Method for preparing 2-tert-butyl-4-methoxyphenol and new crystal form thereof

Abstract

The present invention relates to a stable crystal form, i.e. form A, of 2-tert-butyl-4-methoxyphenol, and to a new preparation method for the 2-tert-butyl-4-methoxyphenol; and the use of the 2-tert-butyl-4-methoxyphenol and the stable crystal form thereof, i.e. form A, in preparing antitumor drugs or immunomodulator drugs. The stable crystal form, i.e. form A, as expressed by a powder X-ray diffraction pattern in an angle of 2θ, using Cu-Kα radiation, has at least 3 absorption peaks selected from the following positions: 6.27±0.10, 6.94±0.10, 12.27±0.10, 13.36±0.10, 14.01±0.10, 14.79±0.10, 15.31±0.10, 17.05±0.10, 18.30±0.10, 19.00±0.10, 20.47±0.10, 20.98±0.10, 22.37±0.10, 23.68±0.10, 24.55±0.10, 25.37±0.10, 30.83±0.10, 33.12±0.10, 40.50±0.10, 42.81±0.10.

Claims

1. A stable crystalline form A of 2-tert-butyl-4-methoxyphenol, wherein: form A has a powder X-ray diffraction pattern expressed in 2θ angles using Cu-Kα radiation having absorption peaks selected from the following positions: 6.27±0.10, 6.94±0.10, 12.27±0.10, 13.36±0.10, 14.01±0.10, 14.79±0.10, 15.31±0.10, 17.05±0.10, 18.30±0.10, 19.00±0.10, 20.47±0.10, 20.98±0.10, 22.37±0.10, 23.68±0.10, 24.55±0.10, 25.37±0.10, 30.83±0.10, 33.12±0.10, 40.50±0.10, and 42.81±0.10.

2. The stable crystal form A of 2-tert-butyl-4-methoxyphenol according to claim 1, comprising at least 98.0% 2-tert-butyl-4-methoxyphenol and less than 2.0% of 3-tert-butyl-4-methoxyphenol.

3. The stable crystal form A of 2-tert-butyl-4-methoxyphenol according to claim 1, comprising at least 99.0% 2-tert-butyl-4-methoxyphenol and less than 1.0% of 3-tert-butyl-4-methoxyphenol.

4. The method for preparing the stable crystal form A of 2-tert-butyl-4-methoxyphenol according to claim 1, comprising the steps shown in (1) or (2): (1) recrystallizing a crude 2-tert-butyl-4-methoxyphenol with petroleum ether or a composite solvent containing more than 80% petroleum ether to obtain the stable crystal form A of 2-tert-butyl-4-methoxyphenol; (2) recrystallizing a crude 2-tert-butyl-4-methoxyphenol with petroleum ether or a composite solvent containing more than 80% petroleum ether as solvent to obtain a high-purity 2-tert-butyl-4-methoxyphenol, wherein the volume of solvent is 1-10 times the volume of the crude 2-tert-butyl-4-methoxyphenol, the chemical purity of 2-tert-butyl-4-methoxyphenol is more than 98%, and the content of the isomer 3-tert-butyl-4-methoxyphenol is less than or equal to 0.5%.

5. A pharmaceutical composition comprising the stable crystal form A of 2-tert-butyl-4-methoxyphenol according to claim 1 and a pharmaceutically acceptable adjuvant, diluent or carrier.

6. The pharmaceutical composition according to claim 5, wherein: the pharmaceutical composition is used as anti-tumor drugs, drugs for the treatment of autoimmune diseases or immunomodulators.

7. The pharmaceutical composition according to claim 5, wherein: the dosage of the stable crystal form of 2-tert-butyl-4-methoxyphenol is 50-1000 mg per person per day.

8. The pharmaceutical composition according to claim 5, wherein: the dosage of the stable crystal form of 2-tert-butyl-4-methoxyphenol is 100-800 mg per person per day.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a reaction formula for preparing high-purity 2-tert-butyl-4-methoxyphenol (2-BHA) of the present invention.

(2) FIG. 2 is a graph showing an X-ray powder diffraction pattern of form A of 2-tert-butyl-4-methoxyphenol.

(3) FIG. 3 is a graph showing a baseline separation analysis spectrum of 2-tert-butyl-4-methoxyphenol and its isomers.

(4) FIG. 4 is a graph showing an HPLC analysis spectrum of 2-tert-butyl-4-methoxyphenol prepared in Example 4.

EMBODIMENT OF THE INVENTION

(5) Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents, biological materials, etc. used in the following examples can be obtained from commercial sources.

Example 1. New Preparation Method for 2-tert-butyl-4-methoxyphenol (2-BHA)

(6) 2-tert-butyl hydroquinone (0.78 g, 5 mmol) was dissolved in anhydrous tetrahydrofuran (5 mL), and then added into sodium hydride (0.12 g, 5 mmol) in tetrahydrofuran (10 mL) slowly in an ice salt bath under the protection of N.sub.2 gas. After completing the addition, the resulting mixture was stirred for 30 minutes, followed by adding iodomethane (0.57 g, 4.5 mmol) dropwise, and then stirred overnight in an ice-salt bath. The reaction was quenched by adding saturated ammonium chloride solution. The reaction product was extracted with ethyl acetate (30 mL×3), washed with saturated brine three times, and recrystallized with petroleum ether (5 mL) to obtain a product with a yield of 78%. .sup.1H NMR (400 MHz, CDCl.sub.3) δ ppm 1.39 (s, 9H), 3.75 (s, 3H), 6.60 (d, J=1.12 Hz, 2H), 6.85-6.86 (m, 1H). MS (m/z)=181.1 (M+1).

Example 2. New Preparation Method for 2-tert-butyl-4-methoxyphenol (2-BHA)

(7) 2-tert-butyl hydroquinone (0.78 g, 5 mmol) was dissolved in anhydrous tetrahydrofuran (10 mL) in an ice-salt bath, and then added into potassium tert-butoxide (0.51 g, 4.5 mmol) in tetrahydrofuran (10 mL) slowly under the protection of N.sub.2 gas. After completing the addition, the resulting mixture was stirred for 30 minutes, followed by adding dropwise iodomethane (0.57 g, 4.5 mmol), and then stirred overnight in an ice-salt bath. The reaction was quenched by adding saturated ammonium chloride solution. The reaction product was extracted with ethyl acetate (30 mL×3), washed with saturated brine three times, and recrystallized with petroleum ether (5 mL) to obtain a product with a yield of 85%.

Example 3. New Preparation Method Two for 2-tert-butyl-4-methoxyphenol (2-BHA)

(8) 2-tert-butyl hydroquinone (0.78 g, 5 mmol) was dissolved in anhydrous tetrahydrofuran (10 mL) in an ice-salt bath, and then added into diisopropylethylamine (0.70 g, 4.5 mmol) in tetrahydrofuran (10 mL) slowly under the protection of N.sub.2 gas After completing the addition, the resulting mixture was stirred for 30 minutes, followed by adding dropwise iodomethane (0.57 g, 4.5 mmol), and then stirred overnight in an ice-salt bath. The reaction was quenched by adding saturated ammonium chloride solution. The reaction product was extracted with ethyl acetate (30 mL×3), washed with 1N hydrochloric acid (10 mL×3), washed with saturated aqueous sodium chloride solution 3 times, and recrystallized with petroleum ether to obtain a product with a yield of 80%.

Example 4. Preparation for Stable Crystal Form of 2-tert-butyl-4-methoxyphenol (2-BHA)

(9) 10 g of 2-tert-butyl-4-methoxyphenol (in which the mass content of 2-tert-butyl-4-methoxyphenol was 90% or the product prepared by any method in Examples 1-3) was added to petroleum ether (20 mL), heated and refluxed for 30 minutes, cooled naturally, filtered with suction, and dried in vacuum to obtain 9.5 g of white crystal with a yield of 95%.

(10) Crystal form determination: as expressed by a powder X-ray diffraction pattern in an angle of 2θ, using Cu-Kα radiation, there are 20 main absorption peaks (as shown in FIG. 2): 6.27±0.10, 6.94±0.10, 12.27±0.10, 13.36±0.10, 14.01±0.10, 14.79±0.10, 15.31±0.10, 17.05±0.10, 18.30±0.10, 19.00±0.10, 20.47±0.10, 20.98±0.10, 22.37±0.10, 23.68±0.10, 24.55±0.10, 25.37±0.10, 30.83±0.10, 33.12±0.10, 40.50±0.10, 42.81±0.10.

Example 5. Purity Analysis for 2-tert-butyl-4-methoxyphenol (2-BHA)

(11) The analysis method for 2-tert-butyl-4-methoxyphenol (2-BHA) and its isomer 3-tert-butyl-4-methoxyphenol (3-BHA) was established using High Performance Liquid Chromatography. Purities of the samples prepared by Example 1, Example 2, Example 3, and Example 4 were measured using stationary phase: C18, 250 mm, Φ5; mobile phase: methanol-water gradient (water phase 55%-10%, methanol 45%-90%). 2-tert-butyl-4-methoxyphenol (2-BHA) and its isomer 3-tert-butyl-4-methoxyphenol (3-BHA) were completely baseline separated (FIG. 3). The purity results of the freshly prepared 2-tert-butyl-4-methoxyphenol by the present invention are shown in Table 1 below, and the representative HPLC spectrum is shown in FIG. 4.

(12) TABLE-US-00001 TABLE 1 Analysis results of 2-tert-butyl-4-methoxyphenol prepared by new method 2-BHA 3-BHA Example 1 >99.5% not detected Example 2 >99.5% <0.01% Example 3 >99.5% <0.01% Example 4   100% not detected

Example 6. Pharmacokinetic Evaluation of 2-tert-butyl-4-methoxyphenol (2-BHA) of Form A in Rats by Intragastric Administration

(13) SD rats, half male and half female, fasted overnight, 6 rats/group, were given 2-tert-butyl-4-methoxyphenol suspended in Tween 80 (2-BHA of form A prepared by Example 4) by intragastric administration, the dose being 100 mg/kg body weight. Before administration, and at 5 min, 30 min, 60 min, 120 min, 180 min, 300 min, 540 min, and 1200 min respectively after administration, blood was collected from fundus venous, and centrifuged, and then plasma was collected and stored at −20° C. The blood drug concentrations were measured at different time points, as shown in Table 2 below.

(14) TABLE-US-00002 TABLE 2 Test results of plasma samples in the 100 mg/kg group given by intragastric administration (ng/mL) Blood sampling time 1♂ 2♂ 3♂ 4♀ 5♀ 6♀ Predose BLLOQ BLLOQ BLLOQ BLLOQ BLLOQ BLLOQ  5 min 159.617 125.112 147.531  80.026 165.939  77.996 30 min 694.651 489.006 359.028 157.878 371.466 240.870  1 h 880.632 560.980 570.039 504.084 603.120 643.208  2 h 267.167 267.234 312.997 687.296 410.399 199.206  4 h 192.535  63.401  86.609 283.840 205.532 146.191  8 h 117.919  27.328 192.532  78.447  42.984 121.700 24 h BLLOQ BLLOQ BLLOQ BLLOQ BLLOQ BLLOQ Note: BLLOQ = below the detection limit

Example 7. Bulk Drug and Tablet Stability Test of 2-tert-butyl-4-methoxyphenol (2-BHA) of Form A

(15) An accelerated stability test for bulk drug was carried out directly from the crystal powder. An accelerated stability test for formulation was carried out on tablets.

(16) Preparation process of formulation: form A of 2-tert-butyl-4-methoxyphenol (2-BHA) (form A of 2-BHA prepared in Example 4), microcrystalline cellulose, lactose and other auxiliary materials respectively were screened through 100 mesh, respectively for use. The prescription amount of form A of 2-tert-butyl-4-methoxyphenol, microcrystalline cellulose, lactose and other auxiliary materials were fully mixed according to the equal volume addition method. The above mixture was added to an aqueous solution of 2-3% polyvinylpyrrolidone under stirring, to obtain a soft material, which was screened through a 20-mesh sieve. The tablet weight regulator was adjusted to make the tablet weight being 250±10 mg, the hardness being 60-80 N, and then the tablet was compressed. After screening for dissolution, homogeneity and reproducibility and the like, the prescription was determined and 3 batches of samples were prepared.

(17) The experimental results under stability accelerated test conditions (40° C.±2° C., RH 75%±5%) are shown in Table 3 and Table 4.

(18) TABLE-US-00003 TABLE 3 Accelerated stability test for bulk drug Acceleration Related Sample NO. time Appearance Content substance 20160808 0 month white 99.5% 0.34% 1 month white 99.7% 0.22% 2 month white 99.4% 0.19% 3 month white 99.5% 0.35% 20160904 0 month white 99.8% 0.14% 1 month white 99.7% 0.21% 2 month white 99.3% 0.39% 3 month white 99.3% 0.35% 20160908 0 month white 99.6% 0.34% 1 month white 99.6% 0.31% 2 month white 99.5% 0.29% 3 month white 99.6% 0.25% Control: 0 month off-white 98.0%  1.8% Commercially 1 month light yellowish 95.1%  3.9% available white 2-tert-butyl-4-met 2 month light yellowish + 92.1%  8.8% hoxyphenol (TCI, red particles J6ONAOT) 3 month light yellowish red 90.2%  9.3% particles

(19) TABLE-US-00004 TABLE 4 Accelerated stability test for formulation Ac- Sample celeration Dis- Related NO. time Appearance Content solution substance 20160918 0 month white tablets, no 98.5% 100.5% 0.24% obvious change in contents 1 month white tablets, no 98.7%  99.3% 0.32% obvious change in contents 2 month white tablets, no 99.4% 102.1% 0.29% obvious change in contents 3 month white tablets, no 99.5%  99.8% 0.15% obvious change in contents 20161014 0 month white tablets, no 99.8%  99.2% 0.14% obvious change in contents 1 month white tablets, no 99.7%  98.9% 0.21% obvious change in contents 2 month white tablets, no 99.3% 100.2% 0.29% obvious change in contents 3 month white tablets, no 99.3%  99.9% 0.33% obvious change in contents 20161108 0 month white tablets, no 99.6% 100.3% 0.24% obvious change in contents 1 month white tablets, no 99.6%  98.9% 0.21% obvious change in contents 2 month white tablets, no 99.5%  99.6% 0.39% obvious change in contents 3 month white tablets, no 99.6% 101.2% 0.25% obvious change in contents

(20) It can be seen that the crystal form has better stability during the preparation process.

INDUSTRIAL APPLICATION

(21) The stable crystal form, i.e. form A, of 2-tert-butyl-4-methoxyphenol (2-BHA) provided by the present invention is easy to prepare, easy to purify, and has better physical and chemical stability than commercially available BHA. The stability is specifically manifested in its good fluidity, not easy to agglomerate, and not easy to oxidize and change color in the environment. After intragastric administration in mice, form A of 2-tert-butyl-4-methoxyphenol (2-BHA) provided by the present invention has small individual differences in plasma concentration, and its maximum plasma concentration and lower area AUC of plasma concentration-time curve have a better correlation with the administration dose.