CH649761A5 - N-SUBSTITUTED IMINODIACETIC ACIDS. - Google Patents

Description

The invention presented here relates to compounds of the following formula

. S y ^ -C-OH

2— -CCH2) n-NH-C-CHn-N

\

CH - C-OH

2 II

or a water soluble salt thereof which is pharmaceutically acceptable. In the above formula, R, and R4 each independently represent a hydrogen atom or a methyl or ethyl group, one of R2 and R3 is an alkyl group containing between 1 and 4 carbon atoms and l the other is an iodine or bromine atom, and n is 0, 1 or 2; this invention also includes compositions containing the bodies of formula I (or the salts thereof) and a reducing agent which can be complexed with tech-netium-99.

In formula I, as in all of the following description, the symbols have the same meaning as above.

Technetium-99 complexes with a body of formula I are used for external visualization of the hepatobiliary system. These 5 complexes have good specificity (that is, when injected into a mammal, a large percentage of the complex passes through the liver and into the bile) and they pass quickly from the liver into the bile, which allows good observations of the biliary system.

Apart from the brain, the liver is the organ which is most often examined by radioactive techniques. Most of these studies involve the intravenous administration of labeled particles, for example colloidal sulfide of Tc-99 which is effectively ingested by Kupffer cells. The diagnosis thus obtained is of great value for the study of the morphology of the liver and the function of Kupffer's cells. The optimal agent for these studies should be rapidly ingested exclusively by healthy Kupffer cells and should be biodegradable and non-toxic.

Radioisotope studies also cover hepatocyte function and the condition of the cystic duct (including the functions of the gallbladder).

The optimal agent for these studies should be rapidly ingested exclusively by hepatocytes, and should pass rapidly through the hepatic system to be excreted in the biliary system. 25 A great deal of specificity is required to obtain the maximum amount of information for diagnosis, while limiting the radioactive dose received by the patient. The time required for the concentration in the liver to be maximum (tmax) and the time required for the concentration to decrease to 50% of the maximum concentration located at 30 tmax (ts ()) must both be short for reduce the duration of this study. This is important in the case of patients who cannot be immobilized for a long time.

A short-term study makes it possible to increase the number of patients to be subjected to this observation, for a definite period of time, which makes it possible to better profit from this visualization equipment.

A short time t50 means that there is a greater relationship between the radioactivity contained in the bile and the radioactivity remaining in the liver, which makes it possible to obtain a better separation between 40 the intrahepatic channels and the rest of the liver, this which improves the image quality and thus facilitates diagnosis.

Until recently, most studies of biliary functions in radioactive medicine were carried out with pink bengal containing I-131 or with bromosulfophthalein containing I-45 131. Although pink bengal containing l 'I-131 is usually the standard product for comparing the agents used in the study of liver functions, the energy of its emitted photons is not optimal for viewing by means of y cameras and the patient's exposure to ß rays that cannot be used for diagnosis so limit the dose which can be administered without risk. The resolution of the images and therefore the information used for diagnosis is limited.

The intake of penicillamine containing Tc-99 by Tubis et al. ("Radiopharmaceuticals", Subramian et al. Eds., The Society of 55 Nuclear Medicine, Inc., New York, 1975, pp. 55-62) in 1974 marked a significant step in the research undertaken to overcome the inherent limitations of the products labeled with iodine-131 and it stimulated the search for hepatobiliary agents labeled with technetium-99. Among the agents labeled with techné-60 tium-99 which have been developed to date, the most useful are N-substituted iminodiacetic acids (hepato-iminodi-acetic acids, HIDA).

Loberg et al., In U.S. Patent No. 4017596, discloses, among other things, the use of a technetium-99 chelate and a substituted "iminodiacetic acid" for external visualization of organs. Eckelmann et al., In U.S. Patent No. 3,725,295, discloses labeling of diethylenetriaminepentaacetic acid (DTPA) with technetium-99.

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The various HIDA derivatives which have been revealed in the literature correspond to the formula:

O

O "

/ TX n H ^ CH -C-OH

('^ V (CH-) -NH-C-CH - N \ = / 2 n 2 CH - C-OH

2 il O -

Analogous products described include 2,6-dimethyl derivatives (Loberg et al., U.S. Patent No. 4017596); 2,6-diethylated, 2,6-diisopropylated, 2-butoxylated, 4-butoxylated, 4-butylated, 4-isopropylated and 4-iodinated derivatives (Wistow et al., "Radiology", 128: 793-794, 1978 ); 2,3-dimethyl, 2,4-dimethyl, 2,5-dimethyl, 3,4-dimethyl and 3,5-dimethyl derivatives (Van Wyk et al., "Eur. J. Nucl. Med." , 4: 445-448,1979), and 2,4,6-trisubstituted derivatives in which at least two of the substituents are alkyl groups containing between 1 and 4 carbon atoms, the third substituent being either a hydrogen atom , or an alkyl group containing between 1 and 4 carbon atoms, and the substituents taken together contain at least three carbon atoms (Belgian Patent No. 855107); 2,6-dime-thylated, 2,6-diethylated, 2,6-diisopropylated, 4-methylated, 4-ethylated, 4-isopropylated, 4-n-butylated, 4-n-pentylated, 4-t- derivatives butylated, 4-phenylated, 4-methoxylated, 3,5-dimethylated, 2,4,6-trimethylated, 2,4,5-trimethylated, 4-fluorinated, 2,4-difluorinated, 2,5-difluorinated and 2,3,4,5,6-pentafluorés (Molten et al., 3rd Int. Symp. Radiopharm. Chem., St. Louis Mo., June 1980). Fields et al., In the "Journal of Labeled Compounds and Radio-pharmaceuticals", XV: 387-399 (1978), present N- (2-phenethylcarbamylmethyl) imidodiacetic acid.

Van Wyk et al. ("Eur. J. Nucl. Med.", 4: 445-448, 1979), in their work on the dimethylated derivatives of HIDA, have shown that the steric effects of the substituents influence the absorption by bile.

Chiotellis et al. in "Int. J. Nucl. Med. Biol. ”, 7: 1-7, 1980, working with 4-butylated HIDA compounds, have shown that the molecular size of the substituents has an important influence on absorption by bile.

The compounds of formula I according to this invention and the salts thereof can be labeled with technetium-99, then be administered intravenously to a patient in order to visualize his hepatobiliary system. The radioactive labeling of the compounds of formula I, and of their salts, can be carried out using techniques well known in the field. According to a preferred method, technetium-99 is combined, which is in the form of an aqueous solution of sodium pertechnetate (Na 99Tc04) with a reducing agent and with a compound of formula I or one of its salts. While the order of addition of these three compounds mentioned above is not critical, it is however preferred to combine the reducing agent with a compound of formula I of this invention. This composition (which is not radioactive) can be supplied to radiochemists, technicians, radio pharmacists, doctors or other people to be marked with technetium-99 just before use.

Stannous ion is the preferred reducing agent. As stannous reducing agents, there may be mentioned stannous chloride and stannous fluoride.

Technetium-99 in the form of an aqueous solution of sodium pertechnetate is readily available commercially from molybdenum-99 / technetium-99 generators, the latter being obtained by elution with saline solutions.

The compounds of formula I of this invention can be prepared by taking nitrilotriacetic acid, acetic anhydride and a substituted amine of formula:

First, nitrilotriacetic acid and acetic anhydride are reacted to obtain nitrilotriacetic anhydride, which is then reacted with an amine of formula II to obtain the corresponding compound of formula I. The reaction proceeds more easily if the compounds are present in stoichiometric ratios.

The compounds of formula I can be transformed into their water-soluble salts, which are pharmaceutically acceptable, using well known methods. The salts preferably chosen are the salts of alkali metals and the salts of alkaline earth metals.

The compounds of formula I (and the salts thereof) can be prepared for their complexation with technetium-99 according to known methods. For example, a ready-to-use solution can be prepared by first dissolving a compound of formula I (or one of its salts) in a base (eg sodium hydroxide) to give a solution having a pH approximately 6 to 7. To this solution is added an acid solution of a reducing agent (for example stannous fluoride in hydrochloric acid). Water can be added to obtain a certain volume. Technetium-99 can preferably be added to this solution in the form of an aqueous solution of sodium pertechnetate. Lyophilized kits can be prepared using the technique described above, except that, before adding technetium-99, the solution is lyophilized. This lyophilized product can be kept under an inert atmosphere.

The preferred compounds of this invention are those of formula I in which n is 0. The compounds which have the following formula will be chosen in particular:

CH

• nh-c-ch0-n;

or a pharmaceutically acceptable water soluble salt thereof and in which one of R'2 and R'3 is a methyl group or an ethyl group and the other is an atom bromine or iodine.

The following examples represent preferred embodiments of this invention.

Example I

Acid 2,2 '- [[2 - [(3-bromo-2,4,6-trimethylphenyl) amino] -2-oxoethyl] -imino Jbisacetic

A) 3-Bromo-2,4,6-trimethylaniline

80 ml of concentrated hydrochloric acid are cooled on a cold water bath at 5 ° C. 13.5 g of 2,4,6-trimethylaniline are added thereto, over a period of 20 min and with vigorous stirring, while keeping the temperature below 15 ° C. The thick mass is cooled to 3 ° C. and 16.8 g of bromine dissolved in 80 ml of concentrated hydrochloric acid are added thereto over a period of 25 min. This mixture is then heated on a water bath for 1 h, then cooled on an ice bath for 1 h. The reaction mixture is then filtered and the salt obtained is washed with three 50 ml portions of cold distilled water. After drying, the crude product is dissolved in 600 ml of distilled water, treated with 3.0 g of Darco and filtered through a Hyflo bed to give a solution. Neutralization with concentrated ammonium hydroxide gives a milky solution from which the product precipitates upon cooling to 10 ° C. After refrigeration for approximately 16 h, the brown product is filtered, washed with cold distilled water and dried under vacuum for approximately 16 h, which gives 12.0 g of the title body, the melting point is 34.0-35.0 ° C.

B) 2,2 '- [[2 - [(3-bromo-2,4,6-trimethylphenyl) aminoJ-2-oxo-ethyl] imino Jbisacetic acid

In a dry medium (CaS04 tube), a suspension of

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9.56 g of nitrilotriacetic acid in pyridine (dried on a molecular sieve) and it is heated to 50 ° C. 5.11 g of acetic anhydride are added dropwise. The reaction mixture clears up and is heated to 100 ° C. This temperature is maintained for 40 min, then the reaction mixture is cooled to 55 ° C and a solution composed of 10.7 g of 3-bromo-2,4,6-tri-methylaniline dissolved in 25 ml of pyridine is slowly added anhydrous. This mixture is then heated to 100 ° C and, after 1.5 hours at this temperature, the mixture is cooled on an ice bath. The reaction mixture is concentrated in a rotary evaporator to a semi-solid which is then dissolved in 125 ml of a 10% w / v solution of sodium hydroxide. The basic layer is extracted with two 100 ml portions of methylene chloride. 100 ml of distilled water are then added to this basic layer and then brought to pH 3 with concentrated hydrochloric acid, which causes precipitation. After refrigeration for about 16 h, the crude product is filtered, washed with cold distilled water and dried under vacuum at 40 ° C. The product obtained is dissolved in 100 ml of 60% aqueous ethanol , treated with 3.0 g of Darco and filtered hot through a Hyflo bed to give a solution. Crystals precipitate and are filtered, washed with three 25 ml portions of 50% aqueous ethanol and dried under vacuum at 40 ° C. This method gives 9.1 g of the title product, the point of which melting is 198-200 ° C, with decomposition.

Example 2

Acid 2,2 '- [[2- [(3-bromo-2,6-diethyl-4-methylphenyl) amino J-2-oxo-ethylJimino Jbisacetic

A) 3-Bromo-2,6-diethyl-4-methylaniline

10 ml of concentrated HCl are cooled to 5 ° C. on an ice-water bath and 1.63 g of 2,6-diethyl-4-methyl-aniline are added dropwise, which produces a mass. 1.59 g of bromine dissolved in 10 ml of concentrated hydrochloric acid are added dropwise over a period of 30 min. The solution is stirred for 3.75 h, then 25 ml of distilled water is added to it. After cooling for 1 h, the reaction mixture is filtered and washed twice with 25 ml portions of cold distilled water. After drying under vacuum for about 16 h, the crude solid (2.3 g) is dissolved in 100 ml of a 10% NaOH solution and it is extracted with a portion of 150 ml and a portion of 100 ml methylene chloride.

After drying over sodium sulfate, the methylene chloride solution is evaporated in a rotary evaporator to give 1.9 g of crude product.

B) 2,2 '- [[2-f (3-bromo-2,6-diethyl-4-methylphenyl) -amino] -2-oxoethyl] imino Jbisacetic acid

A mixture of 1.34 g of nitrilotriacetic acid dissolved in 15 ml of anhydrous pyridine (dried over molecular sieve) is prepared and it is heated to 46 ° C. 0.72 g of acetic anhydride is added thereto (by rinsing with 1 ml of pyridine) and this solution is heated to 100 ° C. After heating for 0.5 h, the solution is allowed to cool to 46 ° C. and a solution composed of 1.7 g of 3-bromo-2,6-diethyl-4-methylaniline dissolved in 6 is slowly added thereto. ml of pyridine. This solution is heated at 100 ° C for 2 h, then cooled and evaporated in a rotary evaporator to obtain a pasty product. This product is dissolved in 25 ml of a 10% sodium hydroxide solution and the resulting solution is extracted twice with 25 ml portions of methylene chloride. The aqueous layer is diluted with 50 ml of distilled water, brought to pH 3.0 with concentrated hydrochloric acid and cooled for about 16 h. By filtration, a solid is recovered which, after drying for 2 h at 60 ° C. under vacuum, gives 1.4 g of crude product. By recrystallization from 25 ml of 50% ethanol, 1.04 g of product are obtained in the form of needles with a melting point of 194.5-195.5 ° C.

Example 3

2,2 '- [[2- [(3-iodo-4-methylphenyl) amino] -2-oxoethylJimino] -bisacetic acid

A mass of 4.78 g of nitrilotriacetic acid dissolved in 40 ml of anhydrous pyridine (dried over molecular sieve) is heated to 60 ° C. 2.55 g of acetic anhydride are then added slowly and the solution is heated to 100 ° C. After heating for 0.5 h, the solution is cooled to 40 ° C. and a solution of 5.8 g of 3-iodo-4-methylaniline dissolved in 20 ml of pyridine is added over a period of 25 min. anhydrous. This solution is heated at 100 ° C for 1.0 h. This mixture is then cooled and evaporated in a rotary evaporator to collect a residue which is dissolved in 65 ml of 10% sodium hydroxide. This solution is extracted twice with 50 ml portions of methylene chloride, diluted with 100 ml of distilled water and brought to pH 3.2 with concentrated HCl. The crude product is kept cold for approximately 16 h, it is filtered, it is washed twice with 50 ml portions of distilled water and it is dried under vacuum at 40 ° C. This crude product (8.0 g ) is recrystallized after having been treated with Darco, which gives 5.7 g of product with a melting point of 213.5-215 ° C, with decomposition.

Example 4

Acid 2,2 '- [[2- [(4-bromo-3-methylphenyl) amino] -2-oxoethylJ-imino Jbisacetic

A mass of 9.56 g of nitrilotriacetic acid dissolved in 80 ml of anhydrous pyridine (dried over a molecular sieve) is heated to 55 ° C. 7.66 g of acetic anhydride are added thereto and this solution is heated to 100 ° C. After heating for 0.5 h, the solution is cooled to 55 ° C and 9.30 g of 4-bromo-3-methylaniline are added thereto, rinsing with 5 ml of pyridine. This solution is heated at 100 ° C for 1.0 h. This mixture is then cooled and evaporated in a rotary evaporator until a pasty solid is obtained which is in turn dissolved in 120 ml of aqueous ammonium hydroxide solution (30 ml of hydroxide d concentrated ammonium / 90 ml of distilled water). The light brown solution is extracted twice with 100 ml portions of methylene chloride and it is brought to pH 3 with 35 ml of concentrated HCl. The white solid which has precipitated is filtered, washed with three 25 ml portions of cold distilled water and dried under vacuum for 2.75 h at 60 ° C. This crude product obtained (12.9 g) is recrystallized from 360 ml of 50% ethanol to give 9.85 g of product, the melting point of which is 206.5-209.0 ° C.

Example 5

Acid 2,2 '- [[2- [(3-bromo-4-methylphenyl) amino] -2-oxoethyl] -imino Jbisacetic

A mixture of 4.78 g of nitrilotriacetic acid dissolved in 40 ml of anhydrous pyridine (dried over molecular sieve) is prepared and it is heated to 50 ° C. 2.55 g of acetic anhydride is slowly added thereto and heat this solution to 100 ° C. After heating for 0.5 h, this solution is cooled to 42 ° C and slowly added 4.81 g of 3-bromo-4-methylaniline dissolved in 5 ml of pyridine. This solution is heated to 100 ° C. After heating for 2 h, the reaction mixture is cooled and evaporated in a rotary evaporator. The product obtained is redissolved in 75 ml of 10% sodium hydroxide and this solution is extracted twice with 50 ml portions of methylene chloride. The aqueous part is diluted with 100 ml of distilled water and then brought to pH 3.2 with concentrated HCl and cooled for approximately 16 h overnight. This solution is then filtered and washed with cold distilled water. After drying for 3 h under vacuum at 60 ° C, 7.14 g of desired crude product is obtained, the melting point of which is 106.0-108.0 ° C. By recrystallization from 150 ml of 75% ethanol, 6.4 g of a solid is obtained which melts at 209.0-210.0 ° C.

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Example 6

Formulations for complexation with technetium-99

The table presents examples of formulations containing compounds of formula I combined with a reducing agent which is stannous fluoride. These formulations are prepared by dissolving the ligand in 0.46M sodium hydroxide so as to form a solution with a pH of about 6 to 7.5. To this is added 0.01 ml of a solution of 70 mg / ml of stannous fluoride in 6M hydrochloric acid and the final volume is brought to 5 ml with water so that the solution is ready for use. 'injection. The formulations in the table have a preferred molar ratio between ligand and tin of 150: 1.

Board

Ligand

Concentration (mg / ml)

tin fluoride ligand pH

Acid 2,2 '- [[2 - [(3-bromo-2,4,6-tri-

methylphenyl) amino] -2-oxoethyl] -

imino] bisacetic

48.6

0.14

6.76

2.2 'acid - [[2 - [(3-bromo-2,6-diethyl-4-

methylphenyl) amino] -2-oxoethyl] -

iminojbisacé tick

51.9

0.14

5.99

2.2 'acid - [[2 - [(3-iodo-4-methyl-

phenyl) amino] -2-oxoethyl] imino] -

bisacetic

50.4

0.14

7.55

Acid 2,2 '- [[2 - [(4-bromo-3-methyl-

phenyl) amino] -2-oxoethyl] imino] -

bisacetic

44.6

0.14

5.96

Acid 2,2 '- [[2 - [(3-bromo-4-methyl-

phenyl) amino] -2-oxoethyl] imino] -

bisacetic

44.9

0.14

7.39

R

Claims (10)

649761 2 1. Compound of the following formula: ■ R. // \NOT O 1 O I ' L H CH - C-OH (CH-) -NH-C-CH - N Z n Z NCH -, - C-OH, k K 2 " 3 4 O or a salt thereof which is pharmaceutically acceptable and which is soluble in water, characterized in that, in the above formula, R! and R4 independently represent a hydrogen atom, a methyl or an ethyl group; one of R2 and R3 represents an alkyl group comprising between 1 and 4 carbon atoms and the other is an iodine or bromine atom, and n is 0.1 or 2. 2. Compound according to claim 1, represented by the following formula: R 0 / 7 ~ <1? ^ CH -C-OK R— ('\\ - NH-C-CH - N A \ - / NCH -.- C-OH 52 " 3 4 O or a water-soluble salt thereof, which is pharmaceutically acceptable. 3. Compound according to one of claims 1 or 2, characterized in that R! and R4 each represents a methyl group. 4. Compound according to one of claims 1 to 3, or a water-soluble salt thereof, which is acceptable from the pharmaceutical point of view, in which one of R2 and R3 is a methyl group or ethyl. 5. A compound according to claim 1, 2,2 '- [[2 - [(3-bromo-2,4,6-trimethylphenyl) amino] -2-oxoethyl] imino] bisacetic acid. 6. Compound according to claim 1, 2,2 '- [[2 - [(3-bromo-2,6-diethyl-4-methylphenyl) amino] -2-oxoethyl] imino] bisacetic acid. 7. A compound according to claim 1, 2,2 '- [[2 - [(3-iodo-4-methylphenyl) amino] -2-oxoethyl] imino] bisacetic acid. 8. A compound according to claim 1, the acid 2,2 '- [[2 - [(4-bromo- 3-methylphenyl) amino] -2-oxoethyl] imino] bisaceous tick. 9. Compound according to claim 1, the acid 2,2 '- [[2 - [(3-bromo- 4-methylphenyl) amino] -2-oxoethyl] imino] bisacetic. 10. Composition containing a reducing agent based on a stannous salt and a compound according to one of claims 1 to 9.