CS214794B2 - Method of making the semiamids of dimeric indol-dihydroindole derivatives genus vinca connected by the bridge - Google Patents

Description

It has been found that some natural alkaloids derived from plants of the species Vinca rosea (Catharanthus roseus don. - alkaloids from the genus Catharanthus or Vinca) are effective in the treatment of experimental cancer in animals. These compounds include leurosine (see U.S. Patent No. 3,370,057), vincaleukoblastine (vinblastine) - hereinafter referred to as VLB (see U.S. Patent No. 3,097,137), leurophormin (see Belgian Patent No. 811110), leurosidine (vinrosidinj and leurocristine (hereinafter referred to as vincristine (both see U.S. Patent No. 3,205,220)), deoxy-VLBs "A" and "B" [see Tetrahedron Letters, 783 (1958)], 4-deacetylvinblastine (see U.S. Pat. No. 3,954,773], 4-deacetoxy-3'-hydroxyvinblastine (see U.S. Patent No. 3,944,554), leurocombin (see U.S. Patent No. 3,890,325) and vincadioline (U.S. Patent No. 3) Two of these alkaloids, VLB and vincristine, are currently on the market as a means of treating cancer, particularly leukemias and related human diseases, and these two commercial alkaloids are usually administered intravenously.

The chemical modification of the alkaloids of the genus Vinca ToylV is somewhat limited by certain circumstances. First of all, it has to be taken into account that the structure of these molecules is extremely complex and that it is therefore very difficult to develop chemical reactions that would modify one particular functional group in the molecule without affecting other groups. Secondly, dimeric alkaloids lacking the desired chemotherapeutic properties have been isolated or produced from fractions obtained from Vinca rosea plants or alkaloids from these plants and the determination of their structure has led to the conclusion that these compounds are closely related to the active compounds. alkaloids, of which often differ only by stereochemistry at a single carbon. Thus, anti-neoplastic efficacy appeared to be limited to very specific frameworks and, accordingly, the prospect of obtaining more effective drugs by modifying these structures seemed to be very small. Successful modifications of physiologically active alkaloids include the preparation of 6,7-dihydro-VLB (see U.S. Pat. No. 3,352,868) and replacement of the acetyl group at C4 (carbon at position 4 of the VLB cyclic system - see below numbering) with a higher alkanoyl group; unrelated acyl groups (see U.S. Pat. No. 3,392,173). Some of these Cxderivatives are capable of prolonging the life of mice inoculated with P1534 leukemia. One of these C4 derivatives wherein the C4-acetyl group VLB is replaced by a chloroacetyl group is also a useful intermediate for the preparation of structurally modified VLB derivatives in which the C1-acetyl group VLB is replaced by a Ν, Ν-dialkylglycyl group (see U.S. Pat. 3 387 001).

C3-carboxamide and -carboxhydrazide derivatives of VLB, vincristine, vincradioline and the like have also been prepared and have been shown to be effective against cancer (see Belgian patent specification 858,451).

These compounds are of particular interest because, for example, the 3-carboxamides of VLBs are more effective against Ridgeway osteogenic sarcoma and Gardner lymphosarcoma than VLB itself, i.e. than the basic alkaR-NH-CH2- (CH2-S- S). containing a carbonyl group on C3, and having a value of 1 to 5. Compounds of this structure have been found to be the main products of the reaction of the C3-carboxazide of a Vinca compound (R-N3) and a compound of formula NH2-CH2-CH2-SH. Some of these amino derivatives are similar in potency to the efficacy of vincristine against the same tumors, one of these amides, namely C3-carboxamide 4- deacetyl-VLB (vindesine) is currently in human clinical trials and appears to be less neurotic than and that it is effective against leukemias, including vincristine resistant leukemias.

Belgian patent specification 858 541 describes and protects bis-derivatives of dimeric compounds of the genus Vinca, linked by a bridge, which can be described by the general formula:

CH 2 - (CH 2) _n -NH-R,

-cystine. This oxidation is, of course, limited to the formation of a disulfide bond from mercaptoalkylamide and is generally not applicable to the synthesis of other bis-derivatives of dimeric compounds of the genus Catharanthus connected by a bridge.

SUMMARY OF THE INVENTION The present invention provides a process for the preparation of half-amides of dimeric indole dihydroindole derivatives of the genus Vinca, linked by a bridge, of formula IIA,

R 6 —NH — CH2— (CH2) _n —Q'- (CH2) _n —CH2 — NH2, (IIA) in which:

R ⁶ represents an indole-dihydroindole partial structure of formula II,

(II) where

R ² is methyl or hydrogen, one of R ³ and R ⁴ represents a hydroxyl group or a hydrogen atom and the other represents an ethyl group, and

R ⁵ represents a hydrogen atom,

Q ‘represents a group S or S-S, and n has a value of 0, 1 or 2, and their pharmaceutically acceptable acid addition salts, characterized in that the azide of the formula

R ^{6 -} N 3 in which

R ⁶ is an indole dihydroindole alkaloid radical of formula II, wherein R ² , R ³ , R ⁴ and R ⁵ are as defined above, reacted with a diamine of formula NH 2 -CH 2 - (CH 2) _n -Q '- ( CH 2) n -CH 2 -NH 2 in which

Q 'and n are as defined above in a ratio of 1 mole of the compound of formula R ⁶ -N 3 for each mole of the diamine of the above formula, whereupon the resulting compound is optionally converted to its pharmaceutically acceptable acid addition salt.

Non-toxic acids useful for preparing pharmaceutically useful acid addition salts of compounds of Formula IIA include inorganic acids such as hydrochloric, nitric, phosphoric, sulfuric, hydrobromic, hydroiodic, nitrous, and phosphoric acids, as well as non-toxic organic acids, including aliphatic mono- and dicarboxylic acids acids, phenylsubstituted alkanoic acids, hydroxyalkanoic and alkanedioic acids, aromatic acids and aliphatic and aromatic sulfonic acids. Such pharmaceutically acceptable salts include, for example, sulfates, pyrosulfates, bisulfates, sulfites, bisulfites, nitrates, phosphates, monohydrogenphosphates, dihydrogenphosphates, metaphosphates, pyrophosphates, chlorides, bromides, iodides, acetates, propionates, decanoates, caprylates, acylates, formates, formates, formates, capronates, heptanoates, propiolates, oxalates, malonates, succinates, suberates, sebacates, fumarates, maleates, benzoates, chlorobenzoates, methylbenzoates, dinitrobenzoates, hydroxybenzoates, methoxybenzoates, phthalates, terephthalates, benzenesulfonates, toluenesulfonates, phenylbenzenesulfonates, phenylbenzenesulfonates, phenylbenzenesulfonates, phenylbenzenesulfonates, citrates, lactates, 2-hydroxybutyrates, glycolates, malic acid salts, tartrates, methanesulfonates, propanesulfonates, 1-naphthalenesulfonates and 2-naphthalenesulfonates.

As an example of the method of the present invention, the following procedure is used, wherein VLB is used as the starting material:

The VLB is reacted with anhydrous hydrazine in an inert solvent dissolving both of the reactants, such as a lower alcohol, in a sealed reaction vessel. The reaction mixture is usually heated to a temperature in the range of 40 to 100 ° C for 12 to 48 hours, during which time the reaction is virtually complete. The product of the reaction is 4-deacetyl-VLB-C3-carboxhydrazide, since reaction with hydrazine not only leads to the conversion of the ester group to C3 to the hydrazide moiety, but also to the hydrolysis of the acetyl group to the C4 hydroxy group. Other ester groups in the molecule are not attacked under the above reaction conditions, except that some 18 množství-demethoxycarbonyl derivative is usually formed. However, the main product of the reaction is 4-deacetyl-VLB-C3-carboxhydrazide. The 4-deacetyl-C3-carboxhydrazides deoxy-VLB "A" and "B" and leurosidine were prepared in an analogous manner. The carboxhydrazides thus formed are then converted to the corresponding azides by treatment with sodium nitrite in the acid. The product of this reaction is usually used in the state in which it was isolated from the reaction mixture, since it was found that azide was not necessary to obtain an adequate yield of the desired bisamide.

Reaction of 1 mole of the azide thus obtained with 1 mole of a diamine of the formula NH 2 -CH 2 - (CH 2) _n -CH 2 - (CH 2) _n - CH 2 -NH 2, where Q 'is as defined above, under standard reaction conditions of azide and amine reaction; as described in Belgian patent specification 858,451, the desired products of formula IIA are obtained.

The resulting semi-amide of formula (IIA) can be readily separated from the optionally co-formed bisamide and can be purified and characterized in a conventional manner. In practice, in general, in addition to the desired bisamide, a poloamide is formed as a by-product even when 2 moles of azide are reacted with 1 mol of diamine. 1 mole of the semi-amide may then be reacted with 1 mole of a second azide of formula R ⁶ --N 3, wherein the residue R ⁶ is different from the residue already present in the poloamide of formula IIA, to form an unsymmetrically substituted bisamide.

The poloamides of formula (IIA) produced by the process of the invention are of major use as intermediates for the preparation of bisamides having activity against cancer.

The starting materials used in the above-described synthesis are prepared as follows.

Preparation of starting materials

4-Deacetyl-VLB-C3-carboxhydrazide

The VLB is heated in anhydrous ethanol with an excess of anhydrous hydrazine for about 18 hours in a sealed reaction vessel at a temperature of about 60 ° C. The reaction vessel is cooled, opened, the contents are removed and the volatiles are evaporated in vacuo. The rest containing

The 4-deacetyl-VLB-C3-carboxhydrazide is taken up in methylene dichloride, the methylene dichloride solution is washed with water, separated and, after drying, the methylene dichloride is evaporated in vacuo. The residue was dissolved in a mixture of equal parts of chloroform and benzene and chromatographed on silica gel. A mixture of benzene, chloroform and triethylamine is used as eluent. Initial chromatographic fractions contain unreacted starting ma7

214784 materials together with 4-deacetyl-VLB formed as a by-product in the reaction. Other fractions contain the 4-deacetyl-18‘-dimethoxycarbonyl-VLB-C 1 -carboxhydrazide previously described by Neuss et al. in Tetrahedron Letters, 1968, 783. The following fractions, which according to thin layer chromatography contain 4-deacetyl-VLB-C3-carboxhydrazide, are combined and the solvent is evaporated in vacuo. The solid residue melts at about 219-220 ° C with decomposition.

4 * Theacetyl-VLB-C3-carboxazole

678 mg of 4-dicetyl-VLB-C3-carboxhydrazide are dissolved in 15 ml of anhydrous methanol, ca 50 ml of 1 N aqueous hydrochloric acid are added to the solution, the resulting solution is cooled to about 0 ^DEG C., ca 140 mg of nitrite are added. The reaction mixture was stirred for 10 minutes while maintaining the temperature at about 0 ° C. Upon addition of sodium nitrite, the solution turned dark reddish brown. The resulting mixture was basified by addition of an excess of cold 5% aqueous sodium bicarbonate solution and the aqueous solution was extracted three times with methylene chloride. The 4-deacetyl * VLB-C3-carboxazide formed in the above reaction is transferred to methylene dichloride and this organic layer is separated. The methylene dichloride solution of 4-deacetylvinblastine-Gs-carboxazide thus obtained is usually used without further purification.

The invention is illustrated by the following non-limiting example.

Example

Preparation of bis [8-- (4-deacetyl-VLB-C3-carboxamido) ethyl] disulfide 4-deacetyl-VLB-C3-carboxhydrazide in aqueous hydrochloric acid is reacted with sodium nitrite to give 4-deacetyl-VLB- C3-carboxazide. The azide formed in this reaction was isolated as a solution in 400 ml of methylene dichloride.

22.5 g of cystamine dihydrochloride are added to 500 ml of methanol, in which 10.8 g of sodium methoxide are dissolved, and the reaction mixture is stirred for about 4 hours, after which time the solvent is evaporated. The residue was stirred with ether for 1 hour and the mixture was filtered. Evaporation of the ether filtrate in vacuo to dryness yielded about 10 g of an oily cystamine residue as a free base.

To a solution of 4-detetyl-VLB-C3-carboxazide in methylene dichloride was added 760 mg of cystamine free base in methylene dichloride. After the addition of 75 ml of tetrahydrofuran, the reaction mixture is stirred at room temperature for about 16 hours under the exclusion of light, then filtered and the filtrate is evaporated to dryness in vacuo. The residue containing fll- [8- (4-deacetyl-VLB-C3-carboxamido) ethyl disulfide] was dissolved in methylene dichloride, washed with water and dried. According to thin-layer chromatography in methylene dichloride-methanol-ethyl acetate (1: 1: 1), the methylene dichloride residue contains two major products. The residue is chromatographed on silica gel using the above-mentioned solvent system as a white reagent. Fractions containing bis [η 8 - (4-deaeetyl-VLB-C 5 -carboxamido) ethyl] disulfide according to thin layer chromatography were combined and the solvent was evaporated. 2.6 g of the expected product are obtained. Another major reaction product is also isolated and purified. This product is the reaction product of 1 mole of 4-deacetyl-VLB-C3-carboxazide and cystamine, i.e. 4-deacetyl-VLB-CS-N-2- (2-aminoethyldithlo) ethylcarboxamide. Higher yields of this product are obtained when 1 mole of azide is reacted with 1 mole of cystamine.

The bis [N - (4-deaeetyl-N 1B-C 1 -carboxamido] ethyl] disulfide thus prepared is identical to the product obtained by the procedure described in Belgian patent specification 858 451.

Disulfate bis [S- (4-desacetyl VLB C-3 karboxamldojethyl] disulfide was prepared in ethanol by adding the stoichiometric amount of 2% (v / bbjem) ethanolic sulfuric acid. Disulfate was also prepared tltřací base solution 2o / _o ethanůlickou sulfuric acid until An aliquot of the solution, diluted with 5 volumes of water, has a ptt value ranging from 3.0 to 3.5, which results in an off-white amorphous salt upon evaporation of ethanol.

Claims (1)

SUBJECT VYNALEZU A process for the preparation of dimers of dimeric indole dihydroindole derivatives from the genus Vinit ⁶ -nh-CH2 - (CHa Q *) in which: R 8 represents an indole-dihydroindole partial structure of formula II, ca, bridged, of formula IIA, - (CH 2) _n —CH 2 -NH 2, (IIA) wherein: R ² is methyl or hydrogen, one of R ³ and R ⁴ represents a hydroxyl group or a hydrogen atom and the other represents an ethyl group, and R ⁵ represents a hydrogen atom, Q ‘represents an S or S-S group and n has a value of 0, 1 or 2, and pharmaceutically acceptable acid addition salts thereof, characterized in that the azide of the formula R ⁶ -Ns in which R ⁶ is an indole dihydroindole alkaloid radical of formula II, wherein R ² , R ³ , R ⁴ and R ⁵ are as defined above, reacted with a diamine of formula NH 2 -CH 2 - (CH 2 -n-Q'- (CH 2) _n -Cl 2 -NH 2 in which Q 'and n are as defined above, in a ratio of 1 mole of a compound of formula R ⁶ -N 3 for each mole of the diamine of the above formula, whereupon the resulting compound is optionally converted to its pharmaceutically acceptable acid addition salt.