PROCESS FOR MAKING A 2-DEOXYURIDINE

Abstract: A process for the preparation of certain 2-deoxyuridines including the steps forming a substituted alkyl 5-0-"protected"-2-deoxyribofuranoside, hydrocarbylating the latter compound, and condensing the hydrocarbylated compound in the presence of a Lewis or Bronsted acid with a silyluracil to form a uridine. Several tritylated ribofuranosides are novel compounds per se.

Description: PROCESS FOR b&K G A 2-DΞOXXURID3NΞ This invention relates to a process for producing therapeutically active material from 2-deoxyribose, and mor particularly, to a method for making a 2-deoxyuridine. EEΓ Ή-ED APPLICAΠGN This application is a continuation-in-part of our copendin application Serial No.: 653,451 filed 24 September 1984. BaCKGRSQrø OF THE INVENTIG,.2ND PRIOR fiKT This invention was made in response to a need for increasin yields of 2-deoxyuridine materials from below about 8% and consequen very high cost. It has now been found that by using a novel sequenc of known organic synthesis- reactions one is able to produce 2-deox uridine materials in substantially higher yield and thus at much lowe cost. This process utilizes fewer steps than heretofore used in th production of such derivatives. Basic organic reactions useful in carrying out the proces of the present invention are found in M. Hoffer, Che . Ber. 93, 277 (1960), particularly at page 2779, third paragraph et seq.; the boo entitled "Protective Groups in Organic Synthesis" by T. . Green, Joh Wiley & Sons, Inc., New York, (1981) pp. 10-86; and Ryan et al, J Org. Chem. 31, page 1181 (1966) . Reference may be had to U. S Patents 4,082,911 and 4,209,613 for discussion of the preparation o other nucleosides. Preferred aiibodiments of the present invention contain a ne step which is both unexpected and surprising in terms of the fact tha it proceeds well. All indications were that it would not be likel that a sugar be.aring an acid labile protecting group, such as a trity protected ribofuranoside or a silyl protected ribofuranoside, could b acid condensed with a silyla εd uracil in an acid catalyze condensation reaction to form directly a 2-deoxyuridine. Both these protecting groups are regarded as acid sensitive (i.e., easily removed by acid) and the condensation catalyst is a Lewis acid (Friedel-Crafts catalyst) which converts to a Bronsted acid (strong acid) on work up. Not only did the reaction proceed well, but the yields of the end product were much greater than expected. Preparation of a 2-deoxy uridine from trifluorothymidine gave yields in the range of 3% to 8%. By the improved synthesis hereof, yields of alpha and beta anomers of greater than 50% have been obtained. A beta-2-deoxyuridine produced, by our process has been found effective in effecting 50% Sarcoma 180 tumor regression in mice. Also shown herein is a method for converting the alpha-anomer to the beta-anomer, i.e., the alpha-anomer is a precursor to the therapeutically active beta-anome . BRIEF STATEMENT OF THE INVENTIO-. Briefly stated, the present invention is a process for making a 2-deoxyuridine. It comprises the steps of (a) protecting the primary hydroxyl group of an alkyl 2-deoxyribofuranoside with a protecting group selected from triphenyl methyl, substituted triphenyl methyl, and silyl radicals to form a blocked alkyl 5-0—"ρrotected"-2- deoxyribofuranoside; (b) introducing a hydroσarbyl group (e.g., lower alkyl, or arylalkyl) at the 3-0 position to form a alkyl 3-0- hydrocarbyl-5-0- π protected"-2-deoxyribofuranoside; (c) condensing a silyluracil with the product of step (b) in the presence of a solvent and a Lewis acid or a Bronsted acid to form a crude 2-deoxyuridine; and optionally (d) deprotecting the protected group in said crude 2- deoxyuridine to form 3 l -0-hydrocarb l-2 , -deoxyuridine. The final 2- deoxyuridine is usually obtained as a mixture of alpha and beta anomers. These are preferably for pharmaceutical purposes, isolated from one another. Other pharmaceutically acceptable derivatives may be made in a known manner. After the hydrocarbylation step (b) , the trityl group, which is a preferred protecting group for hydrocarbylation, may be replaced with other protecting groups to form a 3-O-hydrocarb 1-5-0- π protected"-2-deoxyribofuranosyl-X wherein X is 1-O-alkyl, 1-0-aσyl or 1-halo and the condensation with the silyluracil effected in a manner shown below. • By the terra "substituted" as used herein is meant that at least one hydrogen atom in the alkyl or aryl group in question is replaced with a Cj_-C4 alkyl group, e.g., methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, etc., a C1-C4 alkoxy group, e.g. , methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, isobutoxy, etc., an aryl group, e.g., phenyl, tolyl, etc., a nitro group, a halo group, e.g., chloro, bromo, fluoro, iodo, an acyl group, e.g., acetyl, benzoyl; trifluoromethyl, etc. I3__TAD_ED r___SCRIPTTCN MO SP_3CIFIC EXAMPIES The synthesis of these 2-deoxyuridines can begin with ribose although intermediates are corπraercially available or can be readily synthesized by known procedures. A novel step of this invention responsible for reducing the number of synthesis steps is in the condensation in the presence of an acid of silyluracil with a trityl or silyl protected deoxyribofuranoside. It is surprising that the trityl (triphenyl methyl) group or the silyl group can be used as a protecting group and that such a protecting group remains stable during reaction with the silyluracil under acid condensation conditions. For convenience, the process will be described and illustrated with the production of 3'-O-benz l-2'-deoxy-5- trifluoromethyluridine. The scheme for synthesis of the foregoing 2-deoxyuridine may be represented as follows: HO 2-deoxy-D-ribose Methyl 2-deoxyribofuranoside (I) x'=CMe (ID (II) + (O3C-CI) trityl chloride (III) Methyl 2-deoxy-5-0-trityl- ribofuranoside X l =€Ke (IV) (VI) (Ne Compound) mixed alpha- and beta-3 , -0-Benzyl-2 , -deoxy- 5-trifluoromethyluridine (VIII) In the foregoing scheme, the secondary OH adjacent th hetrocyclic oxygen in (I) reacts readily with what may be considered protecting compound such as a lower alkyl alcohol (C1-C4) , e.g. methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, etc. a lower {C1-C4) acyl group, e.g., acetyl, or a halogen, e.g. chlorine.. We prefer to form the acetal using an acidified (HC1) lowe alkanol, e.g., methanol. . .. A typical preparation starting with 2-deoxy-D-ribose is a follows: EXAMPLE I Methyl 2-Deoxyribofuranoside; . To a solution of 10.0 g (0.072 mole) of 2-deoxy-D-ribose i 200 ml anhydrous methanol at 25°C. was added 40.0 ml of 1% HClMeOH a approximately 10 ml/min. After the addition was complete, the mixtur was allowed to stir under a nitrogen atmosphere for 30 minutes Pyridine (30 ml) was added (ca. 10 ml/min.) and the mixture wa allowed to stir for 10 minutes. The resultant mixture wa concentrated on a rotary evaporator followed by the addition of 50 m of toluene and reconσentration (3 * times) affording 10.6 g of a pal yellow oil. Analysis by HPLC (high pressure liquid chroma ography revealed the material to consist of > 90% anomers of methyl 2 deoxyribofuranoside with the greater majority of the remainder bein anomers of methyl 2-deoxyribopyranoside. The oil was used directly i the next step. Instead of anhydrous methanol, other lower (C1-C4) alkanols such as, anhydrous or absolute ethanol, or anhydrous isopropanol ma be substituted to form the corresponding acetal. The mode of makin such acetals is identical to that illustrated with methanol. EXAMPLE II Isopropyl 2H_>eoxyribofuranoside: Ten grams of 2-deoxy-D-ribose is dissolved in 180 ml o anhydrous isopropyl alcohol. The solution is allowed to stan overnight at ambient temperature. To this is added 20 ml of a 1 solution of anhydrous HC1 in isopropyl alcohol. After stirring for 3 minutes at ambient temperature, the reaction is quenched by th addition of 10 ml of pyridine. The solvent is then removed at reduce pressure affording as a syrup an anomeriσ mixture of the isopropyl 2 deoxyribofuranoside. The next step in the process is to protect the primary 5-O group with a protecting radical, e.g., silyl or , preferably a trity radical, by replacing the hydrogen of the primary hydroxyl group a follows: EXaMPLB III Methyl 2-deoxy5-0-t it * ylxib3fι~raιx ** side; To a solution of 11.2 g (0.07 mole) of methyl 2 deoxyribofuranoside (90% pure) in 60 ml of dry pyridine under a dr nitrogen atmosphere were added 19.0 g (0.07 mole) of triphenylmethy chloride. The mixture was stirred at ambient temperature for thre days. Methanol (35 ml) was then added. The solvents were the evaporated under reduced pressure. The residue was taken up in 200 m of ethyl acetate, washed with 75 ml of 5% sodium bicarbonate followe by a 75 ml wash with DI (deionized) water. The organic layer wa dried (Na2S04) , filtered and the solvent removed under vacuu affording a sticky, viscous oil. This crude methyl 2-deoxy-5-0 tritylribofuranoside compound was used without further purification i subsequent synthetic procedures. ΞXaMPT-E IV Methyl 5-0-(t-ButyM_j--athylsilyl)-2-C>eoxyribofuranoside; To a solution of 22.1 g (0.15 mole) of methyl 2- deoxyribofuranoside (90% pure) in 230 ml dry pyridine under a dry nitrogen atmosphere were added slowly a solution of 21.1 g (0.14 mole) of b^butyldimethylchlorosilane in 70 ml of dry pyridine. The resulting mixture was stirred overnight at ambient temperature. The mixture containing some salts was then heated with stirring at 40- 50°C. for three hours. After cooling to < 25°C., dry methanol (25 ml) was added. The mixture was stirred for one hour. The solvents were then removed at reduced pressure affording an oil-salt mixture. This was taken up in a mixture of 200 ml DI water . and 200 ml chloroform. The chloroform layer was separated, then washed with an additional 100 ml DI water. The chloroform layer was dried $ia2S04) t filtered,, and the solvent removed at reduced pressure. The residual oil was vacuum distilled affording 20.8 g * (0.08 mole, 57%) of a colorless oil bp. 91-98°C. at 0.15 mm Hg, NMR (CDCI3) Sθ.08 (d, 6, SiO_3), 0.88 (d, 9, t-Bu) , 2.05 (m, 2, CH2) , 2.8 (broad m, 1, OH), 3.32 (s, 3, -OCH3), 3.38 (s, 2, -OC 5 !^) , 3.7 (m, 1, -C 4 H) , 4.1 (m, 1, -C--H) t 5.1 (m, 1, anomeric -CH) . Other inert, preferably aprotic solvents, may be used in the syntheses described herein in place of chloroform, e.g., methylene chloride, carbon tetrachloride, benzene, toluene, acetonitrile, ethylene chloride, ethylene dichloride, dioxane, tetrahydrofuran (THF) , dimethylformamide, carbon disulfide, chlorobenzene, sulfolane, molten dimethylsulfoxide, etc. EXAMPLE V Methyl 2-Deoxy-5-0-(r>-Methoxytrityl)ribofuranoside: To a solution of 30 g (0.182 mole) of methyl 2- deoxyribofuranoside (90% pure) in 250 ml of dry pyridine were added 59.4 grams (0.192 mole) of p_-methoxytrityl chloride. The mixture was stirred at ambient temperature under a dry nitrogen atmosphere for 16 hours. Methanol (20 ml) was added and the mixture stirred for an additional 45 minutes. The solvent was removed under vacuum. The residue was taken up in 250 ml of ethyl acetate, washed (4 x 100 ml) with DI water, and dried (Na2S04) . The mixture was filtered and the solvent removed under vacuum affording 78.0 grams of the methyl 2- deoxy-5-0-(r-methoxytrityl)ribofuranoside compound as. a yellow oil. The next step is to alkylate or aralkylate the 5-0-protected derivative as follows: EXAMPLE VI Methyl 3-0-Ber_zyl-2-Deoxy ! -5-0-- * rrityljibofurar-oside: To a stirred mixture of 1.3 g (0.054 mole) of sodium hydride, 10.3 g (7.5 ml, 0.063 mole) of benzyl bromide and 50 ml dry tetrahydrofuran or other aportic solvent under a dry nitrogen, atmosphere was added slowly a solution of 14.8 g (0.038 mole) of crude methyl 2-deoxy-5-0-tritylribofuranoside in 100 ml of dry tetrahydrofuran. After the addition was completed (0.5 hr) , the mixture was stirred at ambient temperature for 4 hrs., then at 65r- 70°C. for an additional 2 hrs. The mixture was cooled, vacuum filtered through filter-aid, then heated at reflux for 2 hrs. with 15 ml (0.2 mole) of pyridine to consume the excess benzyl bromide. The mixture was again cooled and vacuum filtered through filter-aid. The solvent was removed from the filtrate under reduced pressure. Toluene (2 x 150 ml) was then added and evaporated. The residue 24.3 g. was taken up in ethyl acetate (200 ml) , washed with saturated NaCl solution (150 ml) , then with DI water (150 ml) . The organic- phase was dried (Na2S04) , filtered and the solvent evaporated under vacuum. The red-orange oil that remained was used directly in subsequent coupling reactions. An analytical sample was prepared by chromatography on silica gel eluting with 10% ethyl acetate in hexane. The light-yellow oil thus, prepared showed the following: Ifl NMR (CDCI3) .. β 2.05 (m, 2, Cfl2)r 3.18 (s, 3, OCH3), 3.33 (s, 2, CH2) / 3.6 to 4.4 (m, 2, OCH), 4.42 (d, 2, CH2) , 4.9 to 5.1 (m, 1, anomeric CH) , 7.1 to 7.7 (m, 20, ArH); IR (neat) 3090 cπr-L w), " 3060 (m) , 3035 (m) , 2920 (m), 1598 (w), 1490 (m) , 1448 (s) , 1362 (m) , 1080 (s) , 762 (m) , 748 (m), 705 (s) , 633 (m) . The 5-0-trityl group, which may be substituted with C1-C4 alkyl, C1-C4 alkσxy, nitro, halo, etc., groups in, for example, the para position, is quite important here if the above product is to be benzylated. The benzylated product itself is novel. After alkylation, it is possible with the addition of a couple of steps to deprotect the tritylated group and replace the protecting group with alkyl, aralkyl, silyl or the like group such as disclosed in the aforesaid book by T. W. Green, supra., and proceed with the synthesis. However, it has been found that the protecting group for the primary OH must be trityl or silyl in order to effectively hydrocarbylate, e.g., benzylate, the secondary OH. The trityl group is preferred to the silyl group because of its better selectivity. EXAMPTJ3 VII Methyl 3-0-Ben- * yl-5-0-(t-Butyldimethylsilyl)-2-Deoxyribofuranoside; A mixture of 9.0 g. (0.034 mole) of methyl 5-0-(t- butyldimethylsilyl)-2-deoxyribofuranoside, 15 g (0.19 mole) of benzyl _ n _ P T/US85/01813 bromide, and 21 g (0.076 mole) silver carbonate in 50 ml dry dimethylformamide or other aprotic solvent is heated at 60°C. under a dry nitrogen atmosphere for five days. The mixture is cooled and the solids filtered. The filtrate is then concentrated at reduced pressure to 30 ml volume. To this is added 20 ml pyridine and the mixture heated at 65°C. for three hours. The solvents are again removed under reduced pressure affording a dark gummy residue which is taken up in a mixture of 150 ml toluene and 100 ml DI water. The organic phase is separated, washed with water (2 x 100 ml) , dried φ " a2S04) and filtered, The solvent is removed at reduced pressure affording the methyl 3-0-benzyl-5-0-(t-butyldimethylsilyl)-2- deoxyribofuranoside cxsϊtpound as a red oil. ' The following Example VIII illustrates another hydrocarbylation reaction using a methyl providing agent in lieu of a benzyl providing agent. EXAMPLE VIII Methyl 2-Oeoxy--3-0-MetAyl-5--C^Tri * t * y^ To a mixture of 2.6 g (0.11 mole) of sodium hydride in 150 ml of dry tetrahydrofuran under a dry nitrogen atmosphere is added slowly with stirring a solution of 39.0 g (0.10 mole) of methyl 2- deoxy-5-O-tritylribofuranoside in 250 ml of dry tetrahydrofuran. To this mixture a solution of 17.0 g (0.12 mole) of methyl iodide in 25 ml of tetrahydrofuran is added over a one hour period. The mixture is then stirred at ambient temperature for 20 hours. Methanol (20 ml) is then added slowly to decompose the excess sodium hydride. The solvent and excess methyl iodide are then evaporated under reduced pressure. The residue is then taken up in a mixture of 250 ml of toluene and 150 ml of DI water. The organic phase is separated, washed (2 x 100 ml) with water, dried (Na2S04) , filtered, and the solvent removed under reduced pressure affording an anomeric mixture of the methyl 2-deoxy- 3-0-methyl-5-0-tritylribofuranoside compound as a yellow oil. EXAMPIE IX Methyl 3-0-^enzyl-2-Deoxy--5-0-(p-Methox * ^ityl) bo_iuranoside: ■ -A mixture of 5.0 g (13 mmole) of methyl 2-deoxy-5-0-(p- methoxytrityl)ribofuranoside,. 0.5 g (20 πtrnole) of sodium hydride, and 3.4 g (20 mmole) of benzyl bromide in 50 ml dry tetrahydrofuran was heated a reflux under a dry nitrogen atmosphere for two and one-half hours. The mixture was then stirred at ambient temperature overnight. Pyridine (5 ml) was added and the mixture again heated at reflux for three hours. After being cooled to ambient temperature, the mixture was filtered. The solvent was removed from the filtrate at reduced pressure. The residual oil was taken up in 75 ml ethyl acetate and 50 ml of DI water. The phases were separated and the organic phase washed (2 x 50 ml) with water. The solution was dried $Ia2S04) , filtered, and the solvent removed under vacuum affording 6.5 g (12.7 mmole,- - 98%) of the methyl 3-0-benzyl-2-deoxy-5-0-(p- methoxytrityl)ribofuranoside ccipound as an orange oil. EXAMPLE X 3l-C--Ber-_ * yl-2L-Deoxy-5-Trifl∞ To a solution of 11.1 g (0.021 mole, 90% pure) of methyl 3- 0-benzyl-2-deoxy-5-0-tritylribofuranoside in 125 ml acetonitrile under a dry nitrogen atmosphere was added 6.8 g (6.2 ml, 0.021 mole) of Bis- (trimethylsilyl) -5-trifluoromethyluracil. The mixture was cooled to 5°C. with an ice-water bath. Acetonitrile (25 ml) was mixed with 8.3 ml of a CH2CI2 solution of anhydrous stannic chloride containing 0,66 grams of SnCl4 per ml (5.46 g, 0.021 mole). This solution was added slowly over a period of ca. 15 minutes to the stirred reaction mixture while maintaining a temperature of < 5°C. with an ice bath. Afte the addition was completed, the mixture was stirred at 5°C. for a additional 30 minutes. The reaction was then quenched by adding 25 m absolute ethanol. The ice-bath was removed and the mixture stirre for 30 minutes while warming to ambient temperature. The reactio mixture was then poured rapidly into a vigorously stirred mixture o 350 ml of 5% sodium bicarbonate solution and 200 ml of ethyl acetat at * 0-5°C. After stirring for 5 minutes, the emulsion was vacuu filtered through a pad of filter-aid. The filter was washed with 5 ml of ethyl acetate. The combined filtrate and filter washing wa phase separated, the organic layer was washed with 250 ml of deionize water, dried (Na2Sθ4) , filtered, and the solvent removed under vacuu (50 mm Hg at 45°C.) affording 14.7 g of an orange oil. The oil was dissolved in 1000 ml of hot toluene. Upo cooling, a gelatinous precipitate formed. This was collected b vacuum filtration, washed with 100 ml fresh toluene and air drie affording 2.8 g (0.0073 mole, 34.5%) of an off white solid identifie as alpha-3'-0-benzyl-2 l -deoxy-5-trifluoromethyluridine. An analytica sample was prepared by recrystallization from toluene: ^H NMR (DMSO dζ) S 2.5 (m, 2, α_2) , 3.37 (s, 2, HOCH2-) , 3.5 (m, 1, -OH) 4.2 (m, 1, CHOH), 4.52 (s, 2, -<ZΗ_φ), 5.0 (m, 1, -CHOH), 6.18 (d, 1 anomericCH), 7.27 (s, 5, ArH) , 8.15 (broad s, C=CH); [ c ] 20 D -24.7°(C 1.0, EtOH). The filtrate from the isolation of the alpha-anomer wa evaporated to dryness affording an orange gummy oil. The oil wa triturated with hexane (4 x 100 ml) to remove trityl ethyl ether The residual gum (5.5 g) was subjected to HPLC on a.preparative silic column using 20% ethyl acetate in hexane .as eluent. From a shor retention time fraction 0.81 g (0.0021 mole, 10.0%) beta-3'-0-benzyl 2'-deoxy-5-trifluoromethyluridine was isolated by evaporation of th solvent: ΪH NMR (DiSO-dg) f2.32 (m, 2, 2'- H2) , 3.63 (broad s, 2 5'-α_ ), 4.1 (m, 2, 3', 4 * - H), 4.54 (s, 2, ■ &_ ) , 5.27 (t, 1, -OH) 6.10 (t, 1, ar neric-H) , 7.34 (s, 5, ArH), 8.94 (s, 1, CH ** C) , 11.88 ( S , 1, NH) ; [ « ] 20 + 39.40 (c i.o . EtOH) . D Mother liquor rework affords roughly another 20% yield o both the alpha and beta anomers. The silylated uracil is prepared by reacting uracil wit 1.05 to 1.5 equivalents of silylating agent, e.g., trimethylchlorosilane, for each hydroxy, ercapto, or amino group i the uracil c * c * ι * ρound. The silylating agent is dissolved i hexamethyldisilazane (0.66 equivalent HMDS to 0.33 equivalent silane) and the uracil/silylating system heated for 5-18 hours. The produc is isolated by distillation. Other procedures for forming silylate bases, e.g., silylated uracil will be found in ϋ. S. Patent 4,209,613. Instead of the Friedal-Crafts catalyst S Cl4, othe catalysts such as TiCl4, BF3 etherate, trialkylsilyl ester catalys (U. S. Patent 4,082,911) may be used. An example of a pyrimidine (uracil) compound which can b condensed with a tritylated sugar to form a 2-deoxy uridine i accordance herewith is prepared as follows: EXEMPTS XT Bis-(Triiaethyl≤ilyl)-5-Tri luoromethyluracil ϋnder a dry nitrogen atmosphere, a mixture of 450 g (2.5 mole) of 5-trifluoromethyluracil, 850 g (5.3 mole) of hexamethyldisilazane (HMDS) , and 15 g (0.14 mole) of trimethylchlorosilane was heated at 100-120°C. until the evolution of ammonia ceased ( *C 5 hrs.). The temperature was then raised and gentle reflux maintained (125-130°C.) for one hour. The excess HMDS was removed by distillation at water aspirator pressure. The product was then vacuum distilled (bp. 60-64 c -C. at 0.3 mm Hg) affording 730 g (2.25 mole, 90.1%) of the title compound as a hydrolyticall sensitive, colorless oil. The foregoing pyrimidine can be used in coupling reaction leading to the production of the desired 2-deoxyuridine. ExaMP__E xii 3__3-I_en- * ^l-2l-Deoxy-5-Trifluoroπ2ethylurid To a stirred mixture of 3.5 g (0.01 mole) of methyl 3-0 benzyl-5-0-(t.-butyldimethylsilyl)-2-deoxyribofuranoside and 3.4 (0.01 mole) of Bis-(trimethylsilyl-5-trifluoromethyluracil in 30 ml o methylene chloride at • .5°C. was added a solution of 2.9 g (0.01 mole) of stannic chloride in 5 ml of methylene chloride at ca. 0.2 ml/min. The clear yellow solution was stirred for an additional on and one-half hours at 5°C. during which time the color darkened and fine precipitate formed. Anhydrous ethanol (11 ml) was then added t the mixture. After warming to ambient temperature, the mixture wa filtered removing only a small amount of a solid material. * ' Th solvent was then removed under vacuum. The dark residual oil wa triturated (3 x 50 ml) with hexane. The residue was taken up in 10 ml of ethyl acetate, washed with 100 ml of cold saturated sodiu bicarbonate solution forming an emulsion. This was vacuum filtere and the filtrate layers separated. ' The organic phase was washed (2 100 ml) with DI water, dried (Na2S04) , filtered, and the solven removed under vacuum affording 1.0 g of a thick yellow oil. Thi material was chromatographed on 75 cc of silica gel eluting with ethy acetate/hexane (1:1). From early eluting fractions, 150 mg (0.3 mmole, 3.9%) of crude beta-anomer of the title product was obtaine with 200 mg (0.52 πroole, 5.2%) of the alpha-anomer being found i later eluting fractions. The products were identified by thin laye chromatography and ^H * MM analysis. EXflMPLE XIII 3 -Q-Ben2^1-2^3eoxy-5---Tri uororoethyl * -r- ^ .- -To a solution of 6.4 g (12.5 mmole) of methyl 3-0-benzyl-2- deoxy-5-0-(p-methoxytrityl)ribofuranoside and 4.2 g (13.0 mmole) of Bis-(trimethylsily)-5-trifluoromethyluracil in 50 ml of dry acetonitrile at -5°C. was added slowly (over five minutes) a mixture of 3.9 g (15.0 mmole) of stannic chloride, 4 ml methylene .chloride, and 6 ml of acetonitrile. The resulting solution was stirred at -5°C. for an additional 20 minutes. Methanol (15 ml) was then added and the mixture slowly (30 minutes) wanned to ambient temperature. The mixture was then poured into a vigorously stirred, cold solution of 5% sodium bicarbonate (250 ml) . To this was added 250 ml of ethyl acetate. * After being stirred for ten minutes, this mixture was filtered through a pad of filter-aid. The organic phase of the filtrate was separated, washed (2 x 150 ml) with 10% NaCl solution,- dried (Na2Sθ4) , filtered, and the solvent removed under reduced pressure affording 7.9 g of an orange oil. The oil was triturated with hexane (4 x 20 ml) and the semi-solid residue taken up in 750 ml of hot toluene. After being cooled overnight in a refrigerator, a gelatinous precipitate formed. This was collected by vacuum filtration, washed with 50 ml fresh toluene and air-dried affording 1.59 g (4.1 rraiiole, 33%) of the alpha-anomer of the title compound as shown by NMR and TLC. The filtrate was stripped of solvent under reduced pressure affording 3.7 g of an orange oil. Trituration of this oil with hexane (3 x 25 ml) left 2.2 g of residual oil which was chromatographed on 180 g of silica eluting with 40% ethyl acetate in hexane. Fractions containing the beta-anomer of the title compound (by TLC) were combined affording 0.61 g (1.5 mmole 12.6%) of a yellow oil that solidified on standing. Recrystallization from isopropyl alcohol/hexane afforded analytically pure beta-anomer. EXAMP E XIV 3^-Q--Be * n2 * yl-__l-Deoxy-5^Fluorc)uridi--e: To a solution of 4.2 g (0.0061 mole, 73% pure) of methyl 3- 0-benzyl-2-deoxy-5-0-tritylribofuranoside in 40 ml of acetonitrile under a dry nitrogen atmosphere were added 2.0 g (0.0067 mole) of Bis- (trimethylsilyl)-5-fluorouracil. The mixture was cooled to 5°C. with an ice-water bath. A solution of 1.5 g (0.0067 mole) of trimethylsilyltrifluoromethanesulfonate in 1.5 ml of methylene chloride was prepared. This catalyst solution was added slowly over a period of ca. five minutes to the stirred sugar/pyrimidine reaction mixture while maintaining a temperature of < 5°C. The mixture was stirred at 5°C. for an additional 2-1/2 hours. The reaction was then quenched by slow ( *~~J 5 min) addition of 10 ml anhydrous methanol while keeping .the temperature <10°C. The quenched mixture was warmed to ambient temperature and stirred for an additional three hours. The mixture was poured into a 25 ml stirred solution of aqueous 6% sodium bicarbonate. The resulting mixture was extracted with two 25 ml portions of ethyl acetate. The organic extracts were combined and washed with 25 ml of water. After being dried over anhydrous sodium sulfate, the solvent was evaporated under reduced pressure. The residue was triturated with 35 ml of . hexane to remove by-product methyl trityl ether. The residual tacky solid was dissolved in a minimum of acetonitrile. This solution was then subjected to preparative HPLC using a Cβ reverse phase packing (SPHERISORB Cg) and 40/60 acetronitrile-H-jO as eluent. There was obtained 0.63 g (0.0019 mole, 30.7%) of alpha-3 l -0-benzyl-2'-deoxy-5-fluorouridine as the first eluting nucleoside. Also, 0.46 g (0.0014 mole, 21.9%) of the corresponding beta-anomer was obtained from combined later eluting fractions. !H NMR (DMΞO-dg) 62.3 ( , 2, 2* -Orl_) , 3.6 ( , 2, 5 1 - CH2) / 4.1 (m, 2, 3' & 4'-CH) , 4.5 (s, 2, <3__Φ) , 5.3 (t, 1, OH), 6.1 (m, 1, anomeric-CH) , 7.3 (s, 5, ArH), 8.7 (d, 1, CH=C) , 11.9 (s, 1, NH). EXAMPLE XV This example ' illustrates a method for converting the alpha anomer to the beta-anomer. 3___<)-Benzyl-2__-Deoxy-5-Tτifluorcfliethyluridir-^ from alpha-Anomer: *" Alpha-3'-O-Benzyl-2'-deoxy-5-trifluorometh luridine (alpha anomer, 99 + % by HPLC), 5.0 g (0.013 mole), was refluxed for 24 hour with 50 ml hexamethyldisilazane and 2 ml trimethylchlorosilane. Th excess reactants were removed by rotary evaporation which was followe by the addition and similar concentration of 2 x 100 ml toluene. Th residue was dissolved in 25 ml CH2CI2. To this was added 5.4 ml (3. g; 0.0387 moles) triethylamine and 6.4 ml of a 0.48 g/m trimethylsilyltrifluoromethanesulfonate/CH2Cl2 solution (3.1 g; 0.01 moles) . The mixture was stirred for 1.5 hour at room temperatur after which 10 ml of 1% HCl/MeGH was added and stirring continued fo 30 minutes. The resulting mixture was poured into 50 ml 6% NaHOθ3 an extracted with EtOAc, EtOAc extract washed with 50 ml H2P and drie over Na 2 Sθ4. The solvent was removed under reduced pressure. Th residue was subjected to HPLC using a spherisorb Cg ~ */ t* m colum eluting with 50/50 mixture of CH3CNU2 0 - Analysis showed a mixture of 10-20% titled beta ancme compound in 80-90% alpha-anomer. As indicated above, the group for protecting the primary O group on the 2-deoxyribofuranoside, is preferably trityl or substituted trityl. It need not be, and another protecting group, e.g., silyl may be used and then condensation effected with the sily uracil with CH3Q./SnCl4, for example. Where alkylation or aralkylation of the 3-0 secondary CH group is to be carried out, trityl or silyl group is necessary, the trityl group being preferre for the reasons stated above. After the alkylation is complete, th trityl or silyl group may be replaced with another protective grou such as acyl, alkyl, silyl, etc., prior to the condensation step. This extra step of replacing the trityl or silyl group has not bee found to be necessary because of the surprising stability of thes protecting groups in the presence of an acid condensation catalyst. The alkylation of the tritylated compound (Example VI) introduces a H2 -0-C-Q structure. It makes little or no difference what organic radical Q i so long as it survives subsequent reaction conditions. Thus Q may b hydrogen, alkyl (C1-C5) aryl, substituted aryl, heterocyclic, e.g., pyridyl, or containing a heteroatom such as sulfur, nitrogen or phosphorus. A benzyl or methyl group is preferred. These radical may be substituted with alkoxy, e.g., methoxy, ethoxy, isopropoxy, t butoxy; nitro; or alkyl, e.g., methyl, ethyl, isopropyl, t-butyl, cyclohexyl, or substituted alkyl, e.g., methoxy methyl, ethoxyethyl, methoxypropyl, chloromethyl, bromomethyl, trifluoromethyl, etc. To produce the 2-deoxyuridines hereof with deprotecte groups, e.g., hydroxyl, the blocking or protecting group or groups ca be removed in the usual way, for example, by means of alcoholi solutions of ammonia or alkali metal alcoholates (sodium ethylate) or aqueous or alcoholic alkali. The beta-an ner can be isolated from the alpha-anomer by high pressure liquid chromatogtaphy. The beta-ancjmer Example No. XIV is not hygroscopic. The following studies and preparations have been made by Taiho Pharmaceutical Company Ltd. ' and are reported in European Patent Publication 0129984 dated 2 January 1985. The 2 ! -deoxy-5-substituted uridine derivatives of the present invention are useful * as antitumor agents. In their use as antitumor agents, they are ordinarily combined- -with a suitable, pharmaceutically acceptable carrier to be prepared " -as a pharmaceutical preparation having a form suitable for desired administration purposes. The carrier may be, for example, a diluent,- a binder, a lubricant, a coloring agent or a disintegrator . , which are conventionally used and pharmaceutically acceptable. The pharmaceutical preparation may take a form .of tablet, capsule, granule, powder, liquid or the like for oral administration, as well as a form of injection or the like for non-oral administrations such as intravenous injection. The pharmaceutical preparation may also take a form of suppository for intra-rectal administration. The content of the active ingredient (compound produced by the process of the present invention) per unit form of each pharmaceutical preparation can be appropriately decided so as to be proper for that particular form and is not largely different from those in ordinary pharmaceutical preparations. A preferable content of the active ingredient generally is about 25 to 500 mg per unit. Pharmaceutical preparation of the above forms can be done according to the respective usual methods. The administration dosage of each pharmaceutical preparation differs naturally from the condition, the weight, the age and the like of a patient to whom the pharmaceutical preparation is to be administered and, accordingly, cannot be restricted. In general, administration to each adult may be made so that the adult intakes about 100 to 2000 mg of the active ingredient daily. This aηrøunt of the active ingredient can be administered by division into doses for administration one to six times a day. Below, there are shown pharmacological tests results, namely, antitumor- activity values and toxicity values. Further, based on therapeutic indexes calculated from these two kind of values, usefulness of the corrtpounds of the present invention wil be explained. Pfaaπnacological tests (a) Method for determining of antitumor activity value 5 x 10- * Cells of mouse-transplantable tumor Sarcoma 180 wer transplanted to each male ICR/JCL-strain mouse (having a weight of 2 to 30 g) subcutaneously at the back. Each test compound dissolved o suspended in 0.1% Tween 80 (*) - 0.5% CMC (carboxymethylcellulose solution was orally administered to various test groups eac consisting of 7 mice once a day for 7 consecutive days from the nex day of tumor transplanting, in an amount of 1.0 ml of solution o suspension per 100. g weight per day. As to a control group, the sam Tween 80-CMC solution containing no test compound was orall administered once a day for 7 consecutive days in an amount of 1.0 m per 100 g weight per day. On the tenth day from the tumor transplanting, an averag tumor weight for each administration level of each test compound wa determined. This weight was compared with an average tumor weight i control group, and the ratio of tumor enhancement inhibition at eac administration level of each test compound compared with control grou was calculated. From these calculations, the administration level each test compound at which the ratio of tumor enh-ancement inhibitio become 50% was obtained and the level (amount) was taken as th antitumor activity value of each compound. (*) (A trademark for a series of surface active agents, which is a polyoxyethylene derivative of fatty acid partial ester of sorbitol anhydride, manufactured by I.C.I. United States, Inc.) Pharmacolcqical tests - (Continued) (b) Method for determining toxicity value Hitherto, toxicity values of anti-malignant tumor agent have been calculated on the bases of LD50 of test animals, in mos cases.- However, LD50 is measured under serious conditions of tes animal far deviating from conditions of patient where drugs ar actually—used and accordingly LD50 does not represent a practica toxicity of drug. Therefore, in the present test, accumulate toxicity,- which well represents the toxicity of anti-malignant tumo agents,- was focused on and, as an indication for sensitive detectio of the accumulated toxicity, inhibition of weight increase of tes animal was measured. That is, when antitumor activity value wa determined in the above item (a) , the weight of each mouse of eac test group for each test compound was measured daily from the day o tumor transplanting, iircnediately before administration. On the day of tumor weight measurement, the average ne weight increase of each mouse of each test group for each tes compound from the day of tumor transplanting was measured. Thes increases were compared with the average net weight increase o control group and the ratio of net weight increase of each test grou of each test compound to that of control group was calculated. Fr these calculations, there was obtained an addition amount of each tes compound at which weight increase is inhibited by 50% compared wit that of control group, and that amount was taken as a toxicity valu of each compound. (c) Calculation of therapeutic index By the use of the antitumor activity value (hereinafte referred to as A) and the toxicity value * (hereinafter referred to a B) of each c trpound, which were obtained in the above items (a) an (b) , respectively, therapeutic index (hereinafter referred to as C) was calculated in accordance with the following equation: Pharmacological'tests - (Continued) Therapeutic index (C) A larger therapeutic index of a compound means that the compound i better balanced in effect and toxicity and more useful. In Table 1 are shown the results of the above tests, o specific compounds which may be prepared in accordance with th present invention, as well as on comparative compounds, namely, 2 1 deoxy-5-trifluoromethyluridine (F3TCIR) and 2'-deoxy-5-fluorouridin (FudR) . Table 1 Compound Antitumor activity value (A) Toxicity value (B) Therapeutic Ind Administration amount of Administration amount of (C) = (B)/(A) test compound, at which test compound at which tumor enhancement is inhi¬ weight increase of test bited by 50% compared with animal is inhibited by that of control group 50% compared with that of (mg/Kg/day) control group (mg/Kg/day) 3 -O-Benzyl-2 - 17 32 1.88 deoxy-5-trifluoro¬ methyluridine 3 , -0-Benzyl-2 , - 17 35 2.06 deoxy-5-fluoro- uri ine F β R 68 49 0.72 F 3 TdR 58 40 0.69 FudR 93 71 0.76 As is obvious from Table 1, 3 -O-benzyl-2 -deoxy-5- trifluoromethyluridine is equal or superior to F3TdR and FudR i toxicity and far superior to them in antitumor activity. When compared in therapeutic index, the products of Examples XIII and XI are especially useful. Examples of pharmaceutical preparations are illustrated below using the beta ano er of 3 , -0-benzyl-2 , -deoxy-5-trifluoromethyl uridine. EXAMPLE OF PHARMACEUTICAL PREPARATICN-1 (CAPSULES) 3'-O-Benzyl-2'-deoxy-5-trifluorαuethyluridine, lactose, crystalline cellulose and corn starch are mixed in the following proportions. Further, magnesium stearate is mixed with them in the following proportion. This mixture is filled in capsules by the use of a suitable capsule-filling machine so that one capsule contains about 293 mg of .the mixture, whereby an intended capsule product is obtained. Capsule formulation mg/capsule 3 I -0-Benzyl-2 l -deoxy- 200.0 5-trifluoromethyluridine Lactose 30.0 Crystalline cellulose 50.0 Corn starch 10.0 Magnesium stearate 3.0 293.0 EXAMPLE OF lΗABM^CEUTTCAL PREPARATICN-2 (GR ULES) 3 , -0-3enzyl-2 , -deoxy-5-trifluoromethyl uridine, lactos crystalline cellulose and corn starch are mixed in the followi proportion. Thereto is added a 10%-ethanol solution containi hydroxypropyl cellulose and they are kneaded. Then, by the use of appropriate granulator, the kneaded mixture is made into granule After drying, the granules are made uniform so as to have granul size' of " " 12 to 42 mesh. Subsequently, the granules are coated wi hydroxypropyl methyl cellulose in the following proportion by the u of a suitable coating machine. The coated granules are again ma uniform so as to have granular size of 12 to 42 mesh, whereby granule product is obtained. Granule formulation mg/granule 3'-O-Benz l-2'-deoxy- 200.0 5-trifluoromethyluridine Lactose 200.0 Crystalline Cellulose 311.0 Corn Starch . 200.0 Hydroxypropyl Cellulose 10.0 Hydroxypropyl Methyl cellulose 70.0 Fatty Acid Monoglyceride ' 3.5 Titanium Dioxide 5.5 1,000.0 1801 EXAMPLE OF FHAR^CΞUTICAL PREPARATIC_.-3 (TABLETS) 3 , -0-3enzyl-2 l -deoxy-5-t ifluoromethyl uridine, corn starch and calcium cellulose glycolate were mixed in the following proportions. Thereto was added a 10%-ethanol solution containing hydroxypropyl cellulose, and the mixture kneaded. The kneaded mixture was made into granules by the use of an appropriate granulator. After drying, the granules were mixed with magnesium stearate and silicic acid anhydride in the following proportions and then the mixture made into tablets by the use of a suitable tablet machine. The tablets were coated with hydroxypropyl methyl cellulose, whereby an intended tablet product was obtained. Tablet formulation mg/tablet 3 -O-Benzyl-2 -deoxy- 200.0 5-trifluorcmethyl uridine Corn starch 5.0 Calcium cellulose glycolate 20.0 Hydroxypropyl cellulose 2.0 Magnesium stearate 2.5 Silicic acid anhydride 2.5 Hydroxypropyl methyl cellulose 19.999 Polyethylene glycol 6000 0.001 Titanium oxide 2.0 254 Products such as produced in Examples XIII and XIV show ■antitumor activity in mice against Sarcoma 180. The effective dose and the lethal dose has been determined as follows: ___50 ____O0 3'-0-Benzyl-2'-deoxy- 14 mg/kg. 80 mg/kg. + 5- rifluoromethyluri ine Trifluorothyraidine 75 mgAg- 135 mg/kg. Note: "-Test animals alive at indicated dose. The dosage is administered orally. In comparison with the activities of other antitumor agents on Sarcoma 180 in mice, the following results were obtained: Compound j___50 (50% tumor regression) Trifluorothyidine 60-80 mg/kg. CF 3 dC* 60-80 mgAg. Ftorafur 120 mg. kg. 3'-0-Benzyl-2'-deoxy- 14 mg./kg. 5-trifluoromethyluridine *5-Trifluoromethy1-2'-deoxycytidine.

Claims: κ∑ IS CLAIMED IS: 1. A process for making a 2-deoxyuridine which comprises the steps of: (a) replacing the hydrogen of the primary hydroxy group of an alkyl 2-deoxyribofuranoside with a protecting grou selected- from trityl, substituted trityl, and silyl radicals to for an alkyl 5-0-"protected"-2-deoxyribofuranoside; (b) hydrocarbylating said alkyl 5-0- n protected"-2 deoxyribofuranoside with a lower alkyl or aralkyl group to form a alkyl 3-0-hydrocarbyl-5-0-"protected"-2-deoxyribofuranoside. (c) condensing a silyluracil with 3-0-hydrocarbyl-5-0 "protected n -2-deoxyribofuranosyl-X in the presence of an aproti solvent and a Lewis acid or a Bronsted acid to form a crude 2-deox uridine wherein X is 1-0-alkyl, 1-0-acyl or 1-halo; and optionally, (d) deprotecting the protected group in said crude 2 deoxyu idine to form a 3'-0-hydrocarbyl-2 -deoxyuridine. (e) purifying the 3'-0-hydrocarb 1-2*-deoxyuridine. 2. A process as described in Claim 1 wherein the alkyl 2 deoxyribofuranoside of step (a) is formed by reacting 2-deoxy-D-ribos with a C1-C4 alkanol. 3. A process as described in Claim 1 wherein th protecting group for the primary hydroxyl group is a trityl group. 4. A process as described in Claim 1 wherein th protecting group for the primary hydroxyl group in step (a) is a sily group. 5. A process as described in Claim 1 wherein the protecting group for the primary hydroxyl group in step (a) is a substituted trityl group. 6. A process as described in Claim 1 wherein the protecting group for the primary hydroxyl group in step (a) is a methoxy substituted trityl group. -7. A process as described in Claim 1 wherein the protecting group for the hydroxyl group in step (a) is a nitro substituted trityl group. 8. A process as described in Claim 1 wherein the hydrocarbylating group is a lower alkyl, substituted lower alkyl group, or a substituted aralkyl group. 9. A process as described in Claim 1 wherein the hydrocarbylating group is a methyl group. 10. A process as described in Claim 1 wherein the hydrocarbylating group is a benzyl group. 11. Methyl 3-0-benzyl-2-deoxy-5-0-tritylribof ranoside. 12. Methyl 3-0-benzyl-5-0-(t-butyldimethylsilyl)-2-deoxy- ribofuranoside. 13. Methyl 2-deoxy-3-0-methy1-5-0-tritylribofuranoside. 14. Methyl 3-0^benzyl-2-deo * ^-5-0- (£-methoxytrityl)- r ibof ur anoside . 15. The alpha-3 ' -O-benzyl-2 ' -deoxy-5- tr if luoromethyl uridine.

Inventors: DEPASQUALE RALPH J, OLLMAN JAMES E, DEPASQUALE, RALPH, J., OLLMAN, JAMES, E.
Applicants: SCM CORP, SCM CORPORATION
Application year: 1985
Main classification: C07H3
IPC codes: C07H1, C07H15, C07H19