NO168710B - ANALOGY PROCEDURE FOR THE PREPARATION OF A THERAPEUTIC ACTIVE ANTHRACYCLING GYCOSIDE - Google Patents

Description

The invention relates to an analogue method of manufacture

of a therapeutically active anthracycline glycoside of formula (A):

where R 1 means a hydrogen atom, or a pharmaceutically acceptable salt thereof.

The glycoside of formula (A) is prepared by a method

which comprises reacting an N-trifluoroacetyl-protected derivative of a daunomycinone derivative of formula (I):

where the 4-amino group is protected,

with a protected halogen sugar of formula (II):

where Hal means a halogen atom which is preferably a chlorine atom, and to remove the protecting groups from the product obtained to obtain an anthracycline glycoside of formula (A) where R^. is hydrogen; and, if desired, converting said glycoside of formula (A) into a pharmaceutically acceptable salt.

The condensation of 4-demethoxy-4-N-trifluoroacetamido-daunomycinone (I) and protected halosugar (II) can take place in the presence of silver triflate. The process described in US-A-4107423 can be used, giving (7S, 9S)-trifluoroacetyl protected derivatives of the α-glycosides. The 4-demethoxy-4-N-trifluoroacetamido-daunomycinone can be dissolved in anhydrous methylene chloride, and the reaction can take place at 5-10°C. The N-protecting groups can be removed by mild alkaline treatment.

The preparation of the daunomycinone derivative of formula I and of its n-protected derivative has been described in patent application no. 881710 from which this application is divided.

Example 1

4- demethoxy- 4- amino- daunorubicin (A)

0.08 g of 4-demethoxy-4-N-trifluoroacetamido-daunomycinone (I), described in application 88.1710, was dissolved in anhydrous methylene dichloride, and the solution was cooled to 5-10°C. A solution of 0.024 g of 1-chloro-N,O-ditrifluoroacetyl-daunosamine II, which was prepared according to the method described in Cancer Chemotherapy Reports, Part 3, Vol. 6, No. 2, page 123, in diethyl ether, and a solution of 0.150 g of silver trifluoromethanesulfonate in methylene dichloride was added simultaneously and rapidly with vigorous stirring.

After 5 minutes a further 0.070 g of silver trifluoromethanesulfonate was added, and after 5 minutes the reaction was rapidly cooled with collidine.

The mixture was filtered, washed with a saturated aqueous solution of sodium bicarbonate and with water, dried and concentrated under vacuum.

The residue was chromatographed on a column of silica gel eluting with methylene dichloride to give 4-demethoxy-4-N-trifluoroacetamido-N-trifluoroacetyl-daunorubicin.

WlR (200 MHz, CDC13) :

13.76 (s, 1H, 6-0H); 13.41 (s, 1H, 11-010; 7.69 (dd, J=l.2, 7.5 Hz,

1H, 1-H); 7.49 Idd, J=7.5, 8.3 Hz, 1H, 2-H); 6.97 (dd, J=l .2, 8.3 Hz,

1H, 3-H); 6.80 (broad signal, 2H, NH}; 6.64 (d, J=8.9 Hz, 1H, NHCOCF^;

5.50 (d, J=3.9 Hz, 1H, 1'-H); 5.26 (dd, J = 1.8, 3.7 Hz, 1H, 7-H);

4.3-4.2 (in, 3H, 9-0H, 5'-H, 3'-H); 3.65 (nine, 4'-H); 3.26 (dd, J = 1.5, 19.0 Hz, 1H, 10-Heq); 2.95 (d, J = 19.U Hz, 1H, 10-Hax); 2.41 (s, 3H, COCH )•, 2.30 (ddd, J=1.5, 1.8, 15.6 Hz, 1H, 8Heq); 2.16 (dd, J = 3.7, 15.6 Hz, 1H, 8-Hax); 2.0-1.6 (in, 2H, 2'-CH2); 1.30 (d, J= 6.6 Hz,

3H, 5'-.CH ).

The compound was dissolved in 10 ml of acetone and treated with 30 ml of 0.1N aqueous sodium hydroxide at 0°C for 3 hours. Then, a 0.1N aqueous hydrochloric acid solution was added to the mixture to adjust the pH to 4.5, and the aglycone was eliminated by extracting with methylene dichloride. Then the aqueous solution was adjusted to pH 8.6 and extracted with methylene dichloride, dried over anhydrous sodium sulfate, concentrated to a small volume, and acidified to pH 4.5 with 0.1N methanol-hydrogen chloride to give the aforementioned compound as its hydrochloride. Thin-layer chromatography on silica gel plate F254 (Merck) with elution system methylene chloride/methanol/acetic acid/water (80/20/7/3 parts by volume) gave Rf = 0.63; FD-MS/m/z 512 [M<+>].

The glycoside is an antitumor agent. The activity of 4-demethoxy-4-amino-daunorubicin (A) has been investigated by comparing its in vitro cytotoxicity with daunorubicin (DNR) in human colon adenocarcinoma cells, which cells are sensitive (L0V0) or resistant (L0V0/DX) to doxorubicin. The results are shown in table 1.

The in vitro activity of (A) and DNR against disseminated Gross leukemia was also determined. The results are shown in table 2:

T/C % means the median survival time of treated mice/the median survival time of the controls x 100.

TOX means toxic dead.

Claims (1)

Analogous procedure for the preparation of therapeutically active anthracycline glycoside of formula (A): where Ri means a hydrogen atom, or a pharmaceutically acceptable salt thereof, characterized by reacting 4-demethoxy-4-N-trifluoroacetamido-daunomycinone, dissolved in anhydrous methylene chloride, at a temperature of 5-10°C, with an ethereal solution of 1-chloro-N,0-ditrifluoroacetyldaunosamine in the presence of silver trifluoromethanesulfonate, purify on a silica gel column the N-trifluoroacetyl-protected daunorubicin derivative by eluting with methylene dichloride, subject the protected derivative to mild alkaline hydrolysis with 0.1N aqueous sodium hydroxide at 0°C in acetone for 3 hours, followed by extraction with methylene dichloride and subsequent treatment of the concentrated solution with 0.1N methanolic hydrogen chloride to obtain the desired 4-demethoxy-4-amino-daunorubicin in the form of its hydrochloride.