IE53750B1 - Anthracycline glycosides - Google Patents

Abstract

The anthracycline glycosides I (X = H or OH, R1 = H or CH3, R2 = H or OCH3, R3 = H or OCH3, R2 = R3) and their pharmaceutically acceptable acid addition salts have antitumour properties. They are prepared from 4-demothoxy-daunomycinone or 2,3-dimethyl-4-methoxy-daunomycinone by condensation with an appropriate N-protected hexopyranosyl chloride and removal of the protecting group and, in the case X = OH, conversion of the 9-acetyl group to a 9-hydroxyacetyl group.

Description

The invention relates to anthracycline glycosides, to methods for the preparation thereof and to pharmaceutical compositions containing them.

The invention provides anthracycline glycosides of the 5 general formula 1 wherein X represents a hydrogen atom or a hydroxy group, R^ represents a hydrogen atom or a methyl group, one of R2 and Rg represents a methoxy group and the other of R2 and Rg represents a hydrogen atom; and further provides pharmaceutically acceptable acid additions salts of such compounds. These compounds are named as follows: -24-demethoxy-4'-O-methyl-daunorubicin (Ia: R^R^X’H, R2=0CH3), 4-demethoxy-4'-epi-4’-O-methyl-daunorubicin (lb: R1«R2=X=H, R3=OCH3), 4-demethoxy-2,3-dimethyl-4'-O-methyl-daunorubicin (Ic: R1=CH3, R2=OCH3, R3=X=H), 4-demethoxy-2,3-dimethyl-4'-epi-4'-O-methyl-daunorubicin (Id: R1=CH3, R2=X=H, R3=OCH3), 4-demethoxy-4'-O-methyl-doxorubicin (Ie: Rj=R3=H, R2=OCH3, X=0H), 4-demethoxy-4'-epi-4'-O-methyl-doxorubicin (If: R1=R2=H, R,=OCH3, X=OH), 4-demethoxy-2,3-dimethyl-4'-O-methyl-doxorubicin (Ig: R1=CH3, R2=OCH3, R3=H, X=OH), and 4-demethoxy-2,3-dimethyl-4'-epi-4'-O-methyl-doxorubicin (Ih: Rj=CH3, R2=H, R3=OCH3, X=OH).

The anthracycline glycosides of the general formula I may be prepared by a process according to the invention which process comprises condensing 4-demethoxy-daunomycinone or 2,3-dimethyl-4-demethoxydaunomycinone (United States Patent Specification No. 4046878) with 2,3,6-trideoxy-3-trifluoroacetamido-4-0-methyl-L-lyxo-hexopyranosyl chloride or 2,3,6-trideoxy-3-trifluoroacetamido-4-0-methyl-L-arabino-hexopyranosyl chloride (United States Patent Specification No. 4183919) to give one of the protected a-glycosides of the formula Ila. to lid, removing the N-trifluoroacetyl protecting group by mild alkaline hydrolysis to give the corresponding daunorubicin derivative Ia to Id, and optionally converting the daunorubicin derivative to the corresponding doxorubicin ¥5 derivative Ie to Ih by bromination and treatment of the resulting 14-bromo-derivative with aqueous sodium formate.

The conversion of the daunorubicin derivatives Ia to Id to the corresponding doxorubicin derivatives Ie to Ih follows the method described in United States Patent Specification No. 3803124.

The invention further provides a pharmaceutical composition comprising an anthracycline glycoside of the general formula I as herein defined or a pharmaceutically acceptable salt thereof in admixture with a pharmaceutically acceptable diluent or carrier. -4®ie invention is illustrated by the following Examples and biological data.

Example' 1 4-demethoxy-4'1 -O-methyl-daunorublcin (Ia) A solution of 3.68 g of 4-demethoxy-daunoraycinone in 400 ml of anhydrous methylene dlehloride containing 1.4g of 1-chloro-4-0-me thy1-N-tri fluoroace ty1-daunos amine was vigorously stirred in the presence of molecular sieve (30 g, 4A Merck (Trade Mark)) and 1.3g of silver trifluoromethane10 sulphonate . After 10 minutes at room temperature, the reaction mixture was neutralized with 0.55 ml of symcollidine. After 40 minutes the suspension was filtered and the organic phase was washed with 0.01 N aqueous solution of hydrochloric acid, with water, with a saturated aqueous solution of sodium bicarbonate and finally with water to neutrality. The residue, obtained by evaporating off the solvent under vacuum, was dissolved in 150 ml of acetone, treated with 600 ml of 0.2 N aqueous sodium hydroxide and diluted with 450 ml of water. After 5 hours 20at O°C the solution was adjusted to pH 8.5 and extracted with chloroform until the chloroform extracts were no longer coloured. The organic extracts were combined and acidified to pH 5 with 0.1 N methanolic hydrogen chloride. By evaporation under vacuum to a small volume (150 ml) pure 4-demethoxy-4'-0-methyl-daunorubicin (0.6 g) crystallized. The mother liquor was purified on a 537 50 -5column of silica gel buffered at pH 7 with phosphate buffer 14/15, using the solvent system chlorofoxm:methanol: water (10:2:0.2 by volume). The eluate, containing the pure compound, was diluted with water and the organic phase was separated off, washed with water and evaporated to a small volume and thereafter acidified to pH 5 with 0.1 N methanolic hydrogen chloride. A further amount (0.4 g) of 4-demethoxy-4’-0-methyldaunorubicin hydrochloride was obtained; m.p. 189-190°C (with decomposition). TLC on Kieselgel plates (Merck F 254) solvent system chloroform:methanol:water (10:2:0.2 by volume).

HPLC: experimental analysis: column microbondapack C^gj mobile phase: water:acetonitrile (69:31 by volume) at pH 2 with. 10% orthophosphoric acid: flux rate 1.5 ml/min., retention time 22 min.

FD-MS: m/z 511 (M+*) Example 2 4-demethoxY-'4l-0-methyl-doXorublcin (Ie) A solution of 0.5 g of 4-demethoxy-4’-0-methyl-dauno-rubicin, prepared as described in Example 1, in a mixture of methanol (8 ml) and dioxan (20 ml) was treated with bromine to form the 14-bromo derivative. Treatment of the 14-bromo derivative with an aqueous solution of sodium formate at room temperature for 18 hours gave 0.310 g of 4-demethoxy-4’-0-methyl-doxorubicin which was isolated as E3750 -6its hydrochloride m.p. 164-165°C (with decomposition); TLC on Dieselgel plate (Merck F 254) solvent system chlorofoxm:methanol: water (10:2:0.2 by volume); Rf 0.18.

HPLC: experimental conditions: column microbondapack Clg; mobile phase water:acetonitrile (69:31 by volume) at pH 2 with 10% orthophosphoric acid; flux rate 1.5 ml/mln; retention time; 10 min.

Example 3 4-demethoxy-2,3-dixnethyl-4'-O-methyl-daunorubicin (Ic) The coupling reaction between 4-demethoxv-2,3-dimethyl-daunomycinone and l-chloro-4-0-methyl-N-trifluoroacetyldaunosamine under the conditions described in Example 1 afforded the title compound.

Example 4 4-demethoxy-2,3-dimethyl-4'-0-methyl-doxorubicin (Ig) The conversion of compound Ic to the title compound was performed using the procedure described in Example 2.

Example 5 4-demethoxy-41-epi-41-0-methyldaunorubicin(lb) and 4-demethoxy-2,3-dimethyl-41-epi-4'-O-methyl-daunorubicin (Id) The coupling reactions, as described in Example 1, of 4-demethoxy-daunomycinone and 4-demethoxy-2,3-dimethyl-daunomycinone with 2,3,6-trideoxy-3-trifluoroacetamido-4-O-methyl-L-arabino-hexopyranosyl chloride afforded, after hydrolysis of the N-protecting group, the title compounds.

Example 6 4-demethoxy-4'-epl-4l-Q-methyldoxorublcin (If) and 4-methoxy—2,3-dimethyl-4' -epi-4'1 -0-methyl-doxorubicin (Ih) The compounds lb and Id were converted, via their 14-bromo53750 -7derivatives -under the conditions described in Example 2 to compounds If and Ih respectively.

BIOLOGICAL ACTIVITY OF la' and Ie The compounds la and Ie have been tested against the 5 parent compounds, respectively daunorubicin (DNR) and doxorubicin (DX), in several experimental systems, in order to ascertain their cytotoxicity, antitumour acitivity and cardiac toxicity in experimental animals.

Data reported in Table 1 show that Ia is about 5 times more 10 cytotoxic than DNR, and Ie is about 9 times more cytotoxic than DX.

The primary screening in vivo was carried out in CDF-1 mice bearing P388 ascitic leukemia {106 cells/mouse). ResultE are reported in Table 2. Both Ia and Ie were found to be more toxic and more potent than the parent compounds.

Comparison at the Maximal Tolerated Dose (MxTD) shows that Ia is as effective as DNR (giving similar increase of the mice life span) and I® has a good antitumour activity, which is of the same order of magnitude as that of DX.

Several studies have been carried out in C3H mice bearing the Gross leukemia injected i.v. (2xlO6 cells/mouse).

Data on Xa are reported in Table 3. Administered i.v. on day 1 after the tumour inoculation, la was markedly more toxic and more potent than DNR. At the MxTD of 1.25-81.3 mg/Kg, Ia was more effective than DX at the MxTD of mg/Kg. It is well known that DNR is not active when administered by oral route, unless very high doses are given (4-50 mg/Kg). Data -reported in Table 3 show that Ia has a good antitumour activity against Gross leukemia also when given orally. Administered orally on day 1 only, Ia is active at the dose of 1.25-1.3 mg/Kg, which is also the optimal dose in the case of the i.v. treatment. This result suggests that absorption of Ia 0 through the gastrointestinal tract is very efficient. Administered on days 1, 2 and 3 by oral route, la is more active than when administered on day 1 only; at the optimal dose of 0.66 mg/Kg/day it has an antitumour activity of the same order of magnitude as that of 4-demethoxy-daunorubicin, which was investigated in parallel at the optimal dose of 1.9 mg/Kg/day. The observation that the optimal dose of Ia is lower than that of 4-demethoxy-daunorubicin suggests a more efficient absorption through the gastrointestinal tract also in comparison to this compound.

Data on the antitumour activity of Ie in comparison with DX against Gross leukemia are reported in Table 4. The compounds were administered on day 1 after the tumour cells inoculum; DX was given i.v.; Ie was given i.v. and orally. When administered i.v., at the MxTD of 1 mg/Kg, Ie showed a good antitumour activity, similar to that observed after DX treatment. In addition, Ie E3750 -9was active also when administered orally at doses from 1.3 mg/Kg on. le was tested against L 1210 leukemia, which was inoculated In CDF-1 mice i.p. (ascitic form) or i.v. (10^ cells/mouse). Treatment was performed on day 1 after the tumour cell inoculation, i.p. or i.v., respectively. Data reported in Table 5 show that, in the i.p.-i.p. experiment, le at the MxTD of 0.83 mg/Kg was as active DX at the MxTD of 4.4 mg/Kg. In the i.v.-i.v. experiment, le at the tolerated doses of 1 and 1.3 mg/Kg showed antitumour activity superior to that of DX.

In order to assess the antitumour activity against a solid tumour, Ie has been tested in comparison with DX, against the mammary carcinoma of C3H female mice. A third generation tumour transplant was utilized. Treatment started 15 days after the tumour transplant,’and was performed i.v. once a week for 4 weeks. Tumour measurement was performed by caliper every week. Non-tumour bearing mice were treated in parallel, in order to 2D evaluate the general toxicity and the cardiac toxicity, which was investigated in 5 mice, treated with the highest doses of the two compounds, and killed 5 weeks after the last treatment. The results of this experiment are reported in Table 6. DX was very effective, and it inhibited tumour growth by 93-94% (in comparison with the untreated controls) at both the doses tested (6 and 7.5 mg/Kg). Xn the non-tumoured mice treated with DX at 3 7 5 () -ΙΟΙ. 5 mg/Kg, toxic deaths were observed (2/3) and all the mice examined showed histologically detectable heart lesions. Ie at the dose of 0.4 mg/Kg was slightly active; at the doses of 0.,6 and 0.75 mg/Kg it markedly inhibited the tumour growth. In non-tumoured mice treated with Ie at 0.75 mg/Kg no atrium lesions were observed, and only 2 out of 5 mice showed detectable ventricle lesions, which were less severe than those observed after DX treatment.

The data here presented show that Ia and ie are new anthracycline analogues endowed with very interesting biological properties. In comparison with DMR, Ia is about 3 times more potent when administered i.p., and about 8 times more potent when administered i.v. At the MxTD it has an antitumour activity against ascitic P388 and systemic Gross leukemia equal to that of DMR.

In addition, it is active also when administered by oral route, particularly when treatment is performed for 3 consecutive days, at doses lower than those of 4-demethoxy-daunorubicin.

Ie· is about 10 times more potent than DX in vivo.

Comparison at the MxTD shows that it is, in respect to DX, equally active against ascitic P 388 and L 1210 leukemia, systemic Gross leukemia and solid mammary carcinoma, and it is more effective than DX against systemic (i.v. is injected) L 1210 leukemia. In addition, it?active against -IlGross leukemia also when administered orally, and in a preliminary cardiotoxicity test in C3H mice treated chronically i.v. it caused only minimal cardiac lesions.

Compound la, has been studied on P388 leukemia cells resistant to doxorubicin (P388/DX) in vitro and vivo.

P388 leukemia cells resistant to doxorubicin (DX) (received by dr, Schabel) are maintained by serial transfer in mice treated with DX i.p. For experimental 4 purpose, BDF-1 -mice were injected with 10 leukemia cells, i.p., and treated i,p. on day 1 after the tumour inoculation. Results, reported in Table 7, show that daunorubicin (DNR) was not active against this tumour, while compound Ia, at the optimal dose of 0.8 mg/kg increased the life span of the treated mice. P388 and P388/DX leukemia cells were harvested from mice ascitic fluid and adapted to grow in suspension in vitro.

Cytotoxicity tests were carried out exposing the cells to various drug concentrations for 48 hrs; at the end of the exposure period, cells were counted with a Coulter (Trade Mark) Cell Counter, and the ID (dose which uives 50 50* reduction of the cell number in comparison with untreated controls) was calculated. Results, reported in Table 8, show that Ia was about twice as cytotoxic as DNR on P388 leukemia cells, and was very actiye also on P388/DX leukemia cells, while DNR was 163-152 times less active on the resistant than on the sensitive line. 3 7 5 0 -12Compound Xe was further investigated on mammary carcincma of C3H mice. Mice bearing measurable tumour Ord generation transplant) were treated once/week for 4 weeks i.v. with Ie or with DX. Normal mice were treated in parallel, for evaluation of toxicity. Results, reported in Table 9, confirm that Ie was about 10 times more potent than DX, and had a remarkable antitumour activity in this experimental system at non toxic doses, while DX was toxic.

Because of the good antitumour activity against mammary carcinoma, compound Ie was tested against two solid tumours: the colon 26 and the colon 38 adenocarcinomas, transplanted s.c. in BALB/c mice and in BDF-1 mice, respectively. Treatment started on day 1 after the tumour inoculation (early) or when tumour was already palpable (advanced), and was performed i.v. once/week or every 5 days, for 3 or 4 times. Tumour growth was assessed by caliper measurement.

Non-tumour bearing mice were treated in parallel, for toxicity evaluation, and were observed for 90 days. Results of three experiments are reported in Table 10. Against early colon 26, Ie at the maximal tolerated dose of 0,9 mg/kg/day was more active than DX at the maximal tolerated dose of 7,5 mg/kg/day. Against advanced colon 26, Ie at the maximal dose tested of 3 7 5 0 -130.7 mg/kg/day was not toxic, and gave a higher tumour growth inhibition than DX at the -maximal tolerated dose of 6 -mg/kg/day. Against advanced colon 38, Ie at the -maximal dose tested of 0.9 jng/kg/day was as active as DX 9 mg/kg/day in inhibiting tumour growth, but produced a higher increase of survival time.

In conclusion, all data here reported confirm that compounds la and Ie are extremely interesting new anthracyclines, endowed with high potency, activity by oral route, activity against anthracycline resistant tumours (Ia), activity against solid tumours superior to that of DX and not cardiotoxic (Ie).

Table 1 - Colony inhibition test against Hela cells in vitro (Treatment for 24 hrs) Compound Dose (ng/ml) Sg%l) DNR 12.5 42 6.2 66 12 3.1 121 la 25 0 6,2 0 2.5 1.5 73 DX 12,5 20 6,2 79 9 3,1 177 Ie 1G 0 2.5 9,9 1 0.62 82 0.15 1 84 ®Νο, of colonies; % of untreated controls 7 50 - 14 TABLE 2. Antitumour activity against Ρ3ΘΘ leukemia Treatment i.p. on Day 1 Compound Dose (mg/kq) T/Ca ft LTSb Toxic deaths0 DNRd 2.9 154 0/10 0/10 4.4 140,154 0/20 4/20 6.6 109,163 0/20 13/20 Ia 0.5 127 0/10 0/10 0.64 127 0/10 0/10 o.e 172,127 0/20 1/20 1.0 145 0/10 0/10 1.3 95 0/10 10/10 DX 4.4 160 0/10 0/10 6.6 200 2/10 0/10 10.0e 315 4/10 0/10 Ie 0.44 180 0/10 0/10 0.66 215 0/10 0/10 1.0 250 0/7 1/7 1.5 245 2/10 4/10 8 Median survivial time; ft over untreated controls b Long term survivors 0 60 days) c Evaluated on the basis of autoptic findings on dead mice d Data of two experiments e This is the Maximal Tolerated Dose of DX in this experimental system - 15 TABLE 3. Activity of la against Gross leukemia Treatment Route Schedule® Compound mg/kg/day 5 i.v. 1 DNR 10 15 22.5 10 i.v. oral 1 1 Ia 0.58 0.76 1.0 1.25-1.3 1.56 1.95 1.1 1.25-1.3 1.56-1.6 1.95-2.0 oral 1,2,3 4- demethoxy DNR 1.31 1.58-1.46 1.9 2.5 3.3 15 oral 1,2,3 la 0.44 0.66 1.0 1.25 T/Cb Toxic % deaths0 133,150 0/20 175,175,166 3/30 208,191,216 6/30 116 0/10 133 0/10 158,166 0/20 183,208 0/20 100 9/10 116 6/10 133 0/10 133,166 1/20 166,166 3/20 175,183 2/20 125 0/20 133,150 1/20 133,190 1/20 210 2/10 140 6/10 133 0/9 183 0/10 200,220 9/20 140 8/10 d Days after tumour inoculation b,c see Table 2. 3 7 5 0 - 16 Table 4. Activity ol Ie against Gross leukemia Treatment * T/Cb % Toxic deatbsc Route Compound mg/kg i.v DX 10 200 2/8 13 200,216 2/18 16.9 250,266 3/18 Ie 1.0 183,233 0/18 1.3 192,208 4/18 1.7 217,200 7/18 2.2 142 7/10 oral Ie 1.0 125 0/8 1.3 150 0/8 1.7 166 0/8 2.5 166 0/8 a On day 1 after tumour inoculation b,c See Table 2.

Table 5. Activity of le against L1210 leukemia L1210 inoculun Treatment Compound mg/kg T/C& % LTSb Toxic deaths0 i.p. i.p. DX 4.4 . 150 0/9 0/9 6.6 150 0/10 1/10 10.0 162 0/10 1/10 Ie 0.83 162 2/10 0/10 1.0 187 1/10 1/10 1.2 393 4/10 3/10 i.v. i.v. DX 10.0 120 0/10 0/10 13.0 120 0/10 0/10 16.9 133 0/10 0/10 Ie 1.0 200 0/10 0/10 1.3 173 0/10 0/10 1.7 >580 5/10 0/10 *»b.c See Table 2 3 7 5 0 I ιη ιη •χ ιη I ΓΠ X Ο 4J U (0 •Η Ό k (8 ϋ *Ο C η Α «ϋ k Ο» C -H X Ο JJ ε ο C Ή ϋ k ϋ >, k ε ε Rj ε X η · Ο X ο Α α χ C 4J •Η Μ ,* Ο1 C ο >1 0 X Ή •Η k > 0 •Η Ch X Ε ϋ Ο < V © •Μ X ε· η χ X Ό U \*= Ε-< ε* w Σ ϊ Ο C k 0 ο» X k -η □ X Ο ·Η ε χ 9 C &* *Η k X 9 X Ο > ε ο k Ε* 9) >1 θ' Μ •u n •0 *0 • \ c ΓΜ c c in O «Π ΓΠ rr rr (M rr ^4 rJ A c ε jj & k JJ η r- rr ιη γ·* r* ιη ιη ιη *μ r* © m Gt in tn CD 01 k jj c ϋ MJ X JJ k CT k O ε s JJ JJ \ c •H tn rr © η» r* CM •D Ο JJ & k JJ MJ o X Jj 0) >1 •0 in r* k 9» k O E E< M > k β C >n •D O © k Ό ϋ k X •u° O' c •H O X A k X UJ k X ε - C k A C > N > ε Ή k A V fl «* in o - 18 Tableγ · Effect on doxorubicin-resistant P388 leukemia in vivo.

Compound Dose (mg/kg) T/ca % LTSb Toxic deaths'* DNR 2.9 93 0/10 0/10 4.4 87 0/10 1/10 6.6 84 0/10 3/10 la 0.S3 133 0/10 0/10 0.8 142 1/10 0/10 1.2 106 0/10 4/10 aMedian Survival time; % over untreated controls. ^Long-term survivors (> 60 days) Evaluated on the basis of autoptic findings on dead mice 537 50 - 19 Table 8. Effect on sensitive and doxorubicin-resistant P388 leukemia in vitro.

Compound ID50 (ng/ml)b Re P388c P388/DX0 DNR 5.8,2,3 950,350 163,152 Ia 0.35,1.3 1.4,5 4,3.8 £ Data of two experiments. bDose giving 50% reduction of cell- number in comparison with untreated controls.

CP388 leukemia cells sensitive to DX P388 leukemia cells resistant to DX eRatio between IDcn on P388/DX and lDrn on P388 □U qu 3 7 5 Ο - 21 Table 10 Effect of Ie and DX against two transplanted colon adenocarcinomas in mice Tumora Stage Schedule^ Compd. Dose (mg/kg) 5C inhib. T/Cd X Toxic deaths6 Colon 26 early q7dx4 DX 6 56 217 0/10 7.5 82 224 0/10 9.3 81 161 9/10 le 0.6 81 258 0/10 0.75 85 227 0/10 0.9 93 246 1/10 advanced q6dx3 DX 6 34 237 0/9 9 62 237 4/9 Ie 0.6 48 232 0/9 0.7 52 135 0/9 Colon 38 advanced q7dx4 DX 6 65 92 0/10 9 83 144 1/10 le 0.6 55 133 0/10 0.75 60 129 0/10 0.9 81 184 0/10 aTime of start of treatment in respect to tmour development.

Days of i.v. administration.

C% inhibition of tumour growth, as compared with untreated controls.

^Median survival time of treated mice/median survival time of controls, x 100. g Evaluation in non-tancuradmice treated in parallel and observed for 90 days.

Claims (13)

1. An anthracycline glycoside having the general formula I as herein defined or a pharmaceutically acceptable salt thereof.

2. , 4-Demethoxy-4'-O-methyl-daunorubicin.

3. , 4-Demethoxy-4'-O-methyl-doxorubicin.

4. , 4-Demethoxy-4'-epi-4'-O-methyl-daunorubicin.

5. , 4-Pemethoxy-4'-epi-4’-O-methyl-doxorubicin.

6. , 4-Demethoxy-2,3-dimethyl-4’-O-methyl-daunorubicin,

7. , 4-Demethoxy-2,3-dimethyl-4’-O-methyl-doxorubicin.

8. , 4-Demethoxy-2,3-dimethyl-4'-epi-4'-0-methyl-daunorubicin.

9. , 4-Demethoxy-2,3-dimethy1-4 1 -epi-4'-0-methy1-doxorubicin. Ip. A process for the preparation of an anthracycline glycoside having the general formula I as herein defined, the process comprising condensing 4-demethoxy-daunomycinone or 2,3-dimethy1-4-demethoxy-daunomycinone with 2,3,6-trideoxy-3-trifluoroacetamido-4-0-methyl-L-lyxo-hexopyranosyl chloride or 2,3,6-trideoxy-3-trifluoroacetamido-4-0-methyl-L-arabino-hexopyranosyl chloride, and removing by mild alkaline hydrolysis the N-trifluoroacetyl protecting group from the resultant anthracycline glycoside Ila, lib, He or 25 lid as herein defined, and optionally converting the & :ϊ 7 5 0 - 23 resultant daunorubicin derivative la, lb, Ic or Id as herein defined to the corresponding doxorubicin derivative Ie, If, Ig or Ih as herein defined by bromination and treatment of the resultant 14-bromo5 -intermediate with aqueous sodium formate. Ii, A process according to claim 10 in which the condensation of the anthracyclinone with the hexopyranosyl chloride is carried out in a solvent In the presence of a soluble silver salt and molecular sieve.

10. 12, A process according to claim 11 in which the solvent is dichloromethane,

11. 13, A process according to claim 11 or claim 12 in which the soluble silver salt is silver trifluoromethaiesulphonate.

12. 15 14. A process according to claim 10 the process being substantially as described herein with reference to any of Examples 1, 3 and 5, 15. A process according to claim 10 the process being substantially as described herein with reference to 20 any of Examples 2, 4 and 6.

13. 16. A pharmaceutical composition comprising an 5 3 7 S Ο - 24 anthracycline glycoside having the general formula I as herein defined or a pharmaceutically acceptable salt thereof in admixture with a pharmaceutically acceptable diluent or carrier.