CH661661A5 - ANTINEOPLASTIC AGENT. - Google Patents

Description

The invention relates to an antineoplastic agent containing an organic germanium derivative as the main ingredient.

Germanium (Ge), which is a metal, and which is known to be homologous to carbon, has the special property of exerting a semiconductor effect, like silicon (Si), and has been studied in this regard during long time.

Recently, studies of organic germanium derivatives have progressed, their results have been published and have attracted the attention of the public in various technical fields, in particular in the medical field. For example, it is well known, medically and pharmaceutically, that a carboxyethylgermanium sesquioxide of formula (GeCH2CH2C00H) 203 exhibits excellent physiological effects, such as energetic hypotensive and antineoplastic effects, and is free from toxicity or adverse reactions.

In addition, compounds analogous to the sesquioxide type compounds, represented by the abovementioned carboxyethylgermanium sesquioxide, have been the subject of extensive studies. Compounds of the ses-quisulfide (Ge — C — C — CO—) 2S3 type having the same structure as that of the abovementioned compound except that the oxygen atoms linked alternately with germanium atoms to form a macromolecular crosslinked compound are replaced by sulfur atoms having similar bonding properties were prepared by one of the inventors of the present invention.

This type of compound, with their preparation process, has been the subject of a patent (see Japanese patent No. 203090/1982). Although the mechanism of physiological activity of sesquioxide compounds has not been fully elucidated so far, it is generally accepted that these effects are obtained due to the presence of the germanium-oxygen bond contained in the structure . It is therefore to be expected that sesquisulfide type compounds having the same structure as that of sesquioxide type compounds, except that the oxygen atom in the crosslink is replaced by a sulfur atom, which is a homologous oxygen, also exhibit excellent physiological activities.

After very extensive research carried out under these conditions, the inventors have found that some of the organic germanium derivatives, of the sesquisulfide type, exhibit very energetic antineoplastic effects. The present invention has been completed on the basis of this discovery.

The subject of the present invention is an antineoplastic agent comprising as main ingredient an organic germanium derivative having the following general formula:

AT

Ge — CH — CH — COZ | 2S3

wherein A represents a hydrogen atom, a lower alkyl group, such as a methyl or ethyl group, or a phenyl group, B represents a hydrogen atom or a lower alkyl group, such as a methyl or ethyl group , and Z represents a hy-5 droxyl or amino group.

The antineoplastic agent according to the invention contains an organic derivative of germanium, having the general formula (I) as the main ingredient, as previously described. This type of compound has a basic structure comprising a derivative of germylpropionic acid containing a germanium atom and a propionic acid residue containing a functional group CO — Z containing oxygen. In this molecular compound, the above-mentioned germylpropionic acid derivative and the sulfur atoms are linked alternately in a ratio of 2/3. The substituent A in the above general formula (I) is a hydrogen atom, a lower alkyl group, such as a methyl, ethyl, propyl or isopropyl group, or a substituted or unsubstituted phenyl group. The substituent B is a hydrogen atom or a lower alkyl group, as mentioned for the substituent A. The substituent A is arranged in position 20 a, and the substituent B, in position ß, respectively, compared to the atom of germanium.

The substituent Z with respect to the functional group containing oxygen is a hydroxyl group (—OH) or an amino group (—NH2). The organic germanium derivatives, used as the main ingredient of the antineoplastic agent of the invention, therefore include, for example, the following compounds:

(Ge - ch2 - ch2 - cooh) 2s3

çh3

(Ge - ch - ch2 - cooh) 2s3 (Ge - ch2 - ch- cooh) 2s3

ch3

çh3

(Ge - ch - ch - cooh) 2s3 ch3

/ S

v

(i)

(2)

(3)

(4)

(Ge - ch - ch2 - cooh) 2s3 (Ge - ch2 - ch2 - conh2) 2s3

A V

i

(Ge - ch - ch2 - conh2) 2s3

(5)

(6)

(7)

The organic germanium derivatives having the above structure can be prepared by synthesis according to various methods. For example, a method described in the cited pre-55 Japanese patent application, open to public consultation, No. 203090/1982, comprises the addition of trichlorogermanium HGeCl to an acrylic acid derivative (II), to form a derivative trichlorogermylpropionic acid (III), the reaction of this derivative (III) with hydrogen sulfide in the presence of a base, under anhydrous conditions, so as to form a trimercapto compound (IV) and intermolecular elimination hydrogen sulfide from this mercapto compound (IV), in accordance with the following reaction scheme:

65

(I)

CH = CH - COZ + HGeCl3 -B

(II)

> Cl3Ge - CH - CH - COZ B

(III)

3

661 661

SH A

I I

HS — Ge — CH — CH — COZ

I I

SH B (IV)

where the symbols A, B and Z have the same meaning as before.

It is preferable, for some of these compounds, in particular when the substituent Z is NH2, to start the reaction with a substituted or unsubstituted acrylic acid (a compound of formula (II) in which Z = —OH), instead of a substituted acrylamide (a compound of formula (II) in which Z is NH2), since the amide is generally expensive and is not readily available commercially and undesirable side reactions may occur, the addition reaction of this compound with trichlorogermanium taking place as indicated in the reaction scheme below:

CH = CH — COOH + HGeCl3 -B

HAVE

* Cl3Ge — CH — CH — COOH -

Cl3Ge- CH - CH - COC1 -> Cl3Ge - CH - CH - CONH;

H, S

B

HS

SH I

-Ge-I

SH

HAVE

CH-

CH-CONH2 B

(IV)

(I)

In the two aforementioned methods, the trimercapto compound (IV) formed by reaction with hydrogen sulfide can be isolated or not.

The organic germanium derivatives of general formula (I), including the compounds (1) to (7) obtained according to the above process, are generally in the form of colorless and transparent crystals. The antineoplastic agent according to the invention, containing the organo-germanium compound as the main ingredient, can be formulated into tablets, powder, granules, capsules and the like according to a known method.

The antineoplastic agent formulated as indicated above is administered to patients carrying various tumors, in order to inhibit the growth of the carcinoma or to control the latter. It is, however, difficult to confirm the pharmacological effects of the antineoplastic agents of the present invention, by actually administering them to patients, since various problems arise in such an assay. The doses and effects of these agents were therefore demonstrated by biological tests.

An organic germanium derivative was suspended in water and administered orally to mice to which 1 x 10® BMI carcinoma cells were transplanted subcutaneously for a specified period. The antineoplastic agents according to the invention do indeed inhibit the growth of BMI carcinoma, as indicated in Table 1.

Table 1

Compound

Dose

Weight report *

Number of mice

Carcinoma weight (mean ± S.D)

Inhibition rate (%)

T-value

P

Witness

20

1.49 ± 0.53

(1)

10 2

0.0258 0.0052

10 10

1.29 ± 0.34 1.56 ± 0.56

13.6

i. 082

0.335

(2)

50 10 2

0.1205 0.0241 0.0048

10 10 10

1.03 ± 0.31 1.06 + 0.39 1.10 ± 0.32

31 29 26.0

2,427 2,276 2,130

* * *

(3)

10 2

0.0241 0.0048

10 10

1.08 + 0.29 1.06 ± 0.39

28

29

2,270 2,269

* *

(4)

100 10

0.2257 0.0226

10 10

1.17 ± 0.51 1.30 ± 0.40

21 13

1.578 0.997

(5)

50 2

0.0928 0.0037

10 10

1.19 + 0.67 1.63 ± 0.76

20

1.339 0.589

(6)

50 2

0.1299 0.0052

10 10

1.23 + 0.46 1.22 ± 0.31

17

18

1,320 1,481

(7)

25 5 1

0.0466 0.0093 0.0019

10 10 10

0.65 ± 0.31 0.76 ± 0.32 1.17 ± 0.48

56 49 21

4.608 3.987 1.606

** **

* Dose / weight chemical formula of each compound

It is true that the weight of the carcinoma after administration of (GeCH2CH2C00H) 203, mentioned previously as a common example of sesquioxide compounds, at the rate of 100 mg / kg / day is 0.95, but the quantity (dose / molecular weight) is of the order of 0.3215. It therefore appears that the agents

* = P <0.05 Jjesfc = P <0.01

antineoplastics according to the invention remarkably well inhibit the growth of BMI carcinoma.

The physiological mechanism of a tumor in the human body is very complicated, since it involves various factors. By examining the results indicated in Table 1, it may be thought that if one

661 661

4

administers to a human being, at a dose of 1 mg / kg / day (50 mg per day per 50 kg body weight of the subject), an antineoplastic agent of the invention containing the compound (7) as main ingredient, a inhibition rate equivalent to that obtained in mice. Because the dose of the above sesquioxide compounds, used practically for the treatment of cancer, is approximately 500 to 2000 mg / day, and the LDS0 value, depending on the type of organo-germanium compound, is, for the compound (7), of the order of 560 mg / day, it follows that even the upper limit of the dose will be much lower than the LDS0, and that the antineoplastic agent of the invention administered orally can be used for the treatment of tumors on the human body.

The examples below illustrate the invention in more detail.

Experimental example 1:

Synthesis of the organic germanium derivative:

(1) Synthesis of the compound (1)

25.2 g (0.1 mol) of 2-carboxyethyltrichlorogermanium Cl3GeCH2CH2COOH are dissolved in 200 ml of anhydrous benzene. 24 g (0.3 mol) of anhydrous pyridine are added to the solution and the mixture is stirred. Hydrogen sulfide gas is then introduced into this mixture for 60 minutes. The benzene is carefully removed from the oily product obtained, then the residue is dissolved in 100 ml of methanol. The solution is added to 300 ml of purified water and the crystals thus formed are recrystallized from methanol, which gives 16.8 g of 2-carboxyethylgermanium sesquisulfide (1)

(GeCH2CH2COOH) 2S3, in the form of colorless plaques. The yield is 86.7%.

Melting point: 200 ° C (calculated from the DTA spectrum).

Solubilities: easily soluble in DMSO, dioxane, io THF and acetone.

Elementary analysis in the form of Ge2C6H10O4S3:

Calculated: Ge 37.44 C 18.61 H 2.62 S 24.83%

Found: Ge 37.21 C 18.69 H 2.68 S 24.89%

15 IR (KBr, cm-1) 3420, 1707, 425.

NMR (dioxane-d8, a) 1.97, 2.57.

(2) Synthesis of compounds (2) to (7)

These compounds are synthesized in the same manner as that previously described. The physical properties of compounds (2) to (5) are indicated in Table 2, and those of compounds (6) and (7) are indicated in Table 3.

Table 2

Compound

Calculated / found elemental analysis

Fusion point

IR (KBr, cm "1)

Solvent

NMR (5)

Yield

Ge

VS

H

S

(2)

34.92 35.45

23.13 23.17

3.40 3.39

23.15 23.34

185 (dec.)

3450, 2960,1705,1405, 1240,1220, 610,425

CD3OD

1.36 (3H, d, J = 7Hz, -CH-CH3), 2.08 ~ 2.95 (3H, m, -CH-CHJ

5.77

(3)

34.92 35.20

23.13 22.29

3.40 3.45

23.15 22.96

196 (Dec.)

3450, 2980,1705,1465, 1420, 1245, 760, 425

cd3od l, 38 (3H, d, J = 7.5Hz, CH-CH3), 2.03 (2H, m, J = 45Hz, Ge-CH2), 2.94 (lH, m, J = 29Hz, CH -CO)

93.8

(4)

32.73 32.50

27.07 27.13

4.09 4.02

21.68 21.92

235 (dec.)

3400, 2960,1700,1445, 1225, 820, 680, 600,425

cd3od l, 37 (3H, dd, J = 12Hz, CO-CH-CH3), l, 37 (3H, ddJ = 12Hz, Ge-CH-CH3), 2.18 (lH, m, J = 28.5Hz , CH-CO), 2.80 (1H, m, J = 28.5Hz, Ge-CH)

72.1

(5)

26.90 26.41

40.06 40.32

3.36 3.54

17.82 17.86

265 (dec.)

3450, 3040, 2850,1710, 1600, 1410,1230, 700, 425

cd3od

3.00 (2H, d, J = 8Hz, CH2CO), 3.55 (1H, 1, J = 16Hz, Ge-CH-), 7.25 (5H, m, -C6H5)

94.1

Table 3

Compound

Calculated / found elemental analysis

Fusion point

IR (KBr, cm "1)

Solvent

NMR (5)

Yield

Ge

VS

H

NOT

S

(6)

37.66 38.00

18.69 18.86

3.14 3.20

7.27 7.08

24.94 24.90

203 (dec.)

3300, 3200, 1665, 1400, 1020, 600,425

DMF-d,

1.97 (2H, t, J = 15Hz, Ge — CH2), 2.50 (2H, t, J = 15Hz, CH2 - CO), 7.10 (2H, d, J = 60Hz, —NH2)

27.5

(7)

27.00 27.26

40.20 40.34

3.75 3.93

5.21 5.18

17.89 17.66

210 (dec.)

3450, 3350, 3200, 1660, 1600, 1400, 765, 700, 420

DMF-d,

2.43 (1H, t, J = 14Hz, Ge-CH), 3.05 (2H, d, J = 7Hz, CH2-CO), 7.23 (5H, m, -C6H5)

81.8

5

661 661

Experimental example 2:

Effects of Suppression of Tumors by the Antineoplastic Agents of the Invention

CDF 1 female mice of 9 weeks old were used for the tests. Each group comprises 10 mice, the control group comprising 20 mice. 1 x 106 BMI carcinoma cells were transplanted to each of them subcutaneously. From the following day, an antineoplastic agent of the invention, containing the organic germanium derivative of general formula (1) as the main ingredient, was administered orally, in a dose of organo-germanium compound from 1 to 100 mg / kg / day for 5 days, then administration was stopped for 1 day. This cycle was repeated three times. Two days after the final administration, the mice were sacrificed, and the carcinoma was weighed for each mouse, which gave the results indicated in Table 1.

R

Claims (2)

661 661 2 CLAIMS 1. Antineoplastic agent comprising as main ingredient an organic germanium derivative having the following general formula: Ge — CH — CH — COZ J, S3 (I) wherein A represents a hydrogen atom, a lower alkyl group or a phenyl group, B represents a hydrogen atom or a lower alkyl group and Z represents a hydroxyl or amino group. 2. Antineoplastic agent according to claim 1, comprising as main ingredient a compound of formula (I) in which the symbols A and B each represent a hydrogen atom or a methyl or ethyl, propyl or isopropyl group.