JPH0318621B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is based on the general formula (In the formula, R, R′ and R″ are each a hydrogen atom,
It represents a group selected from the group consisting of alkyl groups having 1 to 3 carbon atoms, and n represents an integer of 1 to 3. ) This relates to a novel compound having a chelate-forming group and an amino group or an alkylamino group in the molecule. The compound of the present invention is a new compound that has not been described in any literature, and is useful in nuclear medicine applications for the purpose of extracting specific organs, detecting specific diseases, and testing the dynamics of physiologically active compounds, and is a stable radioactive metal label. This compound is useful in the production of radioactive diagnostic agents. Conventionally, bioactive compounds labeled with iodine-131 have been widely used for non-invasive nuclear medicine diagnosis for the purpose of extracting specific organs, detecting specific diseases, and testing dynamics. Examples include iodine-131-labeled human serum albumin, which is used for extraction and dynamic testing of the blood circulation system, and iodine-131-labeled fibrinogen, which is used for the detection of blood clots.
However, iodine-131 has a long half-life of about 8 days and emits beta rays in addition to gamma rays, which are useful for nuclear medicine diagnosis, so it has the disadvantage of subjecting the patient to a large amount of radiation exposure. has been pointed out. Attempts continue to be made to obtain useful radiodiagnostic agents by introducing radioactive metals with physical properties more suitable for nuclear medicine diagnosis into physiologically active compounds by other methods. That is, this is a labeling method in which a radioactive metal salt is directly applied to a physiologically active compound in the hope of forming a chelate bond. For example, human serum albumin is treated with technetium-99 in the form of pertechnetate in the presence of a suitable reducing agent.
Technetium-99
Method for obtaining m-labeled human serum albumin, indium-111 in the form of indium chloride to bleomycin
This includes a method of obtaining indium-111-labeled bleomycin by reacting an aqueous solution containing . However, the chelate-forming properties of these physiologically active compounds to be labeled are not necessarily high, and even in the case of technetium-99m-labeled human serum albumin and indium-111-labeled bleomycin, they have low stability after in vivo administration and are radioactive. It has been pointed out that the in-vivo behavior of bioactive compounds does not match that of physiologically active compounds and is not satisfactory for use in nuclear medicine diagnosis. The physiologically active compound referred to here refers to a compound that exhibits a specific accumulation in a specific organ or a specific disease site, or
It refers to a compound that behaves in a unique manner in response to various physiological conditions in the body, and by tracking its behavior in the body, it is expected to provide useful information for various diagnoses. It is a compound. Examples include proteins such as human serum albumin, urokinase, and fibrinogen, antibiotics such as bleomycin and kanamycin, hormones, saccharides, fatty acids, and derivatives thereof. If a radioactive metal with excellent physical properties could be stably introduced into such a bioactive compound without damaging the bioactivity of the bioactive compound, it would have extremely useful applications in nuclear medicine diagnosis. The appearance of such a radioactive diagnostic agent is highly anticipated and strongly desired in the field of nuclear medicine. In order to meet the above-mentioned needs, the present inventors have incorporated into the molecule: 1. a chelate-forming group that forms a stable chelate with a radioactive metal that has physical properties suitable for nuclear medicine diagnosis; 2. various physiologically active compounds; We have been conducting intensive research focusing on compounds with amino groups that can easily form more stable bonds under mild conditions without losing activity. This time, the present inventors have discovered that the compound of the present invention, particularly a compound in which R and R' are hydrogen atoms (hereinafter abbreviated as amino-PTS), satisfies the above two conditions, and furthermore, this compound It has been found that radioactive diagnostic agents in which various physiologically active compounds are labeled with radioactive metals satisfy the above-mentioned requirements as nuclear medicine diagnostic agents. As an example, among the novel compounds of the present invention, R and R' are hydrogen atoms and n is 2.
This shows the usefulness of 99m-labeled human serum albumin derivatives. The human serum albumin derivative obtained by reacting the compound of the present invention with human serum albumin by the carbodiimide method or glutaraldehyde method, which is commonly used as a chemical modification method for proteins, is obtained by reacting the compound with pertechnetate in the presence of a stannous salt. By a very simple method of contacting Tc-99m aqueous solution,
An extremely stable technetium-99m-labeled human serum albumin derivative was obtained, and the electrophoretic behavior of this labeled derivative was exactly the same as that of human serum albumin. This technetium-99m-labeled human serum albumin derivative was administered into the tail vein of rats, and its blood concentration over time was compared with that of technetium-99m-labeled human serum albumin and iodine-131-labeled human serum albumin obtained by conventional methods. In comparison, the technetium-99m-labeled human serum albumin derivative obtained using amino-PTS
It was confirmed that significantly higher blood concentrations were maintained over a long period of time compared to technetium-99m and iodine-131-labeled human serum albumin obtained by conventional methods. Table 1 shows the changes in blood concentration in rats.

[Table] The above results demonstrate that the technetium-99m-labeled human serum albumin derivative obtained using Amino-PTS has high in-vivo stability, and is useful for extraction, dynamic testing, and quantitative measurement of the blood circulation system. It has been shown that this method is extremely suitable for nuclear medicine diagnostic applications. Furthermore, pharmacological studies on the properties of the compound of the present invention revealed that the chelate compound formed by the compound of the present invention and radioactive metal ions exhibited unique in vivo behavior, and that it itself could be used for nuclear medical diagnosis. found that it is extremely useful. As an example, among the novel compounds of the present invention, R and R' are methyl groups, and n is 2 (hereinafter abbreviated as methylamino-PTS). This shows the usefulness of 99m-labeled compounds. Methylamino-PTS provides an extremely stable technetium-99m labeled compound by a very simple method of contacting a pertechnetate-Tc-99m aqueous solution in the presence of a stannous salt, and this labeled compound is Electrophoresis using a phosphate buffer of =7.0 confirmed that it was positively charged. This technetium-99m-labeled compound was administered into the tail vein of mice, and after a certain period of time, they were sacrificed and dissected, and the body distribution of radioactivity (% dose/g) was measured over time. The results obtained were summarized. Table 2 shows this.

[Table] From the results shown in Table 2, methylamino-PTS
The technetium-99m-labeled compound obtained using this method has been shown to be extremely useful as a myocardial scanning agent in nuclear medicine diagnosis for the purpose of detecting ischemic areas and quantitatively measuring myocardial blood volume. It was done. That is, taking the ratio of radioactivity concentration in myocardium/radioactivity concentration in blood (myocardial/blood ratio) obtained from the results in Table 2, 30 minutes, 1 hour, and 3 hours after administration are 2.22 and 2.89, respectively. and 4.00,
The myocardial/blood ratio of thallium chloride- ^201Tl , which is currently being used as a myocardial scanning agent, is comparable to that of thallium-201Tl, and considering the superiority of the nuclear properties of technetium-99m and the ease of compound preparation, methyl amino - The usefulness of PTS in the field of nuclear medicine diagnosis is judged to be extremely high. Next, a method for producing the compound of the present invention will be described.
First, among the compounds of the present invention, compounds in which R and R' are alkyl groups having 1 to 3 carbon atoms can be obtained by the following synthetic route using the corresponding dialkylamine derivative as a starting material. (In the formula, R'' represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and n represents an integer of 1 to 3.) That is, the corresponding dialkylamine derivative ()
Yu.V.Markova (Chem.Abst. 63 17951 f
(1965) et al., a proionyl group was introduced by the action of propionyl chloride, and the compound ()
get. () is then treated with isopropyl nitrite to obtain the corresponding isonitroso compound () (method of Nathan Levin et al., Org.Syn.coll.
Vol 3 191 (1955) method applied mutatis mutandis). The method of Paul A.Barrett et al. (British patent, 966,
849. (1960)), by condensing thiosemicarbazide or its N-alkyl derivative to obtain the desired product ().
can be obtained. Next, among the compounds of the present invention, compounds in which R and R' are hydrogen can be obtained by the following synthetic route. (In the formula, R'' represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, and n represents an integer of 1 to 3.) That is, the corresponding amine derivative () is reacted with trifluoroacetic anhydride to form an amino group. As in the case of dialkylamine compounds, p-propionyl derivatives () are obtained via protected acyl derivatives ().Howard Newman's method (J.Org.
After removing the trifluoroacetyl group with potassium carbonate using chem. 30 1287. (1965), the desired dithiosemicarbazone derivative () can be obtained via the corresponding isonitroso compound (). . EXAMPLES The present invention will be explained in more detail with reference to Examples and Reference Examples below. Reference example 1 Synthesis of p-N,N-dimethylaminoethylpropiophenone N,N-dimethylphenylethylamine 22.358
Dissolve g in 225 ml of dry carbon disulfide, add 66 g of anhydrous aluminum chloride, and heat at 50 to 60℃.
While stirring, 15.27 g of propionyl chloride was added dropwise over about 1 hour. After the dropwise addition was completed, the mixture was stirred under reflux for 4.5 hours, and then cold water was added to decompose the aluminum chloride, followed by making it slightly alkaline with sodium hydroxide solution, and then extracting with ethyl ether. After drying the extract over anhydrous sodium sulfate, ethyl ether was distilled off, followed by vacuum distillation to obtain 115
25 g (yield: 81%) of a fraction of ~117°C/1-2 mmHg was obtained. Reference Example 2 Synthesis of p-N,N-dimethylaminoethylisonitrosopropiophenone 2.33 g of p-N,N-dimethylaminoethylpropiophenone obtained in Reference Example 1 was dissolved in 75 ml of absolute ethyl alcohol and dried. After blowing in hydrogen chloride gas under cooling, isopropyl nitrite 1.07
g was added. After stirring overnight at room temperature, the solvent was distilled off to obtain a crude product. The crude product was recrystallized from ethyl alcohol to obtain the desired product in almost quantitative yield. Melting point Hydrochloride 220-222℃ Amine type 186-188℃ Elemental analysis C H N Actual value 57.93% 7.28% 10.56% Calculated value 57.67% 7.07% 10.35% Example 3 1-(p-N,N-dimethylaminoethyl ) Synthesis of phenylpropane-1,2-dione-bis(4-methylthiosemicarbazone) 2.34 g of p-N,N-dimethylaminoethylisonitrosopropiophenone obtained in Reference Example 2 and 4-methylthiosemicarbazide 2.31g 90%
Dissolve in 12ml of ethyl alcohol, add concentrated hydrochloric acid,
After adjusting the pH to 2, the mixture was stirred under reflux for 8 hours. After cooling, the precipitated crystals are recrystallized from ethyl alcohol to obtain 1.0 g of the desired product (yield 25%).
I got it. Melting point (hydrochloride) 230-232°C Elemental analysis C H N Actual value 47.36% 6.65% 22.64% Calculated value 47.48% 6.56% 22.80% Example 4 1-(p-aminomethylene) phenylpropane-1,2-dione -Synthesis of bis(4-methylthiosemicarbazone) Dissolve 2.06 g of p-aminomethyleneisonitrosopropiofenone and 2.31 g of 4-methylthiosemicarbazide in 10 ml of 90% ethyl alcohol, add concentrated hydrochloric acid, and adjust the pH to 2. After adjustment, the mixture was stirred under reflux for 7 hours. The crystals precipitated after cooling were recrystallized from ethyl alcohol to obtain 1.1 g of the target product (yield: 31
%) was obtained. Elemental analysis (hydrochloride) C H N Actual value 41.40% 5.88% 24.21% Calculated value 41.45% 5.96% 24.16% Reference example 5 Synthesis of N-trifluoroacetylphenethylamine After dissolving 12.2 g of phenethylamine in 30 ml of pyridine, 15 ml of trifluoroacetic anhydride was added, and the mixture was stirred at room temperature for about 12 hours. After the reaction was completed, distillation was carried out under reduced pressure to obtain 16.5 g of distillate at 103-104℃/4 mmHg (yield: 75
%) was obtained. Reference Example 6 Synthesis of p-N-trifluoroacetylaminoethylpropiophenone 11.0 g of N-trifluoroacetylphenethylamine obtained in Reference Example 5 was dissolved in 75 ml of dry carbon disulfide, and 22 g of anhydrous aluminum chloride was dissolved. After that, 5.1 g of propionyl chloride was added dropwise while stirring. After the dropwise addition, the mixture was stirred under reflux for 4.5 hours, and then
It was left at room temperature overnight. Thereafter, cold water was added to decompose the aluminum chloride, the mixture was made slightly alkaline with sodium hydroxide solution, and extracted with ethyl acetate. After drying the extract over anhydrous sodium sulfate, ethyl acetate was distilled off to obtain a black residue.
The residue was dissolved in a small amount of hot methanol, decolorized by adding activated carbon, filtered off through activated carbon, and the liquid was cooled to obtain the desired product as crystals. Yield: 3.34g (yield 24.5%). Reference Example 7 Synthesis of p-aminoethylpropiophenone 2.73 g of p-N-trifluoroacetylaminoethylpropiophenone obtained in Reference Example 6 was dissolved in methanol.
The mixture was dissolved in a mixed solvent of 30 ml and water 12 ml, and 2.9 g of potassium carbonate was further added and stirred overnight at room temperature. After the reaction was completed, potassium carbonate was decomposed with 5% hydrochloric acid,
The mixture was made alkaline with 10% sodium hydroxide solution and then extracted with ethyl ether. The extract was dried over anhydrous sodium sulfate, and then filtered to remove the sodium sulfate. By blowing hydrochloric acid gas into the liquid, crystals of p-aminoethylpropiophenone hydrochloride were obtained in an almost quantitative yield. Elemental analysis C H N Actual value 74.36% 8.60% 7.84% Calculated value 74.54% 8.53% 7.90% Reference example 8 Synthesis of p-aminoethylisonitrosopropiophenone p-aminoethylpropiophenone hydrochloride obtained in Reference example 7 2.14 g was dissolved in 50 ml of anhydrous ethyl alcohol, and after dry hydrogen chloride gas was blown into the solution while cooling, 1.07 g of isopropyl nitrite was added.
After stirring overnight at room temperature, the solvent was distilled off to obtain a crude product. The crude product was recrystallized from ethyl alcohol to obtain the desired product in almost quantitative yield. Example 9 1-(p-aminoethyl)phenylpropane-
Synthesis of 1,2-dione-bis(4-methylthiosemicarbazone) 1.22 g of p-aminoethylisonitrosopropiofenone obtained in Reference Example 8 and 1.6 g of 4-methylthiosemicarbazide were mixed with 90% ethyl alcohol.
After dissolving in 10 ml and adjusting the pH to 2 by adding concentrated hydrochloric acid, the mixture was stirred under reflux for 7.5 hours. The crystals precipitated upon cooling were recrystallized from ethyl alcohol to obtain 0.65 g (yield: 30%) of the desired product. Elemental analysis C H N S Measured value 49.46% 6.50% 26.30% 17.74% Calculated value 49.29% 6.34% 26.83% 17.54% Although the present invention has been explained by showing the above examples, those skilled in the art will understand that these examples It should be understood that these are intended to be illustrative of the invention and are not intended to limit its scope in any way.

Claims (1)

[Claims] 1. General formula (In the formula, R, R′ and R″ are each a hydrogen atom,
It represents a group selected from the group consisting of alkyl groups having 1 to 3 carbon atoms, and n represents an integer of 1 to 3. ) New compound 1 (p-aminoalkyl) represented by
Phenylpropane-1,2-dione-bis(thiosemicarbazone) and its N-alkyl derivatives.