HU221982B1 - Glucopiranose intermediate for the synthesis of etoposide phosphate and etoposide - Google Patents

Abstract

Glucopyranose of general formula (III), in which R1 and R2 are hydroxy-protecting, optionally substituted aryl-methyl groups, and the two R2 together can also represent alkylidene groups with 1-5 carbon atoms. The compound is an intermediate in the new synthesis of etoposide phosphate and etoposide. ŕ

Description

The present invention relates to a novel protected glucopyranose of formula (III) which can be used as an intermediate in the synthesis of etoposide phosphate and etoposide.

In the formula, R ₁ and R ₂ are hydroxy protecting, optionally substituted arylmethyl groups, and the two R ₂ 5 taken together may be C 1-5 alkylidene.

The arylmethyl protecting groups on the hydroxy groups may be the same or different and are preferably selected from the group consisting of benzyl or C 1 -C 4 alkyl, hydroxy, phenyl, benzyl, halogen, alkoxy, nitro, carboxy or esters thereof. a benzyl group having one or more substituents.

Ethoposide and teniposide 4'-desmethyl-epipodophyllotoxin-glucoside derivatives are widely used in clinical therapy for the treatment of cancer.

In order to improve the water solubility and administration of etoposide, etoposide phosphate is produced in a "prodrug" form. Ethoposide phosphate is metabolized in the body to etoposide, which can then be used by the body. An example of a water-soluble prodrug is disclosed in U.S. Patent No. 4,904,768, which discloses water-soluble 4'-desmethyl-epipodophyllotoxyglucoside derivatives bearing a 4'-phosphate group. Ethoposide 4'-phosphate was prepared by reacting etoposide with phosphoryl chloride, followed by hydrolysis, or reacting etoposide with diphenylphosphoryl chloride and then removing the phenyl groups by hydrogenation. The preparation of epipodophyllotoxin glycosides is also disclosed in U.S. Patent No. 4,997,931. 4'-Desmethyl-epipodophyllotoxin glycosides are prepared by linking a 4'-protected 4'-desmethyl-epipodophyllotoxin with a protected sugar at the 4'-position. The resulting product is then converted to the corresponding 4'-phosphate.

The above processes for the preparation of etoposide and etoposide phosphate typically require the protection of the phenol, coupling with a protected sugar, and subsequent removal of the protecting groups. In addition, most of these methods require the use of different, different protecting groups to protect the hydroxy and phosphate groups (see, for example, EP-A-0511563). Removing multiple different protecting groups requires more steps. These steps often require acidic or basic conditions, which can also damage the final product, resulting in low production.

Ethoposide phosphate is usually prepared from etoposide by further phosphorylation and deprotection steps. These multiple steps typically result in low total production of the desired compounds 50 and the cost and difficulty of preparing the compounds due to undesired phosphorylation of the glycosidic hydroxy groups on etoposide.

The glucopyranose 55 of formula III of the present invention permits the production of etoposide phosphate by coupling with a protected 4'-desmethyl-4-epipodophyllotoxin-4'-phosphate.

Phosphorylation of the 4'-desmethyl-epipodophyllotoxin of formula (I) by protected di-arylmethyl-II (60)

This results in 4'-desmethyl-epipodophyllotoxin-4'-phosphate, an arylmethyl group protecting the phosphate group of R1. Phosphorylation is preferably carried out by reacting 4'-desmethyl-epipodophyllotoxin with a di (arylmethyl) phosphite, a tetrahalomethane, a tertiary amine and an acylating catalyst. The tetrahalomethane is of the formula CX ₄ wherein X is halogen at the F, Cl, Br and I atoms ^! . In a preferred embodiment, the tetrahalomethane is carbon tetrachloride. The halogens attached to the carbon may be the same or different.

The tertiary amine is preferably N, N-diisopropylethylamine (DIPA), although other suitable tertiary amines may be used. ¹

The acylation catalyst may be a catalyst known in the art. A preferred acylating catalyst is 4- (dimethylamino) pyridine (DMAP).

The compound of formula (II) is then coupled with a hydroxy-protected glucopyranose of formula (III) in the presence of a Lewis acid. In preferred embodiments, the Lewis acid is boron trifluoride diethyl etherate.

Other Lewis acids even as A1C1 _3, ZnCl _2,

Et ₂ AlCl, CF ₃ SO ₃ H, CF ₃ SO 3Ag, Zn (GF ₃ SO ₃ ) ₂ and

TMSCF ₃ SO ₃ . The coupling reaction can also be carried out in the presence of molecular sieves. The coupling reaction is carried out in a halogenated or non-halogenated solvent, most preferably acetonitrile. Other solvents include propionitrile, acetone, methylene dichloride, chloroform, 1,2-dichloroethane and mixtures thereof. I

The di (arylmethyl) -4'-desmethyl-4-epipodophyllotoxin-4'-phosphate is thus a phenolic component; | by reaction with di (arylmethyl) phosphite, a tetrahalomethane, a tertiary amine and an acylating catalyst in a suitable solvent. The 2,3-di-O-benzyl-4,6-O-ethylidene -? tetrabenzyl-protected etoposide phosphate. The protected etoposide 4'-phosphate is crystallized or recrystallized to swallow the C-1 '- J anomer.

The protecting groups are simultaneously swallowed with etoposide phosphate from the glucoside and phosphate groups by hydrogenation or other suitable means.

The process, which is described in detail in our Hungarian Patent Application Publication No. T / 72,461, is suitable for the preparation of etoposide 4'-phosphate in pure form without further difficult purification steps. The protected dibenzyl 4- (2,3-di-O-benzyl-4,6-O-ethylidene-pD-glucopyranosyl) -4'-desmethyl-4-epipodophyllotoxin-4'-phosphate readily crystallizes from the reaction mixture, or by recrystallization, the Cl '-p form can be substantially pure isolated. The desired anomer is usually obtained in a crystallization step. The process provides an arylmethyl, in particular benzyl protected etoposide 4'-phosphate of formula (IV), wherein R _{3 is an} arylmethyl protecting group of the phosphate group, which is readily separated from the reaction mixture in the form of pure Cl '- anomer. crystallized or recrystallized from a suitable solvent. The whole process provides a fast and efficient and efficient process for the preparation of etoposide 4'-phosphate. The phosphate group is easily removed

EN 221 982 Β1 phosphatase, thereby providing an efficient process for the preparation of etoposide and pharmaceutically acceptable salts and solvates thereof.

A preferred hydroxy-protected glucopyranose is represented by the formula (IIIb) wherein R 1 is arylmethyl. In preferred embodiments, R 1 is benzyl, so that glucopyranose can be represented by formula (IIIa). Further, R 1 is a substituted benzyl group formed by C 1-4 alkyl, hydroxy, phenyl, benzyl, halogen atoms such as fluorine, bromine and iodine, alkoxy, nitro and carboxy and its esters. has one or more substituents selected from the group consisting of. Suitable substituted benzyl groups include, for example, 2-methylbenzyl, 3-methylbenzyl, 4-methylbenzyl, 1- or 2-naphthyl, 2-, 3- or 4-phenylbenzyl, 4- (methoxy- carbonyl) benzyl, 2,6-dichlorobenzyl, 2-fluorobenzyl and pentafluorobenzyl. Preferably, the two R ₂ groups together form an ethylidene. In other embodiments, the two R ₂ groups together may be propylidene or isopropylidene.

The compounds of formula (ΠΙ), (IIIa) and (IIIb) are prepared by known methods, for example, as described in U.S. Patent No. 4,997,931. Glucopyranose protected by arylmethyl groups is formed as a mixture of C-1-α, β-anomers. Unlike most anomeric mixtures, the C-1-anomer of (arylmethyl) glucopyranose can be separated from the α-anomer by crystallization. Specifically, the anomeric mixture of glucopyranose of formula (IIIa) crystallized from hexane provides substantially pure C-1-β anomer of compound of formula (IIIa). Further, glucopyranose of formula (IIa) initially solidifies to a 1: 1 ratio of β: α, but over time to 85:15 β: α.

The coupling of the protected glucopyranose (IHb) with the protected 4'-desmethyl-4-epipodophyllotoxin-4'-phosphate (II) is carried out in the presence of a Lewis acid.

Coupling of hydroxy-protected glycopyranose of formula IIa with dibenzyl 4'-desmethyl-4-epipodophyllotoxin-4-phosphate of formula IIa provides dibenzyl 4- (2,3-di-O-benzyl) of formula IVa -4,6-O-Ethylidene-D-glucopyranosyl) -4'-desmethyl-4-epipodophyllotoxin-4'-phosphate results in a mixture of Cl ', P-anomers.

The coupling reaction is readily and rapidly carried out in the presence of boron trifluoride diethyl etherate to give the α- and β-anomers of IVa.

It is not necessary to isolate the β-form of the compound of formula (IHb), and in particular of formula IIa, before coupling. The final ratio of (IVa) a to (IVa) β is independent of the anomeric composition of the starting compound (IIIa) when the reaction is carried out in halogenated solvents. In acetonitrile, coupling of compounds of formula (IIa) and (IIIa) (85:15 β: α) in the presence of boron trifluoride diethyl etherate at -20 ° C results in the ratio of (IVa) β and IVa). It is believed that the anomerization of sugar occurs very rapidly in halogenated solvents while the anomerization in acetonitrile is much slower.

In other embodiments, the ionic strength of the solvent can be increased by adding a suitable salt. Suitable salts are the alkali metal and alkaline earth metal perchlorates. For example, dissolving 0.5 M LiC10 in ₄ acetonitrile increases the (IVa) β: α ratio to 81:19.

The mixture of α, β anomers of the resultant compound of formula IVa can be recrystallized from methanol to give substantially pure C-1 '-p-form in high yield. Single crystallization from methanol or a mixture of methanol and other solvents crystallizes the less polar (IVa) β-anomer almost completely, essentially without contamination with the (IVa) α-anomer.

The coupling reaction is usually carried out at or below room temperature, particularly between -10 and -40 ° C. Although the coupling reaction is slower at lower temperatures, the low temperature favors the formation of the C-1 H-anomer of formula IVa by slowing the anomerization of the compound of formula IIIa in the reaction mixture. For example, dibenzyl 4'-desmethyl-4epipododophyllotoxin-4'-phosphate and 2,3-di-O-benzyl-4,6-Oethylidene-α, pD-glucopyranose (85:15 α: β) -20 ° The coupling reaction at C at acetonitrile yields (IVa) β and (IVa) 72:28 and at -40 ° C 74:26. The same coupling reaction in propionitrile gives 57:43 at -20 ° C and 76:24 at -78 ° C, giving a compound of formula (IVa) β and (IVa) α.

The preferred solvent for the coupling reaction is acetonitrile because the reaction is faster compared to the solvents commonly used for coupling. The unexpected property of acetonitrile is that the reaction is 2 hours; while in dichloroethane it takes about 18 hours. The coupling reaction in acetonitrile is faster than in propionitrile. In addition, the coupling reaction in acetonitrile yields several (IVa) β-anomers. Some solvents for the coupling of 4'-desmethyl-4-epipodophyllotoxin-4'-phosphate and 2,3-di-O-benzyl-4,6O-ethylidene-D-glucopyranose were investigated. The β: α ratio typically increases with the higher dielectric constant of the solvent.

The substituents on the substituted benzyl protecting groups also influence the rate of formation of (IVa) β and (IVa). For example, bulky groups in the ortho-position favor the formation of the C-1 to 4-form of the compound of formula (IV) by providing steric inhibition of the compound (IVa) while the inhibition by the meta and para-substituents is low. Electron-attracting groups are also favored by C-1 ”^ - anomems. The highest β: α ratio is obtained with the pentafluorobenzyl group, which results in a ratio of 80:20 (IVa) C-1 "to: (IVa) C-1" -a.

The (IVa) α, β-anomeric mixture is separated after work-up in a single crystallization step to give pure C-1 '' - β-Ιιοζ. The mixture of (IVa) α, β-anomer is dissolved in methanol. The solution is heated to spin to completely dissolve the compound (IVa) α, β. The solution was allowed to cool to room temperature. The resulting solid is a substantially pure C 1-14 form of the compound of formula IVa.

HU 221 982 Bl

In preferred embodiments, the crystallization of the C-Γ'-β form of the compound of formula IVa is carried out directly in conjunction with the coupling reaction. After the coupling reaction is complete, methanol is added to the solution without further extraction or standard workup and allowed to warm to 0 ° C. The solution was then allowed to stand at 0 ° C for several hours. The resulting solid was found to be substantially pure C-1 '- 4 (IVa).

The ability to directly crystallize the C-1 H-anomer of the compound of formula (IVa) even from a 50:50 anomeric mixture is a significant and unexpected advantage of using the intermediate of the invention. As reported in J. March, Advanced Organic Chemistry, 4th Ed., John Wiley and Sons, New York, 1992, p. 121, very few diastereomeric pairs can be separated by single crystallization.

After recovery of the C-1 H-anomer of the compound of formula (IV), the hydroxy and phosphate protecting groups are removed simultaneously by known methods, preferably by hydrogenation. A compound of formula IVa is hydrogenated in the presence of a catalyst to give a compound of formula V.

The etoposide phosphate of formula (V) can also be converted to the etoposide of formula (VI) by removing the phosphate group

The following non-limiting Examples illustrate the compound of the invention (Examples 1 and 2) and its use (Examples 3-5).

Example 1

2.3-Di-O-benzyl-4,6-O-ethylidene-α, β-D-glucopyranose [(ΙΙΙα / α, β]

This compound is prepared according to the adaptation of the literature for analogous compounds disclosed in U.S. Patent 4,997,931. The anomeric composition according to Ή-NMR was 57:43 β: α.

R f (40% ethyl acetate / hexane) 0.40.

1 H-NMR (CDCl ₃ ): δ 7.39-7.27 (m, 10H); 5.14 (d,

0.5H, J = 3.7Hz); 4.91-4.66 (m, 5.5H); 4.14 (dd,

0.5H, J = 5.0, 10Hz Hz); 4.09 (dd, 0.5H, J = 5.0,

10.3 Hz); 3.94-3.88 (m, 1H); 3.66 (t, 0.5H, j = 9Hz); 3.56-3.25 (m, 3.5 Hz); 3.10 (bs, 1H, conc, dependent OH); 1.36 (d, 3H, J = 5.0 Hz).

J3C-NMR (CDCl3): δ 128.53; 128.42; 128.31; 128.09;

127.95; 127.83; 127.63; 99.50; 97.72; 92.12; 82.94;

81.44; 81.08; 80.89; 79.31; 78.33; 75.23; 75.12;

74.96; 73.81; 68.53; 68.22; 66.22; 62.48; 20.43.

Example 2

2.3-Di-O-Benzyl-4,6-O-ethylidene - $ - D-glucopyranose (ΙΙΙαβ) g of the α, β-anomeric mixture of formula (IIIa) was weighed into a 250 mL flask. Hexane was added and the suspension was refluxed. Sugar becomes an insoluble oil which settles on the bottom. The slurry was allowed to cool to room temperature, then a stir bar was added and the solution was gently stirred overnight. White, fluffy crystals precipitate out and float in the hexane over the dirty solid residue. The crystals were collected by decanting the upper phase into a Buchner funnel. The contaminated solid is left in the flask. The white solid β (IIa) is dried at room temperature under vacuum (20 mm Hg).

1 H-NMR (CDCl 3): δ 7.37-7.27 (m, 10H); 4.90-4.69 (m, 6H); 4.14 (dd, 1H, J = 4.9, 10.4 Hz); 3.66 (t, 1H,

J = 9.0 Hz); 3.54 (t, 1H, J = 10.2 Hz); 3.45 (t, 1H,

J = 9.3 Hz); 3.37-3.27 (m, 2H); 3.23 (d, 1H,

J = 5.5 Hz, conc, dependent OH); 1.36 (d, 3H,

J = 5.1 Hz).

¹³ C-NMR (CDCl ₃ ): δ 128.42; 128.29; 128.11; 127.93;

127.82; 127.63; 99.45; 97.71; 82.93; 81.06; 80.88;

75.22; 74.96; 68.21; 66.21; 20.39.

Example 3

Dibenzyl 4 '-desmethyl-4-epipodophyllotoxin-4' phosphate (Ha)

In a drying oven, a 3-necked 1-L flask is fitted with a dropping funnel, a stir bar, a thermometer and a nitrogen inlet. To the flask was added 4'-desmethyl-epipodophyllotoxin (I) (25.0 g, 62.45 mmol) and anhydrous acetonitrile (367 mL, 0.17 mol). The suspension was cooled to -10 ° C. added

30.1 ml (312.25 mmol) of carbon tetrachloride was maintained at -10 ° C. Then perc, Ν-diisopropylethylaniline (22.84 mL, 131.15 mmol) was added over 3 minutes. 4- (Dimethylamino) pyridine (0.763 g, 6.25 mmol) was added in one portion, followed by the dropwise addition of dibenzyl phosphite (20.00 mL, 90.55 mmol) over 15 minutes. The reaction is somewhat exothermic during the addition, but the internal temperature remains below 10 ° C throughout: under external cooling. The reaction mixture was stirred for 37 minutes at 10 ° C. During this time, the starting material: dissolves; the reaction is monitored by HPLC. 150 ml of 0.5 M potassium dihydrogen phosphate solution was added and the mixture was allowed to warm to room temperature. The mixture was extracted with ethyl acetate (1 x 350 mL) and washed with water (2 x 100 mL). The organic phase was dried over sodium sulfate and concentrated in vacuo to 150 ml. Add 500 ml of isopropyl alcohol. A portion of the solvent (200 mL) was removed in vacuo and a solid precipitated. Isopropyl alcohol (550 mL) was added and the solvent (550 mL) was removed in vacuo. Finally, isopropyl alcohol (250 mL) was added and the mixture was heated to reflux until the solid dissolved. The yellow solution was cooled to room temperature and then at 0 ° C for 4 hours. The white solid was collected on a filter, washed twice with cold isopropyl alcohol, and dried in vacuo (40 ° C; 20 mm Hg). Yield: 37.15 g (90%).

1 H-NMR (CDCl 3): δ 7.37-7.28 (m, 10H); 6.81 (s,

1H); 6.39 (s, 1H); 6.30 (s, 2H); 5.90 (dd, 2H, J = 1.0,

12.7 Hz); 5.28-5.14 (m, 4H); 4.71 (b, 1H,

J = 3.4 Hz); 4.53 (d, 1H, J = 5.1 Hz); 4.25 (dd, 1H,

J = 8.7, 10.7 Hz); 3.66 (s, 6H); 3.27 (dd, 1H, J = 5.2,

104.1 Hz); 2.71-2.61 (m, 1H).

¹³ C-NMR (CDCl 3): δ 175.27; 151.15; 151.11; 148.22;

147.32; 137.28; 136.04; 135.94; 132.19; 131.35;

128.45; 128.30; 128.26; 127.69; 127.64; 110.13;

HU 221 982 Bl

109.32; 107.66; 101.45; 69.62; 69.53; 69.46; 67.75;

66.17; 56.06; 43.81; 40.37; 38.47.

Example 4

Dibenzyl 4- (2,3-di-O-benzyl-4,6-O-ethylidene-D-glucopyranosyl) -4'-desmethyl-4-epipodophyllotoxin-4'-phosphate (IVa) β (coupling in acetonitrile) )

Into a 25 ml round-bottomed oven-dried round-bottom flask equipped with a stirrer, a thermometer, a funnel and a nitrogen inlet, are placed 1.00 g (1.51 mmol) of dibenzyl 4'-desmethyl-4epipodophyllotoxin-4'-phosphate (Ha) , 0 g dry 4 A pore size molecular sieve (1/16 "beads), 0.702 g (1.817 mmol) of 2,3-di-O-benzyl-4,6-O-ethylidene-a, 3-D- glucopyranose (α: β = 85: 15) and 10.0 ml of anhydrous acetonitrile. The solution was stirred until homogenized and then cooled to -20 ° C. Boron trifluoride diethyl etherate (0.50 mL, 4.08 mmol) was added dropwise over two minutes. The reaction mixture was heated at -20 ° C for 80 minutes. A white solid begins to precipitate 45 minutes after the addition of boron trifluoride diethyl etherate. Pyridine (5.23 mL, 64.7 mmol) was then added. The solution was allowed to warm to room temperature and diluted with dichloromethane (10 mL). The white solid dissolves. The solution was filtered to remove the solid residue. The solution is washed with 7 ml of 3% hydrochloric acid and the aqueous phase is re-extracted with 10 ml of methylene chloride. The combined organic phases are finally washed with 7 ml of saturated sodium chloride solution. The organic layer was dried over sodium sulfate and concentrated in vacuo to give a white / yellow solid. HPLC analysis of crude product shows 71.6: 28.4 (IVa) 3: (IVa) α The solid is dissolved in 10 mL of dichloromethane with stirring. 90 ml of methanol are added. A solid precipitates soon. The solution is heated to reflux, during which time the solid is dissolved, and 20 ml of solvent are distilled off. After collecting 19 ml of distillate, the material begins to crystallize. The mixture was allowed to cool to room temperature over 5 hours with gentle stirring. The white solid was collected on a filter and washed twice with room temperature methanol. Solid (IVa) β was dried under vacuum (40 ° C; 20 mm Hg) to give 0.830 g (53.3%) of product.

Rf (50% ethyl acetate: hexane): 0.36.

1 H-NMR (CDCl 3): δ 7.38-7.18 (m, 18H); 7.00-6.98 (m, 2H); 6.82 (s, 1H); 6.54 (s, 1H); 6.25 (s, 2H);

5.97-5.89 (dd, 2H, J = 1.0, 26.7); 5.29-5.18 (m,

4H); 4.89-4.85 (m, 2H); 4.77-4.71 (m, 3H);

4.60-4.49 (m, 3H); 4.39 (t, 1H, J = 10.2 Hz); 4.23 (t, 1H, J = 8.2 Hz); 4.16 (dd, 1H, J = 4.9, 10.4 Hz);

3.63 (s, 6H); 3.55 (t, 1H, J = 10.2 Hz); 3.45-3.34 (m, 2H); 3.32-3.21 (m, 2H); 2.89-2.80 (m, 1H);

1.38 (d, 3H, J = 5.0Hz).

¹³ C-NMR (CDCl 3): δ 174.74; 151.20; 148.72; 147.17;

138.48; 137.45; 137.0; 136.3; 136.2; 132.02; 126.62;

128.42; 128.30; 128.21; 128.07; 127.87; 127.70;

127.67; 110.72; 109.18; 107.73; 102.32; 101.60;

99.55; 81.66; 89.95; 75.40; 75.06; 73.45; 69.45;

68.19; 67.87; 65.97; 43.87; 41.22; 37.48; 20.40.

(IVa) is the C-1 '-a isomer remaining in the mother liquor with a small amount of (IVa) β-product (ΐνβ: IVa 13.7: 86.3).

Example 5

Dibenzyl 4- (2,3-di-O-benzyl-4,6-O-ethylidene-D-glucopyranosyl) -4'-desmethyl-4-epipodophyllotoxin-4'-phosphate (IVa) β (coupling in dichloroethane) )

A 250 ml, 3-neck, round-bottomed round bottom flask equipped with a stirrer, a thermometer, two addition funnels and a nitrogen inlet, was charged with 14.295 g (21.57 mmol) of dibenzyl-4'-demethyl-4-epipodophyllotoxin (Ha). phosphate,

28.6 g of dry 4 A pore size molecular sieve (1/16 ”beads), 10.0 g (25.88 mmol) of α, β-2,3-benzo-benzyl-4,6-O-ethylidene (IIa) α-D-glucopyranose and 143 ml of anhydrous 1,2-dichloroethane. The solution was stirred until homogenized and then cooled to -20 ° C. Boron trifluoride diethyl etherate (7.15 mL, 58.24 mmol) was added dropwise over ten minutes. The reaction mixture was kept at -20 ° C for 18 hours. Pyridine (5.23 mL, 64.7 mmol) is added and the mixture is then brown. The cloudy solution was allowed to warm to room temperature and diluted with methylene chloride (200 mL) and filtered to remove the solid residue. The solution was washed with 100 ml of 3% hydrochloric acid, 100 ml of water and finally 100 ml of saturated sodium chloride solution. The organic layer was dried over sodium sulfate and concentrated in vacuo to give a yellow oil. While stirring, reflux with 1500 ml of methanol. The mixture is allowed to cool to room temperature and stand overnight. The white solid was collected on a filter and rinsed twice with methanol. Solid (IVa) β was dried under vacuum (40 ° C, 20 mm Hg) to give 8.86 g (39.8%) of product. The C-1 '-a isomer of (IVa) α remains in the mother liquor: with a small amount of (IVa) β-product. This remaining coupled product is recovered by further crystallization and / or chromatography. The beta: α ratio of the crude product: before crystallization is 54:46. The overall yield of the coupled product was 81%.

Dibenzyl 4- (2,3-di-O-benzyl-4,6-O-ethylidene-α-D-glucopyranosyl) -4'-desmethyl-4-epipodophyllotoxin-4 '-phosphate (TVa) α R _f (50 % ethyl acetate / hexane): 0.31.

1 H-NMR (CDCl 3): δ 7.38-7.21 (m, 20H); 6.87 (s,

1H); 6.26 (s, 2H); 5.59 (d, 2H, J = 5.8 Hz);

5.29-5.18 (m, 4H); 4.87 (dd, 3H, J = 2.3, 11.1 Hz);

4.79-4.74 (m, 2H); 4.68-4.58 (m, 4H); 4.11 (t, 1H,

J = 7.9 Hz); 3.95 (q, 1H, J = 10.6 Hz); 3.86 (t, 1H,

J = 9.2 Hz); 3.63 (s, 6H); 3.51 (dd, 1H, J = 3.6,

9.4 Hz); 3.45 (d, 1H, J = 7.2 Hz); 3.45-3.35 (m,

3H); 2.82-2.75 (m, 1H); 1.32 (d, 3H, J = 5.0 Hz). ¹³ C-NMR (CDCl 3): δ 174.91; 151.22; 151.18; 148.44;

147.02; 138.56; 137.83; 137.05; 136.27; 136.18;

132.19; 129.27; 128.59; 128.45; 128.34; 128.24;

128.12; 127.94; 127.96; 127.89; 127.72; 127.69;

110.44; 109.81; 107.85; 101.61; 101.08; 99.59;

82.07; 79.39; 78.59; 76.76; 75.09; 74.69; 69.52;

69.46; 69.41; 68.18; 67.04; 62.95; 56.15; 43.82;

41.10; 38.41; 20.40.

Example 6

This example illustrates coupling and crystallization in a single reaction vessel. One 50 ml slurry

EN 221 982 B1 is dried with a stirring bar in an oven, sealed with two closures and cooled under nitrogen. 1.002 g (1.51 mmol) of dibenzyl 4'-desmethyl-4-epipodophyllotoxin-4'-phosphate and 0.702 g (1.81 mmol) of 2,3-di-O-benzyl-4.6 are obtained. -O-ethylidene-α, pD-glycopyranose (85: 15 = β: α). The solids were dissolved in anhydrous acetonitrile (10.0 mL) and cooled to -40 ° C. Boron trifluoride diethyl etherate (0.50 mL, 4.1 mmol) was added dropwise. The solution was stirred at -40 ° C and the reaction was monitored by HPLC. During the reaction, little solid precipitates. After 6 hours, 30 mL of methanol was added dropwise. The suspension was allowed to warm to -30 ° C with stirring and then allowed to stand at 0 ° C for 17 hours without stirring. The solid was collected on a Buchner funnel and washed twice with 15% methanol at room temperature. 0.9668 g (62.0%) of (IVa 3) is obtained with 100% HI.

Claims (4)

PATENT CLAIMS A glucopyranose of formula (III) wherein R 1 and R ₂ are hydroxy protecting, optionally substituted arylmethyl groups and the two R _{2 taken} together It may also be a C 1-5 alkylidene group. A compound according to claim 1, wherein the two R ₂ groups are taken together to form ethylidene and R 1 is benzyl or substituted benzyl. A compound according to claim 2 wherein R represents a benzyl group or a benzyl group substituted by one or more C 1-4 alkyl, hydroxy, phenyl, benzyl, halogen, alkoxy, nitro, carboxy or alkoxycarbonyl groups. 4. Use of a compound according to any one of claims 1 to 6 as an intermediate for the synthesis of etoposide phosphate and / or etoposide.