A kind of analytical method of methoxyethyl acetoacetate isomers

Abstract

The invention discloses an analysis method for isomers of methyloxyethyl acetoacetate, comprising the following steps: S1, using a reverse phase column, taking acetonitrile: sodium hydrogen phosphate solution = 60:40 as a mobile phase, a flow rate of 0.8-1.2 mL / min, a column temperature of 43-47°C, a running time of 30 min, and an injection volume of 10 μL; S2, weighing 40 mg of methyloxyethyl acetoacetate, adding it into a solution prepared by acetonitrile and sodium hydrogen phosphate solution in S1 and fixing the volume to 10 mL; S3, respectively performing three groups of data, wherein the first group is prepared and measured immediately, the second group is left to stand for 24 h, and the third group is left to stand for 48 h; S4, accurately measuring 10 μL of the test solution, injecting it into a liquid chromatograph, and recording a chromatogram. The invention optimizes chromatographic conditions, adopts reverse phase chromatography, uses a reverse phase HPLC system, completes the analysis of methyloxyethyl acetoacetate isomers, takes time as a reference axis, can clearly identify the tautomers of the product in a liquid phase detection process, takes acetonitrile: disodium hydrogen phosphate solution = 60:40 as a mobile phase, adopts a reverse phase column for separation, has a short analysis time, and has the advantages of simple and rapid operation.

Description

Technical Field

[0001] The invention relates to the technical field of product analysis, and in particular to an analysis method for methoxyethyl acetoacetate isomers. Background Art

[0002] Methoxyethyl acetoacetate, also known as 2-Methoxyethyl acetoacetate in English. Methoxyethyl acetoacetate is a key intermediate of cilnidipine. The gas phase can be used as a detection indicator in the production process of methoxyethyl acetoacetate, but the production process monitoring of its downstream intermediates cannot be detected by gas phase. During the liquid phase detection process, we found that the purity of the product was significantly different from that of the gas phase detection, but it was impossible to determine whether the product obtained by the liquid phase detection was an impurity or an isomer. Based on its chemical structure, there are 1,3-dicarbonyl compounds, and there are multiple tautomerisms (such as Figure 1 Therefore, it is not possible to identify the substance obtained by liquid phase detection through complete separation. Summary of the invention

[0003] In view of the problems raised by the background technology, the present invention studies and designs an analysis method for methyl ethyl acetoacetate isomers, the purpose of which is to provide an analysis method for methyl ethyl acetoacetate isomers that can clearly identify tautomers in a liquid phase detection process and is simple and fast to operate.

[0004] The technical solution of the present invention:

[0005] A method for analyzing methoxyethyl acetoacetate isomers comprises the following steps:

[0006] S1, using a reverse phase column, acetonitrile: sodium hydrogen phosphate solution = 60:40 as the mobile phase, flow rate of 0.8-1.2 mL / min, column temperature of 43-47 °C, running time of 30 min, injection volume: 10 μL;

[0007] S2, weigh 40 mg of methyloxyethyl acetoacetate and add it to the solution prepared by acetonitrile and disodium hydrogen phosphate solution in S1 and make up to 10 mL;

[0008] S3, three sets of data were collected respectively, the first set was tested immediately after preparation, the second set was left to stand for 24 hours, and the third set was left to stand for 48 hours;

[0009] S4, accurately measure 10 μL of the test solution and inject it into the liquid chromatograph, and record the chromatogram.

[0010] Further preferably, the disodium hydrogen phosphate solution in S1 is prepared by dissolving disodium hydrogen phosphate 12 hydrate in water and adding phosphoric acid to adjust the pH.

[0011] Further preferably, the flow rate of the mobile phase in S1 is 1 mL / min.

[0012] Further preferably, the column temperature in S1 is 45°C.

[0013] Further preferably, the reverse phase column in S1 is Cosmosil 5C18-AR-II, 5 μm*4.6*250 nm.

[0014] The beneficial effects of the present invention are as follows: the present invention optimizes chromatographic conditions, adopts reverse phase chromatography, uses a reverse phase HPLC system, completes the analysis of methyloxyethyl acetoacetate isomers, and uses time as a reference axis, can clearly identify the tautomers of the product in the liquid phase detection process, and uses acetonitrile: disodium hydrogen phosphate solution = 60:40 as the mobile phase, adopts a reverse phase column for separation, has a short analysis time, and has the advantages of simple and rapid operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is tautomerism of methoxyethyl acetoacetate;

[0016] Figure 2 The HPLC spectra are prepared and measured in the examples;

[0017] Figure 3 This is the HPLC spectrum of the embodiment after standing for 24 hours;

[0018] Figure 4 The HPLC spectrum after standing for 48 hours in the embodiment. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0020] Example:

[0021] S1, dissolve 3.58 g of disodium hydrogen phosphate 12 hydrate in 1000 ml of water, add phosphoric acid to adjust the pH to 6.0, take 400 ml of the liquid and add 600 ml of acetonitrile as the mobile phase;

[0022] S2, set the measurement wavelength: 230nm; reverse phase chromatography column: ODS (Cosmosil 5C18-AR-II particle size 5μm4.6×250nm); column temperature: 45℃; flow rate: 1.0ml / min; injection volume: 10μL;

[0023] S3, take the mobile phase in S1, adjust the pH to 2 as the preparation solution, add 40 mg of the sample to be tested into the preparation solution and make the volume to 10 mL;

[0024] S4, performing blank detection and sample detection;

[0025] Accurately measure 10 μL of the test solution and inject it into the liquid chromatograph, and record the chromatogram:

[0026] A. The first group: test now

[0027] Inject the blank solution and the prepared sample solution in sequence;

[0028] B. Group 2: 24h rest

[0029] The blank solution and the sample solution left to stand for 24 hours were injected in sequence;

[0030] C. Group 3: 48h rest

[0031] The blank solution and the sample solution left to stand for 48 hours were injected in sequence;

[0032] S5, data are shown in Table 1.

[0033] Table 1

[0034]

[0035] Depend on Figure 2 to Figure 4 As can be seen from Table 1, during the pretreatment and sample preparation process before liquid phase detection, the product was affected by various conditions, its main structure content decreased, and tautomerism was produced. With the implementation of pretreatment and the extension of standing time, the change in the ratio of product isomers can be accurately observed, and it gradually stabilized after 48 hours and reached a dynamic equilibrium.

[0036] This method solves the problem of determining product isomers in a simple and quick manner, and also solves the problem of raw material monitoring during the production process.

[0037] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for analyzing methoxyethyl acetoacetate isomers, characterized in that: The following steps are involved: S1, using a reverse phase column, acetonitrile: sodium hydrogen phosphate solution = 60:40 as the mobile phase, flow rate of 0.8-1.2mL / min, column temperature 43-47℃, running time 30min, injection volume: 10µL, reverse phase column using Cosmosil 5C18-AR-II, 5μm*4.6*250nm; S2, weigh 40 mg of methyloxyethyl acetoacetate and add it to the solution prepared by acetonitrile and disodium hydrogen phosphate solution in S1 and make up to 10 mL; S3, three sets of data were collected respectively, the first set was tested immediately after preparation, the second set was left to stand for 24 hours, and the third set was left to stand for 48 hours; S4, accurately measure 10µL of the test solution and inject it into the liquid chromatograph, and record the chromatogram; The methoxyethyl acetoacetate isomers include the following tautomerisms: 。 2. A method for analyzing isomers of methoxyethyl acetoacetate as claimed in claim 1, characterized in that: The following steps are involved: The disodium hydrogen phosphate solution in S1 is prepared by dissolving disodium hydrogen phosphate 12 hydrate in water and adding phosphoric acid to adjust the pH.

3. A method for analyzing isomers of methoxyethyl acetoacetate as claimed in claim 1, characterized in that: The following steps are involved: The flow rate of the mobile phase in S1 is 1 mL / min.

4. A method for analyzing isomers of methoxyethyl acetoacetate as claimed in claim 1, characterized in that: The column temperature in S1 is 45°C.

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