FI84075C - Process for the preparation of new anthracyclines - Google Patents

Description

84075

Method for the preparation of new anthracyclines

The invention relates to a process for the preparation of new anthracycline glycoside derivatives.

According to the present invention there are provided anthracycline glycosides of formula (II)

0 OH

CH3O 6 OH

• ivj

OH

(II a, b)

a: Rx = H b: Rx = H

wherein R 1 represents a hydrogen atom or a hydroxyl group, and pharmaceutically acceptable acid addition salts thereof.

When 3'-epi-daunorubicin (III) is introduced [F.Arcamone, A. Bargiotti, G. Cassinelli; DE Patent 2752115 (June 1, 1978)] 3'-amino group reacts with salicylaldehyde in a mixture of water and acetone at room temperature to give the corresponding 3'-epi-N-salicylidene derivative (IVc) which, by treatment with trifluoromethanesulfonic anhydride in the presence of pyridine the corresponding 3'-epi-N-salicylidene-4'-O-trifluoromethanesulfonate (IVd). This compound dissolved in methanol can then be subjected to acid hydrolysis of the salicylidene protecting group with p-toluenesulfonic acid at room temperature to give the desired compound of formula (Ia) via substitution of the trifluoro-methanesulfonate deprotection group.

CH 3 O OH. 1 · <& 3 '(Ia) Treatment of the 31,41-epiimino-daunorubicin derivative (Ia) with trifluoroacetic anhydride gives the corresponding N-trifluoroacetyl derivative of formula (VIII). Reaction of this compound with a catalytic amount of sulfuric acid in acetone affords 41-deoxy-4'-epi-N-trifluoroacetyl-3'-deamino-3'-hydroxy-daunorubicin (VIII), which upon treatment with aqueous sodium hydroxide gives the compound of formula (IIa). . Typically, the N-trifluoroacetyl group can be removed by mild alkaline hydrolysis at 0 ° C with 0.1 N aqueous sodium hydroxide. The glycoside of formula (IIa) can be isolated as its hydrochloride by treatment with hydrogen chloride in methanol.

A compound of formula (Hb) may be prepared by bromination of a compound of formula (IIa) followed by treatment of the resulting 14-bromo derivative with aqueous sodium formate at room temperature by the method disclosed in U.S. Patent No. 3,803,124. It can also be isolated as its hydrochloride in the same way as the glycoside of formula (IIa).

The methods of the invention are all summarized in the reaction scheme below.

3,84075

In particular, the compounds of the invention are useful as antitumor agents.

Reactocycle O? H O OH O Oh

CH40 o oh ^ „___ CHjO O OH q CHj ° o OH J

NH, I _ NR. I ~ „9

H0 (UI) B> (ivc-d) '' (| J

O OH O OH

(ϋΛέπο

--cjY ^ V

^ CVOH ^ Z ^ T1

V— HO

(vui) (v # 0

c R2: OHOH6H4CH = R3: OH

d R2: oOHC6H4CH = R3: 0SO2CF3 and R4: COCF3

The following examples illustrate the invention.

EXAMPLE 1 3'-epi-N-salicylidene-daunorubicin (IVc)

A solution of 2 g of 3'-epi-daunorubicin (III) in a mixture of 80 ml of water and 20 ml of acetone was treated at room temperature with 0.5 ml of salicylaldehyde at pH 8. After 10 minutes, ethyl acetate 4 was added. 84075 and the organic phase was separated, washed twice with water, dried over anhydrous sodium sulfate, filtered and evaporated to dryness in vacuo.

The residue was first triturated with hexane to remove residual salicylaldehyde, then collected and dried in vacuo at 30 ° C to give the compound of formula (IVc) in almost quantitative yield. Thin layer chromatography (TLC) Rf = 0.21 using a Kieselgel F 254 (Merch) plate and CH 2 Cl 2 -acetone (8/2, v / v) as solvent.

EXAMPLE 2 3'-Deamino-41-deoxy-3'-epi-4'-epi-3 ', 41-epi-imino-Down-rubicin (Ia)

To a solution of 2 g of 3'-epi-N-salicylidene-daunorubicin (IVc) in 20 ml of anhydrous dichloromethane and 2 ml of dry pyridine at -10 ° C was added a solution of 0.8 ml trifluoromethanesulfonic anhydride in 10 ml of dichloromethane. After one hour at -10 ° C, the mixture was diluted with dichloromethane and washed with water, cold 0.1 M hydrochloric acid, cold aqueous 5% sodium bicarbonate or water. The organic phase was dried over anhydrous sodium sulfate, filtered and the solvent removed in vacuo to give the compound of formula (IVd). Thin layer chromatography (TLC) Rf was 0.50 using a Kieselgel F 254 (Merch) plate and a solvent mixture of Cl 2 Cl 2 -acetone (95/5 v / v) as eluent.

The crude product was dissolved in 50 ml of methanol and 0.2 g of p-toluenesulfonic acid monohydrate was added. The solution was kept at room temperature for 1 hour, then 100 ml of water were added and extracted with a small amount of dichloromethane. The pH of the aqueous phase was adjusted to 8 with 0.1 M sodium hydroxide and dichloromethane was added. The organic phase was separated, washed with water, dried over anhydrous sodium sulfate and the solvent was evaporated to a small volume.

The mixture was purified by chromatography on a silica gel column buffered to pH 7 using dichloromethane-ethanol as eluent. The eluate containing product (Ia) was washed with water, evaporated in vacuo, taken up in a small amount of dichloromethane and crystallized. FD MS 509 [M +]; mp 135-137 ° C. Rf = 0.38 by TLC Kieselgel F 254 (Merck), eluting with CH 2 Cl 2 -CH 3 OH-CH 3 COOH-H 2 O (30/4/1 / 0.5 v / v).

1 H-NMR (200 MHz, CDCl 3): 8.02 (dd, J = 1.1, 7.7 Hz, 1H, H1) 7.76 (dd, J = 7.7, 7.7 Hz, 1H, H-2) 7.37 (dd, J = 1.1, 7.7 Hz, 1H, H-3) 5.31 (dd, J = 3.0, 4.8 Hz, 1H, H-1 ') 5.17 (dd, J = 2.0, 3.6 Hz, 1H, H-7) 4.32 (gd, J = <1.7 Hz, 1H, H-5 ') 4.07 (S, 3H, OCH 3 -4) 3.17 (dd, J = 19.2 Hz, 1H, H-10e) 2.95 (d, J = 19.2 Hz, 1H, H-10ax) 2.46 (ddd, J = 2.0 , 2.0 15.0 Hz, 1H, H-8e) 2.43 (s, 3H, COCH 3) 2.30 (ddd, J = 1.5, 4.3, 6.4 Hz, 1H, H-3 ' ) 1.9-2.0 (m, 2H, H-8ax, H-2'ax) 1.87 (ddd, J = 1.5, 3.0, 14.6 Hz, H-2'e) 1.44 (d, J = 6.7 Hz, 3H, CH3-5 ') · 6 84075 EXAMPLE 3 3'-Deamino-4'-deoxy-3'-hydroxy-4'-epi-4'-amino-daunoru- bisin (Ha)

The title compound was prepared starting from the aziridine of formula (Ia). 1 g of the compound of formula (Ia) was converted into the N-trifluoroacetyl derivative (VIII) by treating 1.2 ml of trifluoroacetic anhydride in anhydrous methylene dichloride. After further work-up, the crude product (TLC Rf value 0.7 using a Kieselgel F 254 (Merck) plate, eluting with a solvent mixture CH2Cl2-acetone (4/1, v / v)) was dissolved in 20 ml of acetone and treated with a catalytic amount of sulfuric acid. ° C.

The mixture was diluted with 200 mL of methylene dichloride, washed with water, aqueous 5% sodium hydrogen carbonate and water. The solvent was removed in vacuo and the residue was purified on a silica gel column using methylene dichloride as eluent to give 0.7 g of pure compound (VIII).

TLC Rf value 0.21, using a Kieselgel F 254 (Merck) plate, eluting with a solvent mixture of C 1 -C 4 acetone (4/1, v / v).

The product of formula (VIII) was slowly dissolved in aqueous 0.1 N sodium hydroxide at 0 ° C to hydrolyze the N-trifluoroacetyl protecting group. After 1 hour at 0 ° C, the pH of the solution was adjusted to 8.6 using 0.1 N hydrochloric acid and extracted with methylene dichloride. The solvent was evaporated to give a residue (0.5 g) which was converted into 41-deoxy-4'-amino-4'-epi-3'-deamino-3'-hydroxy-daunorubicin hydrochloride (Ha) by treatment with methanolic hydrogen chloride. MS FD 527 [M &lt; + &gt;]; mp 153 ° C (dec.).

784075 by TLC Rf value 0.18 using a Kieselgel F 254 (Merck) plate, eluent solvent system CH 2 Cl 2 -CH 3 OH-CH 3 -C00H-H 2 O (30/4/1 / 0.5 v / v).

1 H-NMR (200 MHz, CDCl 3): 8.02 (dd, J = 0.9, 8.5 Hz, 1H, H1) 7.77 (dd, J = 8.5, 8.5 Hz, 1H, H-2) 7.38 (dd, J = 0.9, 8.5 Hz, 1H, H-3) 5.52 (dd, J = <1, 4.0 Hz, 1H, H-1 ') 5.28 (dd, J = 1.8, 4.0 Hz, 1H, H-7) 4.07 (S, 3H, OCH 3-4) 3.69 (dg, J = 6.3, 9.5 Hz, 1H, H-5 ') 3.51 (ddd, J = 4.8, 9.5, 11.6 Hz, 1H, H-3') 3.22 (dd, J = 1.9, 18.9 Hz, 1H, H-10e) 2.94 (d, J = 18.9 Hz, 1H, H-10ax) 2.40 (s, 3H, COCH 3) 2.2-2.4 (m, 1H, H -8ax) 2.30 (dd, J = 9.5, 9.5 Hz, 1H, H-4 ') 2.0-2.2 (m, 2H, H-8e, H-2'e) 1.70 (ddd , J = 4.0, 4.6, 13.2 Hz, 1H, H-2'ax) 1.31 (d, J = 6.3 Hz, 3H, CH3-5 ').

EXAMPLE 4 3'-Deamino-3'-hydroxy-4'-deoxy-4'-epi-4'-amino-doxorobicin (Hb) 0.5 Compound of formula (IIa) was dissolved in a mixture of methanol and dioxane. The solution was treated as described in U.S. Patent No. 3,803,124, first with bromine to prepare the 14-bromo derivative and then with aqueous sodium formate to prepare the title compound.

This was converted to its hydrochloride by treatment with methanolic hydrogen chloride.

8 84075 FD MS 543 [M +], TCL Kieselgel F 254 (Merck) plate, solvent system CH 2 Cl 2 -CH 3 OH-CH 3 -C00H-H 2 O (30/4/1 / 0.5 v / v), Rf- value 0.10.

BIOLOGICAL ACTIVITY

The cytotoxic activity of the novel anthracycline glycosides of formula II according to the invention was tested "in vitro" against HeLa cells, P388, P388 / DX, LoVo and LoVo / DX cells.

Exposure time to the compound: 24 hours / comparison with daunorubisii.

The results are shown in Table l.

The compounds, when tested "in vivo" against P388 ascites leukemia and Gross leukemia, showed good antitumor activity compared to daunorubicin, especially when administered orally.

The results are given in Tables 2 and 3.

9 84075

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-C Learn ra O TD QJ> 4- ΓΟ <r- 10 84075 TABLE 2

Effect of P388 against ascites leukemia5 b c d

Compound dose T / C% toxicity Deaths DNA 2.9 155 0/10 4.4 170 8/10 FCE 24782 / XOO-0333 1.96 155 0/10 2.9 150 0/10 4.4 140 9/10 6.6 100 10/10 aExperiments were performed in CDF ^ mice inoculated with 106 leukemia cells ip

bTreatment i.p. one day after tumor inoculation cMean survival of treated mice / mean lifetime of controls x 100 ^ Estimated from necropsy observations.

11 84075 TABLE 3

Effect against Gross leukemia bed Compound dose T / C% toxicity mg / kg Deaths DNR 10 165 0/20 15 192 2/20

Ila 8.2 175 0/20 11.5 230 0/10 16.1 240 0/10 22.5 130 0/10 aExperiments were performed in CH3 mice inoculated with 2 x 10® 1 leukemia cells i.v.

treatment i.v. one day after tumor inoculation Mean survival of treated mice / Mean of control 1 mice x 100 ^ Estimated from necropsy observations.

Claims (6)

A process for the preparation of anthracyclic glycosides of general formula II Wherein OH is a hydrogen atom or a hydroxyl group, and pharmaceutically acceptable acid addition salts thereof, characterized in that a) is reacted with 3'-amino. 3'-epi-daunorubicin, dissolved in a mixture of water and acetone, with salicylaldehyde, b) reacting the resulting corresponding 3'-epi-N-salicylic derivative with trifluoromethane-sulfonic anhydride in anhydrous dichloromethane and in the presence of dry pyridine, c) performs acid hydrolysis of the salicylidene protecting group at room temperature with p-toluenesulfonic acid on the 3'-epi-N-salicylidene-4'-O-trifluoromethanesulfonate dissolved in methanol, d) converts the resulting 3'-deamino -4'-deoxy-3'-epi-4'-epi-3 ', 4'-epi-imino-daunorubicin by treatment with trifluoroacetic anhydride, e) reacting the resulting corresponding N-trifluoroacetyl derivative with a catalytic f) performs a mild alkaline hydrolysis of the N-protecting group at 0 ° C. as obtained 4'-deoxy-4-epi-N-trifluoroacetyl-31-de-amino-3'-hydroxy-daunorubicin. 2. A process according to claim 1, characterized in that the obtained compound of formula II, which Rx represents a hydrogen atom, is further treated with methanolic hydrochloric acid and the product is isolated as the corresponding hydrochloride. 3. A process according to claim 2, characterized in that the obtained hydrochloride is converted to a 14-bromo derivative by reacting it with a bromine solution, and the obtained 14-bromo derivative is hydrolyzed using an aqueous solution of sodium formate. 4. A process according to claim 3, characterized in that a compound of formula II in which Sr is a hydroxyl group is obtained as a free base. 5. Process according to claim 4, characterized in that a further step is carried out in which the obtained base is converted to the corresponding hydrochloride. 6. 31-deamino-4'-deoxy-3'-epi-4'-epi-3 ', 4'-epi-imino-dau-norubicin.