JP2009062287A - Uracil compound or salt thereof, imaging agent comprising the same as active ingredient and imaging agent comprising the same as active ingredient for carrying out tumor diagnosis - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a uracil derivative accumulating TP (thymidine phosphorylase) associated with neovascularization actions on tumors as a target and affording an imaging agent. <P>SOLUTION: The [<SP>125</SP>I]5-iodo-6-(1-(2-iminoimidazolidinyl)methyl)uracil compound is represented by chemical formula. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention belongs to the technical field of uracil compounds or salts thereof labeled with thymidine phosphorylase target radioisotope, imaging agents containing these as active ingredients, and imaging agents for diagnosing tumors containing these as active ingredients. Is.

The nuclear medicine diagnostic method is a state-of-the-art diagnostic imaging method that has a feature that various functions of a living body can be imaged and quantified non-invasively by administering a radiopharmaceutical that emits a minute amount of radiation into the body. Based on the nature of the radiation used, this nuclear medicine diagnostic method is based on Positron Emission Tomography (hereinafter referred to as “PET”) using positron (positron) emitting nuclides and Single Photon CT (single photon emission CT) using single photon emitting nuclides such as γ rays. (Computed Tomography: hereinafter referred to as “SPECT”).
By the way, as a nuclear medicine diagnostic intended for the diagnosis of a malignant tumor ^[18 F] fluoro-deoxy-glucose: inspection method using a (FDG-PET) is known ^([18 F] fluorodeoxyglucose ^"[18 F] FDG" hereinafter) ing. This test method has been widely used in nuclear oncology as it has been approved for insurance in April 2002 in Japan. In FDG-PET, administered [ ¹⁸ F] FDG is taken into cells, is metabolically trapped, and accumulates strongly in cells with active sugar metabolism to evaluate sugar metabolism. That is, since glucose metabolism is active in many tumor cells, [ ¹⁸ F] FDG, which is a glucose-like substance, is strongly accumulated, and high-sensitivity diagnosis is possible with contrast with whole body tissues with low glucose metabolism. However, recent studies have shown that [ ¹⁸ F] FDG is highly accumulative in malignant tumors, but it is also found that it accumulates in some benign diseases, and there is a limit to the differential tumor diagnosis by this test. Has also started to be pointed out (see, for example, Non-Patent Document 1).
In addition, urinary tract tumors are diagnosed at sites where [ ¹⁸ F] FDG is not accumulated, such as liver cancer, gastric cancer, prostate cancer, etc., because it is difficult to determine because it is mixed with [ ¹⁸ F] FDG excreted in urine. Low rates (effectiveness) have also been reported. Therefore, development of an imaging agent for new tumor diagnosis following [ ¹⁸ F] FDG is eagerly desired. By the way, in order for tumors to grow, angiogenesis is essential as a nutrient source. In recent years, as a new treatment for solid tumors, tumor growth and metastasis can be suppressed by inhibiting tumor angiogenesis by targeting angiogenic factors (VEGF, EGF, FGF, TNF, PD-ECGF, etc.) in tumor growth. Attempts to do so have attracted attention (see Non-Patent Document 2).
In recent years, platelet-derived vascular endothelial growth factor (PD-ECGF), one of the angiogenic factors, is the same protein as thymidine phosphorylase (hereinafter referred to as “TP”) by Akiyama et al. It was revealed that it is closely related to tumor angiogenesis, invasion, and metastasis (see Non-Patent Document 3).
TP reversibly catalyzes phosphorolysis from thymidine to thymine and α-D-2-deoxyribose-1-phosphate (α-D-2-deoxyribose-1-phosphate). Furthermore, TP is involved in activation of fluoropyrimidine compounds such as 5-fluorouracil and 5-deoxyfluorouridine, which are anticancer agents. Moreover, TP is expressed at higher levels in solid tumors such as the esophagus, stomach, pancreas, large intestine, lung, bladder, ovary, breast, and kidney than in normal tissues.
Numerous nucleic acid derivatives having a TP inhibitory action have been developed as having a TP inhibitory action and having a pyrimidine ring as a basic skeleton. In this, since uracils having a chloro group at the 5-position and an amino group at the 6-position have been found, many uracils have been known. Among them, 5-bromo-6-[(2 -Iminoimidazolidinyl) methyl] uracil hydrobromide is known as a potent TP inhibitor (see Non-Patent Document 4). However, it is not known that TP inhibitors such as these accumulate in a tumor-specific manner.
Ichiya Y. et al. , Kuwabara Y. et al. , Sasaki M .; Yosida T. , Akashi Y .; , Murayama S .; Nakamura K .; , Fukumura T .; Masuda K .; FDG-PET in infectious: The detection and assessment of activity. Ann. Nucl. Med. 10 (2), 185-191 (1996). Raymond W. , Klecker Jr. , Jerry M. et al. Collins. Thymidine phosphorase as a target for imaging and thermal with thy analogs. Cancer Chemother Pharmacol. 48, 407-412 (2001). Haraguchi M. et al. , Miyada K. Uemura K .; , Sumizawa T. , Furukawa T .; Yamada Kazutaka. , Akiyama S., et al. , Angiogenic activity of enzymes. Nature. 368, 198 (1994). Yano S. Kazuno H., et al. , Sato T. , Suzuki N. , Emura T. Konstanty Wierzba, Yamasita J .; , Tada Y. et al. Yamada Y .; , Fukushima M .; Asao T .; Synthesis and evaluation of 6-methylene-bridged uracil derivatives, Part 2: Discovery of novelties of humanity in the physics. Bioorg. Med. Chem. 12, 3443-3450 (2004).

  An object of the present invention is to provide a radioisotope-labeled compound and an imaging agent for tumor diagnosis containing the same as an active ingredient.

［式中、Ｒ^１は水素原子、ハロゲン原子、シアノ基又は低級アルキル基を示し；Ｒ^２はＯ、Ｓ又はＮＨを示す。］
すなわち、本発明は次のものである。
請求項１の発明は、放射性同位元素により標識された下記一般式（Ｉ）

［式中、Ｒ^１は水素原子、ハロゲン原子、シアノ基又は低級アルキル基を示し；Ｒ^２はＯ、Ｓ又はＮＨを示す。］で表されることを特徴とするウラシル化合物又はその塩である。
請求項２の発明は、一般式（Ｉ）中、Ｒ^１で示される基が、フッ素原子、塩素原子、臭素原子又はヨウ素原子であり、Ｒ^２で示される基が、Ｏ又はＮＨであることを特徴とする請求項１項記載のウラシル化合物又はその塩である。
請求項３の発明は、一般式（Ｉ）中、Ｒ^１で示される基が、^１８Ｆ、^３４ｍＣｌ、^７６Ｂｒ、^１２３Ｉ、^１２４Ｉ、^１２５Ｉ及び^１３１Ｉよりなる群から選ばれる放射性ハロゲノ基であることを特徴とする請求項１又は２の何れか１記載のウラシル化合物又はその塩である。
請求項４の発明は、一般式（Ｉ）中、２’位の炭素が、放射性同位元素^１１Ｃであることを特徴とする請求項１乃至３の何れか１記載のウラシル化合物又はその塩である。
請求項５の発明は、一般式（Ｉ）中、２位の炭素が、放射性同位元素^１１Ｃであることを特徴とする請求項１乃至４の何れか１記載のウラシル化合物又はその塩である。
請求項６の発明は、ウラシル化合物又はその塩が、［^１２３Ｉ］５−イオド−６−（１−（２−イミノイミダゾリジニル）メチル）ウラシル塩酸塩、［^１２４Ｉ］５−イオド−６−（１−（２−イミノイミダゾリジニル）メチル）ウラシル塩酸塩、［^１２５Ｉ］５−イオド−６−（１−（２−イミノイミダゾリジニル）メチル）ウラシル塩酸塩、［^１３１Ｉ］５−イオド−６−（１−（２−イミノイミダゾリジニル）メチル）ウラシル塩酸塩、［^１８F］５−フルオロ−６−（１−（２−イミノイミダゾリジニル）メチル）ウラシル、［２’−^１１Ｃ］５−ブロモ−６−（１−（２−オキソイミダゾリジニル）メチル）ウラシル、［２’−^１１Ｃ］５−クロロ−６−（１−（２−オキソイミダゾリジニル）メチル）ウラシル、［２−^１１Ｃ］５−クロロ−６−（１−（２−イミノイミダゾリジニル）メチル）ウラシル、又は［２−^１１Ｃ］５−ブロモ−６−（１−（２−イミノイミダゾリジニル）メチル）ウラシルであることを特徴とする請求項１乃至５の何れか１記載のウラシル化合物又はその塩である。
請求項７の発明は、請求項１乃至６の何れか１記載のウラシル化合物又はその塩を有効成分として含有するイメージング剤である。
請求項８の発明は、請求項１乃至６の何れか１記載のウラシル化合物又はその塩を有効成分として含有する腫瘍診断をするためのイメージング剤である。 The inventors of the present invention have synthesized and studied a specific radioisotope-labeled compound for the uracil compound represented by the following general formula (I) or a salt thereof as described later. In vivo uptake experiments using A431) revealed that tumor-specific uptake occurred. Based on these findings, the present inventors have found that such a labeled compound is useful as an imaging agent for tumor diagnosis, prediction of therapeutic effect, and estimation of prognosis, thereby completing the present invention.
In addition, the uracil compound represented by the following general formula (I) or a salt thereof is appropriate depending on the type of radiation emitted, energy, half-life, etc. If a nuclide is selected, it is useful as an internal radiotherapy for tumors.

[Wherein, R ¹ represents a hydrogen atom, a halogen atom, a cyano group or a lower alkyl group; R ² represents O, S or NH. ]
That is, the present invention is as follows.
The invention of claim 1 includes the following general formula (I) labeled with a radioisotope:

[Wherein, R ¹ represents a hydrogen atom, a halogen atom, a cyano group or a lower alkyl group; R ² represents O, S or NH. A uracil compound or a salt thereof.
In the invention of claim 2, in general formula (I), the group represented by R ¹ is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and the group represented by R ² is O or NH. The uracil compound or a salt thereof according to claim 1, wherein:
The invention of claim 3 is a radioactive halogeno wherein the group represented by R ¹ in the general formula (I) is selected from the group consisting of ¹⁸ F, ³⁴ mCl, ⁷⁶ Br, ¹²³ I, ¹²⁴ I, ¹²⁵ I and ¹³¹ I. The uracil compound or a salt thereof according to claim 1, which is a group.
The invention according to claim 4 is the uracil compound or the salt thereof according to any one of claims 1 to 3, wherein the carbon at the 2 ′ position in the general formula (I) is a radioisotope ¹¹ C. is there.
The invention according to claim 5 is the uracil compound or salt thereof according to any one of claims 1 to 4, wherein the carbon at the 2-position in the general formula (I) is a radioisotope ¹¹ C. .
According to the invention of claim 6, the uracil compound or a salt thereof is [ ¹²³ I] 5-iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹²⁴ I] 5-iodo-6. -(1- (2-Iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹²⁵ I] 5-iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹³¹ I] 5 -Iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹⁸ F] 5-fluoro-6- (1- (2-iminoimidazolidinyl) methyl) uracil, [2 ′ - ¹¹ C] 5-bromo-6- (1- (2-oxo-imidazolidinyl) methyl) uracil, [2'- ¹¹ C] 5- chloro-6- (1- (2-oxo-imidazolidinyl) methyl ) uracil, [2- ¹ C] 5-chloro-6- (1- (2-imino imidazolidinyl) methyl) uracil, or ^[2- 11 C] 5-Bromo-6- (1- (2-imino imidazolidinyl) methyl) uracil The uracil compound or a salt thereof according to any one of claims 1 to 5, wherein the uracil compound is a salt thereof.
A seventh aspect of the invention is an imaging agent comprising the uracil compound or a salt thereof according to any one of the first to sixth aspects as an active ingredient.
The invention of claim 8 is an imaging agent for diagnosing a tumor comprising the uracil compound or salt thereof according to any one of claims 1 to 6 as an active ingredient.

  The uracil compound or a salt thereof of the present invention is extremely useful as an imaging agent for tumors because it accumulates significantly in a tumor-specific manner. In addition, the imaging agent of the present invention contributes to cancer treatment strategies by providing powerful biochemical information not only for tumor diagnosis but also for determination of treatment policy, prediction of treatment effect, and estimation of prognosis. It is.

  The uracil compound or a salt thereof of the present invention is obtained by labeling the uracil compound represented by the general formula (I) or a salt thereof with a radioisotope. The uracil compound represented by the general formula (I) or a salt thereof is known to inhibit thymidine phosphorylase as a target and inhibit enzyme activity, and is also known to exhibit an antitumor effect by inhibiting the activity. (Patent No. 3087757). However, it is not known that the uracil compound represented by the general formula (I) or a salt thereof accumulates in a tumor-specific manner.

In general formula (I), examples of the halogen atom represented by R ¹ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
In the general formula (I), examples of the lower alkyl group represented by R ¹ include a linear or branched alkyl group having 1 to 4 carbon atoms, and specifically include a methyl group, an ethyl group, and n-propyl. Group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, and tert-butyl group. Among them, a methyl group is preferable.

The radioisotope in the present invention is not particularly limited, but ¹¹ C, ¹⁵ O, ¹³ N, ¹⁸ F, ³⁴ mCl, ⁷⁶ Br, ¹²³ I, ¹²⁴ I, ¹²⁵ I and ¹³¹ I or the like is used.
The site for labeling with a radioisotope in the present invention is not particularly limited as long as it is a site that can be labeled, but for ease of production, the groups represented by R ¹ in the general formula (I), the 2-position, and the 2′-position Is preferred. In the general formula (I), the radioisotope for labeling the group represented by R ¹ is preferably ¹⁸ F, ^{34 m} Cl, ⁷⁶ Br, ¹²³ I, ¹²⁴ I, ¹²⁵ I and ¹³¹ I, The radioisotope for labeling is preferably ¹¹ C, and the radioisotope for labeling the 2 ′ position is preferably ¹¹ C.

Specific uracil compounds or salts thereof in the present invention include [ ¹²³ I] 5-iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹²⁴ I] 5-iodo-6. -(1- (2-Iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹²⁵ I] 5-iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹³¹ I] 5 -Iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹⁸ F] 5-fluoro-6- (1- (2-iminoimidazolidinyl) methyl) uracil, [2 ′ - ¹¹ C] 5-bromo-6- (1- (2-oxo-imidazolidinyl) methyl] uracil, [2'- ¹¹ C] 5- chloro-6- (1- (2-oxo-imidazolidinyl) methyl ] Uracil ^[2- 11 C] 5-chloro-6- (1- (2-imino imidazolidinyl) methyl) ^{uracil, [2-} 11 C] 5- bromo-6- (1- (2-imino imidazolidinyl) Methyl) uracil.

  The salt of the uracil compound of the present invention is not particularly limited as long as it is a pharmaceutically acceptable salt, and an acid addition salt in which a pharmaceutically acceptable acid is allowed to act is preferable. Examples of such acid addition salts include salts with inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid and hydrobromic acid; oxalic acid, maleic acid, fumaric acid, malic acid, tartaric acid, citric acid, benzoic acid, acetic acid, Examples thereof include salts with organic acids such as p-toluenesulfonic acid and methanesulfonic acid, and salts with hydrochloric acid are preferred.

  The uracil compound or a salt thereof of the present invention can be produced by a generally known method, and specifically, for example, can be produced by the following methods [A] to [E].

Ａ法では、化学式（ＩＩ）で表される化合物と放射性標識されたハロゲン化剤を適当な溶媒中で反応させ、一般式（ＩＩＩ）で表される化合物（一般式（Ｉ）中、Ｒ^１で示される基が放射性ハロゲン原子であり、Ｒ^２で示される基がＮＨであるウラシル化合物）を製造する。
反応で用いる溶媒としては、反応に関与しないものであれば特に制限はなく、例えばＮ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、アセトニトリル、ジメチルスルホキシド、ヘキサメチルリン酸トリアミド等の非プロトン性極性溶媒；アセトン、メチルエチルケトン等のケトン類；テトラヒドロフラン、ジオキサン等のエーテル類；メタノール、エタノール、プロパノール等のアルコール類；酢酸、ぎ酸、濃硫酸、水等が例示できる。
ハロゲン化剤としては、^１８Ｆ、^３４ｍＣｌ、^７６Ｂｒ、^１２３Ｉ、^１２４Ｉ、^１２５Ｉ又は^１３１Ｉ等の放射性ハロゲン原子を含む化合物であれば制限はなく、斯かる化合物としては、フッ素、Ｎ−フルオロコハク酸イミド、塩素、Ｎ−クロロコハク酸イミド、塩化スルフリル、次亜塩素酸ソーダ、臭素、Ｎ−ブロモコハク酸イミド、ピリジニウムブロミドパーブロミド、ヨウ素、Ｎ−ヨードコハク酸イミド、及びヨードゲン、クロラミンＴ、Ｎ−クロロコハク酸イミド、Ｎ−ブロモコハク酸イミド、濃硝酸等の酸化剤共存下のヨウ化ナトリウム等が挙げられる。
反応温度は０℃から溶媒の沸点程度であり、好ましくは０〜８０℃である。反応時間は０．５〜２４時間であり、好ましくは１〜１２時間である。この反応においては、化学式（ＩＩ）で表される化合物１モルに対してハロゲン化剤を１〜３モル当量使用するのが好ましい。
なお、本反応の出発物質である化学式（ＩＩ）で表される化合物は、例えば、特許第３０８８７５７公報記載の方法に準じて製造することができる。 [Method A]

In the method A, the compound represented by the chemical formula (II) and a radiolabeled halogenating agent are reacted in an appropriate solvent, and the compound represented by the general formula (III) (in the general formula (I), R ¹ Is a radioactive halogen atom and a group represented by R ² is NH.
The solvent used in the reaction is not particularly limited as long as it does not participate in the reaction. For example, aprotic such as N, N-dimethylformamide, N, N-dimethylacetamide, acetonitrile, dimethyl sulfoxide, hexamethylphosphoric triamide and the like. Examples include polar solvents; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; alcohols such as methanol, ethanol and propanol; acetic acid, formic acid, concentrated sulfuric acid, and water.
The halogenating agent is not limited as long as it is a compound containing a radioactive halogen atom such as ¹⁸ F, ³⁴ mCl, ⁷⁶ Br, ¹²³ I, ¹²⁴ I, ¹²⁵ I, or ¹³¹ I. Examples of such a compound include fluorine, N -Fluorosuccinimide, chlorine, N-chlorosuccinimide, sulfuryl chloride, sodium hypochlorite, bromine, N-bromosuccinimide, pyridinium bromide perbromide, iodine, N-iodosuccinimide, and iodogen, chloramine T, Examples thereof include sodium iodide in the presence of an oxidizing agent such as N-chlorosuccinimide, N-bromosuccinimide and concentrated nitric acid.
The reaction temperature is about 0 ° C to the boiling point of the solvent, preferably 0 to 80 ° C. The reaction time is 0.5 to 24 hours, preferably 1 to 12 hours. In this reaction, it is preferable to use 1 to 3 mole equivalents of the halogenating agent with respect to 1 mole of the compound represented by the chemical formula (II).
The compound represented by the chemical formula (II) which is the starting material for this reaction can be produced, for example, according to the method described in Japanese Patent No. 3088757.

Ｂ法（１）では、化学式（ＩＶ）で表される化合物と放射性標識されたハロゲン化剤を適当な溶媒中で反応させ、一般式（Ｖ）で表される化合物を製造する。
反応で用いる溶媒としては、反応に関与しないものであれば特に制限はなく、例えばＮ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド、アセトニトリル、ジメチルスルホキシド、ヘキサメチルリン酸トリアミド等の非プロトン性極性溶媒；アセトン、メチルエチルケトン等のケトン類；テトラヒドロフラン、ジオキサン等のエーテル類；メタノール、エタノール、プロパノール等のアルコール類；酢酸、ぎ酸、濃硫酸、水等が例示できる。
ハロゲン化剤としては、^１８Ｆ、^３４ｍＣｌ、^７６Ｂｒ、^１２３Ｉ、^１２４Ｉ、^１２５Ｉ又は^１３１Ｉ等の放射性ハロゲン原子を含む化合物であれば制限はなく、例えば、フッ素、Ｎ−フルオロコハク酸イミド、塩素、Ｎ−クロロコハク酸イミド、塩化スルフリル、次亜塩素酸ソーダ、臭素、Ｎ−ブロモコハク酸イミド、ピリジニウムブロミドパーブロミド、ヨウ素、Ｎ−ヨードコハク酸イミド、及びヨードゲン、クロラミンＴ、Ｎ−クロロコハク酸イミド、Ｎ−ブロモコハク酸イミド、濃硝酸等の酸化剤共存下のヨウ化ナトリウム等が挙げられる。
反応温度は０℃から溶媒の沸点程度であり、好ましくは０〜８０℃である。反応時間は０．５〜４８時間であり、好ましくは１〜１２時間である。この反応においては、化学式（ＩＶ）で表される化合物１モルに対してハロゲン化剤を１〜３モル当量使用するのが好ましい。
なお、本反応の出発物質である化学式（ＩＶ）で表される化合物は、例えば、特許第３０８８７５７号公報記載の方法に準じて製造することができる。 [Method B (1)]

In Method B (1), a compound represented by the general formula (V) is produced by reacting a compound represented by the chemical formula (IV) with a radiolabeled halogenating agent in an appropriate solvent.
The solvent used in the reaction is not particularly limited as long as it does not participate in the reaction. For example, aprotic such as N, N-dimethylformamide, N, N-dimethylacetamide, acetonitrile, dimethyl sulfoxide, hexamethylphosphoric triamide and the like. Examples include polar solvents; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; alcohols such as methanol, ethanol and propanol; acetic acid, formic acid, concentrated sulfuric acid, and water.
The halogenating agent is not particularly limited as long as it is a compound containing a radioactive halogen atom such as ¹⁸ F, ³⁴ mCl, ⁷⁶ Br, ¹²³ I, ¹²⁴ I, ¹²⁵ I or ¹³¹ I. For example, fluorine, N-fluorosuccinic acid Imido, chlorine, N-chlorosuccinimide, sulfuryl chloride, sodium hypochlorite, bromine, N-bromosuccinimide, pyridinium bromide perbromide, iodine, N-iodosuccinimide, and iodogen, chloramine T, N-chlorosuccinic acid Examples thereof include sodium iodide in the presence of an oxidizing agent such as imide, N-bromosuccinimide and concentrated nitric acid.
The reaction temperature is about 0 ° C to the boiling point of the solvent, preferably 0 to 80 ° C. The reaction time is 0.5 to 48 hours, preferably 1 to 12 hours. In this reaction, it is preferable to use 1 to 3 mole equivalents of the halogenating agent with respect to 1 mole of the compound represented by the chemical formula (IV).
The compound represented by the chemical formula (IV), which is the starting material for this reaction, can be produced, for example, according to the method described in Japanese Patent No. 3087757.

Ｂ法（２）では、化学式（ＶＩ）で表される放射性標識された化合物とトリホスゲンを適当な溶媒中で反応させ、一般式（ＶＩＩ）で表される化合物（一般式（Ｉ）中、Ｒ^１で示される基が放射性ハロゲン原子であり、Ｒ^２で示される基がＯであるウラシル化合物）を製造する。
反応で用いる溶媒としては、反応に関与しないものであれば特に制限はなく、例えばベンゼン、クロルベンゼン、トルエン、ジクロロメタン、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド等の非プロトン性溶媒；テトラヒドロフラン、１，２−ジメトキシエタン、ジオキサン、エーテル等のエーテル類；ｔ−ブタノール等のアルコール類等が例示できる。
反応温度は０℃から溶媒の沸点程度であり、好ましくは０〜８０℃である。反応時間は１〜１２０分間であり、好ましくは２〜３０分間である。この反応においては、化学式（ＶＩ）で表される化合物１モルに対してトリホスゲンを０．１〜１０．０モル当量使用するのが好ましい。 [Method B (2)]

In Method B (2), a radiolabeled compound represented by the chemical formula (VI) is reacted with triphosgene in an appropriate solvent, and the compound represented by the general formula (VII) (in the general formula (I), R ^A uracil compound in which the group represented by ¹ is a radioactive halogen atom and the group represented by R ² is O).
The solvent used in the reaction is not particularly limited as long as it does not participate in the reaction. For example, aprotic solvents such as benzene, chlorobenzene, toluene, dichloromethane, N, N-dimethylformamide, N, N-dimethylacetamide; Examples thereof include ethers such as tetrahydrofuran, 1,2-dimethoxyethane, dioxane and ether; alcohols such as t-butanol.
The reaction temperature is about 0 ° C to the boiling point of the solvent, preferably 0 to 80 ° C. The reaction time is 1 to 120 minutes, preferably 2 to 30 minutes. In this reaction, it is preferable to use 0.1 to 10.0 mole equivalents of triphosgene with respect to 1 mole of the compound represented by the chemical formula (VI).

Ｃ法では、一般式（ＶＩＩＩ）で表される化合物と［^１１Ｃ］ホスゲンを適当な溶媒中で反応させ、一般式（ＩＸ）で表される化合物（一般式（Ｉ）中、２’位が［^１１Ｃ］であり、Ｒ^２で示される基がＯであるウラシル化合物）を製造する。
反応で用いる溶媒としては、反応に関与しないものであれば特に制限はなく、例えばベンゼン、クロルベンゼン、トルエン、ジクロロメタン、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド等の非プロトン性溶媒；テトラヒドロフラン、１，２−ジメトキシエタン、ジオキサン、エーテル等のエーテル類；ｔ−ブタノール等のアルコール類等が例示できる。
反応温度は０℃から溶媒の沸点程度であり、好ましくは０〜８０℃である。反応時間は１〜６０分間であり、好ましくは１〜２０分間である。
なお、［^１１Ｃ］ホスゲンは、例えば、Ｎｕｃｌ．Ｍｅｄ．Ｂｉｏｌ．，２００２．Ａｐｒ；２９（３）：３４５−５０．に記載の方法に準じて製造することができる。 [Method C]

In Method C, a compound represented by the general formula (VIII) and [ ¹¹ C] phosgene are reacted in an appropriate solvent, and the compound represented by the general formula (IX) (position 2 ′ in the general formula (I)) Is [ ¹¹ C], and the group represented by R ² is O).
The solvent used in the reaction is not particularly limited as long as it does not participate in the reaction. For example, aprotic solvents such as benzene, chlorobenzene, toluene, dichloromethane, N, N-dimethylformamide, N, N-dimethylacetamide; Examples thereof include ethers such as tetrahydrofuran, 1,2-dimethoxyethane, dioxane and ether; alcohols such as t-butanol.
The reaction temperature is about 0 ° C to the boiling point of the solvent, preferably 0 to 80 ° C. The reaction time is 1 to 60 minutes, preferably 1 to 20 minutes.
^{Incidentally, [11} C] phosgene, for example, Nucl. Med. Biol. , 2002. Apr; 29 (3): 345-50. Can be produced according to the method described in 1. above.

Ｄ法では、一般式（Ｘ）で表される化合物と［^１１Ｃ］ホスゲンを適当な溶媒中で反応させ、一般式（ＸＩ）で表される化合物（一般式（Ｉ）中、２位が［^１１Ｃ］であり、Ｒ^２で示される基がＮＨであるウラシル化合物）を製造する。
反応で用いる溶媒としては、反応に関与しないものであれば特に制限はなく、例えばベンゼン、クロルベンゼン、トルエン、ジクロロメタン、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド等の非プロトン性溶媒；テトラヒドロフラン、１，２−ジメトキシエタン、ジオキサン、エーテル等のエーテル類；ｔ−ブタノール等のアルコール類等が例示できる。
反応温度は０℃から溶媒の沸点程度であり、好ましくは０〜８０℃である。反応時間は１〜６０分間であり、好ましくは１〜２０分間である。 なお、本反応の出発物質である一般式（Ｘ）で表される化合物は、特開２００５−３３６１７９号公報または特許第３０８８７５７号公報に記載の方法に準じて製造することができる。 [Method D]

In the method D, a compound represented by the general formula (X) and [ ¹¹ C] phosgene are reacted in a suitable solvent, and the compound represented by the general formula (XI) (in the general formula (I), the 2-position is [ ¹¹ C], and the group represented by R ² is NH.
The solvent used in the reaction is not particularly limited as long as it does not participate in the reaction. For example, aprotic solvents such as benzene, chlorobenzene, toluene, dichloromethane, N, N-dimethylformamide, N, N-dimethylacetamide; Examples thereof include ethers such as tetrahydrofuran, 1,2-dimethoxyethane, dioxane and ether; alcohols such as t-butanol.
The reaction temperature is about 0 ° C to the boiling point of the solvent, preferably 0 to 80 ° C. The reaction time is 1 to 60 minutes, preferably 1 to 20 minutes. In addition, the compound represented by general formula (X) which is a starting material of this reaction can be manufactured according to the method as described in Unexamined-Japanese-Patent No. 2005-336179 or Japanese Patent No. 3087757.

Ｅ法では、一般式（ＸＩＩ）で表される化合物と［^１１Ｃ］ホスゲンを適当な溶媒中で反応させ、一般式（ＸＩＩＩ）で表される化合物（一般式（Ｉ）中、２位が［^１１Ｃ］であり、Ｒ^２で示される基がＯであるウラシル化合物）を製造する。
反応で用いる溶媒としては、反応に関与しないものであれば特に制限はなく、例えばベンゼン、クロルベンゼン、トルエン、ジクロロメタン、Ｎ，Ｎ−ジメチルホルムアミド、Ｎ，Ｎ−ジメチルアセトアミド等の非プロトン性溶媒；テトラヒドロフラン、１，２−ジメトキシエタン、ジオキサン、エーテル等のエーテル類；ｔ−ブタノール等のアルコール類等が例示できる。
反応温度は０℃から溶媒の沸点程度であり、好ましくは０〜８０℃である。反応時間は１〜６０分間であり、好ましくは１〜２０分間である。 なお、本反応の出発物質である一般式（ＸＩＩ）で表される化合物は、特開２００５−３３６１７９号公報または特許第３０８８７５７号公報に記載の方法に準じて製造することができる。 [E method]

In the method E, the compound represented by the general formula (XII) and [ ¹¹ C] phosgene are reacted in an appropriate solvent, and the compound represented by the general formula (XIII) (in the general formula (I), the 2-position is [ ¹¹ C], and the group represented by R ² is O).
The solvent used in the reaction is not particularly limited as long as it does not participate in the reaction. For example, aprotic solvents such as benzene, chlorobenzene, toluene, dichloromethane, N, N-dimethylformamide, N, N-dimethylacetamide; Examples thereof include ethers such as tetrahydrofuran, 1,2-dimethoxyethane, dioxane and ether; alcohols such as t-butanol.
The reaction temperature is about 0 ° C to the boiling point of the solvent, preferably 0 to 80 ° C. The reaction time is 1 to 60 minutes, preferably 1 to 20 minutes. In addition, the compound represented by general formula (XII) which is a starting material of this reaction can be manufactured according to the method as described in Unexamined-Japanese-Patent No. 2005-336179 or Japanese Patent No. 3087757.

  The uracil compound of the present invention or a salt thereof produced by the above reactions can be purified by using generally known separation and purification means such as concentration, solvent extraction, filtration, recrystallization, various HPLCs and the like.

  The uracil compound of the present invention or a salt thereof shows remarkable uptake specific to a tumor based on TP expression. Therefore, tumors can be imaged by detecting annihilation radiation and gamma rays resulting from the combination of positrons emitted from the compound of the present invention and surrounding electrons using nuclear medicine examination techniques such as PET and SPECT.

  The tumor that can be diagnosed with the imaging agent of the present invention is not particularly limited as long as it is a tumor expressing TP, and examples include the esophagus, stomach, pancreas, large intestine, lung, bladder, ovary, breast, kidney, skin, uterus and the like. it can. Moreover, since TP is involved in the activation of fluoropyrimidine compounds such as 5-fluorouracil, the imaging agent of the present invention is also effective for prediction of therapeutic effects and prognosis estimation for fluoropyrimidine compounds. Biochemical information can be provided.

When the imaging agent of the present invention is used as an imaging agent for PET, a uracil compound labeled with a positron emitting nuclide such as ¹¹ C, ¹⁸ F, ³⁴ mCl, ¹²⁴ I, ⁷⁶ Br, or a salt thereof is used, and for SPECT When used as an imaging agent, a uracil compound or a salt thereof labeled with a γ-ray emitting nuclide such as ¹²³ I or ¹³¹ I is used.

  The imaging agent of the present invention can be produced by a conventional method by adding a pharmaceutically acceptable additive to the uracil compound of the present invention or a salt thereof. Such additives include stabilizers such as ascorbic acid and P-aminobenzoic acid, pH adjusters such as hydrochloric acid and sodium hydroxide, suitable buffers such as phosphate buffer, isotonicity such as physiological saline, etc. Agents and the like.

  In the imaging agent of the present invention, the radioactivity of the radioisotope is arbitrary, but the radioactivity is such that sufficient information can be obtained when it is administered to a subject and a nuclear medicine diagnosis is performed. It is desirable that the radiation exposure range be as low as possible. As for the administration method, intravenous administration is generally performed, but any administration method that is advantageous for diagnosis can be used, and other administration methods can be implemented.

The uracil compound of the present invention or a salt thereof can be used internally for tumors by selecting a suitable nuclide based on the type, energy, half-life, etc. of radiation emitted by utilizing the strong accumulation property specific to tumors. It is also useful as a radiation therapy agent.
In the internal radiotherapy agent of the present invention, ¹³¹ I or ¹²⁵ I is preferable as the nuclide used because of the type, energy, and half-life of the emitted radiation.
The tumor that can be treated with the internal radiation therapeutic agent of the present invention is not particularly limited as long as it is a tumor expressing TP. The esophagus, stomach, pancreas, large intestine, lung, bladder, ovary, breast, kidney, skin, uterus Etc. can be illustrated.
The internal radiotherapy agent of the present invention can be produced by a conventional method by adding a pharmaceutically acceptable additive to the uracil compound of the present invention or a salt thereof. The dosage of the internal radiotherapy agent of the present invention is appropriately set depending on the disease, weight, age, sex, etc. of the patient.

  Hereinafter, specific reference examples and examples will be described.

Reference example 1

<Synthesis of 6- (1- (2-Iminoimidazolidinyl) methyl) uracil trifluoroacetate (Compound (1))>
Under an argon atmosphere, 395.2 mg (3.73 mmol, 2 eq) of bromocyan (BrCN) was dissolved in 2.7 mL of water, and 340.6 mg (1.849 mmol) of 6-[(2-aminoethyl) amino] methyluracil. 1 eq) was added and stirred at room temperature with light shielding. Two hours later, the solvent and BrCN were distilled off under reduced pressure to obtain an iminoimidazolidinyl HBr salt (534.7 mg, 1.843 mmol) (yield 99%).
The obtained compound was subjected to reverse phase HPLC to perform salt exchange from HBr salt to THA salt (column: inertosyl ODS-3, 20.0 mm ID × 250 mm, eluent: 0.1% TFA: MeOH = 95.5, flow rate 3.0 mL / min), and the target compound (1) was obtained.
¹ HNMR (d-MeOH) δ: 3.59-3.78 (4H, m), 4.30 (2H, d, J = 1.15), 5.51 (1H, s).

Reference example 2

<Synthesis of 5-iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride (compound (2))>
Under an argon atmosphere, 30.2 mg (0.09 mmol) of the synthesized compound (1) was dissolved in 1.5 mL of a solution (water: acetonitrile = 1: 2), and 25.3 mg (0.11 mmol, 1 of NIS) .2 eq) was added and the mixture was stirred at 50 ° C. for 1 hour. After confirming the progress of the reaction by thin layer chromatography (TLC) method (developing solvent; 0.1% formic acid: methanol = 9: 1), the solvent was distilled off under reduced pressure and subjected to reverse phase HPLC to give a TFA salt. Exchange from water to hydrochloride (column: inertosyl ODS-3, 20.0 mm ID × 250 mm, eluent: 0.01 N HCl: MeOH = 95: 5, flow rate 3.0 ml / min), purpose Compound (2) (32.2 mg, 0.08 mmol) was obtained (93% yield).
< ¹ > H NMR (d-MeOH) [delta]: 3.67 (4H, s), 4.49 (2H, s).
Anal. Calcd. _{for C 8 H 11 ClIN 5 O} 2: C, 25.86; H, 2.98; N, 18.85; Cl, 9.54; I, 34.15. Found: C, 25.37; H, 2.92; N, 18.20; Cl, 9.39; I, 34.06.

Reference example 3

<Synthesis of 5-bromo-6- (1- (2-oxoimidazolidinyl) methyl) uracil (compound (3))>
To 250 mL of t-butanol (t-BuOH) was added 5-bromo-6-[(2-aminoethyl) amino] methyluracil (101.7 mg, 0.39 mmol) and potassium t-butoxide (t-BuOK) (87. 8 mg, 0.78 mmol) was added, and the mixture was stirred at room temperature for 10 minutes under an argon atmosphere. Furthermore, it was refluxed for 1 hour for further dissolution. After returning to room temperature again, triphosgene (111.7 mg, 0.40 mmol) was added and stirred for 5 minutes. Ethanol was added to the reaction solution, and the solvent was distilled off under reduced pressure. The obtained white solid was neutralized by adding 5 mL of water and a 1% t-BuOH aqueous solution so that the pH became 7 with a pH test paper, and the recrystallization operation was performed as it was. The target compound (3) (79.3 mg, 0.28 mmol, white powder) was obtained by recrystallization (yield 70.9%).
< ¹ > H-NMR (MeOH-d4) [delta]: 3.468-3.488 (m, 4H), 4.314 (s, 2H).
Anal. Calcd. _{for C 8 H 9 BrN 4 O} 3: C, 33.24; H, 3.14; N, 19.38. Found: C, 33.33; H, 3.09; N, 19.39.
_{ESI-MS C 8 H 9 BrN} 4 O 3 m / z: 289.291 [M + H] +, mp: 243-245 ℃

<Synthesis of [ ¹²⁵ I] 5-iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride (compound (4))>
Under an argon atmosphere, 50 μL of an NCS 0.3 μg / μL acetone solution was added to [ ¹²⁵ I] NaI (25.9 MBq) (642.8 GBq / mg, PerkinElmer), and the mixture was allowed to stand at room temperature for 10 minutes. The solvent was distilled off with a nitrogen stream. 40 μL of a 2.5 μg / μL solution (water: acetonitrile = 1: 2) of the compound (1) synthesized in Reference Example 1 was added thereto and stirred at 50 ° C. for 1 hour.
After cooling to room temperature, the reaction vessel was rinsed with a solution of 0.01N HCl: MeOH = 95: 5 (2 × 50 μL) and subjected to reverse phase HPLC to perform salt exchange from TFA salt to hydrochloride ( Column: Inertosyl ODS-3, 6.0 mm ID × 250 mm, eluent: 0.01 N HCl: MeOH = 95: 5, flow rate 0.7 mL / min), the target compound (4) was obtained. . By repeating the same operation twice, the target product could be obtained with high purity.
The radiochemical purity and chemical purity of the product were measured by reverse phase HPLC under the same conditions as described above. The measurement results were as follows. Radiochemical yield: 83%; Chemical purity, radiochemical purity>99%; Specific activity: 9.4 GBq / μmol

<[2′- ¹¹ C] 5-Bromo-6- (1- (2-oxyimidazolidinyl) methyl) uracil (Synthesis of Compound (5)>
Although 5-bromo-6-[(2-aminoethyl) amino] methyluracil was activated with t-BuOK (2 eq, 3 eq), (0.5 mg / mL, 10 mg / mL) was prepared. 500 μL of this solution was added to the reaction vessel, and [ ¹¹ C] phosgene was blown at 30 ° C. for 5 minutes. After heating to 130 ° C. to remove t-BuOH, 1.7 mL of water was added to the reaction vessel and stirred, and preparative reverse phase HPLC (mobile bed: 10% EtOH-H ₂ O, H ₃ PO ₄ (pH 2 .32), preparative column: Megapak CIL C ₁₈ 10 mm × 250 mm (JASCO), flow rate: 5.0 mL / min), and the target compound (5) was obtained. For detection, a UV detector (UV-2070 (JASCO)) and a detector for positron measurement (S-1729 (Applied Koken)) as a radioactivity detector were used, and detection was performed at 254 nm. The fraction containing the target substance was passed through a 0.22 μm membrane filter (Vented Milex, Millipore). After the synthesis, the radiochemical purity was measured by HPLC. For the HPLC pump: LC-10ATvp (Shimadzu), detector: SPD-10Avp (Shimadzu), column oven: CTO-10Avp (Shimadzu), column is Shim-pack PREP-ODS (H) 4.6 mm × 250 mm (Shimadzu) ), 15% EtOH / H ₂ O (0.4 mL of phosphoric acid was added to 1 L of mobile phase to adjust pH to 2.2), flow rate of 0.5 mL / min, detection wavelength of 274 nm, 40 Analysis was performed at 0 ° C. ^[11 C] compounds which are labeled body holding time (5) was 7.6 minutes, in HPLC, unlabeled substance, compound (3) by matching the retention time of question ^[11 C] labeled compound The compound (5) was identified.

<In vivo uptake experiment using human skin cancer cells (A431)>
Human 9-week-old nude mice (BALB / cAJc1-nu / nu nude mice) diluted with PBS (−) so that the number of cells is 5 × 10 ⁶ cells / 0.1 mL. ) 100 mL of this cell suspension was implanted in the right abdomen of (average weight 20 g, n = 5 group).
Sixteen days after transplantation, the synthesized compound (4) (37 kBq / 0.1 mL / mouse) dissolved in physiological saline was administered from the tail vein under Nembutal anesthesia.
0.5 hour, 1 hour, 3 hours, 24 hours after administration, whole blood was lethal from the heart under ether anesthesia, blood, plasma, tumor, muscle (left thigh), stomach, heart, spleen, liver, Kidney, lung, small intestine, cecum to large intestine, brain, skin, ovary, fat, bladder, brown fat, uterus were collected. Blood and plasma were 0.2 mL, and the contents of the stomach, small intestine and large intestine were measured without taking them out, and other organs were measured with a γ counter after weighing all or part of the contents. The measurement results are shown in the graph of FIG. The measured organ count was converted to 1 g of tissue weight and standardized as (inject dose% / tissue weight) (% ID / g). .
According to this, the uptake into the tumor was seen immediately after administration, and the decrease in the uptake amount over time was moderate compared to other organs. It was confirmed that there was not much accumulation in the brain (0%), heart (0.1%), and lung (0.5%).
Further, as apparent from the graph of FIG. 2 and the table of FIG. 3, the best ratios of tumor blood ratio and tumor muscle ratio were obtained after 3 hours, which were 34.5 and 68.3, respectively. .
In addition, it was shown from the results of immunoblotting and immunostaining that TP was expressed in the tumor tissue.

<Measurement of TP inhibitory activity>
To 850 μL of a buffer solution (10 mM tris-HCl (pH 7.3), 2 mM EDTA), 100 μL of 0.1 M potassium phosphate (pH 7.1) and 0.11 U of TP (Aldrich) are added, and the final concentration is 1 nM to 10 μM. Then, the compound (4) or (5) synthesized in Experimental Example 1 or 2 was added. Preincubated for 2 minutes at 37 ° C. The reaction was initiated by adding 50 μL of 0.1 M thymidine. The reaction was stopped by incubating at 37 ° C. and taking 300 μL after 5 minutes and adding to 300 μL of 0.5N NaOH. Thymine produced by the enzymatic reaction was quantified by HPLC (column: inertosyl ODS-3, 4.6 mm ID × 250 mm, eluent: ammonium buffer: MeOH = 91: 9, flow rate 1.0 mL / min, Detection wavelength 254 nm).
The enzyme activity inhibition rate of the compound was calculated according to the following formula.
Inhibition rate (%) = 1-[(thymine production amount in compound addition group (nmol / min)) / (thymine production amount in compound non-addition group (nmol / min))]
Based on the inhibition rate obtained from this formula, the compound concentration (IC ₅₀ ) at which the inhibition rate was 50% was calculated.
The IC ₅₀ of compound (4) was calculated to be 4.3 × 10 ⁻³ μM, and the IC ₅₀ of compound (5) was calculated to be 4.50 μM. This confirmed that the compounds (4) and (5) showed a high inhibition rate against TP.
From the above, it has been clarified that the uracil compound of the present invention or a salt thereof is taken up in a tumor-specific manner and accumulates in a tumor tissue based on TP expression. Therefore, the uracil compound or a salt thereof of the present invention is extremely useful as an imaging agent for tumor diagnosis targeting TP.

It is a graph which shows the uptake | capture state to each organ of A431 of a compound (4). It is a graph which shows the uptake | capture state of A431 of a compound (4) to the blood, tumor, and muscle. It is a table | surface figure which shows the uptake | capture ratio of the blood and the muscle with respect to the tumor of A431 of a compound (4).

Claims (8)

The following general formula (I) labeled with a radioisotope

[Wherein, R ¹ represents a hydrogen atom, a halogen atom, a cyano group or a lower alkyl group; R ² represents O, S or NH. ] The uracil compound or its salt characterized by the above-mentioned. In the general formula (I), the group represented by R ¹ is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and the group represented by R ² is O or NH. Or a salt thereof. In general formula (I), the group represented by R ¹ is a radioactive halogeno group selected from the group consisting of ¹⁸ F, ³⁴ mCl, ⁷⁶ Br, ¹²³ I, ¹²⁴ I, ¹²⁵ I and ¹³¹ I, The uracil compound or salt thereof according to any one of claims 1 and 2. In the formula (I), the carbon of the 2 'position, radioisotope ¹¹ uracil compound or a salt thereof of any one of claims 1 to 3, characterized in that a ^C. The uracil compound or a salt thereof according to any one of claims 1 to 4, wherein the carbon at the 2-position in the general formula (I) is a radioisotope ¹¹ C. The uracil compound or a salt thereof is [ ¹²³ I] 5-iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹²⁴ I] 5-iodo-6- (1- (2- Iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹²⁵ I] 5-iodo-6- (1- (2-iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹³¹ I] 5-iodo-6- (1 -(2-Iminoimidazolidinyl) methyl) uracil hydrochloride, [ ¹⁸ F] 5-fluoro-6- (1- (2-iminoimidazolidinyl) methyl) uracil, [2′- ¹¹ C] 5-bromo 6- (1- (2-oxo-imidazolidinyl) methyl) uracil, ^[2'11 C] 5-chloro-6- (1- (2-oxo-imidazolidinyl) methyl) uracil, ^{[2- 11} C] 5-chloro- 6- (1- (2-Iminoimidazolidinyl) methyl) uracil or [2- ¹¹ C] 5-bromo-6- (1- (2-iminoimidazolidinyl) methyl) uracil The uracil compound or a salt thereof according to any one of claims 1 to 5.   An imaging agent comprising the uracil compound or a salt thereof according to any one of claims 1 to 6 as an active ingredient.   An imaging agent for diagnosing a tumor comprising the uracil compound or a salt thereof according to any one of claims 1 to 6 as an active ingredient.

Images