovirus referred to as HIV (Human Immuno-deficiency Virus), ~ormerly known as Human ~-cell Lymphotropic Virus (HTLY-III) or Lymphadenopathy Associated Virus (LAY) plays an essential role in the etiology of AIDS.

AIDS is characterized by a profound immunodeficiency due to low numbers - 20 -of a subset of lymphocyte-T-helper cells, which are one target for HIV
infection. The profound immunodeficiency in AIDS patients makes these patients highly susceptible to a variety of opportunistic infections of bacterial, fungal, protozoal or viral etiology. The etiological agents ; among viral opportunistic infections are often found in the herpes virus group, i.e., Herpes simplex virus (HSV), Varicella Zoster virus (YZV), Epstein-Barr virus (EBV) and, especially, cytomegalovirus (CMV). Other retroviruses affecting humans are HTLV-I and II and examples of retro-viruses affecting animals are feline leukemia virus and equine infectios anaemia virus.
Hepatitis B virus infections cause severe disease such as acute hepa-titis, chronic hepatitis, fulminant hepatitis in a considerable number of persons. It is estimated that there are 200 million patients with chronic hepatitis B infection in the world. A considerable number of the $' ~ ~ 2 1336088 chronic cases progress to liver cirrosis and liver tu~ours. ~n some cases the hepatitis infections also take a rapid and severe course as in fulminant B hepatitis with about 90 ~ mortality. At present there is no known effective treatment against hepatitis B infections.

General outline of the invention A great number of nucleoside analogues exhibit several antimetabolic activities. They do so by substituting for or competing with the natu-rally occuring nucleosides. Recently some nucleoside analogues have beendescribed, which inhibit in cell culture the multiplication of human i~nunodeficiency virus (HIY, also called HTLV-III, LAV), the causative agent of AIDS and AIDS-related complex (ARC). Such compounds are for example azidothymidine, dideoxycytidine and dideoxyadenosine. These and other described HIV-antimetabolic nucleoside analogues have the same geometr;c relationship between the nucleoside base and the glycosidic part as the naturally occuring nucleosides, i.e. they are B-anomers.

We have now, surprisingly, found that some nucleosides and nucleoside analogues with the opposite gew,letric configuration,c~-anomers, are potent inhibitors of HIV multiplication but not of cell-division.
Anti-HIV activities are displayed by such geometric isomers which have - been modified either in the nucleoside base part, the glycoside part or in both parts. The structures of these compounds are disclosed in this invention.

Prior Art The following compounds of the formula I below are known:
1. Compounds of the formula 0 ,ll R 1 HN

~L~

H0 ~ 0 /

133~0~8 wherein R3 is OH and Rl ~s as follows:

Rl 1s H and CH3: T. Nishimura, B. Shinizu, I. Iwai Chem. Pharm. Bull. (Tokyo) 12 (1964), 1471 Rl is C2H5: M. Swierkowski, D. Shugar J. Med. Chem. 12 (1969), 533 pl is n-C3H7 A. Szaboles, J. Sagi, L. Otvos J. Carbohydrates, Nucleosides, Nucleotides 2 (1975), Rl is i-C3H7: M. Draminski, A. Zgit-Wroblewska Polish J. Chemistry 54 (1980), 1085 Rl is C - CH: P.J. Barr, A.S. Jones, P. Serafinowski, R. Walker J. Chem. Soc. Perkin I (1978), 1263 - 1267 and wherein R3 is N3 and Rl is CH3: M. Imezawa, F. Eckstein, J. Org.
Chem. 43 (1978), 3044-3048.

2. The compound of the formula N ~ Rl O '~" N
OH

HO ~

Rl is C _CH is described by P.J. Barr, A.S. Jones, P. Serafinowski, R. Walker, J. Chem. Soc. Perkin I (1978), 1263 - 1267 133~088 23038-76 R1 is H is described by J.J. Fox, N.C. Yung, I. Wempen and M.
Hoffer, J. Am. Chem. Soc., Vol. 83 (1961), 4066-4070.
Both groups 1. and 2. concern only compounds having the 3'-group and the 4'-hydroxymethyl group in a trans-configuration.
Disclosure of the Invention The present invention provides compounds of the formula (I) ~ A

HO~ HO~ (I) a-anomer ~-anomer wherein the radicals A and R3 are defined as followss A is (a) 0 HN~
I

or (b) NH2 I

R is H; alkyl containing 1 to 3 carbon atoms or ., cyclopropyl; -CH=CH2; -CH=CH-CH3; -fH2-CH=CH2; -C-CH3 or -C~CH;

R is F; CN; -C~CH; OCH3; CH2OH; with the proviso that if R is F or OCH3 then R is not H, CH3, C2H5, -CeCH and, if A is (a) and Rl is H, then R3 is not CH2OH, wherein R3 can have cis-or trans-configuration relative to the hydroxymethyl function at position 4', and therapeutically acceptable salts thereof.
The compounds of the invention of formula I inhibit the multiplication of human immunodeficiency virus (HIV). The compounds of the formula I are useful as therapeutic and/or prophylactic agents in the control and treatment of HIV virus infections in mammals and man.
In a more general aspect, the compounds of the formula I are useful as therapeutic and/or prophylactic agents in the control and treatment of infections caused by retroviruses and hepatitis B viru~ in mammals and man.
All retroviruses, including HIV, require the enzyme reverse transcriptase in their natural cycle of replication.
Hepatitis B virus (HBV) is a DNA virus with a unique circular double-stranded DNA genome which is partly single-stranded. It contains a specific DNA polymerase required for viral replication. This DNA polymerase also acts as a reverse transcriptase during the replication of HBV DNA via an RNA

.\ ~ r intermediate.
The compounds of the formula I inhibit the activity of reverse transcriptase of retroviruses including HIV as well as the activity of DNA polymerase of hepatitis B virus.
The present invention has several aspects:
1. the novel compounds included in the formula I;
2. pharmaceutical compositions comprising a compound of the formula I as active ingredient;

3. a compound of the formula I for use in therapy;

4. a ~ompound of the formula I for use in the manufacture of a medicament for therapeutic and/or prophylactic treatment of infections caused by a retrovirus, including HIV, or by hepatitis B virus;

5. a method for the therapeutic and/or prophylactic treatment of infections in mammals and man caused by retrovirus including HIV or hepatitis B virus, by administering to a host in need of such treatment an efficient amount of a compound of the formula I;

6. a commercial package containing a compound of the invention, together with instructions for its use in therapeutic or prophylactic treatment of infections caused by a retrovirus including HIV or by hepatitis B virus.
It is a preferred aspect of the invention to combat HIV
virus infections in man.
The expression "alkyl containing 1-3 carbon atoms" for the radical R means CH3, C2H5, CH2CH2CH3, CH(CH3)2 and cyclopropyl.

When R in formula I is F, CN, C=CH, OCH3 or CH20H it may have either cis-configuration or trans-configuration relative to the hydroxymethyl function at position 4'.
Preferred compounds of the formula I are:
(a) A is O

HN~
I

(b) A is NH2 N~
I

(c) R at position 3' and the hydroxymethyl group at position 4' have the trans-configuration;
(d) R1 is CH3 or C2H5;
~0 (e~ R3 is F, OCH3 or CH2OH;

(f) R is F;
(g) the combination of (a), (c) and (d) above;
(h) the combination of (a), (c), (d) and (e) above;
(i) the combination of (b), (c) and (d) above;
(j) the combination of (b), (c), (d) and (e) above;
(k) the combination of (b), (c), (d) and (f) above.

~tD 7 Examples of preferred compounds are o ~ R1 HN

O ~N

HO
R is CH3; R3 is CH20H;
R1 is C2H5; R3 is CH20H;
R1 is C2H5; R3 is F;

N~
0~

R is CH20H.
In all the examples of preferred compounds R at position 3' and hydroxymethyl at position 4' have the trans-configuration.
In clinical practice the nucleosides of the formula Iwill normally be administered orally, by injection or by infusion in the form of a pharmaceutical preparation comprising the active 1336~

ingredient in the form of the original compound or optionally in the form of a pharmaceutlcally acceptable salt thereof, in association with a pharmaceutically acceptable carrier which may be a solid, semi-solid or liquid diluent or an ingestible capsule.
The compound may also be used without carrier material. As examples of pharmaceutical preparations may be mentioned tablets, dragees, capsules, granulates, suspensions, elixirs, syrups, solutions etc. Usually the active substance will comprise between 0.05 and 20~ for preparations intended for injection and between 10 and 90% for preparations intended for oral administration.
In the treatment of patients suffering from retrovirus, especially HIV, or hepatitis B virus infections, it will be preferred to administer the compounds by any suitable route including the oral, parenteral, rectalr nasal, topical and vaginal route. The parenteral route includes subcutaneous, intramuscular, intravenous and sublingual administration. The topical route includes buccal and sublingual administration. The dosage at which the active ingredients are administered may vary within a wide range and will depend on various factors such as the severity of the infection, the age of patient etc., and may have to be individually adjusted. As a possible range for the amount of the compounds of the invention or a physiologically acceptable salt thereof to be administered per day may be mentioned from about 10 mg to about 10,000 mg, preferentially 100 to 500 mg for intravenous administration and preferentially 100 to 3,000 mg for oral administration.
Examples of pharmaceutically acceptable salts of the ~ 9 133608~ 23038-76 compounds of formula I include base salts, e.g. derived from an appropriate base, such as alkali metal (e.g. sodium), alkaline earth metal (e.g. magne~ium) salts, ammonium and NX~ (wherein X is Cl 4 alkyl). Physiologically acceptable salts of a hydrogen atom or an amino group include salts of organic carboxylic acidæ such as acetic, lactic, gluconic, citric, tartaric, maleic, malic, pantothenic, isethionic, succinic, oxalic! lactobionic and succinic acids; organic sulfonic acids such as methanesulfonic, ethanesulfonic, benzenesulfonic, p-chlorobenzenesulphonic and p-toluenesulfonic acids and inorganic acids such as hydrochloric, hydroiodic, sulfuric, phosphoric and sulfamic acids.
Physiologically acceptable salts of a compound of a hydroxy group include the anion of said compound in combination with a suitable cation such as Na , NH4, NX4 (wherein X i8 a C1 4 alkyl group).
The administered compounds may also be used in therapy in conjunction with other medicament~ such a~ 9-[(2-hydroxy-1-(hydroxymethyl)ethoxy)methyl]guanine, 9-(2-hydroxyethoxymethyl)-guanine (acyclovir), 2-amino-9-(2-hydroxyethoxymethyl)purine, interferon, e.g., a-interferon, interleukin II, and phosphono-formate, or in conjunction with immune modulating therapy including bone marrow or lymphocyte transplants or medications such as levamisol or thymosin which would increase lymphocyte numbers and/or function as is appropriate.
Method~ of PreParation The compounds of the invention may be prepared by one of the following general methods, constituting a further aspect of the invention.

.

13~88 ~ 23038-76 A. Condensing a compound of the formula HO

wherein R3 is as defined above and the hydroxyl groups may be optionally protected, to the N-1 position of a pyrimidine derivative, corresponding to radical A in formula I according to known methods described in the literature~ followed by separation of the a-anomer and removal of any protecting group(s). Such methods are described for example in "Basic Principles in Nucleic Acid Chemistry", Vol. 1 (Academic Press, 1974, Ed. P.O.P.Ts'o), in "Nucleoside Analogues, Chemistry, Biology and Medical Applications" (Pharma Press, 1979, Eds. R.T. Walker, E. De Clercq and F. Eckstein) and in Nucleic Acids Research Vol. 12, 1984, pages 6827 to 6837 (A.J. Hubbard, A.S. Jones and R.T. Walker). An example of such a method is given for the case of a uracil base analogue:
o Jl R1 HN 3~

R~ 0~

R4 ~CH3~35lo R

R50 ~
wherein R4 is F, CN, C~CH, OCH3 or CH20R5, R5 is a protecting ID~ 11 133~Q~g group, of which a great variety is known, and examples of which are p-toluoyl, acetyl, trityl, benzyl. R1 is as defined above.
B. Anomerization of a ~-anomer of the formula A

R50-- o R4~

wherein A is as defined above, R4 is F; CN; OCH3 or CH20R5;
wherein R is H or a hydroxy-protecting group to a mixture of ~-and ~-anomers, whereafter the a-anomer is separated and any protecting groups removed. The anomerization may be performed by known methods, e.g. with an optionally protected ~-nucleoside, for example a silylated nucleoside, with a catalyst, such as for example trimethylsilyl trifluoromethanesulfonate OSiMe3 R50 ~ R

R ~ Rs R1, R , R4 and R5 are as defined above.
C. A transglycosylation reaction whereby the sugar moiety forming a bond, a- or ~-, to one nucleoside base, is transferred to the desired pyrimidine base. The reaction is performed with a catalyst such as for example trimethylsilyl trifluoromethane-~-~ 12 l~Y

~336088 sulfonate, and is followed by separation of the products and deprotection.

osl(CH3)3 ~CH3;35 iO~N~ O~JN~f RsO
I othor products wherein R1, R4 and R5 are as defined above. The radical B is a pyrimidine or purine base, the choice of which is not critical.
D. Introduction of the functional group R3, or a precursor of R3, into the nucleoside a-anomer by substitution of a suitable leaving group, R7, followed by deprotection.

O O

HN~R 1 HNJ~f 1 0~ O~N

R~
~/ ~
R50~ R50~

133~88 o ~3"R 1 ~ ~3"R 1 R50 ~ ~ R50 ~

R1 and R5 are as defined above, R7 is a good leaving group such as for example trifluoromethanesulfonyloxy, R is F, CN, OCH3 and synthos for the C~CH and CH20H groups, such as for example C~C-Si(CH3)3, CH3C02 and HC~ ~ . R9 i~ a suitable protecting group.
An alternative way for introduction of the R8 function is by reaction of the 2,3'-anhydro ~-anomer.

~n ~ 3~

~ . 13~88 ~ R 1 o~N

O~N~
h ~
R50 ~ R50 wherein R1, RS and R8 are as defined above.
The principles of methods A to D above are applicable to the synthesi~ of both uridine and cytidine analogues of formulae I
and II, although the formulae illustrating the reactions only depict uridine analogues.
E. Converting the uracil moiety of the 5-~ubstituted or unsubstituted a-uridine compounds to a cytosine moiety of the corre~ponding a-cytidine analogues. This is carried out by 10conventional methods, the principles of which have been described for example by W.L. Sung (J. Chem. Soc. Chem. Commun. 1981, p.
1089 and J. Organic Chemistry 1982, volume 47, pages 3623 to 3628) and by P. Herdewijn et al. (J. Medicinal Chemi~try 1985, volume 28~ pages 550 to 555).
The following examples will further illustrate the invention.

f~ 15 Preparat~on of intermediate products A. Preparation of 3'F-3'-deoxy-5'-0-acetylthymidine (VSB423) 3'F-3'-deoxythymidine 45 mg (0.184 mmol) ~n acetic anhydride (2.0 mL) was heated with stirring in an oil bath at 80 for 7 hrs. The solution was evaporated in vacuo and the residual acetic anhydride and acetic acid were removed by several additions and reevaporations with benzene-toluene (1:1). The residue was used without further purifications.
Preparation of compounds of the invention Example 1. Preparation of 1-(3-F-2,3-dideoxy- K-D-ribofuranosyl)thymine (VSA 419) ~Method B) Thymine 23 mg (0.18 nn~ol) and 3'F-3'-deoxy-5'-0'-acetylthymidine was suspended in acetonitrile (1.2 mL) and N,0-Bis (trimethylsilyl)-aceta-mide (0.35 mL) was added. The mixture was stirred at room temperature for 1.5 hrs. Trimethylsilyl trifluoromethanesulfonate (0.05 mL) was added. After stirring at room temperature for 192 hrs, the mixture was poured under stirring into a l:l (v/v) mixture of 20 ml of 10 X aqueous KHC03-ethyl acetate. Two phases were separated and the water phase was extracted with ethyl acetate (3 x 10 mL). The combined ethyl acetate phase was filtered and evaporated in vacuo. The residue was dissolved in dichloromethane-ethyl acetate 1:1 and applied to a column of silica gel, and the column was eluated with dichloromethane-ethyl acetate 1:1 to give 28 mg (53 X) starting material (VSB 423) (Rf 0.37 on TLC silicagel CH2C12-EtoAc 1:1) and 18 mg (34 X) of 1-(3-F-Z,3-dideoxy-5-0-acetyl--C~-D-ribofuranosyl)thymine (VSB 424) (Rf 0.29 on TLC silica gel CH2C12-EtoAc 1:1).

NMR (CD30D) 11.95 (s, 3H, CH3-5), 2.12 (s, 3H, CH3C0), 2.3-3.0 (m, 2H, H-2'a,b), 4.15 (d, 2H, J4',5'=4.4 Hz, H-5'a,b), 4.81 (dt, lH, J3~F,4'=30.0 Hz, J4',5'=4.6 Hz, H-4'), 5.23 (dd, IH, J3'F,3'=53.7 Hz, J2',3'=5.0, H-3'), 6.36 (d, lH, Jl',2'=7.57 Hz, H-l'), 7.27 (d, lH, J H-6, CH3=1.47, H-6) -~ ~ 13360~8 13C(CD30D) ~12.80 ~CH3), 20.87 (CH3CO), 39.40 (d, J=20.8 Hz, C-2'), 63.37 ~d, J=12.2 Hz, C-5'), 84.65 (d, J=24.4 Hz, C-4'), 86.50 ~s, C-l') 93.82 (d, J=178 Hz, C-3'), 111.12 (C-S), 135.07 (d, J=6.1 Hz, C-6), 150.48 (C-2), 163.68 (C-4), 170.30 (CH3CO).

The cor,lpound VSB 424 (16 mg) was dissolved in saturated methanolic ammonia (5 mL) and left at room ter,lperature overnight. The solution was evaporated and the residue was treated with acetone-benzene (1:4) to i g~ve crystals of the desired compound, VSA 419 (9.4 mg, 69 X) UV ~ max (H20) 269 nm.

NMR (DMSO-d6) 'H ~1.79 (d, 3H, J CH3, H-6=1.2 Hz CH3), 2.16-2.90 (m, 2H, H-2'), 3.2-3.6 (m, 2H, H-5'), 4,61 (dt, lH, J3'F,4'=23.4 Hz, J4',5'=
rv4 Hz, H-4'), ~.06 (t, lH, J5',0H=5.6 Hz, OH), 5.32 (dd, lH, J3'F,3'=54.2 Hz J2'3'=4.9 Hz, H-3'), 6.18 (dd, lH, Jl'2'=7.7 Hz and 2.1 Hz, H-l'), 7.39 (d, lH, J CH3, H-6=1.2 Hz, H-6) 13C (DMSO-d6) ~12.46 (CH3), rJ39 (C-2'), 61.17 (d, J=ll.O Hz, C-5'), 85.85 (C-l'), 87.15 (d, J=20.8 Hz, C-4'), 94.75 (d, J=173 Hz, C-3'), 109.15 (C-5), 135 63 (d, J=6.1 Hz, C-6), 150.53 (C-2), 163.95 (C-4) Example 2. Preparation of 1-(3-F-2,3-dideoxy-cX-~-ribofuranosyl)--5-propyluracil (VSA 409) (Method C) .
5-Propyluracil (56 mg) and 3'-F-3'deoxythymidine (47 mg) were suspended in acetonitrile (1.2 mL) and N,O-Bis (trimethylsilyl) acetamide (0.35 mL) was added. The mixture was stirred at room temperature for 1.5 hrs. Trimethylsilyl trifluoromethanesulfonate (0.05 mL) was added.
After stirring at room ~emperature for 138 hrs, the mixture was e~a-porated in vacuo and added to H20 (0.5 mL), filtered and washed with H20 (0.5 nL). The combined water phase was applied to a C18-column (HPLC) and eluted with methanol-water (35:65), at a rate of 7.0 ml/min. The ~ -anomer eluted after 12.9 min, and the desired OC~anomer, VSA 409, after 18.0 min. Yield 9.3 mg (18 X), UV i~ max (H20) 269 nm, MS M+272 (10 X), 154 (100 ~), 119 (76 X).

133~88 Example 3. Preparation of 1-(3-F-2,3-dideoxy-~-D-ribofuranosyl)-5-ethYluracil (VSA 411) (Method C) 5-Ethyluracil (51 mg) and 3'F-3'-deoxythymidine (48 mg) were suspended in acetonitrile (1.2 mL) and N,0-Bis (trimethylsilyl) acetamide (0.35 mL) was added. The mixture was stirred at room temperature for 1.5 hrs. Trimethylsilyl trifluoromethanesulfonate (0.05 mL) was added. After stirring at room temperature for 161 hrs., the mixture was evaporated in vacuo, and added to water (0.5 mL), filtered and washed with water 1~ (0.5 mL). The combined water phase was applied to a C18-column (HPLC) and eluted with methanol-water (1:3) at a rate of 8.0 ml/min. The ~-anomer eluted after 12.3 min. and the desired a-anomer, VSA 411, after 16.4 min. Yield 13.1 mg (26%). UV ~max (H20) 267.5 nm. MS M 258 (9~), 140 (100~), 119 (67%).
Bioloqical Tests Test I. Bffect of comPounds of the formula I on HIV in H9 cells Materials and methodss HIV infection of H9 cells H9 cells, 10 cells per well on a 24 well plate, suspended in 2 ml RPMI-medium containing 10% fetal calf serum, 100 ~g/ml penicillin, 10 ~g/ml streptomycin sulfate and 2 ~g/ml polybrene are exposed to HIV (HTLV-IIIB) and different concentrations of the test compounds. The plates are incubated at 37C in 5% C02 for 6 to 7 days. The contents in each well is then homogenized with a pipette and transferred to a centrifuge tube.
After centrifugation for 10 min. at 1500 rpm the supernatent is removed and the cell pellet is analyzed by fixing in methanol on glass plates. Human HIV positive serum diluted 1:80 or ls160 is ~,~

~ 3 3 6~g8 23038-76 added and incubated for 30 min. at 37. The plate is then washed with phosphate-buffered saline (PBS) containing Ca2 and Mg2+.
Sheep antihuman conjugate (FITC) is added and after a new incubation the plate iB again washed with PBS. Contrast staining is done with Evans blue and after drying the frequency of HIV
antigen containing cells is determined in a microscope. The test result is shown in Table 1.

Table 1. Concentration (yM) for 50% inhibition (IC50) of human immuno deficiency virus multiplication in cell culture Compounds IC50(YM) 1-(3-fluoro-2,3-dideoxy-a-D-ribofuranosyl)-5-ethyluracil (VSA 411) 0.1 1-(3-fluoro-2,3-dideoxy-a-D-ribofuranosyl)-5-propyluracil (VSA 409) 2.5 It is seen in Table 1 that the tested compounds are a~tive inhibitors of HIV virus multiplication.
Test II. Cellular toxi~ity Hg cells, 2x107 cells per plate, are incubated in RPMI-1640 medium containing 10% fetal calf serum, 70 mgtl penicillin, 100 mg/l streptomycin and 10 mM hepes, in absence or presence of test compounds. The number of cells per plate is determined after 48 hrs. Cells incubated in absence of test compound then underwent two cell division cycles.
F5000 cells, which are human embryo ~ells, lx105 cells per plate, are incubated in Eagle's minimal essential medium, ~'~' 19 ~.

1 33 ~ O ~ 8 23038-76 supplemented with Earle'~ ~alts, non-essential amino acids, 10%
fetal calf serum, 10 mM hepes, 70 mg/l penicillin and 100 mg/l streptomycin, in absence or presence of test compounds. The number of cells per plate is determined after 48 hrs. Cells incubated in absence of test compounds underwent one cell division cycle. The results are given as TC50, which is the concentration of a compound which gives 50% inhibition of cell multiplication.

fB 20 ~ ~ 21 1~36088 Table 2. Cellular toxicity and H9 and F5000 cells TC50(1~M) Compound H9 F5000 1-(3-fluoro-2,3-dideoxy-C~-D-ribofuranosyl)--5-ethyluracil (VSA 411) 400 500 10 1-(3-fluoro-2,3-dideoxy-C{-D-ribofuranosyl)--5-methyluracil (VSA 419) 250 1-(2-deoxy-C~-D-ribofuranosyl)-5--ethyluracil (YIP 28~) 1000 It is seen in Table 2 that the test compounds exhibit TC50 values which vastly exceed the concentration IC50 according to Table 1 to 50 ~ inhi-bition of HIV virus multiplication.

Claims (19)

1. A compound of the formula or (I) .alpha.-anomer .beta.-anomer wherein the radicals A and R3 are defined as follows:
A is (a) or (b) R1 is H; alkyl containing 1 to 3 carbon atoms or cyclopropyl;
-CH=CH2; -CH=CH-CH3; -CH2-CH=CH2; or -C=CH;

R3 is F; CN; -C?CH; OCH3; CH2OH; with the proviso that if R3 is F or OCH3 then R1 is not H, CH3, C2H5, -C?CH, and, if A is (a) and R1 is H, then R3 is not CH2OH, wherein R3 can have cis- or trans-configuration relative to the hydroxymethyl function at position 4', and therapeutically acceptable salts thereof.

2. A compound according to claim 1 wherein A is and R1 and R3 are as defined in claim 1.

3. A compound according to claim 2 wherein R1 is H, CH3 or C2H5.

4. A compound according to claim 1 wherein R3 at position 3' and the hydroxymethyl group at position 4' have the trans-configuration.

5. A compound according to claim 1 wherein A is and R1 and R3 are as defined in claim 1.

6. A compound according to claim 5 wherein R1 is H, CH3 or C2H5.

7. A compound according to claim 6 wherein R1 is H.

8. A compound according to claim 7 wherein R3 at position 3' and the hydroxymethyl group at position 4' have the trans-configuration.

9. A compound according to claim 1 wherein A is (b), R1 is hydrogen and R3 is CH2OH.

10. A compound according to claim 1 wherein A is (a), R1 is CH3 and R3 is CH2OH.

11. A compound according to claim 1 wherein A is (a), R1 is cyclopropyl and R3 is F.

12. A pharmaceutical composition comprising as active ingredient a compound as claimed in any one of claims 1 to 11, together with a suitable diluent or carrier.

13. The use of a compound as claimed in any one of claims 1 to 11 for therapeutic or prophylactic treatment of infections caused by a retrovirus or by hepatitis B virus.

14. The use of a compound as claimed in any one of claims 1 to 11 for therapeutic or prophylactic treatment of infections in man caused by HIV virus.

15. A commercial package containing, as active pharmaceu-tical ingredient, a compound as claimed in any one of claims 1 to 11 together with instructions for its use in therapeutic or prophylactic treatment of infections caused by a retrovirus or by hepatitis B virus.

16. A commercial package containing, as active pharmaceu-tical ingredient, a compound as claimed in any one of claims 1 to 11, together with instructions for its use for therapeutic or prophylactic treatment of infections in man caused by HIV virus.

17. A process for preparing a pharmaceutical composition for use in therapeutic or prophylactic treatment of infections caused by a retrovirus or by hepatitis B virus, which process comprises admixing a compound as claimed in any one of claims 1 to 11 with a suitable diluent or carrier.

18. A process for preparing a pharmaceutical composition for use in therapeutic or propylactic treatment of infections in man caused by HIV virus, which process comprises admixing a compound as claimed in any one of claims 1 to 11 with a suitable diluent or carrier.

19. A process for the preparation of a compound of the formula or (I) .alpha.-anomer .beta.-anomer or a therapeutically acceptable salt thereof, wherein A and R3 are as defined in claim 1, by A. condensing a compound of formula wherein R3 is as defined in claim 1 and the hydroxyl group is protected, if necessary, to the N-1 position of a pyrimidine derivative corresponding to radical A in formula I, whereafter the .alpha.-anomer of compound I thus formed is separated and any protecting groups removed;
B. to obtain an .alpha.-anomer, anomerization of a .beta.-anomer of the formula (III) wherein A is as defined above, and R4 and R5 are protecting groups, to a mixture of .alpha.- and .beta.-anomers, whereafter the .alpha.-anomer is separated and any protecting groups removed;
C. transglycosylation of a nucleoside of the formula (IV) wherein R4 and R5 are as defined above, and B is a pyrimidine or purine base, to form a nucleoside containing the pyrimidine radical A as defined above, whereafter the .alpha.-anomer is separated and any protecting groups removed;
D. substitution of the radical R7 in a compound of the formula (V) wherein A and R5 are as defined above, and R7 is a leaving group, with a radical R3 as defined above, whereafter any protecting groups are removed;
E. conversion of the uracil moiety in a compound of the formula I to a cytosine moiety wherein R1 is as defined above, whereafter the compound of the formula I thus obtained, if required, is converted to a therapeu-tically acceptable salt.