阅读说明：本技术 一种2-氧代硫代丙酰胺的制备方法 (Preparation method of 2-oxo-thiopropionamide ) 是由 张鹏 蔡正艳 于 2018-06-19 设计创作，主要内容包括：本发明涉及一种2-氧代硫代丙酰胺的制备方法。具体地,本发明公开了一种用于制备Lanabecestat的中间体化合物的制备方法。该方法反应更简单,更安全,适合工业化。(The invention relates to a preparation method of 2-oxo-thiopropionamide. Specifically, the invention discloses a preparation method of an intermediate compound for preparing Lanabecestat. The method has simpler reaction and higher safety, and is suitable for industrialization.)

1. A process for the preparation of 2-oxothiopropionamide, said process comprising the steps of:

(1) subjecting compound 1 to an ammoniation reaction with an organic solution of ammonia, thereby forming compound 2;

(2) compound 2 is thioreacted with phosphorus pentasulfide in an organic solvent to form compound 3, i.e., 2-oxothiopropionamide.

2. The method of claim 1, wherein in step (1), the organic solution of ammonia is one or more of a methanol solution of ammonia and an ethanol solution of ammonia.

3. The method of claim 1, wherein in step (1), the volume to mass ratio (ml/g) of the organic solution of ammonia to compound 1 is 5: 1-10: 1.

4. the method according to claim 1, wherein in the step (1), the concentration of the organic solution of ammonia is 2 to 7 mol/L.

5. The method according to claim 1, wherein in step (1), the temperature of the amination reaction is between 0 ℃ and 50 ℃.

6. The method of claim 1, wherein in step (1), compound 1 is added dropwise to the organic solution of ammonia.

7. The method of claim 1, wherein in step (2), the organic solvent is methyltetrahydrofuran, tetrahydrofuran, ethylene glycol dimethyl ether, dioxane, or a combination thereof.

8. The method according to claim 1, wherein in the step (2), the volume-to-mass ratio (ml/g) of the organic solvent to the compound 2 is 10: 1-15: 1.

9. the method of claim 1, wherein in step (2), the molar ratio of phosphorus pentasulfide to compound 2 is from 1: 3-1: 1.5.

10. the method of claim 1, wherein in step (2), the temperature of the thionation reaction is from room temperature to 50 ℃.

Technical Field

The invention belongs to the field of synthesis of medical intermediates, and particularly relates to a preparation method of 2-oxo-thiopropionamide.

Background

Lanabecestat is an inhibitor of β -amyloid precursor protein lyase 1(BACE1) developed by Alixican as a suitable precursor or mild Alzheimer's disease, and is currently in clinical phase III. In previous phase I studies, phase I was found to significantly and dose-dependently reduce β amyloid levels in the brain of patients and healthy subjects, and was found to have a long-lasting effect, being the only BACE inhibitor found to have a long-lasting effect. The FDA has granted Lanabecestat the rapid channel status (Fast Track designation) for clinical development of treating AD.

The lanabectat structure is as follows:

the existing synthetic route of Lanabecestat is as follows (reference: CN 103380133A):

nucleophilic substitution of p-bromobenzyl bromide (C1) and dimethyl malonate, hydrolysis, decarboxylation, acyl chlorination and Friedel-crafts cyclization to obtain the key intermediate 1 (6-bromoindanone (C6)). And then reacts with methyl acrylate to construct a spiro ring, and the key intermediate 2((1r,4r) -6 '-bromo-4-methoxyspiro [ cyclohexane-1, 2' indene ] -1 '(3' H) -ketone (C9)) is obtained through reduction and methylation. Then imine is synthesized, and then reacts with 2-oxo-thiopropionamide (M2) to close the ring and perform ammoniation to obtain a key intermediate 3(C12), and after resolution, the key intermediate and 5- (prop-1-alkynyl) pyridine-3-yl boric acid undergo Suzuki coupling reaction to obtain lanabemesat (AZD 3293).

The difficulty with this route is the synthesis of the imidazole spiro ring, which uses 2-oxothiopropionamide (M2) which is not available from a suitable commercial source and which requires synthesis. But the thermal stability is poor and the water solubility is high, which brings great difficulty to the synthesis.

The synthesis of M2 used in the original route was as follows (reference: CN 103380133A):

acetyl chloride reacts with a cyano reagent to prepare acetone cyanide, the acetone cyanide is bubbled in 2-methyltetrahydrofuran overnight, and the intermediate M2 is obtained after post-treatment and purification by column chromatography.

The method has great problems, firstly, a cyano reagent is needed for preparing the acetone cyanide, and the toxicity is high; the hydrogen sulfide which is a highly toxic gas is bubbled overnight, so that the hydrogen sulfide is difficult to industrialize; column chromatography is also needed in the post-treatment, so that the industrialization of the method is difficult.

Therefore, there is a need in the art to develop a safer and more industrially applicable method for preparing 2-oxothiopropionamide.

Disclosure of Invention

The invention aims to provide a safer and more suitable industrialized preparation method of 2-oxo-thiopropionamide.

In a first aspect the present invention provides a process for the preparation of 2-oxothiopropionamide, said process comprising the steps of:

(1) subjecting compound 1 to an ammoniation reaction with an organic solution of ammonia, thereby forming compound 2;

(2) compound 2 is thioreacted with phosphorus pentasulfide in an organic solvent to form compound 3, i.e., 2-oxothiopropionamide.

In another preferred example, in step (1), the organic solution of ammonia is one or more of a methanol solution of ammonia and an ethanol solution of ammonia.

In another preferred example, in the step (1), the volume-to-mass ratio (ml/g) of the organic solution of ammonia to the compound 1 is 5: 1-10: 1.

in another preferred example, in the step (1), the concentration of the organic solution of ammonia is 2-7 mol/L.

In another preferred embodiment, in step (1), the temperature of the amination reaction is 0 ℃ to 50 ℃.

In another preferred embodiment, in the step (1), the temperature of the ammoniation reaction is 0 ℃ to 25 ℃.

In another preferred example, in step (1), compound 1 is added dropwise to an organic solution of ammonia.

In another preferred embodiment, in step (1), after the amination reaction is finished, the pure compound 2 can be prepared by simple post-treatment, such as suction filtration and vacuum drying.

In another preferred example, in step (2), the organic solvent is methyltetrahydrofuran, tetrahydrofuran, ethylene glycol dimethyl ether, dioxane or a combination thereof.

In another preferred example, in the step (2), the organic solvent is methyltetrahydrofuran.

In another preferred example, in the step (2), the volume-to-mass ratio (ml/g) of the organic solvent to the compound 2 is 10: 1-15: 1.

in another preferred embodiment, in the step (2), the molar ratio of phosphorus pentasulfide to compound 2 is 1: 3-1: 1.5.

in another preferred example, in the step (2), the temperature of the thionation reaction is from room temperature to 50 ℃.

In another preferred embodiment, in step (2), after the completion of the thionation reaction, the pure compound 3 can be obtained by simple post-treatment, such as silica gel funnel purification, drying, concentration, vacuum distillation.

It is to be understood that within the scope of the present invention, the above-described features of the present invention and those specifically described below (e.g., in the examples) may be combined with each other to form new or preferred embodiments. Not to be reiterated herein, but to the extent of space.

Detailed Description

The present inventors have unexpectedly found, through extensive and intensive studies, a novel process for producing 2-oxothiopropionamide.

The preparation method of the invention overcomes the defects that the existing method for preparing the 2-oxo-thiopropionamide uses a virulent cyano reagent, virulent gas hydrogen sulfide, silica gel column chromatography and the like which are not easy to amplify, and provides a preparation method of the 2-oxo-thiopropionamide which is completely different from the prior art.

The preparation method comprises the steps of preparing 2-oxopropanamide from ethyl 2-oxopropanoate in ammonia methanol solution, and further carrying out thiophosphorus pentasulfide to obtain the 2-oxopropanamide.

Compared with the literature method, the preparation method of the invention adopts safe, cheap and easily obtained ethyl pyruvate, ammonia methanol solution and phosphorus pentasulfide to replace virulent cyano reagent and hydrogen sulfide in the original research route, avoids the use of column chromatography and is easy to realize industrial production.

On this basis, the inventors have completed the present invention.

Preparation method

The present invention provides a process for the preparation of ethyl 2-oxopropanoate, said process comprising the steps of:

(1) subjecting compound 1 to an ammoniation reaction with an organic solution of ammonia, thereby forming compound 2;

(2) compound 2 is thioreacted with phosphorus pentasulfide in an organic solvent to form compound 3, i.e., 2-oxothiopropionamide.

In the present invention, the organic solution of ammonia is a solution commonly used in the art in the first amination step. The present invention particularly preferably uses one or more of a methanol solution of ammonia and an ethanol solution of ammonia, and more preferably a methanol solution of ammonia. The following amounts and concentration ranges are particularly preferred according to the invention: the volume-to-mass ratio (ml/g) of the ammonia methanol solution to the compound 1 is preferably 5: 1-10: 1, the concentration of the ammonia methanol solution is preferably 2-7 mol/L.

In the present invention, the temperature of the first amination reaction may be a temperature commonly used in the art, and the present invention is particularly preferably from 0 ℃ to 50 ℃, and most preferably from 0 ℃ to 25 ℃.

In the present invention, after the amination reaction is completed, the pure compound 2 can be obtained by simple post-treatment, such as suction filtration and vacuum drying.

In the present invention, the solvent for the second-step thionation reaction is a solvent commonly used in the art. In the present invention, methyltetrahydrofuran, tetrahydrofuran, ethylene glycol dimethyl ether, dioxane and the like are particularly preferable, and methyltetrahydrofuran is more preferable. The following ranges of amounts are particularly preferred according to the invention: the volume-to-mass ratio (ml/g) of the solvent to the compound 2 is preferably 10: 1-15: 1.

in the present invention, phosphorus pentasulfide is used in an amount conventional in such reactions in the art, and the following ranges are particularly preferred in the present invention: the molar ratio of the phosphorus pentasulfide to the compound 2 is preferably 1: 3-1: 1.5.

in the present invention, the temperature of the second-step thionation reaction may be a temperature commonly used in the art, and room temperature to 50 ℃ is particularly preferred in the present invention.

In the present invention, after the completion of the above-mentioned thionation reaction, pure compound 3 can be obtained by simple post-treatment such as silica gel funnel purification, drying, concentration and vacuum distillation.

In the present invention, the amination and the thionation may be carried out under the conditions in the art, except those specifically mentioned above.

The intermediate compound 3 of the present invention can be prepared by the method described in the background of the present application.

The above preferred conditions can be arbitrarily combined to obtain preferred embodiments of the present invention without departing from the common general knowledge in the art.

The positive progress effects of the invention are as follows:

the method adopts safe, cheap and easily obtained ethyl pyruvate, ammonia methanol solution and phosphorus pentasulfide to replace virulent cyano reagent and hydrogen sulfide in the original research route, avoids the use of column chromatography, reduces the production cost and is easy to realize industrial production.

In the preparation method, the reaction conversion rate of the step (1) and the step (2) is high, the purity of the product after the reaction is good, complex post-treatment is not needed, and the product, namely the intermediate 2-oxopropanamide or the product 2-oxopropanethide, can be simply and conveniently obtained, and has good purity and high yield.

A similar reaction is reported in the literature for the amination (Chemistry & Biology Interface,4(1),58-65,8 pp.; 2014). In the literature, compound 5 can be obtained by using 4 as a raw material and reacting in an ammonia methanol solution at room temperature for 12-14h, but the yield is only 60%, and the reaction time is long.

In the preparation method, compared with the similar reaction, the ammonification reaction has higher yield and shorter reaction time, and has remarkable advantages.

A similar reaction is reported in the literature for thionation reactions (Suzhou Daxue Xuebao, Ziran Kexueban,23(3), 84-86; 2007). In the literature, compound 7 is obtained by using 6 as a raw material, a Lawson reagent as a thioreagent and ethylene glycol dimethyl ether as a solvent and reacting at room temperature. But the yield is only 61% and the workup of the lawson reagent requires column chromatography purification.

In the preparation method, compared with similar reactions, the yield of the thionation reaction is higher, column chromatography is not needed in post-treatment, and the preparation method is simple and convenient to operate and has obvious advantages.

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out under conventional conditions or conditions recommended by the manufacturers. Unless otherwise indicated, percentages and parts are percentages and parts by weight.

The test materials and reagents used in the following examples are commercially available without specific reference.

As used herein, "room temperature" refers to ambient temperature, typically between 15-30 ℃.