Summary of the invention
The invention provides the preparation method of (S)-Oxiracetam crystal form III, found (S)-oxiracetam new crystal as mentioned below, but for convenience's sake, is called " crystal form II I " by integrity property of the present invention.The method is simple, with low cost, and obtained (S)-Oxiracetam crystal form III purity is high, foreign matter content is low.
The object of the invention is to be achieved through the following technical solutions:
(S) preparation method of-Oxiracetam crystal form III, adopts cooling down mode to prepare, obtains by the following method:
(1). (S)-oxiracetam is dissolved in sec-butyl alcohol solvent with 5mg/mL-50mg/mL, constantly stirs, 40 DEG C ~ 80 DEG C heating for dissolving, filter, form supersaturated solution;
(2). supersaturated solution sealing step (1) obtained is placed on crystallisation by cooling in the low temperature environment of-17 DEG C ~-21 DEG C, and obtaining colourless bulk crystals, is (S)-oxiracetam new crystal III.
In above-mentioned steps (2), crystal littlely reached balance constantly about 24 hours-36 greatly, no longer separated out afterwards.The temperature of described heating for dissolving preferably 40 DEG C ~ 50 DEG C.Low temperature environment preferably-18 DEG C ~-20 DEG C.
Described reaction raw materials and reagent are commercially available prod.
In order to improve yield and the purity of crystal form II I further, be preferably as follows (S)-oxiracetam that mode is obtained:
Intermediate II intermediate III
(S)-oxiracetam
First mixed with the ethanol of 5 ~ 20 times of weight by S-4-amino-3-hydroxybutyrate, then add sulfur oxychloride and react 1 ~ 5 hour at 0 ~ 60 DEG C, S-4-amino-3-hydroxybutyrate and sulfur oxychloride mol ratio are 1:1.5 ~ 1.65; Obtain the alcoholic solution containing intermediate compound I, then collect intermediate compound I from containing the alcoholic solution of intermediate compound I.
The intermediate compound I that will obtain from step (1), in the tetrahydrofuran solvent of the 10-15 times of weight of S-4-amino-3-hydroxybutyrate with halogenated acetic acids ester under triethylamine or lutidine alkali exist catalyzed reaction 5 ~ 10 hours, temperature of reaction is 0 ~ 60 DEG C, then collects and obtains intermediate II; The mol ratio of intermediate compound I and halogenated acetic acids ester is: 1: 1 ~ 3, and the mol ratio of intermediate compound I and described alkaline catalysts is: 1: 2 ~ 3.
By the intermediate II that step (2) obtains, in toluene solvant, carry out ring closure reaction under 50 ~ 120 DEG C of conditions, the time is 3 ~ 8 hours, obtains the solution containing intermediate III, then obtains intermediate III from containing collecting the solution of intermediate III.
By the intermediate III that step (3) obtains, at 20 ~ 30 DEG C, react 4 ~ 16 hours with strong aqua, from reaction product, then collect target product (S)-oxiracetam.
Specifically, the preparation method of above-mentioned (S)-oxiracetam new crystal III:
First S-4-amino-3-hydroxybutyrate is mixed with the ethanol of 5 ~ 20 times of weight, then add sulfur oxychloride to react 1 ~ 5 hour at 0 ~ 60 DEG C, S-4-amino-3-hydroxybutyrate and acylating agent or catalyzer (sulfur oxychloride) mol ratio are 1:1.5 ~ 1.65; Obtain the alcoholic solution containing intermediate compound I, then collect intermediate compound I from containing the alcoholic solution of intermediate compound I.
The intermediate compound I that will obtain from step (1), in the tetrahydrofuran solvent of the 10-15 times of weight of S-4-amino-3-hydroxybutyrate with halogenated acetic acids ester under triethylamine or lutidine alkali exist catalyzed reaction 5 ~ 10 hours, temperature of reaction is 0 ~ 60 DEG C, then collects and obtains intermediate II; The mol ratio of intermediate compound I and halogenated acetic acids ester is: 1: 1 ~ 3, and the mol ratio of intermediate compound I and described alkaline catalysts is: 1: 2 ~ 3.
By the intermediate II that step (2) obtains, in toluene solvant, carry out ring closure reaction under 50 ~ 130 DEG C of conditions, the time is 3 ~ 8 hours, obtains the solution containing intermediate III, then obtains intermediate III from containing collecting the solution of intermediate III.
By the intermediate III that step (3) obtains, at 20 ~ 30 DEG C, react 4 ~ 16 hours with strong aqua, from reaction product, then collect target product (S)-oxiracetam.
(the S)-oxiracetam of above-mentioned collection is dissolved in sec-butyl alcohol solvent with 10mg/mL-50mg/mL, constantly stirs, heat 40 DEG C ~ 50 DEG C dissolvings, filter, form supersaturated solution; The sealing of this solution to be placed in-18 DEG C ~-20 DEG C environment crystallisation by cooling 24 ~ 36 hours, and obtaining colourless bulk crystals, is (S)-oxiracetam new crystal III.
Described reaction raw materials and reagent are commercially available prod.
Beneficial effect of the present invention:
(S)-oxiracetam new crystal III that preparation method of the present invention obtains has oxiracetam equally can promote Phosphorylcholine and the synthesis of adjacent acyl thanomin, promote brain metabolism, hormesis is had to specificity central nervous pathway by hemato encephalic barrier, improve intelligence and memory, to the advantage of memory dysfunction successful.The melting point peak temperature of (the S)-oxiracetam new crystal III prepared by the inventive method is 117.3 DEG C, and in water, dissolution rate is fast, and solubleness >=100mg/mL in water, bioavailability is high.(S)-oxiracetam new crystal III purity that preparation method of the present invention adopts raw material cheap and easy to get, obtained is high, and preparation method's mild condition is easy and simple to handle, introducing impurity is few, favorable reproducibility, and production process is easy to control, security is high, is applicable to suitability for industrialized production.
Embodiment
Below by embodiment, the present invention is specifically described; what be necessary to herein means out is that following examples are only used to further illustrate the present invention; can not be interpreted as limiting the scope of the invention, person skilled in art can make some nonessential improvement and adjustment according to the invention described above content to the present invention.
Embodiment 1
A kind of synthetic method of (S)-oxiracetam, it carries out as follows,
(1) preparation of intermediate compound I:
Get raw material S-4-amino-3-hydroxybutyrate 50g, add in a single neck bottle, add ethanol 250ml, stir, ice-water bath cools, slow instillation thionyl chloride 150ml, keep temperature to be no more than 60 DEG C, solid first has a dissolution process, then separates out again, drip solid when making a concentrated effort to finish to dissolve again, finally form a faint yellow clarified liq.Continue stirring 5 hours, some plate is shown in that raw material primitive reaction is complete, stopped reaction, and directly concentrate except desolventizing obtains pale yellow oil, curing at low temperatures obtains intermediate compound I.Detect through nuclear-magnetism, intermediate compound I is: 1H-NMR (300MHz, D2O): δ 2.76-2.67 (ABsystem, m, 2H), 3.31-3.23 (ABsystem, m, 2H), 3.75 (s, 3H), 4.40 (m, 1H), 4.70 (bs, 3H) .13C-NMR (50MHz, D2O): δ 43.7 (C-2), 48.4 (C-4), 57.0 (OCH), 68.9 (C-3), 177.5 (C-I). intermediate compound I is:
r1 is methyl.
(2) preparation of intermediate II
The intermediate compound I that step (1) obtains is dissolved in the tetrahydrofuran solution of 500ml, be cooled to outer temperature 0 DEG C, add triethylamine (3eq), a large amount of solid is had to generate, stir five minutes, start to drip ethyl bromoacetate 90ml (2eq), dropping process has exothermic phenomenon, dropwise rear continuation stirring 2 hours, point plate is shown in that raw material reaction is complete, stopped reaction, filter, filtrate adds EA (ethyl acetate) 500ml, water 300ml, solid dissolves completely, by saturated for water layer solid sodium chloride, for going out organic layer, water layer EA200ml extracting twice, merge organic layer, the hydrochloric acid 200ml of organic layer 2M washes three times, merge hydrochloric acid aqueous phase, organic phase discards, aqueous phase continuation sodium bicarbonate regulates pH to 8, solid sodium chloride is saturated, EA300ml extracts three times, merge organic phase, anhydrous magnesium sulfate drying, concentrate except desolventizing obtains pale yellow oil, curing at low temperatures obtains intermediate II.Detect through nuclear-magnetism, intermediate II: 1H-NMR (300MHz, D2O): δ 1.3 (t, 3H), 2.28-2.53 (m, 2H), 2.58-2.83 (m, 2H) 3.51 (s, 2H), 3.67 (s, 3H), 4.09-4.12 (m, 3H). intermediate II is:
R1 is methyl, and R2 is ethyl.
(3) preparation of intermediate III
Intermediate II 500ml toluene step (2) obtained dissolves, and is warming up to 120 DEG C, refluxes 8 hours, obtain a red tan solution, and some plate is shown in that raw material reaction is complete.Stopped reaction, concentrated removing toluene, adds EA (ethyl acetate) and dissolves, cross and filter salt, activated carbon decolorizing, concentrate and remove yellow oil obtains intermediate III.Detect through nuclear-magnetism, intermediate III is: 1H-NMR (300MHz, CDCl3) δ 1.280 (t, 3H), 2.38 (dd, 1H), 2.69 (dd, 1H), 3.34 (dd, 1H), 3.77 (dd, 1H), 3.93 (d, 1H), 4.18 (d, 1H), 4.19 (q, 2H), 4.30 (bs, 1H), 4.50 (m, 1H). intermediate III:
r2 is ethyl.
(4) preparation of (S)-oxiracetam
The intermediate III that step (3) obtains is added strong aqua 200ml, stirring at room temperature 18 hours, some plate is shown in that raw material reaction is complete, stopped reaction, concentrated removal water and ammonia, obtain yellow oil, add acetone solution oily matter, add a small amount of crystal seed and stir, separate out solid, a small amount of acetone rinsing bottle wall ,-10 DEG C of crystallizations 5 hours, filter and obtain off-white color crude product 36g.Purity 99.3%, isomer proportion 0.2%.By this dissolving crude product in the water of 100ml, heating makes it dissolve, activated carbon decolorizing half an hour, cross and filter gac, crystallisation by cooling, 5 DEG C of placements are spent the night, filter to obtain white solid 32g next day, purity 99.9%, isomer proportion 0.1%, yield is 48.2%, detect through nuclear-magnetism, levo-oxiracetam: 1H-NMR (300MHz, DMS0-d6) δ 2.10 (d, 1H), 2.57 (dd, 1H), 3.69 (d, 1H), 3.88 (d, 1H), 4.10 (d, 1H), 4.31 (m, 1H), 5.25 (s, 1H), 7.13 (s, 1H), 7.33 (s, 1H). optical value :-37.3.(S)-oxiracetam is that structural formula is as follows:
Embodiment 2
A kind of synthetic method of (S)-oxiracetam, it carries out as follows,
(1) preparation of intermediate compound I:
Get raw material S-4-amino-3-hydroxybutyrate 1g, add in a single neck bottle, add ethanol 20ml, stir, ice-water bath cools, slow instillation thionyl chloride 30ml, keep temperature to be no more than 60 DEG C, solid first has a dissolution process, then separates out again, drip solid when making a concentrated effort to finish to dissolve again, finally form a faint yellow clarified liq.Continue stirring 5 hours, some plate is shown in that raw material primitive reaction is complete, stopped reaction, and directly concentrate except desolventizing obtains pale yellow oil, curing at low temperatures obtains intermediate compound I.Detect through nuclear-magnetism, intermediate compound I is: 1H-NMR (300MHz, D2O): δ 2.76-2.67 (ABsystem, m, 2H), 3.31-3.23 (ABsystem, m, 2H), 3.75 (s, 3H), 4.40 (m, 1H), 4.70 (bs, 3H) .13C-NMR (50MHz, D2O): δ 43.7 (C-2), 48.4 (C-4), 57.0 (OCH), 68.9 (C-3), 177.5 (C-I). intermediate compound I is:
r1 is methyl.
(2) preparation of intermediate II
The intermediate compound I that step (1) obtains is dissolved in the tetrahydrofuran solution of 100ml, be cooled to outer temperature 0 DEG C, add lutidine (1eq), a large amount of solid is had to generate, stir five minutes, start to drip ethyl bromoacetate (2eq), dropping process has exothermic phenomenon, dropwise rear continuation stirring 2 hours, point plate is shown in that raw material reaction is complete, stopped reaction, filter, filtrate adds EA (ethyl acetate) 100ml, water 60ml, solid dissolves completely, by saturated for water layer solid sodium chloride, separate organic layer, water layer EA60ml extracting twice, merge organic layer, the hydrochloric acid 60ml of organic layer 2M washes three times, merge hydrochloric acid aqueous phase, organic phase discards, aqueous phase continuation sodium bicarbonate regulates pH to 8, solid sodium chloride is saturated, EA60ml extracts three times, merge organic phase, anhydrous magnesium sulfate drying, concentrate except desolventizing obtains pale yellow oil, curing at low temperatures obtains intermediate II.Detect through nuclear-magnetism, intermediate II: 1H-NMR (300MHz, D2O): δ 1.3 (t, 3H), 2.28-2.53 (m, 2H), 2.58-2.83 (m, 2H) 3.51 (s, 2H), 3.67 (s, 3H), 4.09-4.12 (m, 3H). intermediate II is:
R1 is methyl, and R2 is ethyl.
(3) preparation of intermediate III
Intermediate II 100ml toluene step (2) obtained dissolves, and is warming up to 120 DEG C, refluxes 8 hours, obtain a red tan solution, and some plate is shown in that raw material reaction is complete.Stopped reaction, concentrated removing toluene, adds EA (ethyl acetate) and dissolves, cross and filter salt, activated carbon decolorizing, concentrate and remove yellow oil obtains intermediate III.Detect through nuclear-magnetism, intermediate III is: 1H-NMR (300MHz, CDCl3) δ 1.280 (t, 3H), 2.38 (dd, 1H), 2.69 (dd, 1H), 3.34 (dd, 1H), 3.77 (dd, 1H), 3.93 (d, 1H), 4.18 (d, 1H), 4.19 (q, 2H), 4.30 (bs, 1H), 4.50 (m, 1H). intermediate III:
r2 is ethyl.
(4) preparation of (S)-oxiracetam
The intermediate III that step (3) obtains is added strong aqua 50ml, stirring at room temperature 18 hours, some plate is shown in that raw material reaction is complete, stopped reaction, concentrated removal water and ammonia, obtain yellow oil, add acetone solution oily matter, add a small amount of crystal seed and stir, separate out solid, a small amount of acetone rinsing bottle wall ,-10 DEG C of crystallizations 5 hours, filter and obtain off-white color crude product 36g.Purity 99.3%, isomer proportion 0.2%.By this dissolving crude product in the water of 100ml, heating makes it dissolve, activated carbon decolorizing half an hour, cross and filter gac, crystallisation by cooling, 5 DEG C of placements are spent the night, filter to obtain white solid 32g next day, purity 99.9%, isomer proportion 0.1%, yield is 48.2%, detect through nuclear-magnetism, levo-oxiracetam: 1H-NMR (300MHz, DMS0-d6) δ 2.10 (d, 1H), 2.57 (dd, 1H), 3.69 (d, 1H), 3.88 (d, 1H), 4.10 (d, 1H), 4.31 (m, 1H), 5.25 (s, 1H), 7.13 (s, 1H), 7.33 (s, 1H). optical value :-37.3.(S)-oxiracetam is that structural formula is as follows:
Embodiment 3
Be dissolved in 2mL sec-butyl alcohol solution by 50mg (S)-oxiracetam obtained for embodiment 1,40 ° of C heating, filter, obtain supersaturated solution, the sealing of this solution to be placed under-19 DEG C of environment cooling crystallization 24 hours, obtaining colourless bulk crystals, is crystal form II I.
Embodiment 4
Crystal type (S) obtained by embodiment 3-Oxiracetam crystal form III crystal parameter is measured.
Resolve the single crystal structure of (S)-Oxiracetam crystal form III, its structure cell is rhombic system, and spacer is P4
1,
α=90.00 °, β=90.00 °, γ=90.00 °, unit cell volume
its crystalline structure as shown in Figure 1, pile up as shown in Figure 2 by structure cell.
The crystallographic parameter of crystal type (S)-Oxiracetam crystal form III is as shown in the table:
aR
1=Σ||F
o|-|F
c||/ΣF
o|.
bwR
2=[Σ[w(F
o 2-F
c 2)
2]/Σw(F
o 2)
2]
1/2,w=1/[σ
2(F
o)
2+(aP)
2+bP],whereP=[(F
o 2)+2F
c 2]/3.
Described crystal type levo-oxiracetam crystal form II I is 10.54 at angle of diffraction 2 θ, 13.70, 14.44, 15.60, 17.12, 18.88, 19.24, 20.66, 20.84, 21.18, 21.82, 22.94, 23.24, 24.88, 27.20, 27.48, 28.24, 30.46, 30.80, 31.52, 32.00, 32.34, 32.90, 33.20, 34.40, 34.62, 37.30, 37.50, 38.28, 38.96, there is diffraction peak at 40.02 degree of places, its monocrystalline simulation X-ray powder diffraction figure as shown in Figure 3, wherein 2 θ are 14.44, 17.12, 18.88, 19.24, 20.66, 20.84, 21.18 ° of places have the strong peak of diffraction peak to occur.Fig. 3 is the powder diagram that above-mentioned crystal type (S)-oxiracetam is simulated from single crystal structural data, monocrystalline simulation is simulated premised on perfect crystallization, and actual central very difficult appearance is definitely perfect, two close peaks may be caused just to merge and to become a peak, and cause peak broadening.The peak of Fig. 4 and Fig. 3 overlaps substantially, and overlap ratio, more than 99%, technically can think that crystal type (the S)-Oxiracetam crystal form III of preparation is pure single crystal form.
Crystal type of the present invention (S)-Oxiracetam crystal form III, its powder X-ray diffraction pattern is expressed with the per-cent I crystal of spacing d, Bragg angle (2 θ) and relative intensity, as follows:
Embodiment 5
Crystal type (S)-Oxiracetam crystal form III, crystal type (S)-Oxiracetam crystal form II, crystal type (S)-Oxiracetam crystal form I are done powder diffraction experiment contrast, as shown in Figure 5.
Embodiment 6
20mg (S)-oxiracetam is dissolved in 2mL sec-butyl alcohol solution, 50 DEG C of heating, filters, supersaturated solution, the sealing of this solution to be placed under-17 DEG C of environment cooling crystallization 3 hours, to obtain colourless bulk crystals, identifying by the method for embodiment 4, is crystal form II I.
Embodiment 7
50mg (S)-oxiracetam is dissolved in 1mL sec-butyl alcohol solution, 45 DEG C of heating, filters, supersaturated solution, the sealing of this solution to be placed under-18 DEG C of environment cooling crystallization 36 hours, to obtain colourless bulk crystals, identifying by the method for embodiment 4, is crystal form II I.
Embodiment 8
30mg (S)-oxiracetam is dissolved in 6mL sec-butyl alcohol solution, 80 DEG C of heating, filters, obtain supersaturated solution, the sealing of this solution is placed on-20 DEG C of environment lower 24 hours cooling crystallizations, obtains colourless bulk crystals, identifying by the method for embodiment 4, is crystal form II I.
Embodiment 9
70mg (S)-oxiracetam is dissolved in 2mL sec-butyl alcohol solution, 60 DEG C of heating, filters, supersaturated solution, the sealing of this solution to be placed under-21 DEG C of environment cooling crystallization 36 hours, to obtain colourless bulk crystals, identifying by the method for embodiment 4, is crystal form II I.
Embodiment 10
Measure on the LC-MS method basis of left oxiracetam in existing biological sample, healthy Beagle dog 6 is selected in experiment, and body weight is 8 ~ 10kg, is divided into two groups, often organizes 3, be used for observing different crystal forms left oxiracetam oral to dog after bioavailability.Study left oxiracetam I crystal formation and the pharmacokinetics of left oxiracetam III crystal formation in dog body, and be reference preparation with oxiracetam, whether the bioavailability evaluating I crystal formation and III crystal formation is equivalent.And by calculating its pharmacokinetic parameter, evaluation of bioequivalence is carried out to it.Result: left oxiracetam I crystal formation and the main pharmacokinetic parameter of left oxiracetam III crystal formation in Beagle dog body as follows: Tmax is respectively (1.561 ± 0.398), (1.498 ± 0.3988), Cmax are respectively (198.076 ± 80.462), (186.205 ± 50.321) mg/ml; T1/2 is respectively (0.915 ± 0.125), (0.909 ± 0.112) h; AUC0-∞ is respectively (456.268 ± 85.567), (436.364 ± 75.204) mg*h/ml.As can be seen here left oxiracetam I crystal formation and left oxiracetam III crystal formation bioavailability completely the same.
Comparative example 1
10mg (S)-oxiracetam is dissolved in 1mL ethanolic soln, 40 DEG C of heating, filter, obtain supersaturated solution, the sealing of this solution to be placed under-19 DEG C of environment cooling crystallization 24 hours, obtain colourless bulk crystals, identify by the method for X powder diffraction, (angle of diffraction 2 θ is 12.011 to be found to be crystal formation I, 15.318, 17.407, 19.633, 21.228, 22.052, 24.577, 25.223, 27.647, 28.161, 29.109, 30.805, 31.276, 31.766, 32.77, 33.477, 35.252, 35.645, 36.236, 37.379, 39.56, 40.489, 41.256, 41.948, 43.443, there is diffraction peak at 44.628 degree of places).
Comparative example 2
10mg (S)-oxiracetam is dissolved in 1mL butanol solution, 50 DEG C of heating, filter, obtain supersaturated solution, the sealing of this solution to be placed under-19 DEG C of environment cooling crystallization 36 hours, obtain colourless bulk crystals, identify by the method for X powder diffraction, (angle of diffraction 2 θ is 12.011 to be found to be crystal formation I, 15.318, 17.407, 19.633, 21.228, 22.052, 24.577, 25.223, 27.647, 28.161, 29.109, 30.805, 31.276, 31.766, 32.77, 33.477, 35.252, 35.645, 36.236, 37.379, 39.56, 40.489, 41.256, 41.948, 43.443, there is diffraction peak at 44.628 degree of places).
Comparative example 3
10mg (S)-oxiracetam is dissolved in 1mL pyridine solution, 50 DEG C of heating, filters, obtain supersaturated solution, the sealing of this solution to be placed under-17 DEG C of environment cooling crystallization 36 hours, not to have crystal to separate out.
Comparative example 4
10mg (S)-oxiracetam is dissolved in 1mLTHF solution, 50 DEG C of heating, filter, obtain supersaturated solution, the sealing of this solution to be placed under-17 DEG C of environment cooling crystallization 36 hours, obtain colourless bulk crystals, identify by the method for X powder diffraction, being found to be crystal form II (is 10.669 at angle of diffraction 2 θ, 13.25, 13.847, 14.198, 16.729, 17.934, 18.746, 18.816, 20.273, 20.413, 21.431, 21.617, 21.663, 23.38, 24.324, 24.415, 26.069, 26.107, 27.901, 28.621, 28.925, 29.449, 29.484, 31.702, 36.516, 37.685, there is diffraction peak at 39.721 degree of places).