CA1291122C - 3'-hydroxy-4'-epi-amino anthracyclines - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

This invention discloses new anthracycline glycosides having the general formula II:

Description

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1 The invention relates to novel anthracycline glycoside derivatives, to their preparation and to pharmaceutical compositions containing them.
The present invention provides anthracycline glycosides having the formula (II):

H~

wherein a: Rl = H H
b: Rl OH II a,b wherein Rl represents a hydrogen atom or hydroxyl group; and pharmaceutically acceptable acid addition salts thereof By reaction of the 3'~amino group of 3'-epi-daunorubicin (III) [F. Arcamone, A. Bargiotti, G.
- Cassinelli: German Patent 2,752,115 (June 1, 1978)]
with salicylaldehyde, in a mixture of water and acetone at room temperature, the corresponding 3'-epi-N-salicylidene derivative (IVG) is obtained which by treatment with trifluoromethanesulfonic anhydride in ~anhydrous~methylene dichloride and in the presence of ~ pyridlne;gives~the corresponding 3'-epi-N-salicylidene-~ ~ : ~

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4'~0-trifluoromethansulfonate (IVd). This compound, dissolved in methanol, is then subjected to acidic hydrolysis of the salicylidene protecting group by means of p-toluensulfonic acid at room temperature to give, via the displacement of trifluoromethanesulfonate leaving group, the compound of formula (Ia):

4l3 .I a Treatment of the obtained 3',4'-epimino daunorubicin derivative (Ia) with trifluoroacetic anhydride gives the corresponding N-trifluoroacetyl derivative:(VIIij. Reaction of this compound with a :catalytic amount of sulfuric acid in acetone gives 4'-deoxy-4'-epi-N-trifluoroacetyl-3' deamino-3'-hydroxy-daunorubiclo (VIII~ wh~ich, by treatment with aqueous sodium hydroxide, gives the compound (IIa). The N-~ trifluoroacetyl group is removed by mild alhaline hydro;Iysi~s,~ at a temperature of 0C by means of O.lN

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I aqueous sodium hydroxide. Glycoside (IIa) can be isolated as its hydrochloride by treatment with hydrogen chloride in methanol.
The compound (IIb) is prepared by bromination of (IIa) followed by treatment of the resultant 14-bromo derivative with aqueous sodium formate at room temperature, according to the procedure described in United States patent specification number 3,803,124 (issued April 9, 1974 to Societa Farmaceutici ~0 Italia). It may be isolated as its hydrochloride in the same manner as glycoside (IIa).
The process of the invention is summarized in the reaction scheme below.
The present invention also provides a ~5 pharmaceutlcal composition comprising as active ingredient, an anthracycline glycoside of the invention or pharmaceuticalIy acceptable acid addition salt :
the~reof together with a pharmaceutically acceptable carrier or dlluent. A therapeutically effective amount of~a compound of formula (II) is combined with an inert carrler. ConventlonaI carriers may be used and the compositlon may be formulated in conventional manner.
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'f~',3 l The compounds of the invention are useful in methods of treatment of the invention are useful in methods of treatment of the human or animal body by therapy. In particular, the compounds of the invention are useful as antitumor agents.

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- s-O OH O OH O OH
~CCH~ $~ OH ~OH
CH~O O H
CH30 0 OH o ~ _ CH~O O OH o _ O
C~l~ CH ~
HO (111) R~ (Ivc-d) ( l,) ~ ~--(lla)--(llb) CH~O O OH , C~O O OH

t ~ ;~ CF~COH~

(Vll~ ) ~ (Vlll) C R~ ~OOHC6H4CH~ OH
d R2 OOHC6H~C~ 52CF~ ~ :
R~: COCF~
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1 The following Examples illustrate the invention.

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 min. ethyl acetate was added and the organic phase separated off, washed with water twice, dried over anhydrous sodium sulphate, filtered and evaporated to dryness under vacuum.
The residue was first triturated with hexane to eliminate the traces of salicylaldehyde, then collected and dried under vacuum at 30C to give (IVc) in almost quantitative yield. Rf 0.21 on TLC Kieselgel*F 254 (Merck~* using as eluent the solvent mixture CH2CL2-Acetone (8/2 v/v).

3'-deamino-4'-deoxy-3'-epi-4'epi-3',4'-epimino-daunorubicin (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 kept at -10C, was added a solution of 0.8 ml of trifluoromethane sulfonic anhydride in 10 ml of dichloromethane. After 1 hour at -10C, the mixture was diluted with dichloromethane and washed with water, cold O.lM hydroclorlc acid, cold aqueous 5% sodium hydrogen carbonate and water. The organic phase, dried over anhydrous sodium sulphate, was filtered off and the solvent removed in vacuo to give (IVd) Rf 0.50 on TLC Kieselgel* F 254 (Merck)* using as eluent the solvent mixture CH2C12-Acetone (95/5/v/v).
The crude product was dissolved in 50 ml of methanol and added with 0.2 g~of p-toluensulfonic acid monohydrate.
Thè solution was kept at room temperature for 1 hr, then ` was added 100 ml of water and extracted with little dichloromethane. The aqueous phase was adjusted to pH 8 *Trade Marks ' 2Y' `
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1 with O.lM sodium hydroxyde and dichloromethane added. The organic phase ws separated off, washed with water, dried over anhydrous sodium sulphate and the solvent evaporated to small volume.
The mixture was purified by chromatography on a column of silica gel buffered at pH 7 using dichloromethane-ethanol as eluent~ The eluate containing the product (Ia) was washed with water, evaporated in vacuum, picked up with a little dichloromethane and crystallyzed FD MS 509 [M~] m.p. 135-137 C
Rf 0.38 on TLC Kieselgel*F 254 (Merck)* using as eluent the mixture CH2CL2-CH30H-CH3COOH-H20 (30/4/1/0.5 V/V).
H - NMR (200'MHz, CDC13):
8.02 (dd, J=l.l, 7.7Hz, lH, H-l) 7.76 (dd, J=7.7, 7.7Hz, lH, _-2) 7.37 (dd, J=l.l, 7.7Hz, lH, H-3) 5.31 (dd, J=3.0, 4.8Hz, lH, _-1') 5.17 (dd, J=2.0, 3.6Hz, lH, H-7) 4.32 (qd, J=<l, 6.7Hz, lH, H-5') 4.07 (s, 3H, OCH3-4) 3.17 (dd, J=19.2Hzj lH, H-lOe) 2.95 (d, J=19.2Hz, lH, H-lOax) 2.46 (ddd, J=2.0, 2.0, 15.0Hz, lH, H-8e) 2.43 (s, 3H, COCH3) 2.30 (ddd, J=1.5, 4.3, 6.4Hz, lH, _-3') 1.9-2.0 (m, 2H, H-8ax, H-2'ax) 1.87 (ddd, J=1.5, 3.0, 14.6Hz, lH, H2'e) 1.44 (d, J=6.7Hz, 3H, CH3-5') 3'-deamino-4'-deoxy-3'-hydroxy-4'-epi-4'-amino-daunorubicin (IIa) The title~compound was prepared starting from the aziridine~Ia. lg of Ia was transformed into the N-trifluoroacetyl~derivative VIIi by treatment with 1.2 ml of trifluoroacetic anhydride in anhydrous methylene *Trade Marks 1 dichloride. After work up the crude material [Rf 0.7 on TLC, Kieselgel F 254 (Merck) using as eluent the solvent mixture CH2C12-Acetone (4/1 V/V)] was dissolved in 20 ml of acetone and treated with a catalitic amount of sulforic acid at 10C.
The mixture was diluted 200ml of methylene dichloride, washed with water, aqueous 5% sodium hydrogen carbonate and water. The solvent was removed in vacuum and the residue purified on a column of silic gel using methylene dichloride as the eluting system to afford 0.7 g of pure IIa.
Rf 0.21 on TLC, Kieselgel F 254 (Merck) using as eluent the solvent mixture CH2C12-Acetone (4/1 V/V).
The product IIa was slowly dissolved in aqueous O.lN
sodium hydroxyde, at 0C in order to perform the hydrolysis of the N-trifluoroacetyl protecting group.
After 1 hr at 0C, the solution was adjusted to pH 8.6 with O.lN hydrochloric acid and extracted with methylene dichloride. The solvent was evaporated off, affording 0.5g of a residue that was converted by treatment with methanolic hydrogen chloride into the hydrochloride of 4'-deoxy-4'-amino-4'-epi-3~-deamino-3'-hydroxy-daunorubicin.
MS FD 527 [M+], m.p.l53 C (dec).
Rf 0.18 on TLC Kieselgel* F 254 (Merck)* using the solvent system CH2C12-CH30H-CH3COOH-H20 (30/4/1/0-5 V/V) H - NMR (200 MHz, CDC13) 8.02 (dd, J=O.9, 8.5Hz, lH, H-l) 7.77 (dd, J=8.5, 8.5Hz, lH, H-2) 7.38 (dd, J=O.9, 8.5Hz, lH, H-3j 5.52 (dd, J=<l, 4.0Hz, lH, H-l') 5.28 (dd, J=1.8~, ~4.0Hz, lH, H-7) 4.07 (~s, 3H, OCH3-4) 3.69 (dq,;J=6.3, 9.5Hz, lH, H-5') 3.51 (ddd, J-4.8, 9.5, 11.6Hz, lH, H-3') 3.22 (dd, J=l.9, 18.9Hz,~lH, _-lOe) .
*Trade Marks ;
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1 2.94 (d, J=18.9Hz, lH, H-lOax) 2.40 ts, 3H, COCH3) 2.2-2.4 (m, lH, H-8ax) 2.30 (dd,J=9.5, 9.5Hz, lH, H-4') 2.0-2.2 (m, 2H, H-8e, H-2'e) 1.70 (ddd, J=4.0, 4.6, 13.2Hz, lH, H-2'ax) 1.31 (d, J=6.3Hz, 3H, CH3-5') 3'-deamino-3'-hydroxy-4'-deoxy-4'-epi-4'amino doxorubicin hydrochloride (IIb) 0.5 g of IIa dissolved in a mixture of 7.5 ml of anhydrous methanol, 21 ml of dioxane and 0.53 ml of ethyl orthoformate was treated with 2.10 ml of a solution of 0.93 g of bromine in 10 ml of chloroform. After 3 hours at 10C the reaction mixture was poured into a mixture of 105 ml of ethyl ether and 50 ml of petroleum ether. The resulting red precipitate, after being filtered and washed with ethyl ether several times to completely remove the acidity, was dissolved in a mixture of 15 ml of acetone and 15 ml of 0.25 N aqueous hydrogen bromide. After 15 hours at room temperature, 9 ml of water were added and the solution was extracted several times with chloroform to remove the aglycones. Thus, the aqueous phase was extracted with n-butanol until the extracts became colorless. Evaporation of the combined organic solvent extracts ~n-butanol) under vacuum to a small volume (about 9 ml) and precipitation with ethyl ether yielded 0.45 g of the 14-bromo derivative. This latter compound was dissolved in 9 ml of 0.25 N aqueous hydrogen bromide and treated with 0.75 g of sodium formate in 8 ml of water.
The reaction mixture was kept at room temperature with stirring for 48 hours and then lN hydrochloric acid was added until the pH reached 4. The result~ng mixture was extracted~with a 1:1 mixture of ethyl ether and ethyl acetate~in order to remove some lipophilic impurities.

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- 9a -1 The aqueous phase, after being adjusted to pH 7.6 with aqueous NaHC03 was repeatedly extracted with chloroform until the extracts were colorless.
The combined chloroform extracts were dried with Na2S04 and evaporated to a small volume (about 45 ml~
under vacuum. The resulting red solution, adjusted to pH
3.5 with anhydrous methanolic hydrogen chloride, was added with excess ethyl ether to give 0.30 g of the title compound (IIb).
m.p. 180C (dec.) TLC on Kieselgel F 254 (Merck) using the eluent system CH2C~-CH30H--CH3COOH-H20 (30:4:1:05 v/v) R~=0.10.

*Trade Marks a~9~ ~

BIOLOGICAL ACTIVITY

The cytotoxic activity of the new anthracycline glycoside of the inven-tion IIa ~7aS tested "in vitro" ag?~inst HeLa cells, P388, P388/DX, LoVo and LoVo/DX.

Time Of exposure to the compound: 24 hours/in comparison with daunorubi-cin.
The results are shown in Table 1.
The compound, when tested "in vivo" against P-388 ascitic leukemia and Gross leukemia,~:exibited good antitumour activity, in comparison with daunorubicln, espéclally when orally administered.
The results:are given~in:Tables 2 and 3.
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- 12 - ~ d' l Table 2 Effect against P 388 ascitic leukemia Compound doseb T/co/oc To~ic deaths DNR 2.9 155 0/10 j ~ 4.4 170 8/10 IIa 1.96 155 0/10 ` 2.9 150 0/10 4.4 140 9/10 6.6 100 10/10 .
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Experiments were performed in CDF1 mice, inoculated with 10 leukemia cells i.p.
. Treatmen~i.p. on day 1 after tumcr looculum.

Median survival time of treated mice/median survival time of controls~x 100.
d Evaluated on the basls of autoptic findings.

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Table 3 Effect against Gross leukemia Compo~d doseb T/C%C 38x~ds mg/Kg -~NR 10 165 Gt20 192 2~20 IIa 8.2 175 0/20 11.5 230 0~10 16.1 240 0/10 22.5 ~ 130 0~10 .

~ Expe~iments were~performed in C3H mice, inoculated with 2xlO~:leukemla~cells l.V.

Treatment l.v. on day 1 after tumor inoculum.

CMedian survlval time of treated mice/median survival time ~ ` of controls x 100.

lS ~ Evaluated on~the~bas~s~of autoptlc~find mes~.
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Claims (11)

1. An anthracycline glycoside having the formula (II):

II

wherein R1 represents a hydrogen atom or a hydroxyl group, and pharmaceutically acceptable acid addition salts thereof.

2. A compound as claimed in claim 1, which is 3'-deamino-4'-deoxy-3'-hydroxy-4'-epi-4'-amino-daunorubicin or its hydrochloride.

3. A compound as claimed in claim 1, which is 3'-deamino-4'-deoxy-3'-hydroxy-4'-epi-4'-amino-doxozuficin or its hydrochloride.

4. A process for the preparation of an anthracycline glycoside of the general formula II as defined in claim 1, which comprises;

a. reacting 3'-amino-3'-epi-daunorubicin dissolved in a mixture of water and acetone, with salicylaldehyde;

b. reacting the thus produced corresponding 3'-epi-N-salicylidene derivative with trifluoromethane sulfonic anhydride in anhydrous dichloromethane and in the presence of dry pyridine;

c. submitting the thus produced 3'-epi-N-salicylidene-4'-O-trifluoro-methane sulfonate dissolved in methanol to acidic hydrolysis of the salicylidene protecting group by means of p-toluenesulfonic acid;

d. transforming the thus produced 3'-deamino-4'-deoxy-3'- epi -4'-epi-3' ,4'-epimino-daunorubicin by treatment with trifluoroacetic anhydride;

e. reacting the thus produced corresponding N-trifluoroacetyl derivative with a catalytic amount of sulfuric acid;

Claim 4 continued...

f. submitting the thus produced 4'-deoxy-4'-epi-N-trifluoroacetyl-3'-deamino-3'-hydroxy-daunorubicin to a mild alkaline hydrolysis of the N-protecting group.

5. A process as claimed in claim 4 wherein the thus produced compound of formula IIa wherein R1 represents a hydrogen atom, is further treated with methanolic hydrogen chloride and isolated as the relevant hydrochloride.

6. A process as claimed in claim 5 wherein the relevant hydrochloride is transformed by reacting it with a solution of bromine to form the 14-bromo derivative and the thus produced 14-bromo derivative is subjected to hydrolysis using an aqueous solu4ion of sodium formate.

7. A process as claimed in claim 6 wherein the thus produced compound of the formula II wherein R1 is a hydroxyl group is obtained as a free base.

8. A process as claimed in claim 7 further including the step of converting the thus produced free base into the corresponding hydrochloride.

9. A pharmaceutical composition comprising an anthracycline glycoside of formula II as defined in claim 1 or a pharmaceutically acceptable acid addition salt thereof, together with a pharmaceutically acceptable carrier or diluent.

10. A process as claimed in claim 4 wherein part c is conducted at room temperature.

11. A process as claimed in claim 4 wherein part f is conducted at 0°C.