IL29104A - Derivatives of 4'-demethyl-epipodophyllotoxin glucoside and and their preparation - Google Patents

Description

29104/2 on 3 an I Derivatives of 41^emethyl-epipodophyllotoxin glucoside and their preparation SAMDOZ A.G.

Ci27568 The present invention relates to new glucosides and a process ir production.

The present invention provides oompounds of general formula I, which R^ signifies a hydrogen atom, and Rg signifies an alkyl or alkenyl radical, or a cycloalkyl radical of 5 or 6 ring carbon atoms, or an aralkyl or aralkenyl radical wherein the aromatic ring may optionally be substituted, preferably by one or more hydroxy, alkyl, alkoxy, nitro or halogen radicals, or an aryl radical substituted by, preferably, one or more hydroxy, alkyl, alkoxy, nitro or halogen radicals, or each of R^ and Rg signifies an alkyl radical, or The present invention further provides a process for the production of compounds of general formula I, characterized in that a V-demethyl-epipodophyllotoxin-P-D-glucoside of general formula II, in which signifies a hydrogen atom or a carbobenzoxy radical, is reacted with a compound of general formula III, in which and have the above significance, or with a lower acetal or ketal thereof, in the presence of an acid, suitably a Lewis or sulphonic acid, catalyst, and any carbobenzoxy radical which may be present is subsequently split off.

The reaction is usually desirably carried out in the absence of moisture. It is also usually preferable to carry out the reaotion in the absence of oxygen, e.g. by providing a nitrogen atmosphere.

Suitable Lewis acid catalysts include anhydrous zinc chloride. Suitable sulphonic acid catalysts include jg-toluenesulphonic acid and Dimethylacetal, diethylacetal, the cyclic ethylene aoetal or the corresponding ketals may be used as acetals or ketals of the compounds of general formula III. It is preferred, in order to obtain a higher yield from the condensation, to remove the resulting reaction water or the resulting lower alcohol by azeotropio distillation in a vacuum at a low temperature (e.g. 20° to 30°C) or, in the case where water of reaction is formed, to use a catalyst which also has water-binding properties.

The process of the invention may, for example, be effected by adding a V-demethyl-epipodophyllotoxin-0-D-glucoside of general formula II to a compound of general formula III or to the corresponding lower acetal or ketal, and then adding the catalyst, in the absence of moisture and optionally in an atmosphere of nitrogen. It is also possible, however, to dissolve o suspend a compound of general formula II in a dry inert solvent, e.g. nitromethane, and to react this solution or suspension with a compound of general formula III or with the corresponding lower acetal or ketal in the presence of the catalyst, optionally in an atmosphere of nitrogen. Condensation usually takes place at a temperature of 20° to 35°C and is completed after half an hour to twenty hours. For purposes of isolation the reaction mixture may be taken up in. a water-immiscible solvent, e.g. chloroform, optionally after filtering off the catalyst, and is optionally shaken out several times with water in order to remove water-soluble catalysts and by-products. The organic phase may subsequently be dried and concentrated by evaporation in a vacuum. The residue may then be liberated from an excess amount of a compound of general formula III or of the correspondin lower acetal or ketal by digesting or macerating with pentane, petroleum ether or hexane, or directly by recrystallization or repreoipitation. Any carbobenzoxy radical which may still be present after condensation is split off in manner known per se, e.g. by hydrogenolysis.

The starting materials, i.e. 41 -demethyl-epipodophyllotoxin-β-D-glucosides of general formula II, used for the production of the new compounds of general formula I, may be produced by reacting ' -demethyl-epipodophyllotoxin of formula IV in an anhydrous organic solvent which is inert under the reaction conditions, at a temperature of -20° to ~5°C in the presence of an acid-binding agent with chloroformic acid benzyl ester, to give ^'-carbobenzoxy^ '-demethyl-epipodophyllotoxin of formula V, subsequently condensing this with 2,5,4,6-tetra-0-acetyl-3-D-glucose in the presence of boron trifluoride ethyl-etherate in an organic solvent which is inert under the reaction conditions, at a temperature below 0°C, to give tetra-O-acetyl- -carbobenzoxy-4' -demethyl-epipodo-phyllotoxin-3-D-glucoside of formula VII, and then either splitting off the carbobenzoxy radical hydrogeno-lytically and subjecting the resulting tetra-O-acetyl-V-demethyl-epipodophyllotoxin-3-D-glucoside of formula VIII to an alcoholysis in the presence of anhydrous zinc acetate, whereby V-demethyl-epipodophyllotoxin-P-D-glucoside is obtained, or first splitting off the acetyl radicals from the compound of formula VII by alcoholysis in the presence of anhydrous zinc acetate, whereby ¾' -carbobenzoxy- ' -demethyl-epipodophyllotoxin-3-D-glucoside results.

The new compounds of general formula I have a strong cytostatic effect in vitro on mastocytoma cells and fibroblast cultures. They are further characterized by a strong effect towards experimental tumors, particularly mouse leukaemia L-1210. Particularly interesting compounds include those wherein signifies a hydrogen atom and signifies a methyl or ethyl radical.

The compounds of the invention are indicated for use in therapy in the treatment of pathological processes accompanied by abnormal cell multiplication, e.g. malignant neoplasms.

An indicated suitable dose of the compounds of general formula I ranges from about 1 to 50 mg daily.

The compounds of the invention may be used as pharmaceuticals on their own or in the form of appropriate medicinal preparations for administration, e.g. orally, enterally or parenterally. In order to produce suitable medicinal preparations, the compounds are worked up with organic or inorganio, physiologically inert adjuvants. Examples of such adjuvants ares for tablets and drage"es s lactose, starch, talcum and stearic aoid for syrups s solutions of cane sugar, invert sugar and glucose i for injectable solutionss water, alcohols, glycerin and vegetable oils; for suppositories ι natural or hardened oils and waxes.

The preparations may furthermore contain suitable stabilizing, preserving and wetting agents, solubilizers, sweetening and colouring substances and flavourings.

With regard to the references to the radicals alkyl, 'alkenyl, aralkyl, aralkenyl and alkoxy in the definitions of and R^, for practical reasons the said alkyl, alkenyl and alkoxy radicals preferably have no more than 10 carbon atoms and the said aralkyl and aralkenyl radicals preferably have no more than 16 carbon atoms (excluding any carbon atom-containing substituents in the aromatic ring) .

The term "in manner known per se" as used herein designates methods in use or described in the literature on the subject.

In the following non-limitative Examples all temperatures are indicated in degrees Centigrade. The melting or decomposition points were determined on a Kofler block.

EXAMPLE 1 ^'-demethyl-epipodophyllotoxin-g-D-propylidene-glucosidg♦ 1.5 g of dry -demethyl-epipodophyllotoxin-p-D-glucoside are suspended in 25 cc of nitromethane, and 1 ce of propionaldeh de and 125 rag of _~toluenesulphonic acid are then added.' The mixture is stirred at room temperature in an atmosphere of nitrogen and in the absence of moisture for 2 hours. After this time_the initial suspension is almost clear and almost no starting material can be detected in the thin layer chromatogram (silica gel plates, eluant: chloroform + 15 % of methanol) . Working up is effected by diluting with 500 cc of chloroform and shaking out four times with 25 cc each of water. The neutral organic phase is dried over sodium sulphate and concentrated by evaporation in a vacuum.

The crude material is subsequently chromatographed on 100 g of silica gel "Merck" (grain size 0.05 to 0.2 mm), whereby chloroform containing 2 of methanol is continuously used as eluant. The fractions which are uniform in accordance with the thin layer chromatogram are recrystalllzed from 10 cc of hot methanol and yield V-demethyl-epipodophyllotoxin-3-D-propylldene-glucoside in the form of a colourless crystalline preparation having a M.P. of I78-I820, [a] = -107.2° (c - Ο.558 in chloroform).

The following Table gives a number of other hitherto unknown compounds which were synthesized in a manner analogous to that indicated in Example 2, the properties of these compounds and the starting materials used in each oase.

Produoed from 4'-demethyl- Compound epipodophyllotoxin- M.P. β-D-glucoside a n d '-demethyl-epipodophyllotoxin- n-butyraldehyde I7O-I760 β-D-buty 1idene-glucoside 4 '-demethyl-epipodophyllotoxin- isobutyraldehyde I8I-I85° β-D-isobutylidene-glucoside 4'-demethyl-epipodophyllotoxin- pivalaldehyde 162-165° β-D-pivalylidene-glucoside 4'-demethyl-epipodophyllotoxin- valeraldehyde 23 -251° β-D-pentylidene-glucoside 4'-demethyl-epipodophyllotoxin- 2-methylpentanal 143-1500 β-D- (2-methylpentylidene) -glucoside 4 ' -demethyl-epipodophyllotoxin- n-hexanal 219-2380 β-D-hex 1ldene-glucoside EXAMPLE ¾{ -demethyl-epipodophyllotoxin-β-Ρ- (2-butenylidene) - glucoslde. 1 g of dry 4'-demethyl-epipodophyllotoxin-0-D-glucoside is suspended in 20 cc of nitromethane, and 20 cc of crotonaldehyde (freshly distilled) and 2 g of Dowex ion exchange resin (type 0 WX2, dry, dry contents 27 %) are added. The reaction is effected in an atmosphere of nitrogen and in the absence of moisture at room temperature as indicated in Example 2. After 1 hour only one main spot can be detected in the thin layer chromatogram (eluant: chloroform + 6 of methanol) , and the mixture is worked up. The reaction mixture is filtered off from the ion exohange resin and this is subsequently washed well with chloroform. The filtrate is diluted with 500 cc of chloroform and shaken out 4 times with 2 cc each of water. The organic phase is filtered through sodium sulphate and is concentrated by evaporation in a vacuum, whereby a yellow oil is obtained, which is purified on 110 g of silica gel "Merck". Chloroform + 2 of methanol is continuously used as eluant. The column chromatography yields ' -demethyl-epipodophyllotoxin-3-D- (2-butenylidene) -glucoside, which is almost uniform according to the thin layer chromatogram (silica gel plates, eluant: chloroform + 6 % of methanol). The compound is re-crystallized twice from 6 cc of hot ethanol, whereby a colourless crystalline product is obtained, having a M.P. of 195-199° » [ ]^ -99.2° (c = O.813 in chloroform) .

EXAMPLE 4; 4' -demethyl-epipodophyllotoxin-3-D-hexahydro-benzylidene- glucoside. a) From 4' -demethyl-epipodophyllotoxin-3-D-glucoside. 2.0 g of 4l-demethyl-epipodophyllotoxin-0-D-glucoside are suspended in a solution of 2.0 cc of hexahydrobenzaldehyde in 30 cc stirring is effected at 20° in the absence of moisture for 1 hour, 50 mg of jo-toluenesulphonic acid are added, and stirring is effected for a further 5 hours. Dilution is subsequently effected with 250 cc of chloroform, the undissolved material is filtered off and the chloroform phase is washed with water until neutral. After drying the solution over sodium sulphate and concentrating by evaporation in a vacuum, the residue is chromatographed on silica gel. By-products and then pure 4' -demethyl-epipodophyllotoxin-3^D-hexahydrobenzylidene-glucoside are eluted with chloroform containing 2 % of methanol. The compound is obtained in the form of crystals having a M.P. of 228-231° from ethanol, [ ]^1» -98.0° (c - 1.020 in chloroform). b) From 1-carbobenzoxy- 1 -deraethyl-epipodophyllotoxin-3-D-glueoside. .6 g of 41-carbobenzoxy-41-demethyl-epipodophyllotoxin-β-D-glucoside and 5 cc of hexahydrobenzaldehyde are dissolved in 80 cc of absolute, alcohol-free chloroform while heating slightly. After cooling the solution to 20°, 25 mg of j>-toluenesulphonic acid mono-hydrate are added, and stirring is effected at 20° in an atmosphere of nitrogen for 6 hours, whereby 3 co of absolute chloroform are added after each hour and are again distilled off in a vacuum. 1 cc of hexa-hydrobenzaldehyde is subsequently added, and the mixture is allowed to react at 55° for 1 hour. 0.3 cc of absolute pyridine are then added to the reaction mixture and washing is effected 4 times with 30 cc each of water. The organic phase is dried over sodium sulphate and after concentrating by evaporation in a vacuum yields a crude product which is purified by chromatography on silica gel. By-products and then pure 41 -carbobenzoxy- 1 -demethyl-epipodophyllotoxin-3-D-hexahydrobenzylidene-glucoside are eluted with chloroform containing 2 % of methanol. The compound is obtained in the form of a colourless powder having a M.P.

The protective radical is removed by dissolving 2.75 £ of ' -carbobenzoxy-4' -demethyl-epipodophyllotoxin-3-D-hexahydrobenzylidene-glucoside in 100 cc of ethanol/acetone (2:1) , adding 0,5 g of palladium charcoal (10 % Pd) and hydrogenating at 20° at atmospheric pressure until the splitting off of the carbobenzoxy radical has been completed. The catalyst is then filtered off, is washed with 0 cc of hot acetone, and the filtrate is concentrated by evaporation in a vacuum. The residue is crystallized from acetone/ether and then from eihanol, whereby 4' -demethyl-epipodophyllotoxin-3-D-hexahydrobenzylidene-glucoside, having a M.P. of 226-230°, ia]^= -98.6° (c = 1.066 in chloroform), is obtained.

EXAMPLE 5: ' -demethyl-epipodophyllotoxln-P-D-cyclopentylmethylene- glucoside.

IO.5 g of 4'-carbobenzoxy-4'-demethyl-epipodophyllotoxin-β-D-glucoside and 7 g of cyclopentane-carboxaldehyde are dissolved in 12 cc of absolute alcohol-free chloroform while heating slightly. After cooling the solution to 20° , 40 mg of jD-toluenesulphonic acid monohydrate are added, and stirring is effected at 35° in an atmosphere of nitrogen for 6 hours, whereby 30 cc of absolute chloroform are added after each hour and are again distilled off in a vacuum. 1 g of cyclopentane-carboxaldehyde is subsequently added and the mixture is again allowed to react for 1 hour. 0.5 co of absolute pyridine are then added to the reaction mixture, and washing is effected 4 times with 30 cc each of water. The organic phase is dried over sodium sulphate and after concentrating by evaporation in a vacuum yields a crude product which is purified by chromatography on silica gel. By-products and then pure 4'-carbobenzoxy-4'-demethy 1-epipodophyllotoxin-3-D-cyclopentylmethylene-glucoside are eluted with drying in a high vacuum at 80° , the compound is obtained as a colourless powder having a M.P. of 147-148°, ία]β1= -75 -7° (o - 0.990 in chloroform) .

The protective radical is removed by dissolving 8.4 g of 4' -carbobenzoxy- ' -demethyl-epipodophyllotoxin-P-D-cyclopentylmethylene-glucoside in 150 cc of ethanol/acetone (2: 1) , adding 0. 5 g of palladium charcoal (10 Pd) and hydrogenating at 20° and atmospheric pressure. After the splitting off of the carbobenzoxy radical has been completed, the catalyst is filtered off, is washed with 50 cc of warm acetone, and the filtrate is concentrated by evaporation in a vacuum.

After crystallizing the residue twice from ethanol/ether, 4,-demethyl-epipodophyllotoxin-p-D-cyclopentylmethylene-glucoside, having a M.P. of 255-23 ° , is obtained. A crystalline form thereof, having a M.P. of 21 195-196° , [a]D o -98.9° (c = Ο.99 in chloroform), crystallizes from ethyl acetate.

EXAMPLE 6: ' -demethyl-epipodophyllotoxin-P-D-phenyl-ethylidene- glucoside . 6 g of Dowex Ion exchange resin (type 5° WX2, dry) and 1.5 cc of phenylacetaldehyde-dimethylacetal are added to a suspension of 1. 5 g of dry 4'-demethyl-epipodophyllotoxin-3-D-glucoside in 60 cc of nitromethane. The mixture is stirred at room temperature in an atmosphere of nitrogen and in the absence of moisture. After about 1 1/2 hours a clear solution results, and only traces of starting material can be detected in the thin layer chromatogram (eluant: chloroform + 6 % of methanol) . The catalyst is filtered off and the light yellow filtrate is diluted with 0.75 cc of pyridine (pH increase from -2 to 6) and 400 cc of chloroform. Shaking out is then effected thrice with 25 cc each of water. The organic phase is filtered through product is chromatographed on 80 g of silica gel "Merck", whereby a uniform material may be eluted with chloroform containing 1.5 % of methanol (thin layer chromatography on silica gel plates, eluants: a) chloroform + 6 % of methanol, b) chloroform + 30 % of acetone) .

After recrystallization from chloroform/me hanol, colourless 4' -demethyl-epipodophyllotoxin-p-D-phenyl-ethylidene-glucoside, having a M.P. of 165-170°, -82.0° (c = 0.971 in acetone), is obtained.

EXAMPLE 7» 4' -demethyl-epipodophyllotoxin-3-D-hydrocinnamylidene- glucoside. 1.5 g of dr 41 -demethyl-epipodophyllotoxin-3-D-glucoside are suspended in 30 cc of nitromethane, and subsequently 1.5 cc of . hydrocinnamaldehyde (freshly distilled) and 300 mg of £-toluene-¾ sulphonic acid are added. The mixture is stirred at room temperature in an atmosphere of nitrogen and in the absence of moisture until a clear solution results (after 30 minutes) . Working up is effected by diluting the reaction solution with 500 cc of chloroform and shaking out 4 times with 25 cc each of water. The neutral organic phase is dried over sodium sulphate and concentrated by evaporation in a vacuum. The residue is chromatographed on 100 g of silica gel "Merok". Unconverted hydrocinnamaldehyde is removed by elution with chloroform. The following fractions (with chloroform + 2 % of methanol) yield uniform hydrocinnamylidene derivative, which after recrystallization from 5 cc of hot ethanol yields pure 4' -demethyl-epipodophyllotoxin-P-D- - j hydrocinnamylidene-glucoside in the form of colourless prisms having a M.P. of 193-199°, ["k = -IO3.90 (c - O.605 in chloroform).

EXAMPLE 8; ' -demethyl-epipodophyllotoxin-P-D- (o-nitro-cinnamylidene) - glueoside. 6.0 g of o-nitrocinnamaldehyde and 6.0 g of Dowex ion exchange resin (type 5 WX2, dry) are added to a suspension of 1.5 g of dry 4,-demethyl-epipodophyllotoxin-3-D-glucoside in 75 cc of nitromethane, and stirring is effected in an atmosphere of nitrogen and in the absence of moisture. After about 2 hours a clear solution results and only small amounts of starting material are detected in the thin layer chromatogram (silica gel plates, chloroform containing 6 % of methanol as eluant) . Working up is effected by filtering off the catalyst and washing with chloroform. The combined filtrates are diluted with 400 cc of chloroform and shaken out J times with 25 cc each of water. The organic phase is dried over sodium sulphate and concentrated by evaporation. The resulting crude product is chromato-graphed on 100 g of silica gel "Merck", whereby chloroform and then chloroform + 2 of methanol is used as eluant. The fractions which are uniform in accordance with thin layer chromatography (tested on silica gel plates with chloroform + 6 # of methanol as eluant) are combined and recrystallized from 50 cc of hot methanol. 4'-demethyl-epipodo-phyllotoxin-3-D-(£-nitro-cinnamylidene)-glucoside is obtained in the form of colourless crystals having a M.P. of 244-254° , [«Ι^ -76.9° (c = Ο.639 in acetone) .

EXAMPLE 9i 4t-demethyl-epipodophyllotoxin-P-D-cinnamylidene-glucoside. cc of freshly distilled cinnamaldehyde are added to 1.5 g of dry l-demethyl-epipodophyllotoxin-3-D-glucoside) and J.O g of Dowex ion exchange powder (type ° WX2, dry) are added. The mixture is stirred at room temperature in an atmosphere of nitrogen and in the absence of moisture. After 1 hours almost no starting material plates and chloroform + 1 % of methanol as eluant) . After filtering off the catalyst and washing with chloroform, the concentrated filtrate is purified by column chromatography on 100 g of silica gel "Merck". Unconverted cinnamaldehyde is eluted with chloroform and the remaining substance with chloroform + 2 of methanol. A material which is uniform in accordance with thin layer chromatography is obtained. After recrystallization from 20 cc of ethanol, 4l-demethyl-epipodophyllotoxin-p-D-cinnaraylidene-glucoside, having a M.P. of 239-246° , [«-β1» -86.1° (c - Ο.56 in acetone), is obtained.

EXAMPLE 10: ' -demethyl-epipodophyllotoxin-P-D- (p-fluorobenzylidene) - glucoside . Ο.25 g of anhydrous zinc chloride are added to a solut^pn of 0.5 g of dry 1-deraethyl-eplpodophyllotoxin-3-D-glucoside in 10 cc of £-fluorobenzaldehyde, and shaking is effected at room temperature in an atmosphere of nitrogen and in the absence of moisture for 5 to 4 hours. After about 3 hours only traces of unconverted glucoside can be detected in the thin layer chromatogram (silica gel plates, eluant: chloroform + 6 of methanol) . Working up is effected by diluting the reaction solution with 30 cc of chloroform and shaking out thrice with 10 cc each of water. The chloroform phase is dried over sodium sulphate and concentrated by evaporation in a vacuum. The resulting oily residue is added dropwise while stirring to 1 0 cc of pentane, whereby a flaky precipitate results. When the crude product separates in greasy form, it is dissolved in a small quantity of acetone and again precipitated by adding the solution dropwise to 1 0 cc of fresh pentane. The crude condensation product is purified by chromatography on 100 g of silica gel "Merck" (grain size 0.05 to 0.2 ram). The primary fractions which are eluted with chloroform + 2 of methanol yield uniform 4'-demethyl- epipodophyllotoxin^-D- (j5-fluorobenzylidene) -glucoside. Colourless crystals, having a M.P. of 265-27Ο0, [a]D = -IO50 (c - O.509 in chloroform) .

EXAMPLE 11: ' -demethyl-epipodophyllotoxin-P-D-salicylidene-glucoside . co of pure salicylaldehyde are added to 1. 5 g of dry t-demethyl-epipodophyllotoxin-3-D-glucoside, and 3 ·0 g of Dowex ion exchange powder (type 0 WX2, dried at 120° in a high vacuum for 3 hours) are added. The air in the flask is removed with nitrogen and the reaction mixture is stirred at room temperature in the absence of moisture. The course of the condensation reaction is controlled by thin layer chromatography on silica gel plates with chloroform + 15 $ of methanol as eluant.

After hours the catalyst is filtered off and rewashed with chloroform. The concentrated filtrate is purified on 100 g of silica gel "Merck" (grain size 0.02 to 0.2 mm). After separating the salicylaldehyde (chloroform extract) , the compound is eluted with chloroform + 5 # of methanol. A material which is uniform in accordance with thin layer chromatography is obtained. For purposes of analysis the compound is dissolved In 5 co of acetone and this solution is added dropwise while stirring to 100 co of pentane. 1-demethyl-epipodophyllotoxin-3-D-sallcylidene-glucoside is obtained in the form of a colourless amorphous powder, having a M.P. of PO 182-188° , [a] = -103.7° (c = Ο.663 in chloroform).

The following Table gives a number of other hitherto unknown compounds which were synthesized in a manner analogous to that indicated in Example 11, the properties of these compounds and the starting materials used in each case.

Produced from 1 -demethyl- Compound epipodophyllotoxin- β-D-glucoside an d '-demethyl-epipodophyllotoxin- m-methoxybenzaldehyde 2 β-D-(m-methoxy-benzylidene)-glucoside '-demethyl-epipodophyllotoxin-. o-chlorobenzaldehyde 1 β-D- (o-chloro-benzylidene) -glucoside '-demethyl-epipodophyllotoxin- m-chlorobenzaldehyde 1 0-D- (m-chloro-benzylidene) -glucoside EXAMPLE 12t 4'-demethyl-epipodophyllotoxin-3-D- (o-methoxy-benzylidene)- glucoside. 9 g of o-raethoxybenzaldehyde are dissolved in 60 cc of nitromethane. 1.5 g of dry 1-demethyl-epipodophyllotoxin-3-D^ glucoside and 150 mg of jo-toluenesulphonic acid are subsequently added. The gray-yellow suspension is stirred at room temperature in an atmosphere of nitrogen and in the absence of moisture. The course of the condensation reaction is controlled by thin layer chromatography [system a) chloroform + 6 of methanol, b) chloroformmethanol/water (70:25:5)]. After hours only a small quantity of starting material is present, aside from the aldehyde condensation product and an impurity which runs somewhat slower. Working up is effected by diluting the reaction mixture with 500 cc of chloroform and shaking out 4 times with 25 cc each of water. The organic phase is filtered through sodium sulphate and concentrated by evaporation in a vacuum. An oily brown-yellow material is obtained, which is purified on 120 g of silica gel "Merck". After separating the aldehyde (chloroform extract), the remaining substance is eluted with chloroform containing 2 % of methanol. This chromatography yields the o-methoxy-benzylidene derivative which is completely uniform in accordance with thin layer chromatography. Recrystallization from 13 cc of hot alcohol yields colourless crystals having a M.P. of 23-20°, [α]β « -74.4° (c = 0.884 in acetone) .

EXAMPLE 13: 4'-demethyl-epipodophyllotoxin-P-D- (p-hydroxy-benzylidene)- glucoside. 12 g of £-hydroxybenzaldehyde, 4 g of Dowex Ion exchange resin (type 0 WX2, dry weight 26.4 ) and 100 cc of nitromethane are added to 2 g of dry 4'-deraethyl-epipodophyllotoxin-3-D-glucoside. The nitrogen and in the absence of moisture, and the course of the condensation reaction is controlled by thi layer chromatography (silica gel plates, chloroform + 1 of methanol as eluant) . After about 3 hours the reaction has not yet been entirely completed. Working up is effected by filtering the suspension and washing out the filter residue thrice with chloroform. The combined filtrates are then diluted with 3OO cc of chloroform and shaken out thrice with 25 cc each of water. After drying over sodium sulphate and concentrating.by evaporation, the organic phase yields a light yellow coloured residue which is chromato-graphed on 80 g of silica gel for purification. The excess aldehyde is first removed by elution with chloroform and chloroform + 2.5 $> of methanol. The later eluates obtained with chloroform containing 4 of methanol contain the condensation product which is uniform in accordance with thin layer chromatography. The crude compound is dissolved in 4 cc of acetone and is added dropwise while stirring to 70 cc of pentane, whereby 4'-demethyl-epipodophyllotoxin-3-D-(_-hydroxy-benzylidene)-glucoside precipitates as a colourless amorphous powder having a M.P. of 196-201° , ia]^~ -96.2° (c = O.98I in methanol) .

EXAMPLE 14; ' -demethyl-epipodophyllotoxin-β-Ρ-(o-methyl-benzylidene)- glucoside. 1.5 g of dry 4'-demethyl-epipodophyllotoxin-3-D-glucoside are -suspended in 30 cc of nitromethane, and 9 co of o-toluylaldehyde and 150 mg of p_-toluenesulphonic acid are added. The mixture is stirred at room temperature in the absence of air and moisture. After 2 hours a clear solution results, and the starting material has almost disappeared in the thin layer chromatogram (eluant: chloroform + 15 # of methanol) . Working up is effected by diluting the reaction solution 2 cc each of water. The organic phase is dried over sodium sulphate and concentrated by evaporation. The residue is poured onto a column of 70 g of silica gel "Merck". Unconverted o-toluylaldehyde is separated by elution with chloroform. The following fractions (with chloroform + 2 of methanol) yield the £-methyl-benzylidene derivative which is uniform in accordance with thin layer chromatography. For purposes of analysis the oompound is dissolved in 3 cc of acetone and this solution is added dropwise while stirring to 300 cc of pentane. 1 -demethyl-epipodophyllotoxin-3-D- (o-methyl-benzylidene) -glucoside is obtained as a colourless amorphous powder having a M.P. of 17 -l80°, [α]^1" -94.7° (c = 0.730 in chloroform).

EXAMPLE 15: ' -demethyl-epipodophyllotoxin-p-D-(m-hydroxy-benzylidene) - glucoside. 1.5 g of dry V-demethyl-epipodophyllotoxin^-D-glucoside and subsequently 150 mg of £-toluenesulphonic acid are added to a solution of 9 g of m-hydroxybenzaldehyde in 75 cc of nitromethane. The yellowish suspension is stirred in an atmosphere of nitrogen and in the absence of moisture for 5 hours, whereby a clear solution results.

Working up is effected by diluting the reaction solution with 500 cc of chloroform and shaking out 5 times with 2 cc each of water. The organic phase is filtered through sodium sulphate and concentrated by evaporation in a vacuum. A light yellow powdery substance is obtained, which is chromatographed on 110 g of silica gel "Merck". After separating the aldehyde with chloroform + 3 % of methanol, the remaining substance is eluted with chloroform + 6 of methanol. The fractions which are uniform in accordance with thin layer chromatography are dissolved in acetone, are subsequently concentrated in a vacuum to about 7 cc, and 20 cc of ether are added. 1 -demethyl-epipodophyllo- a colourless amorphous powder having a M.P. of 189-194° , [a]^1-* -99.9° (c = Ο.766 in methanol).

EXAMPLE 16: ' -demethyl-e ipodophyllotoxin-β-Ρ- (m-nitro-benzylidene) - glucoside . g of m-nitrobenzaldehyde are dissolved in 5 cc of nitromethane and 1.5 g of dry 4l-demethyl-epipodophyllotoxin^-D-glucoside and 6 g of Dowex ion exchange resin (type 0 WX2, dry) are subsequently added. The mixture is stirred at room temperature in an atmosphere of nitrogen and in the absence of moisture. After 1 hour only a small amount of starting material is present in the thin layer chromatogram (eluant: chloroform + 6 of methanol) . Working up is effected by filtering off the catalyst and washing the filtrate with chloroform. The dark-coloured filtrate is diluted with 400 cc of chloroform and shaken out thrice with 2 cc each of water. The chloroform phase is dried over sodium sulphate and concentrated by evaporation A liquid is obtained which gradually crystallizes. The crude material is dissolved in 30 cc of chloroform and chromatographed on 120 g of silica gel "Merck". After separating the aldehyde (chloroform extract), the remaining substance is eluted with chloroform + 2 # of methanol. This chromatographic purification yields a material which is uniform in accordance with thin layer chromatography. For purposes of analysis the compound is dissolved in 20 cc of acetone and this solution is added dropwise to 100 cc of pentane. A light yellow amorphous powder, having a M.P. of I78-I850 , -α1β1= -77.5° (c = O.83I in acetone), is obtained.

EXAMPLE 17: 4* -demethyl-epipodophyllotoxin-fi-D- (p-methyl-benzylidene) - glucoside. 1.5 g of 4,-demethyl-epipodophyllotoxin-3-D-glucoside are suspended in 30 cc of nitromethane, 9 cc of js-toluylaldehyde and 75 mg temperature in the absence of oxygen and moisture. After about 4 minutes the reaction mixture is diluted with 450 cc of chloroform and shaken out thrice with 2 cc each of water. The organic phase is dried over sodium sulphate and the solvent is evaporated in a vacuum. The resulting yellow oil is chromatographed on 80 g of silica gel "Merck" for purification. After separating the excess aldehyde with chloroform as eluant, elution with chloroform + I.5 of methanol yields fractions of the condensation produot which are uniform in accordance with thin layer chromatography (tested on silica gel plates with chloroform + 6 of methanol as eluant) . Recrystallization of the primary fractions from chloroform/methanol (1:1) and from pure methanol yields pure ' -demethyl-epipodophyllotoxin-3-D- (p_-methyl-benzylidene) -glucoside having a M.P. of 248-265°, [a]^5= -166.8° (c « O.791 in pyridine) .

EXAMPLE l8; ' -demethyl-epipodophyllotoxin-3-D- (p-lsopropyl-benzylidene) -glucoside. Ο.75Ο g of dry zinc chloride are added to a solution of 1.5 g of dry 4'-demethyl-epipodophyllotoxin-3-D-glucoside in 30 cc of cuminaldehyde , and stirring is subsequently effected in an atmosphere of nitrogen and in the absence of moisture. After about 2 1/2 hours only a small quantity of free glucoside is detected in the thin layer chromatogram (silica gel plates, eluant: chloroform + 6 of methanol) . Working up is effected by taking up the yellowish suspension in 200 cc of chloroform, adding 1 0 cc of water and shaking thoroughly. The aqueous phase is separated and again extraoted twice with 40 cc each of chloroform. All the chloroform phases are combined, washed thrice with 30 cc each of water, dried over sodium sulphate and then concentrated by evaporation. The residue, an orange-red oil, is be removed by elution'with chloroform. The condensation product is separated from the column with chloroform + 2 of methanol. The fractions which are uniform in accordance with thin layer chromatography are dissolved in 2 cc of methanol and are stirred at room temperature with 700 mg of active charcoal (Merck p.a.) for 10 minutes. The solution is filtered through talcum, concentrated by evaporation in a vacuum, and the residue is taken up in 5 oo of acetone. This solution is added dropwise to 75 cc °f pentane, whereby 1-demethyl-epipodo-'·' benzylidene) -glucoside . 50 g of vanillin and 6 g of Dowex ion exchange resin (type 50 WX2, dry) are added to a suspension of 1.5 g of dry V-demethyl-epipodophyllotoxin-P-D-glucoside in 30 cc of nitromethane and the reaction mixture is shaken in an atmosphere of nitrogen and in the absence of moisture. After about 1 l/2 hours the catalyst is filtered off, the filtrate is diluted with 500 cc of chloroform and shaken out thrice with 2 cc each of water. The organic phase is dried over sodium sulphate and the solvent is subsequently evaporated in a vacuum. For purification the residue is chromatographed on 100 g of silica gel "Merck", whereby chloroform + % of methanol is used as eluant. The fractions which are uniform in accordance with thi layer chromatography (silica gel plates, chloroform + 15 # of methanol as eluant) are combined and recrystallized from 15 cc of hot methanol. 1 -demethyl-epipodophyllotoxin-3-D- (4-hydroxy-3-methoxy-benzylidene)-glucoside is obtained in the form of a colourless crystalline material - 26 - ^ 2580 EXAMPLE 20; ' -demethyl-epipodophyllotoxin-p-D- (2 , 3-dimethoxy- benzylldene) -glucoside.

I5.O g of 2,3-dimethoxy-benzaldehyde and 6.0 g of dried ion exchange resin (Dowex, type 5° WX2, dry) are added to a suspension of 1.5 g of l-demethyl-epipodophyllotoxin-3-D-glucoside in 30 cc of nitromethane. After shaking the reaction mixture in an atmosphere of nitrogen in the absence of moisture for 1 hour, a conversion of about 85 % can be ascertained in accordance with thin layer chromatography ί [thin layer chromatogram control: silica gel plates and chloroform methanol/water (70:25: 5) as eluant] . Working up is effected by filtering off the catalyst and washing out the filter residue with chloroform. The combined filtrates are diluted with 400 cc of chloroform and shaken out thrice with 2 cc each of water. After drying over sodium sulphate the organic phase is concentrated by evaporation. The residue is chromatographed on 100 g of silica gel "Merck", whereby chloroform + 2 of methanol is used as eluant. The combined primary fractions, a uniform material in accordance with thin layer chromatography, are taken up in 10 cc of acetone, and this solution is added dropwise to 100 cc of pentane, whereby amorphous 4' -demethyl-epipodo-phyllotoxin-β-ϋ- (2, 3-dimethoxy-benzylidene) -glucoside precipitates.

M.P. 174-177° [α1ο5= -86.1° (c = O.803 in chloroform).

EXAMPLE 21: 4 ' -demethyl-epipodophyllotoxin-g-D- (2-ethoxy-3-methoxy- benzylidene) -glucoside. 0.750 g of dry zinc chloride are added to a suspension of 1.5 g of 4' -demethyl-epipodophyllotoxin-3-D-glucoside in 30 cc of 2-ethoxy-3-methoxy-benzaldehyde, and the mixture is stirred in an atmosphere of nitrogen and in the absence of moisture. After about 2 1/2 hours only a small amount of unconverted glucoside can be - 27 - ~ϊ 2580 chloroform + 6 % of methanol) . Working up is effected by adding 100 cc of chloroform and 100 cc of water to the suspension and shaking thoroughly. The aqueous phase is subsequently extracted twice more with cc each of chloroform. All the chloroform phases are combined, sodium filtered over/sulphate and subsequently concentrated by evaporation.

The residue, a yellow-orange solution, is chromatographed on 75 g of silica gel "Merck". After eluting the excess aldehyde with chloroform, the condensation product may be removed from the column with chloroform + 2 % of methanol. The fractions which are uniform in accordance with, thin layer chromatography are combined, dissolved in 2 cc of methanol and stirred at room temperature with a small amount of active charcoal : for 10 minutes. After filtering over talcum until clear the light yellow solution is concentrated by evaporation. The resulting yellowish foam is taken up in of acetone and this solution is added . dropwise while stirring to 100 cc of pentane, whereby a flaky precipitate results. After filtering and drying V-demethyl-epipodophyllotoxin^-D- (2~ethoxy-3-methoxy-benzylidene)-glucoside is obtained as a colourless 22 powder having a M.P. of 166-175°, [<¾ = -83.2° (c - Ο.863 in chloroform.

EXAMPLE 22; 1 -demethyl-epipodophyllotoxln- -D-anisylidene-glucoside. cc of anisaldehyde and Ο.25 g of anhydrous zinc chloride are added to 0.5 g of dry V-demethyl-epipodophyllotoxin-0-D-glucoside and the reaction mixture is shaken in an atmosphere of nitrogen at room temperature. After a reaction period of about 6 hours only traces of the starting material can be detected in the thin layer chromatogram (silica gel plates, eluant: chloroform + 6 of methanol). The reaction solution is diluted with 30 cc of chloroform and washed several times with water. The chloroform phase is dried over sodium sulphate and con is taken up in 5 cc of acetone and this solution is added dropwise while stirring to 200 cc of pentane, whereby the crude condensation product separates as a flaky precipitate. For purification chromatography is effected on 100 g of silica gel (grain size 0.05 to 0.2 mm) . The primary fractions which are eluted with chloroform + 2 of methanol are combined and recrystallized from absolute alcohol. 4f-demethyl-epipodophyllotoxin-3-D-anisylidene-glucoside is obtained as a colour,- 20 less crystalline material having a M.P. of 28-250° , [a]^ = -92. 5° ; (c = O.503 in chloroform).

EXAMPLE 23 : 4' -demethyl-epipodophyllotoxin^-D-isopropylidene-glucoside. 3.0 g of anhydrous zinc chloride are added to a mixture of 1.5 g of dry l-demethyl-epipodophyllotoxin-3-D-glucoside in 75 cc of acetone, and stirring is effected in an atmosphere of nitrogen and in the absence of moisture. The course of the condensation reaction is controlled by thin layer chromatography (silica gel plates, eluant: chloroform methanol/water (70: 25s ) and/or chloroform + 6 of methanol). After stirring for about 90 minutes the clear reaction solution is added dropwise to 500 cc of ice-cold chloroform, and the resulting precipitate is filtered off. The filtrate is washed with water until neutral, is dried over sodium sulphate and concentrated by evaporation. The residue is chromatographed on 100 g of silica gel (Merck, grain size 0.05-0.2 mm), whereby chloroform + 5 % of methanol is used as eluant. The uniform primary fractions are combined, taken up in 10 cc of acetone, and this solution is added dropwise while stirring to 100 cc of n-pentane, whereby 4'-demethyl-epipodophyllotoxin-3-D-isopropylidene-glucoside is obtained in the form of colourless flakes. After filtering off and drying an amorphous colourless powder having a M.P. of 173-176° is obtained, [a] -106.3° (0 = Ο.938 in chloroform) .

EXAMPLE 24; ' -demethyl-epipodophyllotoxln-p-D-cyclopentylldene- glucoside . g of Dowex 5° WX2 ion exchange powder (dried in a high vacuum for 3 hours, dry content 27 ) are added to a mixture of 2 g of dry 4l-demethyl-epipodophyllotoxin- -D-glucoside in 40 cc of cyclo-pentanone, and the mixture is stirred at room temperature in an atmosphere of nitrogen and in the absence of moisture. The course of the condensation reaction is controlled by thin layer chromatography (silica gel plates, eluant: chloroform + 15 of methanol). After , about 2 hours the catalyst is filtered off. The filtrate is diluted with 500 00 of chloroform and is then washed several times with water. The organic phase is dried over sodium sulphate and concentrated by evaporation. The resulting residue is chromatographed on 120 g of silica gel (Merck, grain size 0.05 to 0.2 mm), whereby chloroform + 4 of methanol is used as eluant. Primary fractions are obtained which, however, are not yet completely uniform. To obtain a pure compound chromatography is again effected on 80 g of silica gel, whereby chloroform + 30 # of acetone is used as eluant. The fractions which are uniform in accordance with thin layer chromatography are combined and recrystallized from ethanol/ether. Pure 41 -demethyl-epipodophyllo-toxin- -D-cyclopentylidene-glucoside having a M.P. of I76-I820 , [a] = -IO5.80 (c = Ο.834 in chloroform), is obtained.

EXAMPLE 25: ' -demethyl-epipodophyllotoxin-g-D-cyclohexylidene- glucoside. cc of cyclohexanone and 0.5 g of anhydrous zinc chloride are added to 1 g of dry 4'-demethyl-epipodophyllotoxin- -D-glucoside, and the mixture is shaken at room temperature in an atmosphere of nitrogen and in the absence of moisture. The course of (silica gel plates, eluant: chloroform + 6 % of methanol). After 2 1/2 hours the clear reaction solution is diluted with 60 cc of chloroform and is shaken out several times with water. The organic phase is dried over sodium sulphate and concentrated by evaporation in a vacuum. The resulting residue is chromatographed on 100 g of silica gel (Merck, grain size 0.05 to 0.2 mm), whereby chloroform + 2 % of methanol is used as eluant. The uniform primary fractions are combined and are recrystallized from absolute alcohol. 4'-demethyl-r epipodophyllotoxin-3-D-cyclohexylidene-glucoside is obtained in the form of colourless crystals having a M.P. of I88-I900 , [a]^ = -IO3.O0 (c = O.515 in chloroform).

The starting material ' -demethyl-epipodophyllotoxin-β-D-glucoside used for the production of the new compounds of general formula I is produced in accordance with the process described in the following sections A, B, C, D, E and F.

A) 41 -d^m^th^l-epi£dophjl 1oto ^n^ 2 g of 4'-demethyl-podophyllotoxin are dissolved in 25 cc of acetone and 15 cc of water, and after the addition of 5 cc of concentrated hydrochloric acid heating is effected at reflux for two hours. The acid is subsequently neutralized with solid barium carbonate filtration is effected and the acetone, is removed from the filtrate in a vacuum at 40° . The precipitated material is taken up in chloroform + 5 3> °f acetone, the solution is dried over sodium sulphate and concentrated by evaporation in a vacuum. The resulting residue is chromato graphed on silica gel with chloroform + 1 % of methanol, whereby small quantities of impurities are first obtained, then pure 4'-demethyl-epipodophyllotoxin and finally unconverted starting material. The pure - jl - 2580 B) '^carbobenzoxv- 1^d^methjl-ep^podophy^lotoxin^ 60 g of very finely pulverized 4' -demethyl-epipodophyllo-toxin are suspended in 1000 cc of anhydrous ethylene chloride, and after the addition of 19 cc of absolute pyridine cooling is effected to -10° . A solution of 34 g of chloroformic acid benzyl ester in 100 cc of ethylene chloride is added dropwise at rlO° while stirring and crude product from acetone/ether and then twice from methanol yields 4'1 -carbobenzoxy- ' -demethyl-epipodophyllotoxin having a double M. P. of 117-119°/202-2050. The solvent-free form, having a .P. of 201-204°, 21 [a]D = -43·9° (c = Ο.535 in chloroform), is obtained by drying in a high vacuum, first at 95-110° and then at 130°, or by crystallization from acetone/ether.

C) Tetra-O-acet^lj^^-^ar obe^^ £-D- lucosi.de . 26.8 g of 4' -carbobenzoxy-4' -demethyl-epipodophyllotoxin are dissolved in 70 cc of ethylene chloride while heating. The solution is cooled to +1°, and 26.0 g of 2,3»4>6-tetra-0-acetyl- -D-glucose are added while stirring. As soon as the mayor portion of tetraacetyl-β-D-glucose is dissolved, cooling is rapidly effected to -11° to -12° in the absence of moisture. Notwithstanding the presence of small amounts of undissolved starting materials, 17· 5 cc of boron trifluoride ethyl-etherate (48 BF^) which has been previously cooled to -10° , are then added dropwise at an internal temperature of -10 to -12° - 52 - 258O at -10° for a further 40 minutes. A mixture of 17.5 cc of absolute pyridine and 55 °c °f ethylene chloride is then added dropwise while stirring and cooling, and after the addition of a further 200 cc of ethylene chloride shaking out is effected 4 times with 100 cc each of water. The organic phase is dried over sodium sulphate, concentrated by evaporation in a vacuum, and the residue is dried in a high vacuum at 70° . The crude product is dissolved in 125 cc °f hot ethanol, 27 cc of water are added while stirring, and the mixture is stirred while cooling externally with ice water until the initially viscous and lumpy precipitate is converted into a sandy powder. The precipitate is then filtered with suction, is washed with a mixture of ethanol/water (1: 5) and dried in a high vacuum at 70° . This crude product is dissolved in J00 cc of hot methanol, a small amount of undissolved flakes is filtered off, and the filtrate is concentrated by evaporation in a vacuum. After drying the residue in a high vacuum at 70° , tetra-O-acetyl- ' -carbobenzoxy-4' -demethyl-epipodophyllotoxin- P-D-glucoside is obtained in the form of a white foam. [a]D = -41.7° (chloroform). For further purification crystallization is effected from a mixture of benzene/pentane or benzene/cyclohexane . Pure tetra-O-acetyl-4' -carbobenzoxy- 4'-demethyl-epipodophyllotoxin- -D-glucoside has a M.P. of I67-I690, [α]β = -46.6° (chloroform).

D) Tetra-0-acet 4J_-deme h^l^ejaipodo h^llotoxin-0-D-£lucoside .

The carbobenzoxy radical is split off from tetra-0-acetyl-41 -carbobenzoxy-4' -demethyl-epipodophyllotoxin-0-D-glucoside by dissolving 15.4 g of this compound in 100 cc of acetone/ethanol (1: 2) , adding 0.5 cc of glacial acetic acid and 2 g of palladium charcoal (with 10 % of Pd) , and hydrogenating at 20° . The catalyst is acetone/raethanol, and the filtrate is concentrated by evaporation in a vacuum. 100 cc of boiling ethanol are poured over the residue, this is allowed to crystallize, and after filtering with suction and washing with methanol the crystals are dried in a vacuum. Pure tetra-O-acetyl-V-demethyl-epipodophyllotoxin-p-D-glucoside crystallizes in fine needles having a .P. of 225-227°, [ 1β1= -64.4° (c = 1.024 in chloroform) .

E) 4 ' -d^meth^l^-^^ d£h^].l£toxi^n^^D^^u^os^ide^ 2.0 g of the tetra-0-acetyl-4'-demethyl-epipodophyllotoxin-β-D-glucoside obtained in accordance with section D) and 1 g of anhydrous zinc acetate are heated at reflux in 30 cc of absolute methanol for 25 hours. The resulting white precipitate is subsequently dissolved by the addition of a few cc of glacial acetic acid and slight heating, the solvent is removed in a vacuum at 40°, and the residue is taken up in 50 cc of chloroform/butanol (4: 1) . The organic phase is washed twice with 10 cc each of water. After drying over sodium sulphate concentration is effected by evaporation in a vacuum and the residue is chromatographed on silica gel. Nonpolar portions are first eluted and then pure 4'-demethyl-epipodophyllotoxin-P-D-glucoside is eluted with isopropylacetate/methanol (9: 1) , saturated with water. The individual fractions are examined in the thin layer chromatogram on silica gel plates with isopropylacetate/methanol (4:1) as eluant, saturated with water* and the glucoside fractions are combined and crystallized twice from methanol. 4'-demethyl-epipodophyllotoxin-e-D-glucoside has a M.P. of 222-230° , another crystalline form thereof has a M.P. of 262-264° , -88° (c = O.507 in methanol). c - 34 - 2580 F) 4 '^earbobenzox^-4 '^deme;thyl.-epjLpodoph l g of pure tetra-0-acetyl-4,-carbobenzoxy-4'-demethyl-epipodophyllotoxin-3-D-glucoside, 3.6 g of anhydrous zinc acetate and I.45 g of anhydrous sodium acetate are heated at reflux while stirring in I50 cc of methanol. After 2 and 4 hours 12.5 cc of methanol are distilled off each time. 12.'5 cc of methanol are then added every two hours and again distilled off. After a total of l8 hours the splitting off of the acetyl radicals is completed, and a mixture of about 60 % of l-carboberizoxy-4,-demethyl-epipodophyllotoxin-3-D-glucoside and about 40 % of 4,-demethyl-epipodophyllotoxin-P-D-glucoside is obtained The reaction is controlled by thin layer chromatography on silica gel plates with isopropylacetate/methanol (4:1) saturated with water; development is effected by spraying with a 0.2 solution of cerium- (IV) sulphate in 50 % of sulphuric acid and heating to IIO-I3O0 Working up is effected by adding 5 cc of glacial acetic acid, concentrating in a vacuum at a bath temperature of 50° and drying in a high vacuum at 50° during 15 minutes. The residue is taken up in 250 cc of chloroform/isopropanol (4:1) and 25 cc of water. The aqueous phase is separated and the organic phase is again washed with 25 cc of water. The two water washings are again extracted with 50 cc of chloroform/isopropanol, and after drying over sodium sulphate the combined organic phases are concentrated by evaporation in a vacuum. The residue is then suspended in 30 cc of acetone, the suspension is shaken thoroughly and the acetone then removed in a vacuum. This process is repeated twice more. The residue is then dried in a high vacuum at 75° - 55 - 2580 during 2 hours. -carbobenzoxy-4' -demethyl-epipodophyllotoxin-fi-D-glucoside may be obtained in a not entirely pure form from the mixture of 41 -carbobenzoxy-41 -demethyl-epipodophyllotoxin-P-D-glucoside and 4'-demethyl-epipodophyllotoxin-0-D-glucoside by crystallization from methanol. Chromatography on a 100-fold quantity of silica gel and elution with isopropylacetate/methanol (9s l) * saturated with water, yield pure 4'-carbobenzoxy-4'-demethyl-epipodophyllotoxin-β-D-glucoside which has a M.P. of I 5-I560 after crystallization 21 from acetone. [a] = -92.0° (c = 1.00 in chloroform).

Claims (43)

-36 - 258Ο HAVING £JOW particularly described and ascertained the nature of our said invention and in what manner the same is to- be performed, we declare that what we claim is:

1. A method for the preparation of compounds of general formula I, in which R^ signifies a hydrogen atom, and Rg signifies an alkyl or .alkenyl radical, or a cycloalkyl radical of 5 or 6 ring carbon atoms, or an aralkyl or aralkenyl radical wherein the aromatic ring may optionally be substituted, preferably by one or more hydroxy, alkyl, alkoxy, nitro or halogen radicals, or an aryl radical substituted by, preferably, one or more hydroxy, alkyl, alkoxy, nitro or halogen radicals, or each of R1 and Rg signifies an alkyl radical, or Ji^ and Rg,together with the carbon atom to which they are attached, signify a saturated oycloaliphatio ring having 5 or 6 ring carbon atoms, characterized in that a 4' -demethyl-epipodophyllotoxin-3-D-glucoside of general formula II, In which signifies a hydrogen atom or a oarbobenzoxy radical. Is reacted with a compound of general formula III, in which and Rg have the above significance, or with a lower acetal or ketal thereof, in the presence of an acid, preferably a Lewis or sulph'onic acid, catalyst, and any oarbobenzoxy radical which may be present is subsequently split off.

2. A method according to Claim 1, wherein the reaction is carried out in the absence of moisture and using a dry solvent which is inert under the reaction conditions.

3. A method according to Claim 1 or 2, wherein the reaction is carried out in the absence of oxygen. V- - 58 - 2580

4. A method according to any one of Claims 1 to 3, wherein there is used as catalyst anhydrous zinc chloride, £-toluenesulphonic acid or a dried cation exchange resin having sulphonic acid radicals in the H+ form.

5· A method according to any one of Claims 1 to 4, wherein there is used a catalyst having water-binding properties.

6. A method according to any one of Claims 1 to 4, wherein reaction water or resulting lower alcohol is removed by azeotropic distillation in a vacuum at 20° to 30°C.

7. A method according to Claim 1, substantially as described in any one of the foregoing specific Examples.

8. Compounds of formula I, as defined in Claim 1, whenever obtained by a method claimed in any one of Claims 1 to 7·

9. Compounds of formula I, as defined in Claim 1.

10. '-demethyl-epipodophyllotoxin-0-D-ethylidene-glucoside.

11. 4l-demethyl-epipodophyllotoxin-3-D-propylidene-glucoside.

1 . 4' -demethyl-epipodophyllotoxin-p-D-butylidene-glucoside .

13. 41 -demethyl-epipodophyllotoxin-3-D-isobutylidene-glucosid

14. 4t-demethyl-epipodophyllotoxin-P-D-pivalylidene-glucoside

15. 4'-demethyl-epipodophyllotoxin-3-D-pentylidene-glucoside.

16. 4' -demethyl-epipodophyllotoxin-3-D- (2-methylpentylidene) -glucoside.

17. 4'-demethyl-epipodophyllotoxin^-D-hexylidene-glucoside. 39 - " 2580

18. 4'-demethyl-epipodophyllotoxin-0-D- (2-butenylidene)-glucoside.

1 . 4'-demethyl-epipodophyllotoxin-0-D-hexahydro-benzylidene-glucoside.

20. 4' -demethyl-epipodophyllotoxin-0-D-cyclopentylmethylene-glucoside.

21. 4'-demethyl-epipodophyllotoxin-0-D-phenyl-ethylidene-glucoside .

22. 1 -demethyl-epipodophyllotoxin-0-D-hydrocinnamylidene-glucoside.

23. 41 -demethyl-epipodophyllotoxin-0-D- (o-nitro-cinnamylidene) -glucoside .

24. 41 -demethyl-epipodophyllotoxin-3-D-cinnamylidene-glucoside .

25. 4' -demethyl-epipodophyllotoxin-β-D- p_-fluorobenzylidene) -glucoside .

26. 41 -demethyl-epipodophyllotoxin- -D-salicylidene-glucoside .

27. 41 -deraethyl-epipodophyllotoxin-P-D- (m-methoxy-benzylidene)-glucoside .

28. 41 -demethyl-epipodophyllotoxin-P-D- (o-chloro-benzylidene) -glucoside .

29. ' -demethyl-epipodophyllotoxin-0-D- (m-chloro-benzylidene) -glucoside.

30. 4' -demethyl-epipodophyllotoxin-0-D- (o-methoxy-benzylidene)-glucoside . - 40 -

51. -demethyl-epipodophyllotoxin-3-D- (j>-hydroxy-benzylidene) -glucoside.

32. 4'-<demethyl-epipodophyllotoxin-3-D- (o-methyl-benzylidene) -glucoside.

33. V-demethyl-epipodophyllotoxin-3-D- (m-hydroxy-benzylidene) -glucoside.

34. 4'-,demethy1-epipodophyllotoxin-rl -D-(m-nitro-benzylideng) -glucoside .

35. glucoside.

36. -demethyl-epipodophyllotoxin-3-D- _-isopropyl- , benzylidene) -glucoside.

37. 41-demethyl-epipodophyllotoxin-0-D-(4-hydroxy-3-methoxy-benzylidene) -glucoside.

38. 4' -demethyl-epipodophyllotoxin-0-D- (2,3-dimethoxy-benzylidene) -glucoside.

39. 41 -demethyl-epipodophyllotoxin-0-D- (2-ethoxy-3-methoxy-benzylidene) -glucoside .

40. 4' -demethyl-epipodophyllotoxin-p-D-anisylidene-glucoside .

41. 41 -demethyl-epipodophyllotoxin-3-D-isopropylidene-glucoside .

42. 4' -demethyl-epipodophyllotoxin-P-D-cyclopentylidene-glucoside.

43. 41 -demethyl-epipodophyllotoxin-3-D-cyolohexylidene-glucoside. 45* A pharmaceutical composition which comprises a compound claimed in any one of Claims 8 to 42 in association with an inert, physiologically acceptable carrier or dilvent. 44» A pharmaceutical composition according to Claim 43, wherein the amount of said compound is suitable for the ad-ministration of a daily dose of 5 to 50omg. 45· A pharmaceutical composition according to Claim 43» substantially as hereinbe ore <teescribed.