JP2866712B2 - New heterocyclic compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a novel compound, a carbamoylmethyliminodiacetic acid having a heterocyclic group, a compound and technetium 99m
( ^99m Tc), a ^99m Tc-labeled complex formed from the compound, a composition comprising the compound for preparing the complex and a pertechnetate reducing agent, and a cancer or abscess site containing the complex as an active ingredient. To a radiological diagnostic agent for

[Prior Art] Conventionally, radioactive diagnostic agents such as gallium citrate ( ⁶⁷ Ga) and thallium chloride ( ²⁰¹ Tl) have been widely used clinically for the purpose of examining the dynamics of cancer in nuclear medicine.

[Problems to be Solved by the Invention] The above-mentioned known diagnostic agents have the property of accumulating in cancer, but have the disadvantage that their selectivity is low and it is difficult to obtain clear scintigraphic images. Therefore, ^99m T which is most widely used as a radionuclide for radiological diagnostic agents to be administered to the body
It has been desired to develop a cancer diagnostic agent complexed with c.

An object of the present invention is to provide a novel technetium complex that enables diagnosis of a cancer or abscess site.

[Means for Solving the Problems] It is well known that cancer and abscess tissues have more anionic residues of acidic mucopolysaccharides than normal sites and are inclined toward the acidic side. Therefore, we attempted to prepare a complex having a cationic residue in order to interact with these anionic residues and temporarily accumulate them selectively in the target tissue. In addition, when the pH decreases, the hydrophilicity of the complex increases, and a cationic residue is required to suppress the return of the complex from the target tissue. The present inventors have results of investigation of ^99m Tc complexes of the ligand having a heterocyclic ring for the purpose of developing an excellent cancer diagnostic agent, ^99m T exhibits an extremely superior performance as compared to conventional diagnostic agents
The present invention to find a c-labeled cancer diagnostic preparation has been completed. This complex has the advantage that it has a fast blood clearance, shows high accumulation in cancers and abscesses, and can detect cancer and abscess sites in a short time after administration.

 Hereinafter, the present invention will be described in detail.

The present invention has the general formula: Wherein R is a heterocyclic group selected from the group consisting of 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidyl, pyrazyl and 6-purinyl. A carbamoylmethyliminodiacetic acid having a heterocyclic group bonded thereto. That is, the compound of the present invention specifically includes 2-pyridylcarbamoylmethyliminodiacetic acid, 3-pyridylcarbamoylmethyliminodiacetic acid, 4-pyridylcarbamoylmethyliminodiacetic acid, 2-pyrimidylcarbamoylmethyliminodiacetic acid, Zircarbamoylmethyliminodiacetic acid and 6-purinylcarbamoylmethyliminodiacetic acid.

The heterocyclic group-bonded carbamoylmethyliminodiacetic acid of the present invention is obtained, for example, by synthesizing nitrilotriacetic anhydride in the presence of acetic anhydride in pyridine using nitrilotriacetic acid as a raw material, as shown in Example 1 of this specification. A heterocyclic compound, i.e., 2-aminopyridine, 3-aminopyridine, 4
-Aminopyridine, 2-aminopyrimidine, aminopyrazine or adenine (also known as 6-aminopurine) can be added and condensed.

As described above, the novel compound of the present invention is obtained by condensing a heterocyclic compound, such as pyridine, pyrimidine, or purine, having an amino group bonded thereto with nitrilotriacetic acid, which is a chelating ligand, and then reacts the compound with technetium 99m ( ^99m Tc ) And the ^99m Tc-labeled complex formed from them were found to be particularly useful for diagnosis of cancer and abscess sites. Up to now technetium 99m
Was never used as a diagnostic for cancer or abscess sites.
Accordingly, the present invention also provides a ^99m Tc-labeled complex formed from a heterocyclic group-bonded carbamoylmethyliminodiacetic acid represented by the above formula and ^99m Tc. Of course, the complex of the present invention
It is to be understood that those having substituted analogs of the heterocyclic group shown in the above formula having similar properties or related heterocyclic groups other than the heterocyclic group can also form part of the present invention.

^99m Tc has a short half-life of about 6 hours, and in an experiment with a mouse described below, 80 hours after administration of the complex of the present invention.
85% transfer to the bladder and urine, indicating low bioaccumulation. In addition, no acute toxicity of the complex of the present invention was observed, particularly as long as the effective amount was tested by intravenous administration in mice.

^{Biodistribution} after administration of the ^99m Tc-labeled complex of the present invention, intravenously injected into tumor-bearing mice or abscess mice, blood over time,
As a result of taking out urine, tissues and organs and measuring and examining the radioactivity, all the complexes were 1% after administration in the case of tumor-bearing mice.
In the case of the abscess-bearing mouse, the cancer or abscess / blood ratio became 1.0 or more 30 minutes after the administration, and it was recognized that the mouse or the abscess significantly accumulated in the cancer or abscess site shortly after the administration. This fact is
This was also supported by the results of scintigraphy (FIGS. 1 and 2) after administration of the complex of the present invention to tumor-bearing and abscess-bearing mice. At this time, the complex of the present invention accumulates about 85% in the bladder and urine one hour after administration, and at the same time, accumulates in the intestine, liver and kidneys in an amount of 5 to 7%. It showed that clearance was fast.

Thus, ^99m Tc-labeled complexes of the present invention, conventionally known gallium citrate ⁽⁶⁷ Ga), as compared with radioactive diagnostic agents such as thallium chloride ⁽²⁰¹ Tl), showed a high integration or selectivity to cancer and abscesses site In addition, the test can be performed after about 45 minutes for cancer and about 20 minutes for abscess, enabling rapid diagnosis.

The ^99m Tc-labeled complex of the present invention can be easily prepared by mixing the heterocyclic group-bonded carbamoylmethyliminodiacetic acid, pertechnetate and pertechnetate reducing agent of the present invention. Accordingly, the present invention further provides a composition comprising a heterocyclic-linked carbamoylmethyliminodiacetic acid and a pertechnetate reducing agent for preparing a ^99m Tc-labeled complex.

As used herein, "pertechnetate reducing agent" refers to an agent that reduces pertechnetate to a low valence state that favors the formation of a strong chelate compound, and generally uses a water-soluble reducing agent. . In preparing the composition of the present invention, the composition may be in the form of a solution, a lyophilized product, or a powder mixture. Further, a substance having an antioxidant action such as, for example, ascorbic acid or erythorbic acid may be added to the composition of the present invention as a stabilizer, and the addition of such a stabilizer is rather preferable. Furthermore, the addition of isotonic agents such as sodium chloride, preservatives such as benzyl alcohol, or acids and bases for adjusting the pH, does not interfere with the purpose of the present composition. The form of addition of the water-soluble reducing agent to the composition of the present invention may be, in addition to the usual method of adding a water-soluble compound having a reducing ability to the composition as it is, a metal ion having a reducing ability may be added to a cation exchange resin. It can be added to the composition in the form of adsorbed to the composition. As the water-soluble reducing agent referred to in the present specification, pharmaceutically acceptable ones are used, and preferably, stannous salts and sodium dithionite are used. The stannous salt is a salt formed by divalent tin, and specifically, for example, halide ions such as chloride ion and fluoride ion, inorganic acid residue ions such as sulfate ion and nitrate ion; tartaric acid A salt formed with organic acid residue ions such as ions, acetate ions and citrate ions.

The present invention further provides a radiodiagnostic agent for detecting a cancer or abscess site, comprising the ^99m Tc-labeled complex of the present invention as an active ingredient. The ^{radiodiagnostic} agent of the present invention comprises an effective amount of an aqueous solution of the composition of the present invention containing ^99m Tc in the form of pertechnetate, and an acid, base, or acid for adjusting the pH of the aqueous solution.
Appropriate additives such as buffers, stabilizers, tonicity agents, preservatives and the like can be included. Contact during inspection
The radioactivity of ^99m Tc is optional, but it should be sufficient to provide sufficient information when performing the intended nuclear medicine diagnosis, and to minimize the radiation exposure of the subject. Needless to say, the range of radioactivity is desirable, but 10 to 800 MBq is common.

In addition, as for the administration method, intravenous administration or intraarterial administration is performed, but any administration method that is advantageous for expressing its activity after administration of the radiological diagnostic agent of the present invention may be used. Can be implemented. Effectively used for nuclear medicine diagnosis of cancer and abscess site by performing imaging or radioactivity measurement with a gamma camera or scintillation scanner continuously or temporarily at a time suitable for the purpose of diagnosis after administration Can be.

 Hereinafter, the present invention will be described in detail with reference to Examples.

Example 1 1) Synthesis of 4-pyridylcarbamoylmethyliminodiacetic acid Nitrilotriacetic acid (NTA) (M.
W.191.14) Add 2.00 g, add about 20 ml of anhydrous pyridine and suspend. Care should be taken not to mix moisture because it is an anhydrous reaction. Attach a Dimroth and silica gel tube and heat in an oil bath. Next, 1.25 ml of acetic anhydride is added, and the mixture is refluxed with stirring in an oil bath at 100 ° C. for 1 hour to synthesize NTA anhydride. After cooling, an equimolar amount of 4-aminopyridine (MW 9
4.12) Add 0.98g directly and wash with a small amount of anhydrous pyridine. Thereafter, the mixture is refluxed for 1 hour under stirring in a 100 ° C. oil bath. After cooling and suction filtration, the solvent is distilled off. The residue is purified by passing through a column of LH20 (solvent; methanol: water (1: 1)). If the fraction with UV absorption is made weakly acidic, mp
Colorless crystals of 218-221 ° C were obtained. Anal.Calcd.C ₁₁ H ₁₃ N ₃ O ₅ :
C, 49.47; H, 4.93; N, 15.61. Found: C, 49.44; H, 4.90; N, 15.
72. MS: 268 (M + l).

2) Synthesis of 3-pyridylcarbamoylmethyliminodiacetic acid Nitrilotriacetic acid (NTA) (M.
W.191.14) Add 2.00 g, add about 20 ml of anhydrous pyridine and suspend. Care should be taken not to mix moisture because it is an anhydrous reaction. Attach a Dimroth and silica gel tube and heat in an oil bath. Next, 1.25 ml of acetic anhydride is added, and the mixture is refluxed with stirring in an oil bath at 100 ° C. for 1 hour to synthesize NTA anhydride. After cooling, an equimolar amount of 3-aminopyridine (MW 9
4.12) Add 0.98g directly and wash with a small amount of anhydrous pyridine. Thereafter, the mixture is refluxed for 1 hour under stirring in a 100 ° C. oil bath. After cooling and suction filtration, the solvent is distilled off. Water was added, and the precipitated crude crystals were recrystallized from water-methanol and purified to give colorless crystals having a mp of 225 to 228 ° C. Anal.Calcd.C
_{11 H 13 N 3 O 5:} C, 49.44; H, 4.90; N, 15.72. Found: C, 49.96; H,
4.96; N, 15.72. MS: 268 (M + l).

3) Synthesis of 2-pyridylcarbamoylmethyliminodiacetic acid Nitrilotriacetic acid (NTA) (M.
W.191.14) Add 2.00 g, add about 20 ml of anhydrous pyridine and suspend. Care should be taken not to mix moisture because it is an anhydrous reaction. Attach a Dimroth and silica gel tube and heat in an oil bath. Next, 1.25 ml of acetic anhydride is added, and the mixture is refluxed with stirring in an oil bath at 100 ° C. for 1 hour to synthesize NTA anhydride. After cooling, an equimolar amount of 2-aminopyridine (MW 9
4.12) Add 0.98g directly and wash with a small amount of anhydrous pyridine. Thereafter, the mixture is refluxed for 1 hour under stirring in a 100 ° C. oil bath. After cooling and suction filtration, the solvent is distilled off. The residue is purified by passing through a column of LH20 (solvent; methanol: water (1: 1)). When the fraction having UV absorption was weakly acidified with 1N HCl, colorless crystals of mp 198 to 202 ° C. were obtained. Anal.Calcd.C _{11
H 13 N 3 O 5: C} , 49.44; H, 4.90; N, 15.72. Found: C, 49.24; H, 4.
71; N, 16.03. MS: 268 (M + l).

4) Synthesis of 2-pyrimidylcarbamoylmethyliminodiacetic acid Nitrilotriacetic acid (NTA) (M.
W.191.14) Add 2.00 g, add about 20 ml of anhydrous pyridine and suspend. Care should be taken not to mix moisture because it is an anhydrous reaction. Attach a silica gel tube and Dimroth and heat in an oil bath. Next, 1.25 ml of acetic anhydride is added, and the mixture is refluxed in an oil bath at 100 ° C. for 1 hour to synthesize an anhydride of NTA. After cooling, NTA was equimolar to 2-aminopyrimidine (MW 95.1
0) Add 0.99g directly and wash with a small amount of anhydrous pyridine.
Thereafter, the mixture is refluxed for 1 hour in a 100 ° C. oil bath. After cooling and suction filtration, the solvent is distilled off. The residue is purified by passing through a column of LH20 (solvent; methanol: water (1: 1)). The fractions with UV absorption are made weakly acidic with 1N HCl and concentrated. Add a small amount of alcohol to the solution and mp 213-215 ° C
To obtain colorless crystals. Anal.Calcd.C ₁₀ H ₁₂ N ₄ O ₅ : C, 44.78; H,
4.51; N, 20.89. Found: C, 44.75; H, 4.58; N, 20.72. MS: 269
(M + 1).

5) Synthesis of pyrazylcarbamoylmethyliminodiacetic acid Nitrilotriacetic acid (NTA) (M.
W.191.14) Add 2.00 g, add about 20 ml of anhydrous pyridine and suspend. Be careful not to get moisture because it is an anhydrous reaction. Attach a silica gel tube and Dimroth and heat in an oil bath. Next, 1.25 ml of acetic anhydride is added, and the mixture is refluxed for 1 hour in an oil bath at 100 ° C. to synthesize an anhydride of NTA. After cooling, 0.99 g of aminopyrazine (MW95.12) equimolar to NTA
Is added directly and washed with a small amount of anhydrous pyridine. afterwards,
Reflux for 1 hour in a 100 ° C. oil bath. After cooling and suction filtration, the solvent is distilled off. The residue was dissolved in a small amount of water and made weakly acidic with 1N HCl to precipitate crystals. The crystals were recrystallized from water-methanol to obtain colorless crystals having an mp of 220 to 221 ° C. Ana
_{l.Calcd.C 10 H 12 N 4 O 5} : C, 44.78; H, 4.51; N, 20.89. Found:
C, 44.65; H, 4.62; N, 20.89. MS: 269 (M + l).

* Repeated re-unification increased m.p. a little.

6) Synthesis of 6-purinylcarbamoylmethyliminodiacetic acid Nitrilotriacetic acid (NTA) (M.
W.191.14) Add 2.00 g, add about 20 ml of anhydrous pyridine and suspend. Be careful not to get moisture because it is an anhydrous reaction. Attach a silica gel tube and Dimroth and heat in an oil bath. Next, 1.25 ml of acetic anhydride is added, and the mixture is refluxed for 1 hour in an oil bath at 100 ° C. to synthesize an anhydride of NTA. After cooling, 1.41 g of adenine (MW135.13) equimolar to NTA is added directly. In order to dissolve adenine as much as possible, anhydrous pyridine as a solvent is further added, and the mixture is refluxed with stirring in an oil bath at 100 ° C. for 1 hour (all adenine is not dissolved). After cooling, suction filtration is performed to remove unreacted adenine, and then the solvent is distilled off. The residue was purified with an LH20 column (solvent; methanol: water (1:
Purify by passing through 1)). 1 fraction with UV absorption
When slightly acidified with N HCl, scale-like colorless crystals having an mp of 212 to 213 ° C were obtained. Anal.Calcd.C ₁₁ H ₁₂ N ₆ O ₅ : C, 42.86; H, 3.92;
N, 27.26. Found: C, 42.81; H, 3.98; N, 27.26. MS: 309 (M
+1).

Example 2 Preparation of composition for forming ^99m Tc-labeled complex In 1 ml (pH 7.4) of 0.05 M heterocyclic group-bonded carbamoylmethyliminodiacetic acid aqueous solution (using water for injection), 20 mg of stannous chloride as a pertechnetate reducing agent / ml (0.1N HCl solution) was added, followed by passing through a 0.22μ membrane filter to obtain the desired composition.

Example 3 Preparation of Radiodiagnostic Agent ^{Containing 99m} Tc-Labeled Complex as Active Ingredient 1.0 ml of the composition obtained in Example 2 was added to pertechnetate-
Add 2-3 ml of ^99m Tc solution (300-500 MBq), then add 0.22
The desired radioactive diagnostic agent was obtained through a μ membrane filter.

Example 4 Properties of a radioactive diagnostic agent containing a ^99m Tc-labeled complex as an active ingredient In order to examine the labeling rate of a ^99m Tc complex contained in the radioactive diagnostic agent obtained in Example 3, (1) thin-layer chromatography,
(2) Electrophoresis was performed and scanning was performed using a radiochromatography scanner.

(1) Thin Film Chromatography Using a silica gel thin layer plate, development was performed with 70% acetonitrile water as a developing solvent. When developed with this solvent, radioactivity peaks were found at the upper limit for pertechnetate and at the origin for ^99m Tc-tin colloid. The complex solution obtained in Example 3 is
Most of the radioactivity peaks were observed around Rf 0.8 (Table-
1). A radioactivity peak peculiar to the NTA derivative was faintly detected near an Rf value of 0.34. In addition, the amounts of free ^99m TcO ₄ ^- and technetium oxide were slight, and it was determined that the diagnostic agent of the present invention did not hinder the properties of the diagnostic agent at all.

(2) Electrophoresis Electrophoresis was performed under the following conditions.

Indicator: filter paper Electrophoresis solution: acetate buffer (pH 4.8) Electrophoresis conditions: 600 V, 30 minutes The results of filter paper electrophoresis are shown in Table-2.

As a result, as for the radioactivity band, one band was detected at about 1 cm on the negative side, and free ^99m TcO ₄ ⁻ (moved to 5 cm on the negative side).
The existence of was denied. It is also suspected that a complex of NTA formed by hydrolysis of the compound is formed,
Since it moved to 4.5cm, its existence could be denied.

Example 5 Biodistribution of a radioactive diagnostic agent containing a ^99m Tc-labeled complex as an active ingredient in tumor-bearing mice In this example, a ^99m Tc-labeled complex in which the ligand having a heterocyclic ring is 4-pyridylcarbamoylmethyliminodiacetic acid was used. In some cases, the same results as those shown below were obtained in the case of the other five complexes of the carbamoylmethyliminodiacetic acid of the present invention having a heterocyclic group.

0.15 ml (37 MBq) of the radiological diagnostic obtained in Example 3 was administered to the tail vein of an ICR male mouse (body weight: about 35 g) transplanted with Ehrlich's ascites tumor into the thigh, and blood and urine were collected over time. In addition, tissues and organs were excised and the radioactivity in each sample was measured. The results are shown in Table-3.

As can be seen from the table, the cancer / blood ratio of the ^99m Tc-4-pyridylcarbamoylmethyliminodiacetic acid complex was about 1.0 one hour after administration, and was found to accumulate in cancer in a short time after administration. It was proved to be extremely useful for the purpose.

Example 6 Biodistribution of a radioactive diagnostic agent containing a ^99m Tc-labeled complex as an active ingredient in an abscess-bearing mouse In this example, a ^99m Tc-labeled complex in which the ligand having a heterocycle is 4-pyridylcarbamoylmethyliminodiacetic acid was used. In some cases, the same results as those shown below were obtained in the case of the other five complexes of the carbamoylmethyliminodiacetic acid of the present invention having a heterocyclic group.

An ICR male mouse (about 35 g in weight), which caused abscess by administering 0.05 ml of liquid paraffin / turpentine oil (1/1),
0.1 ml of the radiodiagnostic agent obtained in Example 3 was administered to the tail vein, blood and urine were collected with time, and tissues and organs were extracted to measure the radioactivity in each sample. The results are shown in Table-4.

As can be seen from the table, the abscess / blood ratio of the ^99m Tc-4-pyridylcarbamoylmethyliminodiacetic acid complex was 30% after administration.
The result was 1.0 or more per minute, and accumulation in the abscess was observed shortly after administration, confirming that it was extremely useful for nuclear medicine diagnostic purposes.

Example 7 Scintigraphy of a radioactive diagnostic agent containing a ^99m Tc-labeled complex as an active ingredient in a tumor-bearing mouse The radioactive diagnostic agent obtained in Example 3 was transplanted into the right upper limb of Ehrlich ascites carcinoma shown in Example 5 Intravenous injection was performed, and scintigrams 45 minutes after administration were obtained with a gamma camera equipped with a parallel collimator over time (FIG. 1).

As a result, the extraction of cancer was recognized from about 20 minutes after administration of the complex, and was clearly depicted from 30 minutes after the administration. From these results, it was confirmed that this drug was useful as a cancer diagnostic agent. Similar results were obtained in the case of a ^99m Tc complex of a ligand having five other heterocycles.

Example 8 Scintigraphy of a radioactive diagnostic agent containing a ^99m Tc-labeled complex as an active ingredient in abscess-bearing mice An intravenous injection of the radioactive diagnostic agent obtained in Example 3 into a mouse in which an abscess was induced by the method described in Example 6. And Example 7
A scintigram of 20 minutes after administration was obtained in the same manner as in (2).

As a result, the appearance of the abscess induced in the upper right limb was approximately
Recognition started at 10 minutes, and became clearer after 20 minutes. From these results, it was confirmed that this drug was useful as a diagnostic agent for abscess. Similar results were obtained in the case of a ^99m Tc complex of a ligand having five other heterocycles.

[Effect of the Invention] The ^99m Tc-labeled complex of the present invention has a fast blood clearance,
The complex is useful as a diagnostic agent for cancer and abscess sites because it shows high accumulation in cancer and abscess sites and can detect cancer and abscesses shortly after administration.

[Brief description of the drawings]

FIG. 1 is a photograph showing a scintigram of a radiological diagnostic agent containing ^99m Tc-4-pyridylcarbamoylmethyliminodiacetic acid as an active ingredient in a tumor-bearing mouse 45 minutes after administration. Figure 2 is a photograph showing a scintigram after 20 minutes administration in charge of abscesses mice radioactive diagnostic agent to ^99m Tc-4-pyridylcarbamoyl methyl imino diacetate active ingredient.

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification symbol FI C07D 241/20 C07D 473/34 361 473/34 361 C07F 11/00 Z C07F 11/00 A61K 49/02 B (58) Field (Int.Cl. ⁶ , DB name) C07D 213/75 C07D 239/42 C07D 241/20 C07D 473/34 C07F 11/00 C01G 19/06 C01B 17/66 A61K 49/02 CA (STN) REGISTRY (STN )

Claims (6)

(57) [Claims] (1) a general formula: Wherein R is a heterocyclic group selected from the group consisting of 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidyl, pyrazyl and 6-purinyl. Ring-bonded carbamoylmethyliminodiacetic acid. 2. A ^99m Tc-labeled complex formed from the heterocyclic group-bonded carbamoylmethyliminodiacetic acid according to claim 1 and technetium 99m ( ^99m Tc). 3. A composition for preparing the ^99m Tc-labeled complex according to claim 2, comprising a carbamoylmethyliminodiacetic acid having a heterocyclic group according to claim 1 and a pertechnetate reducing agent. Composition. 4. The composition according to claim 3, wherein the pertechnetate reducing agent is a stannous salt or sodium dithionite. 5. The stannous salt is stannous chloride.
A composition according to claim 1. 6. A ^{radiodiagnostic} agent for detecting cancer and abscess site, comprising the ^99m Tc-labeled complex according to claim 2 as an active ingredient.