CN115466185A - A kind of preparation method of 6PPD metabolite - Google Patents

Abstract

The invention relates to the technical field of drug metabolism, in particular to a preparation method of 6PPD metabolites. The preparation method provided by the present invention comprises the following steps: mixing 4-aminodiphenylamine, diacetone alcohol, an organic solvent and a hydrogenation reagent to carry out reductive amination reaction to obtain the 6PPD metabolite with the structure shown in formula I. The preparation method provided by the invention uses 4-aminodiphenylamine, diacetone alcohol and hydrogenation reagent as raw materials, and through rational design of the reaction synthesis route: through a one-step reductive amination reaction, the successful preparation of 6PPD metabolites is achieved, and the yield is high. It can provide a reference substance for the study of the metabolic mechanism of 6PPD, and can be used to study the metabolic process of the drug in the environment. It is of great value for the systematic research and risk assessment of 6PPD and its metabolites. Moreover, the preparation method provided by the invention has low preparation cost, strong operability, high safety factor, and can realize industrial production.

Description

A kind of preparation method of 6PPD metabolite

technical field

The invention relates to the technical field of drug metabolism, in particular to a preparation method of 6PPD metabolites.

Background technique

6PPD, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, CAS No. 793-24-8, is a commonly used antiozonant with excellent antioxidant properties , anti-ozone, anti-flex cracking, etc., suitable for all kinds of synthetic rubber and natural rubber, and can also be used as a thermal oxygen stabilizer for polyethylene, polypropylene, and acrylic resins.

The main metabolite of 6PPD in rats is 2-methyl-4-((4-(phenylamino)phenyl)amino)pentan-2-ol, the chemical structure of which is shown in Formula I. At present, there is a lack of data on the environmental behavior and toxicity of 6PPD metabolites. In the preparation process of the structure shown in formula 1 disclosed in US Patent US3388096A, Adams catalyst (PtO ₂ ) needs to be used. Systematic research on drugs brings difficulties and affects the accuracy of 6PPD risk assessment.

Contents of the invention

The object of the present invention is to provide a method for preparing 6PPD metabolites. The preparation method provided by the present invention has low cost, and the prepared 6PPD metabolites have high yield, strong operability, and are suitable for industrial production.

In order to achieve the above object, the present invention provides the following technical solutions:

The present invention provides a kind of preparation method of 6PPD metabolite, comprises the following steps:

4-aminodiphenylamine, diacetone alcohol, an organic solvent and a hydrogenation reagent are mixed for reductive amination reaction to obtain the 6PPD metabolite of the structure shown in formula I;

Preferably, the hydrogenation reagent includes one or more of sodium borohydride, sodium cyanoborohydride and sodium triacetoxyborohydride.

Preferably, the molar ratio of the hydrogenation reagent to the 4-aminodiphenylamine is (1-2):1.

Preferably, the molar ratio of the diacetone alcohol to the 4-aminodiphenylamine is (1-2):1.

Preferably, the temperature of the reductive amination reaction is 10-40° C., and the holding time of the reductive amine reaction is 8-24 hours.

Preferably, the organic solvent includes tetrahydrofuran, methanol or dichloromethane.

Preferably, the reductive amination reaction solution is directly obtained after the reductive amination reaction, further comprising the following steps:

Diluting the reductive amination reaction solution with water to obtain a diluted reaction solution;

Mixing and extracting the diluted reaction solution and an organic extractant to obtain an extracted organic phase;

The extracted organic phase is washed, dried, organic solvent removed and column chromatographed sequentially to obtain the 6PPD metabolite with the structure shown in formula I.

Preferably, the organic extractant is ethyl acetate.

Preferably, the eluent used in the column chromatography separation and purification is a mixed solvent of ethyl acetate and petroleum ether, and the volume ratio of ethyl acetate and petroleum ether is 1:4.

Preferably, the column chromatography is flash column chromatography.

The invention provides a method for preparing 6PPD metabolites, comprising the following steps: mixing 4-aminodiphenylamine, diacetone alcohol, an organic solvent and a hydrogenation reagent for reductive amination reaction to obtain the 6PPD metabolites. The preparation method provided by the present invention uses 4-aminodiphenylamine, diacetone alcohol and hydrogenation reagent as raw materials, and through rational design of the reaction synthesis route: under the condition of no catalyst, the reductive amination reaction is carried out in one step, and the formula I is realized. The successful preparation of 6PPD metabolites with the indicated structure, and the yield is high, can provide reference substances for the study of the metabolic mechanism of 6PPD, and can be used to study the metabolic process of the drug in the environment, systematic research and risk of 6PPD and its metabolites Evaluations are of great value. At the same time, the preparation method provided by the present invention has low preparation cost, strong operability and high safety factor, and can realize the industrial production of the 6PPD metabolite with the structure shown in formula I.

Further, the reductive amination reaction directly obtains a reductive amination reaction solution, further comprising the following steps: diluting the reductive amination reaction solution with water to obtain a diluted reaction solution; mixing the diluted reaction solution and an organic extractant to extract , to obtain the extracted organic phase; the extracted organic phase was washed, dried, removed the organic solvent and column chromatography in sequence to obtain the 6PPD metabolite of the structure shown in formula I. The present invention can further improve the purity of the 6PPD metabolite with the structure shown in formula I by extracting the reductive amination reaction solution and separating and purifying it by column chromatography, so as to provide a high-purity reference substance for the research on the metabolic mechanism of 6PPD. The results of the examples show that the purity of the 6PPD metabolite with the structure shown in formula I prepared by the present invention is ≥99%.

Description of drawings

Fig. 1 is a synthetic route diagram of the 6PPD metabolite with the structure shown in formula I provided by the embodiment of the present invention.

detailed description

The present invention provides a kind of preparation method of 6PPD metabolite, comprises the following steps:

4-aminodiphenylamine, diacetone alcohol, an organic solvent and a hydrogenation reagent are mixed for reductive amination reaction to obtain the 6PPD metabolite of the structure shown in formula I;

In the present invention, unless otherwise specified, all preparation raw materials/components are commercially available products well known to those skilled in the art.

In the present invention, the structural formula of the 4-aminodiphenylamine is shown in formula II:

In the present invention, the hydrogenation reagent preferably includes one or more of sodium borohydride, sodium cyanoborohydride and sodium triacetoxyborohydride, more preferably sodium cyanoborohydride.

In the present invention, the organic solvent preferably includes tetrahydrofuran, methanol or dichloromethane, more preferably methanol.

In the present invention, the molar ratio of the hydrogenation reagent to the 4-aminodiphenylamine is preferably (1-2):1, more preferably 1.5:1.

In the present invention, the molar ratio of the diacetone alcohol to the 4-aminodiphenylamine is preferably (1-2):1, more preferably 1.1:1.

The present invention has no special requirements on the amount of the organic solvent, as long as the raw materials of the reductive amination reaction are completely dissolved and the reductive amination reaction proceeds smoothly.

In the present invention, the temperature of the reductive amination reaction is preferably 10-40°C, more preferably 25°C.

In the present invention, the holding time of the reducing amine reaction is preferably 8-24 hours, more preferably 12 hours.

In the present invention, the reductive amination reaction directly obtains the reductive amination reaction solution, and the present invention preferably further includes the following steps:

Diluting the reductive amination reaction solution with water to obtain a diluted reaction solution;

Mixing and extracting the diluted reaction solution and an organic extractant to obtain an extracted organic phase;

The extracted organic phase is washed, dried, organic solvent removed and column chromatographed sequentially to obtain the 6PPD metabolite with the structure shown in formula I.

In the present invention, the ratio of the volume of the dilution water to the volume of the organic solvent is preferably 1:4.

In the present invention, the organic extractant is preferably ethyl acetate. The number of extractions is preferably 3 times, and the ratio of the volume of ethyl acetate to the volume of the organic solvent during each extraction is preferably 1:1. In the present invention, the extracted organic phases obtained each time are combined to obtain the extracted organic phase.

In the present invention, the washing is preferably washed with saturated brine.

In the present invention, the drying is preferably performed using anhydrous sodium sulfate.

In the present invention, the specific implementation of the removal of the organic solvent is preferably vacuum distillation, and the present invention has no special requirements for the specific implementation process of the vacuum distillation.

In the present invention, column chromatography is preferably performed on the residue from the removal of the organic solvent.

In the present invention, the eluent used in the column chromatography is preferably a mixed solvent of ethyl acetate and petroleum ether, and the volume ratio of ethyl acetate and petroleum ether is preferably 1:4. In the present invention, the column chromatography is preferably flash column chromatography.

In the present invention, the eluate obtained by the column chromatography is preferably dried to obtain the 6PPD metabolite with the structure shown in formula I.

In the present invention, the 6PPD metabolite with the structure shown in formula I is a red oily liquid.

In order to further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the protection scope of the present invention.

Example 1

According to the flow chart shown in Figure 1, prepare the 6PPD metabolite of structure shown in formula I:

After dissolving 4-aminodiphenylamine (1.84g, 10.00mmol) and diacetone alcohol (1.28g, 11.00mmol) in methanol (20mL), add sodium cyanoborohydride (0.94g, 15.00mmol), and react at 25°C for 12 hour h. After the reaction was completed, it was diluted with water (5 mL), extracted with ethyl acetate (20 mL×3), washed with saturated brine, dried over anhydrous sodium sulfate, and evaporated to remove the solvent under reduced pressure, and the residue was separated and purified by flash column chromatography (v:v= 1:4, ethyl acetate/petroleum ether), the red oily liquid obtained is the 6PPD metabolite of the structure shown in formula I, namely: 2-methyl-4-((4-(phenylamino)phenyl)amino) Pentan-2-ol, 2.07 g, 73% yield). ¹ H NMR (600MHz, Chloroform-d) δ7.25–7.17(m,2H),7.08–6.97(m,2H),6.95–6.87(m,2H),6.85–6.79(m,1H),6.79– 6.66(m,2H),3.90–3.72(m,1H),1.73–1.63(m,2H),1.35(s,3H),1.27(s,3H),1.16(d,J＝6.2Hz,3H) .HRMS(ESI)C ₁₈ H ₂₅ N ₂ O ⁺ [M+H] ⁺ calculated value: 285.1961, measured value: 285.1967. HPLC: 99.72% (λ = 280nm, t _R = 12.18min).

Example 2

According to the flow chart shown in Figure 1, prepare the 6PPD metabolite of structure shown in formula I:

After dissolving 4-aminodiphenylamine VIII (1.84g, 10.00mmol) and diacetone alcohol (1.16g, 10.00mmol) in tetrahydrofuran (20mL), add sodium borohydride (0.38g, 10.00mmol) and react at 10°C for 24 hours . After the reaction was completed, it was diluted with water (5mL), extracted with ethyl acetate (20mL×3), washed with saturated brine, dried over anhydrous sodium sulfate, evaporated to remove the solvent under reduced pressure, and the residue was separated and purified by flash column chromatography (1:4 acetic acid ethyl ester/petroleum ether), the red oily liquid obtained is the 6PPD metabolite of the structure shown in formula I, namely: 2-methyl-4-((4-(phenylamino)phenyl)amino)pentane-2- Alcohol, 1.56g, yield 55%).

Example 3

The 6PPD metabolite of the structure shown in formula I is prepared according to the flowchart shown in Figure 1: 4-aminodiphenylamine VIII (1.84g, 10.00mmol) and diacetone alcohol (2.32g, 20.00mmol) are dissolved in dichloromethane ( After 20 mL), sodium triacetoxyborohydride (4.24 g, 20.00 mmol) was added and reacted at 40°C for 8 hours. After the reaction was completed, it was diluted with water (5mL), extracted with ethyl acetate (20mL×3), washed with saturated brine, dried over anhydrous sodium sulfate, evaporated to remove the solvent under reduced pressure, and the residue was separated and purified by flash column chromatography (1:4 acetic acid ethyl ester/petroleum ether), the red oily liquid obtained is the 6PPD metabolite of the structure shown in formula I, namely: 2-methyl-4-((4-(phenylamino)phenyl)amino)pentane-2- Alcohol, 1.19g, yield 42%).

In conclusion, the preparation method of the 6PPD metabolite with the structure shown in formula I provided by the present invention is reasonable in design, strong in operability and high in yield, and can realize industrial production. And the purity of the 6PPD metabolite of the structure shown in formula I prepared by the present invention is more than or equal to 99%, which can provide a high-purity reference substance for the research on the metabolic mechanism of 6PPD, and can be used to study the metabolic process of the drug in the environment. Systematic research and risk assessment of pesticides are of great value. At the same time, the preparation method provided by the present invention has low preparation cost, strong operability and high safety factor, and can realize the industrial production of the 6PPD metabolite with the structure shown in formula I.

Although the foregoing embodiment has described the present invention in detail, it is only a part of the embodiments of the present invention, rather than all embodiments, and other embodiments can also be obtained according to the present embodiment without inventive step, and these embodiments are all Belong to the protection scope of the present invention.

Claims (10)

1. A method for preparing a 6PPD metabolite, comprising the steps of:

mixing 4-aminodiphenylamine, diacetone alcohol, an organic solvent and a hydrogenation reagent for reductive amination reaction to obtain a 6PPD metabolite with a structure shown in a formula I;

2. the method of claim 1, wherein the hydrogenation reagent comprises one or more of sodium borohydride, sodium cyanoborohydride, and sodium triacetoxyborohydride.

3. The process according to claim 1 or 2, wherein the molar ratio of the hydrogenation reagent to the 4-aminodiphenylamine is (1-2): 1.

4. The preparation method according to claim 1, wherein the molar ratio of the diacetone alcohol to the 4-aminodiphenylamine is (1-2): 1.

5. The method according to claim 1, wherein the temperature of the reductive amination reaction is 10 to 40 ℃, and the holding time of the reductive amination reaction is 8 to 24 hours.

6. The method of claim 1, wherein the organic solvent comprises tetrahydrofuran, methanol, or dichloromethane.

7. The method according to claim 1 or 5, wherein the reductive amination directly obtains a reductive amination reaction solution, further comprising the steps of:

adding water to dilute the reductive amination reaction solution to obtain a diluted reaction solution;

mixing and extracting the diluted reaction solution and an organic extractant to obtain an extracted organic phase;

and (3) sequentially washing, drying, removing the organic solvent and carrying out column chromatography on the extracted organic phase to obtain the 6PPD metabolite with the structure shown in the formula I.

8. The method of claim 7, wherein the organic extractant is ethyl acetate.

9. The preparation method of claim 7, wherein the eluent used in the column chromatography is a mixed solvent of ethyl acetate and petroleum ether, and the volume ratio of the ethyl acetate to the petroleum ether is 1:4.

10. The method of claim 7 or 9, wherein the column chromatography is flash column chromatography.

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