CN109384813B

CN109384813B - Preparation method of tenofovir disoproxil fumarate analogue

Info

Publication number: CN109384813B
Application number: CN201710649577.9A
Authority: CN
Inventors: 黄小光; 朱少璇; 陈红英; 陈溪; 肖颖; 陈金瑞
Original assignee: Guangzhou Baiyunshan Pharmaceutical Holdings Co ltd Baiyunshan Pharmaceutical General Factory
Current assignee: Guangzhou Baiyunshan Pharmaceutical Holdings Co ltd Baiyunshan Pharmaceutical General Factory
Priority date: 2017-08-02
Filing date: 2017-08-02
Publication date: 2021-04-06
Anticipated expiration: 2037-08-02
Also published as: CN109384813A

Abstract

The invention discloses a method for preparing a tenofovir disoproxil fumarate analogue. The invention takes adenine as raw material, and reacts with (A) and (B) in the presence of alkaliR) And (2) carrying out substitution reaction on propylene carbonate, carrying out substitution reaction on propylene carbonate and (diethoxyphosphonyl) methyl-4-methylbenzenesulfonate, hydrolyzing by using concentrated hydrochloric acid solution, crystallizing to obtain anhydrous tenofovir, reacting the obtained product with chloromethyl isopropyl carbonate to obtain tenofovir monoester, and reacting with 2-bromopropane to obtain the target compound. The invention has the advantages of cheap and easily obtained starting raw materials, simple process and improved material utilization rate and total yield. The intermediate of the method is purified by a recrystallization method, and the yield and the purity are high.

Description

Preparation method of tenofovir disoproxil fumarate analogue

Technical Field

The invention belongs to the field of pharmaceutical chemistry, and particularly relates to an antiviral drug tenofovir disoproxil fumarate analog (((((R) -1- (6-amino-9))H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate.

Background

The invention relates to an antiviral drug tenofovir disoproxil fumarate analog (((((R) -1- (6-amino-9)H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate (formula vi).

Tenofovir disoproxil fumarate (formula vii) is a nucleotide reverse transcriptase inhibitor (NtRTIs) developed by Gilead sciences, usa, and FDA approved for its marketing in 2001 for the treatment of aids (HIV infection) and 2008 for the treatment of chronic hepatitis b (HBV infection). The tenofovir disoproxil fumarate has the characteristics of good tolerance, low drug resistance rate, low rebound rate after drug withdrawal, low renal toxicity and the like, and particularly has better clinical application prospect on HIV-associated HBV infected patients. The tenofovir disoproxil fumarate is a prodrug of tenofovir, and is esterified and salified into tenofovir disoproxil fumarate which has water solubility, can be quickly absorbed and metabolized and degraded in vivo into tenofovir, and plays an antiviral role.

In the process of producing a raw material drug of tenofovir disoproxil fumarate (VII), a small amount of process impurity tenofovir disoproxil fumarate analogue (VI) is generated, and the chemical name is as follows: ((((((R)-1- (6-amino-9)H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate (abbreviationiPr-POC PMPA). The research on impurities is one of the key projects in the research on the quality of medicines, and the content of the impurities is a direct index reflecting the purity of the medicines. In the qualitative and quantitative analysis of impurities, a certain amount of impurities is required as a reference, and the reference needs to have a high purity. Therefore, it is of great significance to obtain impurities with higher purity by a synthetic method.

At present, research on synthetic methods of tenofovir disoproxil fumarate impurity (VI) has been reported, but the synthetic methods still have some defects and shortcomings, such as:

(1) chuanqiong et al (journal of Chinese medical industry, 2014,45 (9): 818-821) reported that adenine is used as a starting material, andR) -propylene oxide reaction, ether formation reaction, hydrolysis reaction with TMSBr to obtain tenofovir. The related substance B (tenofovir monoester) is obtained by the reaction of tenofovir and chloromethyl isopropyl carbonate, and the yield is only 42.2%; the related substance B (tenofovir monoester) reacts with isopropanol in the presence of DEAD and triphenylphosphine to obtain related substance E (abbreviation:iPr-POC PMPA), i.e., the target compound (((((((i) PMPA) synthesized in the present invention)R) -1- (6-amino-9)H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate in only 67.9% yield. The total yield of the last two steps was 28.7%. In the route, the purification of the related substance B and the purification of the related substance E both need silica gel chromatographic column purification, need a large amount of organic solvent, and obtainLow rate and large pollution, and is not suitable for preparing the impurity reference substance in large quantity.

(2) Reported in Liangchaoyang et al (chemical management, 2013, 7: 68-70) ((((((s))R) -1- (6-amino-9)H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate was synthesized in a 60.5% yield from tenofovir monoisopropyl ester, known as T3-monoisopropyl ester in the literature; then reacting tenofovir monoisopropyl ester with chloromethyl isopropyl carbonate to obtain impurity ((((((L) (methyl) propyl ester)R) -1- (6-amino-9)H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate, known as T-D in the literature, and the reaction product of this step requires silica gel column purification, large amounts of organic solvents, low yields, high contamination, yields of only 40%, and a total yield of 24.2% in the two steps. It is not suitable for preparing the impurity reference substance in large quantity.

(3) Chen Guo Hua et al (CN 201410502508.1) adopted the strategy of taking tenofovir diisopropyl ester as the starting material, then hydrolyzing in NaOH aqueous solution to obtain tenofovir monoisopropyl ester, and the reaction product of the step needs to be purified by a silica gel chromatographic column with methanol/dichloromethane system as eluent, and the yield is 82.8%. Reacting tenofovir monoisopropyl ester with chloromethyl isopropyl carbonate to obtain impurity ((((((L) (methyl) propyl ester)R) -1- (6-amino-9)H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate, which reaction product also required column purification on silica gel with methanol/dichloromethane system as eluent in a yield of only 38.4%. The total yield of the two-step reaction was 31.8%. Meanwhile, the two-step reaction requires silica gel chromatographic column purification, needs a large amount of organic solvent, has large pollution and low yield, and is not suitable for preparing the impurity reference substance in large quantity.

In the reaction processes of the above 3 methods, the intermediate and the final product are purified by using a silica gel chromatographic column, and the chromatographic column purification process generally needs a large amount of organic solvent, which has the disadvantages of high pollution, low yield, unsuitability for mass preparation of the analogue and unsuitability for application in industrial scale-up production.

Disclosure of Invention

According to the inventionAims to provide a tenofovir disoproxil fumarate analogue (VI) with a chemical name of (((((R) -1- (6-amino-9)H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate. The method has simple synthesis process, does not use a silica gel chromatographic column to purify the intermediate and the target product, and is suitable for the requirement of industrial production.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

using adenine as initial raw material, under the base catalysis, reacting with (A), (B), (C) and (D)R) Reaction of propylene carbonate, crystallization to give (A)R) -1- (6-amino-9H-purin-9-yl) propyl-2-ol (ii); (II) reacting with (diethoxyphosphonyl) methyl-4-methylbenzenesulfonate in the presence of alkali to obtain (I)R) -diethyl (((1- (6-amino-9H-purin-9-yl) propyl-2-ol) oxy) methyl) phosphate (iii); (III) reacting with concentrated hydrochloric acid solution, and crystallizing to obtain anhydrous tenofovir (IV); (IV) reaction with organic base and chloromethyl isopropyl carbonate toR) - (((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (v) (abbreviation: tenofovir monoester); (V) reacting with an organic base and 2-bromopropane in the presence of a phase transfer catalyst to give ((((((R) -1- (6-amino-9)H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate (vi) (abbreviation:iPr-POC PMPA), the synthetic route is represented by the following formula:

in order to realize the synthetic route, the specific process of the invention is as follows:

the first step is as follows: (R) Preparation of (II) -1- (6-amino-9H-purin-9-yl) propyl-2-ol

At a reaction temperature of 120-140 ℃, adenine (I) is dissolved in an organic solvent, and is reacted with (A), (B), (C) and (C) in the presence of a baseR) Reaction of propylene carbonate, crystallization to give (A)R) -1- (6-amino-9H-purin-9-yl)) Propyl-2-ol (II);

the second step is that: (R) Preparation of (E) -diethyl (((1- (6-amino-9H-purin-9-yl) propyl-2-ol) oxy) methyl) phosphate (III)

At a reaction temperature of-10 to 40 ℃, (b) reacting the product obtained in the first stepR) Dissolving (1- (6-amino-9H-purine-9-yl) propyl-2-alcohol (II) in an organic solvent system, and reacting with (diethoxyphosphonyl) methyl-4-methylbenzenesulfonate in the presence of inorganic base to obtain (I), (II)R) -diethyl (((1- (6-amino-9H-purin-9-yl) propyl-2-ol) oxy) methyl) phosphate (iii);

the third step: preparation of anhydrous tenofovir (IV)

At a reaction temperature of 30-100 ℃, (b) reacting the product obtained in the second stepR) Reacting diethyl (((1- (6-amino-9H-purin-9-yl) propyl-2-ol) oxy) methyl) phosphate (III) with 36% -38% concentrated hydrochloric acid solution, and crystallizing to obtain anhydrous tenofovir (IV);

the fourth step: (R) Preparation of (- ((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V)

At the reaction temperature of 30-60 ℃, dissolving the product obtained in the third step in an organic solvent, and reacting with chloromethyl isopropyl carbonate in the presence of an organic baseR) - ((((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V)

The fifth step: (((((R) -1- (6-amino-9))HPreparation of-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate (VI)

And (3) dissolving the product (V) obtained in the fourth step in an organic solvent at the reaction temperature of 60-90 ℃, and reacting the product (V) with 2-bromopropane in the presence of a phase transfer catalyst and an organic base to obtain the tenofovir disoproxil fumarate analogue (VI).

In order to obtain higher yield and product purity, the process is optimized. In the process, the used organic solvent is an aprotic polar organic solvent; the alkali used in the first step is hydroxide of alkali metal; the inorganic base used in the second step is a metalate of tert-butyl alcohol; the organic base used in the fourth or fifth step is selected from aliphatic amines containing 1 to 15 carbon atoms or aromatic amines containing 4 to 15 carbon atoms; the phase transfer catalyst used in the fifth step is a quaternary ammonium salt phase transfer catalyst.

Further, the aprotic polar organic solvent is preferably one or a combination of more than one of N, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, and N-methylpyrrolidone; the hydroxide of alkali metal is preferably one or more of NaOH, KOH and CsOH; the tert-butyl alcohol metalate is selected from one or the combination of more than one of lithium tert-butoxide, sodium tert-butoxide, potassium tert-butoxide and magnesium tert-butoxide; the fatty amine containing 1-15 carbon atoms is selected from triethylamine or diisopropylethylamine; the aromatic amine containing 4-15 carbon atoms is selected from pyridine or imidazole; the quaternary ammonium salt phase transfer catalyst is preferably one or more of tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium iodide, triethylbenzylammonium chloride, triethylbenzylammonium bromide or triethylbenzylammonium iodide.

The optimized specific process comprises the following steps:

the first step is as follows: (R) The preparation of (II) -1- (6-amino-9H-purin-9-yl) propyl-2-ol is carried out by dissolving adenine (I) as initial raw material in organic solvent and reacting with (I), (II) and (III) in the presence of alkaliR) Reaction of propylene carbonate to giveR) -1- (6-amino-9H-purin-9-yl) propyl-2-ol (ii). The alkali is hydroxide of alkali metal, selected from one or more of NaOH, KOH and CsOH, preferably NaOH; the organic solvent is aprotic polar organic solvent selected from one or more of DMF, DMAC, NMP or DMSO, preferably DMF; (R) The dosage of the propylene carbonate is 1 to 4 times of the mole number of the adenine (I), and preferably 1.3 to 2 times; the reaction temperature is 120-140 ℃; the crystallization solvent is a premixed solvent of methanol and isopropanol in a volume ratio of 1: 2-2: 1 and a mixture of the premixed solvent and the reaction solvent used in the original reaction system, and the premixed solvent is preferably selected according to the volume ratioA mixed solution of methanol and isopropanol in a ratio of 1: 1; the crystallization temperature is-10 to 20 ℃, preferably 0 to 20 ℃.

The second step is as follows: (R) The (E) -diethyl (((1- (6-amino-9H-purin-9-yl) propyl-2-ol) oxy) methyl) phosphate (III) is prepared by dissolving the product (II) obtained in the first step in an organic solvent system and reacting the resulting solution with (diethoxyphosphonyl) methyl-4-methylbenzenesulfonate (abbreviation: DESMP) reaction to giveR) -diethyl (((1- (6-amino-9H-purin-9-yl) propyl-2-ol) oxy) methyl) phosphate (iii). Wherein the metalate of tert-butanol used is selected from lithium tert-butoxide, sodium tert-butoxide, potassium tert-butoxide or magnesium tert-butoxide, preferably magnesium tert-butoxide; the organic solvent is aprotic polar organic solvent selected from one or more of DMF, DMAC, NMP or DMSO, preferably DMF; the reaction temperature is-10 to 40 DEG C^oC, preferably 0-25 ℃; the product obtained after the post-treatment is directly put into the next reaction.

The third step is as follows: the preparation of the anhydrous tenofovir (IV) comprises the steps of reacting the intermediate (III) with concentrated hydrochloric acid (the mass percentage concentration is 36-38%), crystallizing and drying to obtain the anhydrous tenofovir (IV). Wherein the dosage of the concentrated hydrochloric acid is 1-8 times, preferably 3-6 times of the mole number of the intermediate (III); the reaction temperature is 30-100 ℃, and preferably 70-90 ℃; the solvent for the crystallization and purification of the anhydrous tenofovir (IV) is water, and the crystallization temperature is 0-10 ℃.

The fourth step is as follows: (R) - (((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V) is prepared by dissolving the intermediate tenofovir (IV) anhydrous in an organic solvent and reacting with chloromethyl isopropyl carbonate in the presence of an organic base to (C)R) - ((((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V). Wherein the organic solvent is aprotic polar organic solvent selected from one or more of DMF, DMAc, NMP or DMSO; the organic base is aliphatic amine containing 1-15 carbon atoms or aromatic amine containing 4-15 carbon atoms, and is selected from Triethylamine (TEA), Diisopropylethylamine (DIPEA), pyridine or imidazoleOne or more of the combination; the dosage of the organic base is 1-5 times of the mole number of the anhydrous tenofovir (IV); the dosage of chloromethyl isopropyl carbonate is 1-5 times of the mole number of the anhydrous tenofovir (IV); the reaction temperature is 30-60 ℃, and preferably 40-60 ℃; the product obtained by post-treatment is directly put into the next reaction.

The fifth step is as follows: ((((((R) -1- (6-amino-9)HThe (VI) purin-9-yl) propyl-2-yl) oxy) methyl (isopropoxy) phosphine) oxy) methyl isopropyl carbonate is prepared by dissolving the intermediate (V) in an organic solvent and reacting with 2-bromopropane in the presence of a phase transfer catalyst and an organic base to obtain ((((((((S) ((VI))R) -1- (6-amino-9)H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate (vi) (abbreviation:iPr-POC PMPA). The 2-bromopropane used is (R) - ((((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V) in a molar amount of 1 to 5 times the molar amount of the quaternary ammonium salt phase transfer catalyst selected from the group consisting of tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, tetra-n-butylammonium iodide, triethylbenzylammonium chloride, triethylbenzylammonium bromide and triethylbenzylammonium iodide, preferably tetra-n-butylammonium iodide and triethylbenzylammonium iodide; the amount of the phase transfer catalyst is (R) - ((((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V) in 0.5 to 2 times the number of moles; the organic base is aliphatic amine containing 1-15 carbon atoms or aromatic amine containing 4-15 carbon atoms, and is selected from one or more of Triethylamine (TEA), Diisopropylethylamine (DIPEA), pyridine or imidazole; amount of organic base used (R) - ((((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V) in 1 to 5 times the number of moles; the organic solvent used in the reaction is an aprotic polar organic solvent, and is selected from one or more of DMF, DMAC, NMP or DMSO. The reaction temperature is 60-90 ℃, and preferably 70-80 ℃.

The Chinese names and English abbreviation of the chemical substances related in the invention are compared as follows:

(Diethoxyphosphono) methyl-4-methylbenzenesulfonate abbreviated: DESMP

(((((R) -1- (6-amino-9))H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate (vi) abbreviation:iPr-POC PMPA

dimethylformamide is abbreviated as: DMF (dimethyl formamide)

Dimethylacetamide for short: DMAC

N-methylpyrrolidone abbreviation: NMP

Dimethyl sulfoxide is abbreviated as: DMSO (dimethylsulfoxide)

Triethylamine is abbreviated as: TEA (TEA)

Chloromethyl isopropyl carbonate abbreviation: CMIC

Diisopropylethylamine abbreviation: DIPEA

Trimethylchlorosilane is abbreviated as: TMSCl

Trimethyl bromosilane is abbreviated as: TMSBr.

Compared with the prior art, the method has the advantages of simple synthesis process, no need of silica gel chromatographic column for purifying intermediate and target product, high yield, little pollution and high purity of obtained impurities, and has the following specific advantages and innovation points:

1. the invention selects the cheap and easily available (A)R) Propylene carbonate as chiral source, in the presence of a base, with adenine to give (A)R) -1- (6-amino-9H-purin-9-yl) propyl-2-ol (ii), the reagents used in the improved process are relatively inexpensive, and the method is relatively simple compared to zeitzchun et al (journal of chinese medical industry, 2014,45 (9): 818-R) -process for the reaction of propylene oxide: the advantages are as follows: due to (a)R) High reactivity of propylene oxide leads to easy neutralization of the primary adenine amine groupR) More byproducts are generated in the propylene oxide reaction, and the product yield is low; (ii)R) The boiling point of the propylene oxide is low and is only 35 ℃, the danger in the production process is high, and the requirement on the sealing property of equipment is high. Therefore, the invention usesR) Propylene carbonate is a chiral source reagent, side reactions are few, impurities are few, the yield is high, the process safety is high, the intermediate (II) obtained by crystallization has high purity, and the product is produced in the reaction processThe three wastes are less, and the method is very suitable for large-scale industrial production.

2. The invention improves the preparation method of the reaction product of the third step, namely the anhydrous tenofovir (IV), and compared with the method of Lewis acid type hydrolysis reagent trimethyl bromosilane or trimethyl chlorosilane adopted by Chuaiqiang and the like, the method of the invention adopts 36-38% of concentrated hydrochloric acid as the hydrolysis reagent, has the advantages that: the cost is low, TMSBr or TMSCl is about 300 yuan/kg, and 36% -38% concentrated hydrochloric acid is only 2-3 yuan/kg; secondly, the energy consumption is low, excessive TMSBr or TMSCl is generally removed by decompression and concentration at a higher temperature after the hydrolysis reaction is finished in methods such as Chuanqiong and the like, then the pH is adjusted to be 2.8-3.2 by using a sodium hydroxide solution to separate out crystals, and solid can be separated out by directly adjusting the pH to be 2.8-3.2 by using the sodium hydroxide solution at 5 ℃ after the hydrochloric acid is used as a hydrolysis reagent for reaction, so that the operation process is simplified, the energy consumption is reduced, and the method is favorable for large-batch industrial production.

3. In the fifth step of the reaction, quaternary ammonium salt is used as a catalyst, so that the reaction yield can be improved, and the molar yield of the last step of the reaction is 72-81%, see example 9 and example 10. Compared with the method of firstly adding isopropyl and then adding chloromethyl isopropyl carbonate, which is reported by Liangchaoyang et al (chemical management, 2013, 7: 68-70), the method of the invention has higher yield, and the reaction yield of the last step of the Liangchaoyang et al method is only 40%. Meanwhile, the product obtained by the method has high purity, the High Performance Liquid Chromatography (HPLC) area normalization method purity is more than or equal to 98 percent, and the method is suitable for large-scale industrial production.

Detailed Description

The present invention is described by the following specific examples, by which the present invention can be better understood, but the scope of the present invention is not limited by these examples:

example 1:

80.00g (0.592 mol) of adenine was charged in a three-necked flask, 380ml of N, N-Dimethylformamide (DMF) was added thereto, and 9.48g (0.237 mol) of sodium hydroxide was added thereto under stirring, followed by addition of (I), (II), (III), (IVS) 78.60g (0.770 mol) of propylene carbonate, heating to 130 ℃, reacting for 18 hours, stopping the reaction, cooling to 40 ℃, adding a mixed solution of 240ml of methanol and 240ml of isopropanol, cooling to 12 ℃, crystallizing at constant temperature for 1 hour, filtering, washing a filter cake with a mixed solution of 40ml of methanol and 40ml of isopropanol (4 ℃), pumping, and placing in a vacuum drying oven for vacuum drying at 45 ℃ for 4.5 hours to obtain 87.70g (0.454 mol) of white solid with the molar yield of 76.7%.

¹H NMR (400 MHz, DMSO-d ₆)：δ = 8.15 (s, 1H), 8.05 (s, 1H), 7.18 (s, 2H), 5.03 (d, J = 4.0 Hz, 1H), 4.11 (q, J = 7.4 Hz, 1H), 4.07 – 3.98 (m, 2H), 1.07 (d, J = 5.8 Hz, 3H) ppm.

¹³C NMR (100 MHz, DMSO-d ₆) ：δ = 155.9 (C-6′), 152.2 (C-2′), 149.7 (C-4′), 141.4 (C-8′), 118.5 (C-5′), 64.6 (C-2), 50.1 (C-1), 20.8 (C-3) ppm.

MS (ESI, +): m/z [M+H]⁺ calcd forC₈H₁₁N₅O: 193.1; found: 194.2.

UV（MeOH）：λ_max＝260nm.

Anal. calcd for C₈H₁₁N₅O_:C 49.73, H 5.74, N 36.25. Found C 49.78, H 5.65, N 36.20.

Example 2:

Adding adenine (40.00 g) (0.296 mol) into a three-neck flask, adding N, N-Dimethylformamide (DMF) 190ml, adding sodium hydroxide (0.94 g) (0.0235 mol) under stirring, and adding (C), (D) and (D)R) 39.20g (0.384 mol) of propylene carbonate, heating to 120 ℃, reacting for 27 hours, stopping the reaction, cooling to 70 ℃, adding a mixed solution of 120ml of methanol and 120ml of isopropanol, cooling to 15 ℃, crystallizing at constant temperature for 12 hours, filtering, washing a filter cake with a mixed solution of 20ml of methanol and 20ml of isopropanol (4 ℃), pumping, and placing in a vacuum drying oven for vacuum drying at 60 ℃ for 2 hours to obtain 45.51g (0.215 mol) of white solid with molar yield of 45.51g andthe content was 72.6%.

Example 3:

40.00g (0.207 mol) of intermediate (II) and N-methylpyrrolidone (NMP) (160 ml) were added to a dry three-necked flask, stirred and dissolved, and the mixture was dissolved in 25 ml^oC adding 70.00g (0.414 mol) of magnesium tert-butoxide, then heating to 70^oAnd C, slowly adding 100.00g (0.311 mol) of (diethoxyphosphonyl) methyl-4-methylbenzenesulfonate, reacting for 4 hours at a constant temperature of 70 ℃, then cooling to 20 +/-5 ℃, slowly adding 36.75g (0.612 mol) of acetic acid into the reaction system, adjusting the pH to 6-7, keeping the temperature at 15-25 ℃, adding 900ml of ethyl acetate into the mixture, stirring for 30 minutes, standing, and pouring out the supernatant. And (3) putting the filter cake into a bottle, adding 300ml of ethyl acetate, stirring for 30min at 15-25 ℃, filtering, combining the filter cake and the first filtrate, filtering the combined filtrate again, concentrating the filtrate under reduced pressure to obtain a light yellow oily substance, and directly putting the light yellow oily substance into the next reaction (example 5) with quantitative calculation of the yield of a crude product.

Example 4:

40.00g (0.207 mol) of intermediate (II) and DMF (160 ml) were added to a dry three-necked flask, stirred and dissolved, and the mixture was dissolved at 25%^oC adding 70.00g (0.414 mol) of magnesium tert-butoxide, then heating to 80%^oAnd C, slowly adding 100.00g (0.311 mol) of (diethoxyphosphonyl) methyl-4-methylbenzenesulfonate, reacting for 4 hours at a constant temperature of 80 ℃, then cooling to 20 +/-5 ℃, slowly adding 36.75g (0.612 mol) of acetic acid into the reaction system, adjusting the pH to 6-7, keeping the temperature at 15-25 ℃, adding 1200ml of ethyl acetate into the mixture, stirring for 30 minutes, further heating to 55 +/-5 ℃, stirring for 30 minutes, cooling to 20 +/-5 ℃, standing, pouring out a supernatant, filtering, concentrating the filtrate under reduced pressure to obtain a light yellow oily substance, quantitatively calculating the yield of a crude product, and directly putting the crude product into the next reaction (example 6).

Example 5:

the third step: preparation of anhydrous tenofovir (IV)

The pale yellow oil obtained in example 3 was dissolved in 61ml (0.725 mol) of 36% concentrated hydrochloric acid solution, 75%^oC, reacting for 11h, and cooling to 45 h^oAnd C, concentrating, adding ethyl acetate (320 ml) into the concentrate for washing and 160ml of water, separating, washing the water phase with ethyl acetate (320 ml), cooling the water phase to 5 ℃, adjusting the pH to be 2.8-3.2 by using 40% sodium hydroxide solution, stirring at the same temperature for crystallization for 8h, filtering the solid, washing with 150ml of cold water, and drying in vacuum at 80 ℃ for 12h to obtain 36.33g (0.127 mol) of anhydrous tenofovir (IV), wherein the total molar yield of the two steps (examples 3 and 5) is 61%.

¹H NMR (400 MHz, DMSO-d ₆) ：δ = 8.14 (s, 2H), 7.27 (s, 2H), 4.26 (dd, J= 14.4, 4.0 Hz, 1H), 4.18 (dd, J = 14.4, 5.6 Hz, 1H), 3.97 – 3.86 (m, 1H), 3.59 (qd, J = 13.2, 9.6 Hz, 2H), 3.39 – 2.80 (bs, 2H), 1.03 (d, J = 6.3 Hz, 3H) ppm.

¹³C NMR (100 MHz, DMSO-d ₆) ：δ = 155.7 (C-6′), 152.1 (C-2′), 149.7 (C-4′), 141.6 (C-8′), 118.2 (C-5′), 75.3 (C-2), 75.2 (C-2), 65.1 (C-4), 63.5 (C-4), 46.4 (C-1), 16.9 (C-2a) ppm.

³¹P NMR (162 MHz, DMSO-d ₆)：δ = 17.33.

MS (ESI, -): m/z [M－H]^－ calcd for C₉H₁₄N₅O₄P: 287.1; found: 286.2.

HRMS (ESI, -): m/z [M－H]^－ calcd for C₉H₁₄N₅O₄P: 287.0783; found: 286.0708.

UV（MeOH）：λ_max＝206nm, 260nm.

Anal. calcd for C₉H₁₄N₅O₄P_:C 37.64, H 4.91, N 24.38. Found C 37.68, H 4.96, N 24.36.

Example 6: preparation of anhydrous tenofovir (IV)

The light yellow oily substance obtained in the example 4 is dissolved in 120ml (1.45 mol) of 36% concentrated hydrochloric acid solution, the mixture is reacted for 14h at 90 ℃, the mixture is cooled to room temperature, ethyl acetate (320 ml) and water (160 ml) are added, the water phase after liquid separation is washed by ethyl acetate (320 ml), the pH value is adjusted to 2.8-3.2 by 40% sodium hydroxide solution, the mixture is cooled to 5 ℃, stirred and crystallized for 6h, the solid is filtered, washed by 150ml cold water, and dried for 8h at 80 ℃ in vacuum, so that 35.70g (0.124 mol) of anhydrous tenofovir (IV) is obtained, and the total molar yield of the two steps of reactions (examples 4 and 6) is 60%.

Example 7: (R) Preparation of (- ((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V)

Adding 10.38g (0.036 mol) of anhydrous tenofovir (IV) and 42ml of DMF (DMF) into a dry three-neck flask, stirring and dissolving, sequentially adding 14.63g (0.145 mol) of triethylamine and 11.03g (0.072 mol) of chloromethyl isopropyl carbonate at room temperature, then heating to 55 ℃, reacting at the same temperature for 15h, cooling to room temperature, filtering, concentrating the filtrate, adding 40ml of water and 40ml of ethyl acetate, fully mixing, separating, washing the aqueous phase twice with 40ml of ethyl acetate (40 ml multiplied by 2), concentrating the aqueous phase to a viscous liquid, adding 90ml of isopropanol, stirring at 0 ℃ for 1h, filtering, and concentrating the filtrate to obtain (A), (B), (CR) - ((((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V) 9.01g (0.022 mol), molar yield 62%.

¹H NMR (400 MHz, DMSO-d ₆) : δ = 8.19 (s, 1H), 8.18 (s, 1H), 7.77 (s, 2H), 5.44 (dt, J = 13.6, 5.4 Hz, 2H), 4.78 (dt, J = 12.5, 6.2 Hz, 1H), 4.30 (dd, J = 14.4, 3.8 Hz, 1H), 4.18 (dd, J = 14.4, 6.0 Hz, 1H), 4.13 – 4.02 (bs, 1H), 3.99 – 3.92 (m, 1H), 3.67 (qd, J = 13.5, 9.1 Hz, 2H), 1.21 (d, J = 6.2 Hz, 6H), 1.05 (d, J = 6.2 Hz, 3H) ppm.

¹³C NMR (100 MHz, DMSO-d ₆) ：δ = 154.4 (C-6′), 152.8 (C-9), 150.0, 149.1 (C-2′), 142.2 (C-4′), 118.1 (C-8′), 84.4 (C-5′), 75.1, 75.0 (C-7), 72.1 (C-2), 64.6 (C-11), 63.0 (C-4), 46.9 (C-1), 21.3 (C-12, C-11a), 16.7 (C-2a) ppm.

³¹P NMR (162 MHz, DMSO-d ₆) ：δ = 17.83.

MS (ESI): m/z [M－H]^－ calcd for C₁₄H₂₂N₅O₇P: 403.1; found: 402.1.

HRMS (ESI): m/z [M－H]^－ calcd for C₁₄H₂₂N₅O₇P: 403.1257; found: 402.1246.

UV（MeOH）：λ_max＝260nm.

Anal. calcd for C₁₄H₂₂N₅O₇P_:C 41.69, H 5.50, N 17.36. Found C 41.66, H 5.36, N 17.59.

Example 8: (R) Preparation of (- ((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V)

Adding 12.64g (0.044 mol) of anhydrous tenofovir (IV) and DMF (55 ml) into a dry three-neck flask, stirring and dissolving, sequentially adding 17.81g (0.176 mol) of triethylamine and 26.86g (0.176 mol) of chloromethyl isopropyl carbonate at room temperature, then heating to 40 ℃, reacting at the same temperature for 12h, cooling to room temperature, filtering, concentrating the filtrate, adding 50ml of water and 50ml of ethyl acetate, fully mixing, separating the liquid, washing the aqueous phase twice (50 ml multiplied by 2) with ethyl acetate, concentrating the aqueous phase to a viscous liquid, adding 100ml of isopropanol, stirring at 0 ℃ for 1h, filtering, and concentrating the filtrate to obtain (A), (B), (C), (B), (CR) - ((((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V) 13.56g (0.034 mol), 76% molar yield.

Example 9: (((((R) -1- (6-amino-9))HPreparation of-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate (VI)

2.00g (5.0 mmol) of intermediate (V) is dissolved in 15ml of polar solvent DMF, and 1.01g (10 mmol) of triethylamine, 0.81g (2.5 mmol) of tetra-n-butylammonium bromide and 2-bromopropane are added in sequence with stirring1.23g (10.0 mmol) of alkane, reacting at 70 deg.C for 48h, cooling to room temperature, adding water 7ml and ethyl acetate 30ml, shaking, standing, separating, extracting the aqueous phase with ethyl acetate twice (30 ml. times.2), combining the organic phases, washing with cold water 20ml at 4 deg.C, washing with saturated saline solution 20ml, and adding anhydrous Na₂SO₄Drying, filtering and concentrating the filtrate to obtain 1.60g (3.6 mmol) of viscous liquid with a molar yield of 72%. The purity of HPLC area normalization method is more than or equal to 98 percent.

¹H NMR (400 MHz, CDCl₃) ：δ = 8.32 (s, 1H), 7.99 (d, J = 2.2 Hz, 1H), 6.00 (s, 2H), 5.68 – 5.53 (m, 2H), 4.91 (dq, J = 12.7, 6.3 Hz, 1H), 4.83 – 4.66 (m, 1H), 4.35 (dt, J = 14.4, 3.4 Hz, 1H), 4.12 (ddd, J = 17.5, 11.9, 7.0 Hz, 1H), 3.98 – 3.79 (m, 2H), 3.62 (ddd, J = 13.7, 9.4, 6.8 Hz, 1H), 1.35 – 1.21 (m, 15H) ppm.

¹³C NMR (100 MHz, CDCl₃) ：δ = 155.4 (C-6′), 153.2 (C-9), 153.1 (C-9), 152.6 (C-2′), 150.1 (C-4′), 141.9 (C-8′), 128.8 (C-5′), 119.0 (C-7), 84.5 (C-2), 84.4 (C-2), 73.1 (C-11), 72.3 (C-5b), 72.2 (C-5b), 64.2 (C-4c), 64.1 (C-4c), 62.5 (C-4c), 62.4(C-4c), 56.7 (C-1), 48.2 (C-5c), 48.1 (C-5c), 29.7 (C-5c′), 29.3 (C-5c′), 23.9 (C-12), 23.7(C-12), 22.7 (C-12), 21.6 (C-12), 19.1 (C-11a), 16.4 (C-11a), 14.1 (C-2a) ppm.

³¹P NMR (162 MHz, CDCl₃) ：δ = 20.93, 20.88.

MS (EI): m/z [M]⁺ calcd for C₁₇H₂₈N₅O₇P: 445.2; found: 445.0.

HRMS (EI): m/z [M]⁺ calcd for C₁₇H₂₈N₅O₇P: 445.1726; found: 445.1719.

UV（MeOH）：λ_max＝260nm.

Anal. calcd for C₁₇H₂₈N₅O₇P_:C 45.84, H 6.34, N 15.72. Found C 45.88, H 6.36, N 15.79.

Example 10: (((((R) -1- (6-amino-9))HPreparation of-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methyl isopropyl carbonate (VI)

Dissolving 2.00g (5.0 mmol) of intermediate (V) in 15ml of polar solvent DMF, adding 1.01g (10 mmol) of triethylamine, 1.85g (5.0 mmol) of tetra-n-butylammonium iodide and 1.23g (10.0 mmol) of 2-bromopropane in this order with stirring, reacting at 80 ℃ for 48 hours, cooling to room temperature, adding 7ml of water and 30ml of ethyl acetate, shaking, standing, separating, extracting the aqueous phase twice with ethyl acetate (30 ml. times.2), combining the organic phases, washing with 20ml of cold water at 4 ℃, washing with 20ml of saturated saline, washing with anhydrous Na, and purifying with sodium chloride₂SO₄Drying, filtering and concentrating the filtrate gave 1.80g (4.04 mmol) of a viscous liquid in 81% molar yield. The purity of HPLC area normalization method is more than or equal to 98 percent.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents and are included in the scope of the present invention.

Claims

1. A preparation method of a tenofovir disoproxil fumarate analogue (VI),

the method is characterized by comprising the following steps:

firstly, adding 12.64g of anhydrous tenofovir (IV) and 55ml of DMF into a dry three-neck flask, stirring and dissolving, sequentially adding 17.81g of triethylamine and 26.86g of chloromethyl isopropyl carbonate at room temperature, then heating to 40 ℃, reacting for 12H at the same temperature, cooling to room temperature, filtering, concentrating the filtrate, adding 50ml of water and 50ml of ethyl acetate, fully mixing, separating liquid, washing the water phase with ethyl acetate twice, 50ml of ethyl acetate each time, concentrating the water phase to a viscous liquid, adding 100ml of isopropanol, stirring for 1H at 0 ℃, filtering, and concentrating the filtrate to obtain (R) - ((((((((((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V);

in the second step, 2.00g of (R) - (((((((((1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) phosphine) oxy) methyl isopropyl carbonate (V) was dissolved in 15ml of a polar solvent DMF, and 1.01g of triethylamine, 1.85g of tetra-n-butylammonium iodide and 1.23g of 2-bromopropane were sequentially added with stirring, followed by reaction at 80 ℃ for 48 hours, cooling to room temperature, adding 7ml of water and 30ml of ethyl acetate, shaking, standing, liquid separation, extraction of the aqueous phase with ethyl acetate twice, each 30ml of ethyl acetate, combination of the organic phases, washing with 20ml of cold water at 4 ℃, washing with 20ml of saturated saline, and washing with anhydrous Na₂SO₄Drying, filtering and concentrating the filtrate to obtain viscous liquid (((((((R) -1- (6-amino-9H-purin-9-yl) propyl-2-yl) oxy) methyl) (isopropoxy) phosphine) oxy) methylisopropyl carbonate (VI).