Abstract:
The invention concerns: (i) [4-(4-cyanobenzyl)phenyl]glycopyranosides of formula (I) wherein; the glycopyranosyl group R represents a β-D arabinopyranosyl, β-D-lyxopyranosyl, β-D-ribopyranosyl, β-D-mannopyranosyl, β-L-arabinopyranosyl, β-L-xylopyranosyl, α-L-arabinopyranosyl, α-L-xylopyranosyl or β-L-rhamnopyranosyl group; and (ii) their esters resulting from esterification of at least a OH function of each glycopyranosyl group with a C 2 -C 4  alkanoic or cycloalkanoic acid, as novel industrial products. Said novel [4-(4-cyanobenzyl)phenyl]glycopyranosides are useful in therapy for fighting against athermatous plaque.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates, by way of novel industrial products, to 4-cyano-4′-hydroxybenzophenone derivatives of formula I below, which are benzophenone glycopyranosides. It further relates to the process for their preparation and to their use in therapeutics, especially in the form of compositions in which they are present as active principles.  
         PRIOR ART  
         [0002]    EP-A-0051023 has disclosed compounds which contain a hydroxybenzophenone residue substituted by a β-D-xylosyl group and which have valuable pharmacological activity for the treatment or prevention of venous thrombosis.  
           [0003]    Also, EP-A-0133103 has disclosed derivatives of the benzylphenyl β-D-xyloside type which possess hypocholesterolemic and hypolipidemic properties. It is also known that derivatives in which the β-D-xylosyl radical has been replaced with a β-D-thioxylosyl radical have been described in EP-A-0365397 and EP-A-0290321, said compounds being useful on account of their antithrombotic activity.  
           [0004]    Finally, the article by F. BELLAMY et al., J. Med. Chem., 1993, 36 (no. 7), pages 898-903, has disclosed compounds derived from benzophenone substituted by glycosyl groups, among which only the derivatives of the β configuration have antithrombotic activity. A study of these products demonstrated that these compounds, particularly those containing a β-D-xylosyl group, were good substrates for galactosyltransferase I and, consequently, were capable of initiating the synthesis of glycosaminoglycans (GAGs). This mode of action, obtained after oral administration of the product, is very probably responsible for the antithrombotic activity, and only those derivatives in which the D-xylose is of the β configuration exhibit activity in this therapeutic field. There is therefore a correlation between the action on GAG synthesis and the antithrombotic activity which meant that the compounds other than those derived from β-D-xylose were of no value in this therapeutic field.  
         OBJECT OF THE INVENTION  
         [0005]    According to the invention, it is proposed to provide a novel technical solution for obtaining novel products of therapeutic value in respect of arterial atheromatous plaque, either for treating said plaque or for preventing its appearance.  
         SUBJECT OF THE INVENTION  
         [0006]    According to the novel technical solution of the invention, [4-(4-cyanobenzoyl)phenyl]glycopyranoside compounds are used which, surprisingly, in the light of the publications cited above, exhibit activity in the prevention or regression of arterial atheromatous plaque.  
           [0007]    According to a first feature of the invention, novel products are recommended which are selected from the group consisting of:  
           [0008]    (i) the glycopyranoside compounds of formula I:  
                         
 
           [0009]    in which the glycopyranosyl group R is a β-D-arabinopyranosyl, β-D-lyxopyranosyl, β-D-ribopyranosyl, β-D-galactopyranosyl, β-D-mannopyranosyl, β-L-arabinopyranosyl, β-L-xylopyranosyl, α-L-arabinopyranosyl, α-L-xylopyranosyl or β-L-rhamnopyranosyl group; and  
           [0010]    (ii) their esters resulting from the esterification of at least one OH group on each glycopyranosyl group by a C 2 -C 4  alkanoic or cycloalkanoic acid.  
           [0011]    According to a second feature of the invention, a process is proposed for the preparation of the compounds of formula I above and their esters.  
           [0012]    According to yet a third feature of the invention, a therapeutic composition is provided which contains, in association with a physiologically acceptable excipient, a therapeutically effective amount of at least one compound of formula I or one of its esters.  
           [0013]    According to another feature of the invention, it is also recommended to use a compound of formula I or one of its esters as an active principle for the preparation of a drug to be used in therapeutics for combating atheromatous plaque, particularly for its prevention or treatment.  
         DETAILED DESCRIPTION  
         [0014]    The novel compounds according to the invention comprise the products of formula I and their esters; they are pyranoside derivatives of 4-cyano-4′-hydroxybenzophenone [or 4-(4-hydroxybenzoyl)benzonitrile]. The preferred products, in which the glycoside radical is in the pyranose form, have the formulae below, which are given according to the structure of the glycopyranosyl group R:  
           [0015]    (a) β-D-arabinose structure (β-D-Ara):  
                         
 
           [0016]    (b) β-D-lyxose structure (β-D-Lyx):  
                         
 
           [0017]    (c) β-D-ribose structure (β-D-Rib):  
                         
 
           [0018]    (d) β-D-galactose structure (β-D-Gal):  
                         
 
           [0019]    (e) β-D-mannose structure (β-D-Man):  
                         
 
           [0020]    (f) β-L-arabinose structure (β-L-Ara):  
                         
 
           [0021]    (g) β-L-xylose structure (β-L-Xyl):  
                         
 
           [0022]    (h) α-L-arabinose structure (α-L-Ara):  
                         
 
           [0023]    (i) α-L-xylose structure (α-L-Xyl):  
                         
 
           [0024]    (j) β-L-rhamnose structure (β-L-Rha):  
                         
 
           [0025]    In these formulae, R 1  is a hydrogen atom or a group COR 2 , R 2  being a C 1 -C 3  alkyl group selected from methyl, ethyl, propyl, isopropyl and cyclopropyl groups.  
           [0026]    The process for the preparation of a compound of formula I or one of its esters according to the invention comprises:  
           [0027]    (1 o ) reacting a peracetylated pentose or hexose of the pyranosyl structure of formula II:  
                         
 
           [0028]    in which Z is H, CH 3  or CH 2 OAc,  
           [0029]    selected from the group consisting of 1,2,3,4-tetraacetyl-D-arabinose, 1,2,3,4-tetraacetyl-D-lyxose, 1,2,3,4-tetraacetyl-D-ribose, 1,2,3,4,6-pentaacetyl-D-galactose, 1,2,3,4,6-pentaacetyl-D-mannose, 1,2,3,4-tetraacetyl-L-arabinose, 1,2,3,4-tetraacetyl-L-xylose and 1,2,3,4-tetraacetyl-L-rhamnose,  
           [0030]     with 4-(4-hydroxybenzoyl)benzonitrile of formula III:  
                         
 
           [0031]     to give, after purification, the corresponding oside compound of formula IV:  
                         
 
           [0032]    in which Z is as defined above; and then  
           [0033]    (2 o ) if necessary, carrying out a displacement reaction on the acetyl groups of the resulting oside compound of formula IV in order to replace them with hydrogen atoms to give the corresponding compound of formula I in which R 1  is H, it being possible for the other esters (in which R 1  is other than Ac) to be obtained by esterifying the compound of formula I in which R 1  is H with a C 3 -C 4  acid.  
           [0034]    Advantageously, the reaction II+III of step (1 o ) is carried out in an organic solvent (especially dichloromethane), in the presence of a Lewis acid (for example tin tetrachloride), at a temperature between 25° C. and the boiling point of the solvent, for 10 to 30 hours.  
           [0035]    In step (2 o ), the replacement of the Ac groups with hydrogen atoms is advantageously performed as follows. The compound of formula IV is reacted with NH 3  in solution in an anhydrous alcohol (especially methanol) in order to displace the Ac groups and replace them with H.  
           [0036]    In a variant, the reaction II+III→IV of step (1 o ) can be replaced with the reaction V+III→IV, where V is a corresponding peracetylated halogenopentose or halogenohexose. Under these circumstances, step (1 o ) becomes step (1′) below, namely:  
           [0037]    (1′) reacting a peracetylated halogenopentose or halogenohexose of the pyranosyl structure of formula V:  
                         
 
           [0038]    in which X is a halogen atom (i.e. F, Cl, Br or I, the preferred halogen atom being Br) and Z is H, CH 3  or CH 2 OAc,  
           [0039]    selected from the group consisting of 1-bromo-2,3,4-triacetyl-D-arabinose, 1-bromo-2,3,4-triacetyl-D-lyxose, 1-bromo-2,3,4-triacetyl-D-ribose, 1-bromo-2,3,4,6-tetraacetyl-D-galactose, 1-bromo-2,3,4,6-tetraacetyl-D-mannose, 1-bromo-2,3,4-triacetyl-L-arabinose, 1-bromo-2,3,4-triacetyl-L-xylose and 1-bromo-2,3,4-triacetyl-L-rhamnose,  
           [0040]     with 4-(4-hydroxybenzoyl)benzonitrile of formula III:  
                         
 
           [0041]     to give, after purification, the corresponding oside compound of formula IV:  
                         
 
           [0042]    in which Z is as defined above.  
           [0043]    Advantageously, the reaction V+III→IV is carried out in an anhydrous solvent such as dichloromethane, 1,2-dichloroethane or acetonitrile, in the presence of a coupling agent such as silver trifluoromethanesulfonate or silver oxide, at a temperature of the order of −10 to +10° C., for 5 to 40 hours.  
           [0044]    The reactions II+III→IV and V+III→IV are applicable to the preparation of all the compounds of formula IV according to the invention.  
           [0045]    Other advantages and characteristics of the invention will be understood more clearly from the following Preparatory Examples and pharmacological tests. Of course, these details as a whole do not imply a limitation but are provided by way of illustration. 
       
    
    
     EXAMPLE 1  
     [4-(4-Cyanobenzoyl)phenyl] 2,3,4-tri-O-acetyl-β-D-arabinopyranoside  
       [0046]    A solution of 0.8 g (2.52.10 −3  mol) of 1,2,3,4-tetra-O-acetyl-D-arabinopyranose and 0.567 g (2.52.10 −3  mol) of 4-(4-hydroxybenzoyl)benzonitrile in 15 ml of anhydrous dichloromethane is prepared. 6.3 ml of a 1 M solution of tin tetrachloride in dichloromethane are added and the reaction mixture is refluxed for 24 hours. After cooling, the reaction medium is poured into ammonium chloride solution and extracted with ethyl acetate. The organic phase is washed with sodium bicarbonate solution and then with sodium chloride solution, after which it is dried over magnesium sulfate and finally concentrated under reduced pressure. The yellow oil obtained is purified by chromatography on silica gel using an ethyl acetate/hexane mixture (3/7; v/v) as the eluent to give 97 mg of the expected product in the form of a beige powder (yield=8%).  
         [0047]    M.p.=75-76° C.  
         [0048]    [α] D   26 =−254° (c=0.3; DMSO)  
       EXAMPLE 2  
     [4-(4-Cyanobenzoyl)phenyl] β-D-arabinopyranoside  
       [0049]    A mixture of 90 mg (0.19.10 −3  mol) of the compound obtained according to Example 1 and 20 ml of a 2 M solution of ammonia in methanol is prepared and stirred for 20 hours at room temperature. The solvent is then driven off under reduced pressure and the residue is purified by chromatography on silica gel using a methanol/dichloromethane mixture (4/96; v/v) as the eluent to give 40 mg of the expected product in the form of a cream-colored solid (yield=72%).  
         [0050]    M.p.=157-158° C.  
         [0051]    [α] D   26 =−190° (c=0.3; DMSO)  
       EXAMPLE 3  
     [4-(4-Cyanobenzoyl)phenyl] β-D-lyxopyranoside  
       [0052]    [4-(4-Cyanobenzoyl)phenyl] 2,3,4-tri-O-acetyl-β-D-lyxopyranoside is obtained by following a procedure analogous to Example 1 and starting from 1,2,3,4-tetra-O-acetyl-D-lyxopyranose. It is treated with ammonia according to the procedure described in Example 2 to give the expected product in the form of a light yellow powder with a yield of 7.5%.  
         [0053]    M.p.=185-187° C.  
         [0054]    [α] D   25 =−73° (c=0.3; DMSO)  
       EXAMPLE 4  
     [4-(4-Cyanobenzoyl)phenyl] 2,3,4-tri-O-acetyl-β-D-ribopyranoside  
       [0055]    The expected product is obtained in the form of a white solid with a yield of 15.5% by following a procedure analogous to Example 1 and starting from 1,2,3,4-tetra-O-acetyl-D-ribopyranose.  
         [0056]    M.p.=135-137° C.  
         [0057]    [α] D   23 =−66° (c=0.46; CH 2 Cl 2 )  
       EXAMPLE 5  
     [4-(4-Cyanobenzoyl)phenyl] β-D-ribopyranoside  
       [0058]    The expected product is obtained in the form of a white powder with a yield of 51% by following a procedure analogous to Example 2 and starting from the compound obtained according to Example 4.  
         [0059]    M.p.=157-158° C.  
         [0060]    [α] D   27 =−82° (c=0.17; DMSO)  
       EXAMPLE 6  
     [4-(4-Cyanobenzoyl)phenyl] 2,3,4,6-tetra-O-acetyl-β-D-galactopyranoside  
       [0061]    The expected product is obtained in the form of a beige solid with a yield of 4% by following a procedure analogous to Example 1 and starting from 1,2,3,4,6-penta-O-acetyl-D-galactopyranose.  
         [0062]    M.p.=82° C.  
         [0063]    [α] D   26 =+11° (c=0.21; DMSO)  
       EXAMPLE 7  
     [4-(4-Cyanobenzoyl)phenyl] β-D-galactopyranoside  
       [0064]    The expected product is obtained in the form of a light yellow powder with a yield of 40% by following a procedure analogous to Example 2 and starting from the compound obtained according to Example 6.  
         [0065]    M.p.=242° C.  
         [0066]    [α] D   23 =−10° (c=0.22; DMSO)  
       EXAMPLE 8  
     [4-(4-Cyanobenzoyl)phenyl] 2,3,4,6-tetra-O-acetyl-β-D-mannopyranoside  
       [0067]    A solution of 2.72 g (12.10 −3  mol) of 4-(4-hydroxybenzoyl)benzonitrile in 15 ml of hexamethylphosphotriamide (HMPA) is prepared and 400 mg (13.3.10 −3  mol) of an 80% dispersion of sodium hydride in oil are added at room temperature. The mixture is stirred for 1 hour and a solution of 2.5 g (6.1.10 −3  mol) of 2,3,4,6-tetra-O-acetyl-D-mannopyranosyl bromide in 15 ml of HMPA is then added. The reaction mixture is stirred at room temperature for 18 hours and then hydrolyzed on ice. The mixture obtained is extracted 3 times with ether and the combined organic phases are washed with 1 N sodium hydroxide solution and then with water, dried over magnesium sulfate and concentrated under reduced pressure. The residue is purified by chromatography on silica gel using a toluene/ethyl acetate mixture (8/1; v/v) as the eluent to give 1.09 g of the expected product in the form of a beige solid (yield=30%).  
         [0068]    M.p.=80° C.  
         [0069]    [α] D   23 =−62° (c =0.6; DMSO)  
       EXAMPLE 9  
     [4-(4-Cyanobenzoyl)phenyl] β-D-mannopyranoside  
       [0070]    The expected product is obtained in the form of a beige powder with a yield of 44% by following a procedure analogous to Example 2 and starting from the compound obtained according to Example 8.  
         [0071]    M.p.=122° C.  
         [0072]    [α] D   23 =−46° (c=0.23; DMSO)  
       EXAMPLE 10  
     [4-(4-Cyanobenzoyl)phenyl] 2,3,4-tri-O-acetyl-β-L-arabinopyranoside  
       [0073]    The expected product is obtained in the form of a light yellow solid with a yield of 18% by following a procedure analogous to Example 1 and starting from 1,2,3,4-tetra-O-acetyl-L-arabinose.  
         [0074]    M.p.=69-70° C.  
         [0075]    [α] D   27 =+179° (c=0.365; DMSO)  
       EXAMPLE 11  
     [4-(4-Cyanobenzoyl)phenyl] β-L-arabinopyranoside  
       [0076]    The expected product is obtained in the form of a white powder (after recrystallization from methanol) with a yield of 65% by following a procedure analogous to Example 2 and starting from the compound obtained according to Example 10.  
         [0077]    M.p.=216° C.  
         [0078]    [α] D   26 =+174° (c=0.47; DSMO)  
       EXAMPLE 12  
     [4-(4-Cyanobenzoyl)phenyl] 2,3,4-tri-O-acetyl-β-L-xylopyranoside  
       [0079]    A solution of 658 mg (2.95.10 −3  mol) of 4-(4-hydroxybenzoyl)benzonitrile in 20 ml of acetonitrile is prepared and 1 g (2.95.10 −3  mol) of 2,3,4-tri-O-acetyl-L-xylopyranosyl bromide and then 683 mg (2.95.10 −3  mol) of silver oxide are added at room temperature, with stirring. The mixture is stirred at room temperature for 24 hours and then filtered. The precipitate is rinsed on the filter with ethyl acetate. The combined organic phases are washed with 1 N sodium hydroxide solution, filtered, washed with 1 N hydrochloric acid solution and then with water and dried over magnesium sulfate. The solution is concentrated under reduced pressure and the crude product obtained is purified by chromatography on silica gel using a toluene/ethyl acetate mixture (85/15; v/v) as the eluent to give 980 mg of the expected product in the form of a fine white powder (yield=69%).  
         [0080]    M.p.=158° C.  
         [0081]    [α] D   26 =−10° (c=0.43; DMSO)  
       EXAMPLE 13  
     [4-(4-Cyanobenzoyl)phenyl] β-L-xylopyranoside  
       [0082]    The expected product is obtained in the form of a white solid with a yield of 88% by following a procedure analogous to Example 2 and starting from the compound obtained according to Example 12.  
         [0083]    M.p.=204° C.  
         [0084]    [α] D   26 =−3° (c=0.37; DMSO)  
       EXAMPLE 14  
     [4-(4-Cyanobenzoyl)phenyl] 2,3,4-tri-O-acetyl-α-L-xylopyranoside  
       [0085]    The expected product is obtained in the form of a beige solid with a yield of 39% by following a procedure analogous to Example 1 and starting from 1,2,3,4-tetra-O-acetyl-L-xylose.  
         [0086]    M.p.=56° C.  
         [0087]    [α] D   27 =−129° (c=0.33; DMSO)  
       EXAMPLE 15  
     [4-(4-Cyanobenzoyl)phenyl] α-L-xylopyranoside  
       [0088]    The expected product is obtained in the form of a white powder with a yield of 74% by following a procedure analogous to Example 2 and starting from the compound obtained according to Example 14.  
         [0089]    M.p.=189° C.  
         [0090]    [α] D   27 =−139° (c=0.49; DMSO)  
       EXAMPLE 16  
     [4-(4-Cyanobenzoyl)phenyl] 2,3,4-tri-O-acetyl-β-L-rhamnopyranoside  
       [0091]    The expected product is obtained in the form of a beige powder with a yield of 4% by following a procedure analogous to Example 1 and starting from 1,2,3,4-tetra-O-acetyl-L-rhamnopyranose.  
         [0092]    M.p.=85° C.  
         [0093]    [α] D   29 =+31° (c=0.17; DMSO)  
       EXAMPLE 17  
     [4-(4-Cyanobenzoyl)phenyl] β-L-rhamnopyranoside  
       [0094]    The expected product is obtained in the form of a white solid with a yield of 76% by following a procedure analogous to Example 2 and starting from the compound obtained according to Example 16.  
         [0095]    M.p.=96° C.  
         [0096]    [α] D   24 =+55° (c=0.28; DMSO)  
       EXAMPLE 18  
     [4-(4-Cyanobenzoyl)phenyl] 2,3,4-tri-O-acetyl-α-L-arabinopyranoside  
       [0097]    The expected product is obtained in the form of a fine white solid with a yield of 62% by following a procedure analogous to Example 12 and starting from 2,3,4-tri-O-acetyl-α-L-arabinopyranosyl bromide.  
         [0098]    M.p.=148° C.  
         [0099]    [α] D   24  =+4.3° (c=0.48; CHCl 3 )  
       EXAMPLE 19  
     [4-(4-Cyanobenzoyl)phenyl] α-L-arabinopyranoside  
       [0100]    The expected product is obtained in the form of a white powder with a yield of 63% by following a procedure analogous to Example 2 and starting from the compound obtained according to Example 18.  
         [0101]    M.p.=170° C.  
         [0102]    [α] D   24 =+24° (c=0.40; DMSO)  
         [0103]    The antiatheromatous activity of the compounds according to the invention was evaluated as a function of their ability to lower the serum cholesterol level in mice subjected to a fatty diet. Several publications have in fact demonstrated a close correlation between an excess of lipids and a marked increase in the risk of atheroma (cf. Lancet 1996, 348, pages 1339-1342; Lancet 1990, 335, pages 1233-1235). This correlation affords a test which is more rapid than direct experiments on the atheromatous plaque, which require a lengthy treatment of the animals and an expensive histological study of the walls of the aortic arch.  
         [0104]    The test used consists in administering a single dose of the compound to female mice of the C57BL/6J strain. The protocol is as follows: On the first day (D0), the mice are fasted from 9 am to 5 pm, a blood sample being taken at 2 pm. At 5 pm, a given amount of food (a fatty diet comprising 1.25% of cholesterol and 0.5% of cholic acid) is distributed. On the second day (D1), the food leftovers are weighed at 9 am and the mice are fasted from 9 am to 2 pm. A blood sample is taken at 2 pm. For the treated groups of mice, the compound is administered at 9 am on the second day (D1) by tubage in the form of a suspension in a 3% aqueous solution of gum. The control groups receive only the aqueous gum.  
         [0105]    The compounds were tested at a dose of 100 mg/kg. The total serum cholesterol is assayed and the results are expressed as the percentage inhibition of the increase in cholesterolemia compared with the control group. The results obtained are given in the “Activity” column of Table I. It may furthermore be noted that analysis of the cholesterol content of the different classes of serum lipoproteins shows a favorable effect of the product on the ratio HDL cholesterol/total cholesterol.  
         [0106]    It was also demonstrated that the compounds of formula I according to the invention do not induce GAG synthesis.  
         [0107]    The products of formula I and their esters according to the invention can preferably be administered orally in the form of tablets or gelatin capsules each containing 20 to 500 mg of a compound of formula I or one of its esters as the active principle, in association with excipients. The dosage will be about 1 to 4 units per day. The products according to the invention are advantageously prescribed for atheromatous plaque and particularly for preventing or treating the risk of atheroma.  
                                     TABLE I                                                                                      Ex.   R   R 1     Activity (%)                        1   β-D-Ara   COCH 3     −25            2   β-D-Ara   H   −29            3   β-D-Lyx   H   −28            4   β-D-Rib   COCH 3     −23            5   β-D-Rib   H   −36            6   β-D-Gal   COCH 3     −33            7   β-D-Gal   H   −32            8   β-D-Man   COCH 3     −17            9   β-D-Man   H   −39           10   β-L-Ara   COCH 3     −22           11   β-L-Ara   H   −31           12   β-L-Xyl   COCH 3     −45           13   β-L-Xyl   H   −45           14   α-L-Xyl   COCH 3     −36           15   α-L-Xyl   H   −32           16   β-L-Rha   COCH 3     −37           17   β-L-Rha   H   −50           18   α-L-Ara   COCH 3      −2*           19   α-L-Ara   H    −31*