RU2163903C2 - Method of incorporation of tritium label in organic compounds and highly tritium-labeled methyl-(e)-{2-[6-(2-cyanophenoxy)- -pyrimidine-4-yloxy]phenyl]}-3-methoxyacrylate - Google Patents

Abstract

FIELD: organic chemistry, biochemistry, medicine, biology. SUBSTANCE: invention proposes method of synthesis of highly tritium- -labeled organic compounds showing sensitivity to the oxygen presence and lability under hydrogenation conditions. Tritium water is obtained by keeping PdO or mixture PdO with PdO/Al₂O₃ in gaseous tritium atmosphere. The end product is obtained by keeping the parent organic substance to yield tritium water in medium of dioxane with triethylamine. All solid and liquid required components are added into reactor. Then reactor is frozen in the point of reagents location, filled with gaseous tritium followed by freezing the upper part of reactor and heating the bottom of reactor with reagents. After the repeated evacuation of reactor its bottom part is frozen again, kept in this frozen state and after ceasing reactor freezing is kept at 18-25 C for 12-20 h at stirring its content. New method provides producing the novel highly-tritium labeled organic compound methyl-(E)-{2-[6-(2-cyanophenoxy)pyrimidine-4-yloxy] -phenyl} -3-methoxyacrylate of the formula (I)

Description

 The invention relates to the field of organic chemistry and may find application in biochemical and biomedical research.

 Modern methods for the study of physiologically active compounds require their presence in the form of highly labeled compounds.

 Many physiologically active compounds are labile under hydrogenation conditions and, therefore, when obtaining highly labeled with tritium compounds, one has to resort to a set of gentle methods that ensure the preservation of the structure of the starting compounds.

One of such known labile organic physiologically active compounds under hydrogenation conditions is, for example, alprazolam. There is a method of producing this tritium-labeled organic compound by producing tritium water while keeping PdO or a mixture of PdO with PdO / Al ₂ O ₃ in an atmosphere of gaseous tritium by heating, reacting the starting aromatic substance with the obtained tritium water in dioxane mixed with triethylamine. This known method provides for the implementation of the evacuation of the reactor before filling it with gaseous tritium and freezing the reactor when it is again evacuated (RF patent N 2083579, C 07 D 487/04, publ. 10.07.97 [1] - prototype).

 Using this known method, it is possible to obtain organic substances highly labeled with tritium, the molecules of which include galloid aryls, heterocycles and which are therefore labile under hydrogenation conditions.

 Among physiologically active compounds, there are compounds which are not only labile under the conditions of the hydrogenation reaction, but also are sensitive to the presence of oxygen. Such compounds cannot be obtained in a known manner [1] in the form of highly tritiated compounds.

The Merck Index an encyclopedia of chemicals, drugs and biologicals Elevehtth Edition and 12 th. 1989 - 1996, N V. USA [2].One of these compounds, which is sensitive to the presence of oxygen and labile under the conditions of the hydrogenation reaction, is the known compound: methyl- (E) - {2 [6- (2-cyanophenoxy) pyrimidin-4-yloxy] phenyl} -3-methoxyacrylate formulas I

The Merck Index an encyclopedia of chemicals, drugs and biologicals Elevehtth Edition and 12 th. 1989 - 1996, N V. USA [2].

 This known compound has physiological (fungicidal) activity (C. Albert et al., Proc. 1988. Br. Grop. Prot. Conf. - Pests Dis., 1, 17, Patent EP 120321 [3]).

 However, the known compound of formula I is not described as a tritium-labeled compound.

 The technical result achieved by the implementation of the present invention is the selection of conditions allowing to obtain highly labeled with tritium organic compounds, labile both under hydrogenation and in the presence of oxygen, which makes it possible to obtain new highly labeled with tritium organic compounds.

This technical result is achieved by the fact that the method of introducing a tritium label into organic compounds labile in the presence of oxygen and under the conditions of the hydrogenation reaction consists in introducing into the reactor solid and liquid components of the reaction mixture: the starting compound subjected to the introduction of a label, a solvent in the form of a mixture dioxane with triethylamine and a catalyst in the form of PdO or a mixture of PdO with PdO / Al ₂ O ₃ , freezing the lower part of the reactor at the location of solid and liquid components in it, evacuating the reaction torus, transferring the solvent to the upper part of the reactor by freezing it, filling the reactor with gaseous tritium, producing tritium water and condensing it in the upper part of the reactor by heating its lower part while maintaining cooling in its upper part, freezing the resulting tritium water together with the solvent in the lower part of the reactor by removing cooling from the upper part of the reactor and cooling its lower part, freezing the entire volume of the reactor, removing excess tritium gas by repeated vacuum umirovka reactor and the interaction of the starting compound with the obtained tritium water by stopping the cooling of the reactor and stirring the reaction mixture at a temperature of 18-25 ^o C for 12-20 hours

Согласно известному способу [1] высокомеченные тритием органические соединения можно получать, если в реактор внести исходное вещество, PdP и PdO/Al₂O₃, подвергнуть реактор вакуумированию, напустить в него газообразный тритий и подвергнуть содержимое реактора нагреванию при 69-71^oC в течение 15-20 мин. При этом происходит образование тритиевой воды, пары которой заполняют объем нагреваемого реактора. Для того чтобы исключить потерю образовавшейся тритиевой воды, реактор замораживают, вакуумируют для удаления избыточного газообразного трития, вносят в реактор смесь диоксана с триэтиламином и после герметизации реактора в нем проводят реакцию взаимодействия исходного вещества со свежеполученной тритиевой водой. Таким образом, компоненты реакционной массы вносят в реактор дважды: сначала в виде PdO или смеси PdO с PdO/Al₂O₃ и исходного вещества, а затем - в виде смеси диоксана с триэтиламином. Такое двукратное внесение в реактор компонентов смеси создает вероятность контакта исходного вещества с кислородом воздуха, что вызывает деструкцию целевого продукта, если тритиевую метку вводят в органическое соединение, лабильное в присутствии кислорода.The specified technical result is also achieved by obtaining tritium-labeled methyl- (E) - {2 [6- (2-cyanophenoxy) pyrimidin-4-yloxy] phenyl} -3-methoxyacrylate of the formula I

According to the known method [1], tritium-labeled organic compounds can be obtained by introducing into the reactor the starting material, PdP and PdO / Al ₂ O ₃ , vacuuming the reactor, introducing gaseous tritium into it, and subjecting the contents of the reactor to heating at 69-71 ^° C within 15-20 minutes In this case, tritium water is formed, the vapors of which fill the volume of the heated reactor. In order to exclude the loss of the resulting tritium water, the reactor is frozen, evacuated to remove excess tritium gas, a mixture of dioxane with triethylamine is introduced into the reactor, and after sealing the reactor, the reaction of the starting material with freshly obtained tritium water is carried out in it. Thus, the components of the reaction mixture are introduced into the reactor twice: first in the form of PdO or a mixture of PdO with PdO / Al ₂ O ₃ and the starting material, and then in the form of a mixture of dioxane with triethylamine. Such a twofold introduction of the mixture components into the reactor creates the probability of contact of the starting material with atmospheric oxygen, which causes the destruction of the target product if the tritium label is introduced into an organic compound labile in the presence of oxygen.

 By the method according to the invention, measures have been taken to exclude the possibility of contact of the starting material with atmospheric oxygen. In accordance with the method according to the invention, all solid and liquid components of the reaction mixture are introduced into the reactor at a time, which eliminates the need for a second opening of the reactor, carried out when implementing the known method [1], not intended for introducing labels into compounds that are simultaneously sensitive to the presence of oxygen and labile under the conditions of the hydrogenation reaction.

In order to avoid losses during the first evacuation, the mixture of dioxide with triethylamine introduced simultaneously with other components is subjected to freezing of the introduced components before this evacuation by the method according to the invention. After filling the reactor with gaseous tritium, the reaction of the formation of tritium water is carried out by keeping the reaction mixture at 69-71 ^o C. However, in contrast to the known method [1], when implemented, the resulting tritium water formed in the form of vapors fills the reactor volume in the form of vapors, when sold of the new method, the reactor is cooled with liquid nitrogen (frozen) in its upper part. This ensures local condensate collection of the resulting tritium water, as well as dioxane and triethylamine.

 Further, as in the known method [1], a reactor cooled by liquid nitrogen is subjected to evacuation, which eliminates the loss of freshly formed tritium water, as well as dioxane and triethylamine vapors. Then the reactor is sealed and the tritium water and the solvent are thawed by freezing its lower part, in which the organic matter and the catalyst are located. After stopping the freezing of the reactor at its subsequent holding at room temperature with stirring of the reaction mixture, freshly formed tritium water reacts with the starting material to form the target product highly labeled with tritium.

 The method is illustrated by the following examples.

Example 1. Synthesis of tritium-labeled methyl (E) - {2 [6- (2-cyanophenoxy) pyrimidin-4-yloxy] phenyl} -3-methoxyacrylate. The starting organic compound, 10 mg methyl (E) - {2 [6- (2-cyanophenoxy) pyrimidin-4-yloxy] phenyl} -3-methoxy acrylate, 50 mg PdO and 300 μl of dioxane triethylamine (30: 1). The lower part of the reactor (ampoules) is frozen with liquid nitrogen, vacuum, the solvent is thawed into the upper part of the reactor without stopping cooling, gaseous tritium is injected to a pressure of 300 hPa, and palladium oxide is heated at 65-85 ^o C. The resulting tritium water condenses in the cooled zone. Then the cooling of the upper part of the ampoule is removed, the tritium water and the solvent are thawed to the zone where the catalyst and the starting organic compound are. At a temperature of liquid nitrogen, the reactor is evacuated, sealed and heated to room temperature. The reaction is carried out with stirring at room temperature for 12-20 hours. Then, the contents of the reactor ampoule are frozen with liquid nitrogen, the catalyst is filtered off and washed with methanol (5x0.5 ml). Tritium water is removed by repeated evaporation of the resulting product with methanol (5x3 ml). The target product is purified by HPLC on a Separon C column ₁₈ , 7 μm, 4x150 mm, v - 0.8 ml / min, in a 70% methanol system with 0.1% trifluoroacetic acid, retention time - 5.47 min (radiochemical purity after discharge - above 97%).

The yield of labeled methyl (E) - {2 [6- (2-cyanophenoxy) pyrimidin-4-yloxy] phenyl} -3-methoxyacrylate is 15-20% with a molar radioactivity:
a) when carrying out the reaction for 12 hours - 3.0 Ci / mmol,
b) during the reaction of 20 hours - 4.5 Ci / mmol.

Example 2. According to the method of example 1 was obtained tritiated with methyl tritium (E) - {2 [6- (2-cyanophenoxy) pyrimidin-4-yloxy] phenyl} -3-methoxyacrylate, but a mixture of PdO and 5% PdO was used / Al ₂ O ₃ . After the last freezing, the reactor was kept at a temperature of 18 ^o C.

 The yield of labeled methyl (E) - {2 [6- (2-cyanophenoxy) pyrimidin-4-yloxy] phenyl} -3-methoxyacrylate is 10-15%, molar radioactivity is 2.8 Ci / mmol. By the method according to the invention, other labeled compounds were also obtained from starting compounds labile under hydrogenation conditions and sensitive to the presence of oxygen, including unsaturated, heteroaromatic sulfur-containing compounds.

 Thus, the method according to the invention allows to obtain highly labeled with tritium compounds from the starting compounds, which are labile to hydrogenation conditions and sensitive to the presence of oxygen.

Claims (2)

1. The method of introducing a tritium label into organic compounds labile in the presence of oxygen and under conditions of a hydrogenation reaction, which consists in introducing into the reactor solid and liquid components of the reaction mixture: the starting compound subjected to the introduction of a label, a solvent in the form of a mixture of dioxane with triethylamine and catalyst in the form of PdO or a mixture of PdO with PdO / Al ₂ O ₃ , freezing the lower part of the reactor at the location of solid and liquid components in it, evacuating the reactor, transferring the solvent to the upper part actor by freezing it, filling the reactor with gaseous tritium, obtaining tritium water and condensing it in the upper part of the reactor by heating its lower part while maintaining cooling in its upper part, by freezing the obtained tritium water together with the solvent in the lower part of the reactor by removing cooling from the upper part of the reactor and cooling its lower part, freezing the entire volume of the reactor, removing excess tritium gas by re-evacuating the reactor and interacting Corollary starting compound with tritiated water obtained by terminating the reactor cooling and stirring the reaction mixture at a temperature of 18-25 ^o C for 12-20 hours. 2. Highly labeled tritium methyl- (E) - {2- [6- (2-cyanophenoxy) pyrimidin-4-yloxy] phenyl} -3-methoxyacrylate of the formula I