阅读说明：本技术 一种咪喹莫特中间体的合成方法 (Synthetic method of imiquimod intermediate ) 是由 计雄荣 马彦婷 周禾 于 2021-07-08 设计创作，主要内容包括：本发明公开了一种咪喹莫特中间体的合成方法,包括以下步骤：步骤一：在催化剂条件下,喹啉与NBS在溶剂中加热反应,得到化合物2；步骤二：在溶剂中,将化合物2与异丁胺混合,加入催化剂加热反应,得到化合物3；步骤三：化合物3与NBS在溶剂中加热反应,得到化合物4；步骤四：第一阶段,化合物4与甲酰胺在催化剂的作用下,加热反应；第二阶段,再以盐酸处理得到化合物1。与现有技术相比,本发明方法起始原料价格便宜,各步反应操作简单收率较高,三废少,生产效率高。(The invention discloses a synthetic method of an imiquimod intermediate, which comprises the following steps: the method comprises the following steps: under the condition of a catalyst, heating quinoline and NBS in a solvent to react to obtain a compound 2; step two: mixing the compound 2 with isobutylamine in a solvent, adding a catalyst, and heating to react to obtain a compound 3; step three: heating the compound 3 and NBS in a solvent for reaction to obtain a compound 4; step four: in the first stage, the compound 4 and formamide are heated and reacted under the action of a catalyst; in the second stage, the compound 1 is obtained by treatment with hydrochloric acid. Compared with the prior art, the method has the advantages of low price of the starting raw materials, simple reaction operation in each step, higher yield, less three wastes and high production efficiency.)

1. A synthetic method of an imiquimod intermediate is characterized by comprising the following steps:

the method comprises the following steps: under the condition of a catalyst, heating quinoline and NBS in a solvent to react to obtain a compound 2;

step two: mixing the compound 2 with isobutylamine in a solvent, adding a catalyst, and heating to react to obtain a compound 3;

step three: heating the compound 3 and NBS in a solvent for reaction to obtain a compound 4;

step four: in the first stage, the compound 4 and formamide are heated and reacted under the action of a catalyst; in the second stage, the reaction product in the first stage is not separated and then treated by hydrochloric acid to obtain the compound 1.

2. The method for synthesizing imiquimod intermediate according to claim 1, wherein in the first step, the solvent is one or more selected from methanol, ethanol, ethyl acetate, acetonitrile, tetrahydrofuran, toluene, xylene, and N, N-dimethylformamide; the catalyst is selected from one or more of copper sulfate, copper chloride, copper nitrate, basic copper carbonate and copper oxide.

3. The process for the synthesis of imiquimod intermediate according to claim 1, wherein in step one, the reaction temperature is 5-100 ℃, preferably 50-60 ℃; the reaction time is 1h-10h, preferably 3h-4 h; the molar ratio of the reaction mass was quinoline: NBS: catalyst 1: 1-3: 0.05 to 0.5, preferably quinoline: NBS: catalyst 1: 1.2: 0.1.

4. the method for synthesizing imiquimod intermediate according to claim 1, wherein in the second step, the solvent is one or more selected from methanol, ethanol, ethyl acetate, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, tetrahydrofuran, toluene, xylene, and N, N-dimethylformamide; the catalyst comprises a main catalyst, an auxiliary catalyst A and an auxiliary catalyst B, wherein the main catalyst is one or more of potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydride, sodium ethoxide, sodium methoxide, sodium tert-butoxide and potassium tert-butoxide; the cocatalyst A is one or more of potassium iodide, sodium iodide, ammonium iodide and cuprous iodide; the cocatalyst B is one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, tetramethylammonium bromide, tetramethylammonium chloride, benzyltrimethylammonium chloride and other transfer catalysts; the molar ratio of the reaction mass was compound 2: isobutylamine: main catalyst: cocatalyst A: cocatalyst B ═ 1: 1-3: 1-3: 0.1-0.5: 0.1-0.5, preferably compound 2: isobutylamine: main catalyst: cocatalyst A: cocatalyst B ═ 1: 1.1: 2.0: 0.15: 0.15.

5. the method for synthesizing imiquimod intermediate according to claim 1, wherein in the second step, the reaction temperature is 50-200 ℃, preferably 120-130 ℃; the reaction time is 1h-10h, preferably 4h-5 h.

6. The method for synthesizing imiquimod intermediate according to claim 1, wherein in step three, the solvent is one or more selected from methanol, ethanol, ethyl acetate, acetonitrile, tetrahydrofuran, toluene, xylene, and N, N-dimethylformamide.

7. The method for synthesizing imiquimod intermediate according to claim 1, wherein in step three, the reaction temperature is 5-100 ℃, preferably 60-70 ℃; the reaction time is 1h-10h, preferably 3h-4 h; the molar ratio of the reaction mass was compound 3: NBS ═ 1: 1-3, preferably compound 3: NBS ═ 1: 1.1.

8. the method for synthesizing imiquimod intermediate according to claim 1, wherein in step four, the solvent is one or more of methanol, ethanol, N-butanol, ethyl acetate, acetonitrile, tetrahydrofuran, toluene, xylene, N-dimethylformamide or no solvent; the catalyst is one or more of potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydride, sodium ethoxide, sodium methoxide, sodium tert-butoxide and potassium tert-butoxide.

9. The method for synthesizing imiquimod intermediate according to claim 1, wherein in the fourth step, the reaction temperature in the fourth step is 50-200 ℃, the first stage is preferably 110-120 ℃, and the second stage is preferably 90-100 ℃; the reaction time is 1h-10h, the first stage is preferably 6h-7h, the second stage is preferably 5h-6h, and the molar ratio of the reaction materials is that the compound 4: formamide: catalyst 1: 1-3: 1-3, preferably compound 4: formamide: catalyst 1: 1.2: 2.5.

Technical Field

The invention belongs to the technical field of imiquimod intermediate synthesis, and particularly relates to a synthetic method of an imiquimod intermediate (3-amino-4- (2-methylpropylamino) quinoline).

Background

Imiquimod (CAS No.99011-02-6), an imidazole quinoline amine interleukin agonist developed and produced by 3M Pharmaceuticals company in the United states, belongs to a genital wart treatment drug. The immunomodulator can be clinically used for treating the condyloma acuminatum of adult genitals and perianal areas, and is a preferred medicine for treating the condyloma acuminatum due to convenient use, good tolerance and a unique action mechanism. In addition, imiquimod has been reported to be useful for viral skin diseases such as verruca vulgaris, verruca plana, molluscum contagiosum, herpes simplex, etc., skin tumors such as basal cell carcinoma, bowen's disease, bowenoid papulosis, actinic keratosis, cutaneous T-cell tumor, kaposi's sarcoma, etc., and may be effective for vitiligo and alopecia areata.

Amino-4- (2-methylpropylamino) quinoline (CAS No.99010-09-0), a key intermediate for preparing imiquimod, and the cost and the operation process thereof directly determine the cost of the imiquimod.

By investigating the synthesis process, the prior methods are found to be obtained by reducing nitro compounds, such as WO2014120995, WO2008023333, Journal of Medicinal Chemistry,48(10),3481-3491,2005, and the like. A large amount of strong acid wastewater is generated in the nitration reaction, and a highly toxic brown yellow gas is generated in the reaction process, so that the nitration reaction has certain potential safety hazard.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems in the prior art, the invention provides a synthetic method of an antiviral drug imiquimod intermediate, namely a synthetic method of (3-amino-4- (2-methylpropylamino) quinoline.

The technical scheme is as follows: in order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

a synthetic method of an imiquimod intermediate comprises the following steps:

the method comprises the following steps: under the condition of a catalyst, heating quinoline and NBS in a solvent to react to obtain a compound 2;

step two: mixing the compound 2 with isobutylamine in a solvent, adding a catalyst, and heating to react to obtain a compound 3;

step three: heating the compound 3 and NBS in a solvent for reaction to obtain a compound 4;

step four: in the first stage, the compound 4 and formamide are heated and reacted under the action of a catalyst; in the second stage, the reaction product in the first stage is not separated and then treated by hydrochloric acid to obtain the compound 1.

Preferably, in the step one, the solvent is one or more of methanol, ethanol, ethyl acetate, acetonitrile, tetrahydrofuran, toluene, xylene and N, N-dimethylformamide; the catalyst is selected from one or more of copper sulfate, copper chloride, copper nitrate, basic copper carbonate and copper oxide.

Preferably, in the first step, the reaction temperature is 5-100 ℃, preferably 50-60 ℃; the reaction time is 1h-10h, preferably 3h-4 h; the molar ratio of the reaction mass was quinoline: NBS: catalyst 1: 1-3: 0.05 to 0.5, preferably quinoline: NBS: catalyst 1: 1.2: 0.1.

preferably, in the second step, the solvent is one or more of methanol, ethanol, ethyl acetate, N-methylpyrrolidone, dimethyl sulfoxide, acetonitrile, tetrahydrofuran, toluene, xylene and N, N-dimethylformamide; the catalyst comprises a main catalyst, an auxiliary catalyst A and an auxiliary catalyst B, wherein the main catalyst is one or more of potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydride, sodium ethoxide, sodium methoxide, sodium tert-butoxide and potassium tert-butoxide; the cocatalyst A is one or more of potassium iodide, sodium iodide, ammonium iodide and cuprous iodide; the cocatalyst B is one or more of tetrabutylammonium bromide, tetrabutylammonium chloride, tetramethylammonium bromide, tetramethylammonium chloride, benzyltrimethylammonium chloride and other transfer catalysts; the molar ratio of the reaction mass was compound 2: isobutylamine: main catalyst: cocatalyst A: cocatalyst B ═ 1: 1-3: 1-3: 0.1-0.5: 0.1-0.5, preferably compound 2: isobutylamine: main catalyst: cocatalyst A: cocatalyst B ═ 1: 1.1: 2.0: 0.15: 0.15.

preferably, in the second step, the reaction temperature is 50-200 ℃, preferably 120-130 ℃; the reaction time is 1h-10h, preferably 4h-5 h.

Preferably, in the third step, the solvent is one or more of methanol, ethanol, ethyl acetate, acetonitrile, tetrahydrofuran, toluene, xylene and N, N-dimethylformamide.

Preferably, in the third step, the reaction temperature is 5-100 ℃, preferably 60-70 ℃; the reaction time is 1h-10h, preferably 3h-4 h; the molar ratio of the reaction mass was compound 3: NBS ═ 1: 1-3, preferably compound 3: NBS ═ 1: 1.1.

preferably, in the fourth step, the solvent is one or more of methanol, ethanol, N-butanol, ethyl acetate, acetonitrile, tetrahydrofuran, toluene, xylene and N, N-dimethylformamide or has no solvent; the catalyst is one or more of potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydride, sodium ethoxide, sodium methoxide, sodium tert-butoxide and potassium tert-butoxide.

Preferably, in the fourth step, the reaction temperature in the fourth step is 50-200 ℃, the first stage is preferably 110-120 ℃, and the second stage is preferably 90-100 ℃; the reaction time is 1h-10h, the first stage is preferably 6h-7h, the second stage is preferably 5h-6h, and the molar ratio of the reaction materials is that the compound 4: formamide: catalyst 1: 1-3: 1-3, preferably compound 4: formamide: catalyst 1: 1.2: 2.5

Has the advantages that: the invention provides a novel synthesis method of an antiviral drug imiquimod intermediate (3-amino-4- (2-methylpropylamino) quinoline, compared with the prior art, the synthesis method has the advantages of low price of starting raw materials, simple reaction operation in each step, higher yield, less three wastes and high production efficiency.

Detailed Description

The present invention will be further described with reference to the following examples in order to provide a thorough understanding of the present invention. The experimental procedures used in the following examples are all conventional procedures unless otherwise specified. The materials and reagents used in the following examples are commercially available without specific reference

Example 1

Step one, preparation of compound 2

In a 500ml four-necked flask, 200ml of ethanol, 25.83g of quinoline (0.20mol), 42.72g of NBS (0.24mol) and 3.75g of copper nitrate (0.020mol) were sequentially added, and the mixture was stirred at room temperature for 0.5 hour, and then heated to 50 ℃ for 3 hours. HPLC detection indicated 1-2% remaining starting material. The temperature is reduced to 20 ℃, the reaction liquid is poured into 200ml of water, and the mixture is stirred for 2 hours. And (4) carrying out suction filtration, stirring a filter cake for 1 hour at the water temperature of 200ml, carrying out suction filtration, and drying at 50 ℃ to obtain an off-white solid with the yield of 86.9%.

¹H NMR(400MHz,CDCl₃)δ(ppm):8.75(d,1H),8.30(dd,1H),8.15(d,1H),7.82(dd,1H),7.76(d,1H),7.62(dd,1H)。

Step two, preparation of Compound 3

Into a 250ml four-necked flask, 150ml of N-methylpyrrolidone, 20.81g of Compound 2(0.10mol), 8.04g of isobutylamine (0.11mol), 27.64g of potassium carbonate (0.20mol), 2.49g of potassium iodide (0.015mol) and 4.83g of tetrabutylammonium bromide (0.015mol) were charged in this order, and the temperature was raised stepwise. The temperature is firstly preserved for 2h at 80 ℃ and then is raised to 120 ℃ and preserved for 4 h. HPLC detection indicated 1-2% remaining starting material. Cooling to 20 ℃, filtering, pouring the filtrate into 200ml of water, stirring for 2 hours, and filtering. And adding 50ml of ethanol into the wet product, refluxing for 1h, cooling to 5 ℃, stirring for 2h, performing suction filtration, and drying at 50 ℃ to obtain a light yellow solid with the yield of 79.8%.

¹H NMR(400MHz,CDCl₃)δ(ppm):8.90(dd,1H,),8.76(dd,1H),8.25(d,1H),7.87(dd,1H),7.66(d,1H),7.34(dd,1H)，4.10(brs,1H),3.01(d,2H),1.29(dq，1H),1.10(d，6H)。

Step three, preparation of Compound 4

In a 500ml four-necked flask, 150ml of DMF, 20.03g of Compound 3(0.10mol) and 19.58g of NBS (0.11mol) were sequentially charged, stirred at room temperature for 0.5h, and then warmed to 60 ℃ for 4 h. HPLC detection indicated 2-3% remaining starting material. Cooling to 20 ℃, pouring the reaction liquid into 200ml of water, stirring for 2 hours, and filtering. The filter cake was recrystallized from 90ml acetonitrile to give an off-white solid with a yield of 92.7%.

¹H NMR(400MHz,CDCl₃)δ(ppm):：8.95(s,1H),8.33-8.39(m,1H),7.60-7.51(m,1H),7.31-7.22(m,2H),4.97(t,1H),3.02(d,2H),1.61(m,1H),1.12(d，6H)。

Step four, preparation of Compound 1

350ml of n-butanol, 27.92g of Compound 4(0.10mol) and 5.40g of formamide (0.12mol) were sequentially added to a 1000ml four-necked flask, and the mixture was heated to 110 ℃ to react for 6 hours. HPLC detection indicated 2-3% remaining starting material. Cooling to 20 deg.C, vacuum filtering, and concentrating the filtrate to dryness. 90ml of toluene and 28ml of concentrated hydrochloric acid are added to the residue, and the reaction is carried out for 5 hours at 90 ℃. Cooling to 10 deg.C, and vacuum filtering. 200ml of water is added into the filtrate, the mixture is stirred for 2 hours at room temperature and filtered by suction.

The wet product was recrystallized from DMF and water 1:1 to give an off-white solid with 88.6% yield.

¹H NMR(400MHz,CDCl₃)δ(ppm):：8.69(s,1H),8.21-8.29(m,1H),7.70-7.69(m,1H),7.39-7.30(m,2H),4.82(s,2H),4.86(t,1H),3.23(d,2H),1.77(m,1H),1.09(d，6H)。

Example 2

Step one, preparation of compound 2

In a 500ml four-necked flask, 200ml of ethanol, 25.83g of quinoline (0.20mol), 42.72g of NBS (0.24mol) and 1.59g of copper oxide (0.020mol) were sequentially added, stirred at room temperature for 0.5h, and then warmed to 50 ℃ for 3 h. HPLC detection indicated 1-2% remaining starting material. The temperature is reduced to 20 ℃, the reaction liquid is poured into 200ml of water, and the mixture is stirred for 2 hours. And (4) carrying out suction filtration, stirring a filter cake for 1 hour at the water temperature of 200ml, carrying out suction filtration, and drying at 50 ℃ to obtain an off-white solid with the yield of 77.3%.

¹H NMR(400MHz,CDCl₃)δ(ppm):8.75(d,1H),8.30(dd,1H),8.15(d,1H),7.82(dd,1H),7.76(d,1H),7.62(dd,1H)。

Step two, preparation of Compound 3

Into a 250ml four-necked flask, 150ml of N-methylpyrrolidone, 20.81g of Compound 2(0.10mol), 8.04g of isobutylamine (0.11mol), 8.02g of sodium hydroxide (0.20mol), 2.49g of potassium iodide (0.015mol) and 4.83g of tetrabutylammonium bromide (0.015mol) were charged in this order, and the temperature was raised stepwise. The temperature is firstly preserved for 2h at 80 ℃ and then is raised to 120 ℃ and preserved for 4 h. HPLC detection indicated 1-2% remaining starting material. Cooling to 20 ℃, filtering, pouring the filtrate into 200ml of water, stirring for 2 hours, and filtering.

And adding 50ml of ethanol into the wet product, refluxing for 1h, cooling to 5 ℃, stirring for 2h, performing suction filtration, and drying at 50 ℃ to obtain a light yellow solid with the yield of 79.5%.

¹H NMR(400MHz,CDCl₃)δ(ppm):8.90(dd,1H,),8.76(dd,1H),8.25(d,1H),7.87(dd,1H),7.66(d,1H),7.34(dd,1H)，4.10(brs,1H),3.01(d,2H),1.29(dq，1H),1.10(d，6H)。

Step three, preparation of Compound 4

In a 500ml four-necked flask, 150ml of acetonitrile, 20.03g of Compound 3(0.10mol) and 19.58g of NBS (0.11mol) were sequentially added, stirred at room temperature for 0.5h, and then warmed to 60 ℃ for 4 h. HPLC detection indicated 2-3% remaining starting material. Cooling to 20 ℃, pouring the reaction liquid into 200ml of water, stirring for 2 hours, and filtering. The filter cake was recrystallized from 90ml acetonitrile to give an off-white solid with 88.1% yield.

¹H NMR(400MHz,CDCl₃)δ(ppm):：8.95(s,1H),8.33-8.39(m,1H),7.60-7.51(m,1H),7.31-7.22(m,2H),4.97(t,1H),3.02(d,2H),1.61(m,1H),1.12(d，6H)。

Step four, preparation of Compound 1

350ml of n-butanol, 27.92g of Compound 4(0.10mol) and 9.01g of formamide (0.20mol) were sequentially added to a 1000ml four-necked flask, and the mixture was heated to 110 ℃ to react for 6 hours. HPLC detection indicated 2-3% remaining starting material. Cooling to 20 deg.C, vacuum filtering, and concentrating the filtrate to dryness. 90ml of toluene and 28ml of concentrated hydrochloric acid are added to the residue, and the reaction is carried out for 5 hours at 90 ℃. Cooling to 10 deg.C, and vacuum filtering. 200ml of water is added into the filtrate, the mixture is stirred for 2 hours at room temperature and filtered by suction.

The wet product was recrystallized from DMF and water 1:1 to give an off-white solid with a yield of 90.1%.

¹H NMR(400MHz,CDCl₃)δ(ppm):：8.69(s,1H),8.21-8.29(m,1H),7.70-7.69(m,1H),7.39-7.30(m,2H),4.82(s,2H),4.86(t,1H),3.23(d,2H),1.77(m,1H),1.09(d，6H)。