The synthetic method of gemcitabine hydrochloride
Technical field
The present invention relates to the synthetic method of a kind of new type anticancer new drug gemcitabine hydrochloride (2 '-deoxidation-2 ', 2 '-two fluorouracil nucleoside hydrochlorides).
Background technology
Gemcitabine is a kind of new antimetabolic antitumour drug, and human leukocyte, some mouse solid knurl and the xenotransplantation of people's tumour are had good inhibitory effect.As a kind of Difluoronucleosides class metabolic antagonist anticarcinogen that destroys cellular replication, gemcitabine is the water-soluble analogues of cytosine deoxyriboside, to ribonucleotide reductase is a kind of surrogate of substrate material of inhibition, this kind of enzyme is at DNA in the synthetic and repair process, is vital to the generation of needed deoxynucleotide.Clinically, gemcitabine is particularly useful for treating inoperable late period or transitivity carcinoma of the pancreas and treats local progressivity or the transitivity nonsmall-cell lung cancer.
Gemcitabine synthetic key is synthetic intermediate compound (A)
Wherein, P represents protecting group.
US4526988, US4808614 disclose the method for a kind of synthetic (A), and protecting group P is TBS, as shown in Scheme 1:
The used protecting group TBS price of this law is more expensive, the cost height.
US5223608 has disclosed the method for another kind of synthetic (A), as shown in Scheme 2:
Route (2)
US6001994 has disclosed the method for another synthetic (A), shown in route (3):
Route (3)
More than the routes of three synthetic (A) following common trait is arranged:
A. two protecting group p in (A) are same group: TBS, benzenesulfonyl, have also enumerated protecting groups such as p-toluenesulfonyl, p-nitrophenyl alkylsulfonyl in the above in addition related patent.
B. all passed through following intermediate (B):
The alkyl of R:C1~C4.
C. tetrahydrofuran (C) all is behind (B) hydrolysis, forms through the intramolecularly esterification, and is as follows:
X: represent O or S.
Y: represent the arbitrary protecting group or the H that enumerate among a.
Reported at present as the described cyclization method of c, all unavoidably form following impurity:
R: define as b.
R ': C1~C6 alkyl.
In addition, CN1526711 discloses a kind of polymeric (R)-2 that utilizes, the 3-O-method of acetone-Glycerose for material choice synthetic (E) that contract
(E)
Follow-up cyclization is similar to aforementioned three kinds of routes.
But as described in c, the method for present cyclisation synthetic (C) all inevitably generates following impurity (D):
So the invention discloses the generation that a kind of new synthetic method can be avoided this by product.
Patents such as US5744597, US4526988, US4692434, US4808614, US06217547 have also related to gemcitabine another committed step in synthetic: (A) with the condensation of cytosine(Cyt).US5637688 discloses finishing of a kind of " treating different things alike " and has contracted and be incorporated in the method that crystallization in Virahol, the methanol solution obtains gemcitabine hydrochloride.
Summary of the invention
The new synthetic method that the purpose of this invention is to provide a kind of gemcitabine hydrochloride.
Technical scheme of the present invention is that raw material obtains product through Reformatsky addition, ization, hydrolysis, hydroxyl sulfonylation, cyclization, carbonyl reduction, hydroxyl sulfonylation, condensation, hydrolysis deprotection, crystallization with trimethyl orthoacetate hydroxyl protection, sodium periodate oxidation, aldehyde with D-N.F,USP MANNITOL.Shown in route (4):
Route (4)
(I): (1S, 2S)-2-((4R)-2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl)-1-((4S)-2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl)-1
Utilize D-N.F,USP MANNITOL to be raw material, under Catalyzed by p-Toluenesulfonic Acid,, respectively 1,2 and 5,6 hydroxyl protection is got up, form intermediate (1) with trimethyl orthoacetate reaction.Reaction is solvent with DMF, finishes under the room temperature.Because the methoxyl group on 4 of the dioxo amyl group has the different of arrangement with methyl, so intermediate (1) is actually the mixture of four isomerss:
But, need not in the reaction process these four kinds of materials are separated, because of will on 2 carbon of dioxo pentamethylene, forming carbonyl behind the deprotection, shown in intermediate (V), will not produce stereoisomerism on this position.
(II): (4S)-2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl-4-aldehyde
Intermediate (1) sodium periodate oxidation, selectivity be the C-C bond rupture of adjacent glycol, and simultaneously hydroxyl oxidize is got aldehyde radical.As described in the building-up process of (I), because the existence of four kinds of isomer, intermediate (II) is actual to be the mixture of a pair of diastereomer:
(11)-A (II)-B
In addition, as described in (I) synthetic, also need not these two kinds of isomer are separated.
Lead tetra-acetate can substitute Periodic acid as oxygenant, but because plumbiferous wastewater treatment difficulty, the value of recycling is little, therefore not as the sodium periodate practicality.
(III): (R)-2,2-two fluoro-3-hydroxyl-3-((4S)-2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl) ethyl propionate
In tetrahydrofuran (THF), zinc powder and ethyl bromide difluoride reaction generate Grignard reagent, and the aldehyde radical Reformatsky addition with (II) obtains (III) again.Because this reaction has produced new chiral centre, has produced following four kinds of diastereomers:
Therefore need be after reaction be finished, to have adsorbed chiral reagent---the resin column (weight percentage of cinchovatin is 1%~5%) of cinchovatin separates.Collect (III)-A, (III)-B and be used for the synthetic of (IV).
(IV): (R)-2,2-two fluoro-3-benzoyloxy-3-((4S)-2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl) ethyl propionate
Under minor N-methylmorpholine catalysis; the mixed solvent of forming in methylene dichloride and triethylamine (methylene dichloride by volume: triethylamine=5: 1~1: 1); with Benzoyl chloride with (III)-A, (III)-B the reaction; realize the protection of hydroxyl, obtain a pair of diastereomer of product (IV):
(IV)-A (IV)-B
(IV)-A, (IV)-B all can be used for the synthetic of (V).
(V): (3R, 4S)-5-acetoxy-3-benzoyloxy-2,2-two fluoro-4-hydroxypentanoic acids
The mixed solvent of acetonitrile and water (count acetonitrile by volume: water=1: 1~1: 5), with trifluoroacetic acid catalysis, the ketal in selective hydrolysis (IV) structure and α-difluoro Valeric acid ethylester, and the benzoic ether structure is hydrolyzed hardly.This is because ketal very easily hydrolysis under acidic conditions, in addition since the μ position two strong electron-withdrawing substituents---the existence of fluorine makes Valeric acid ethylester also be easy to hydrolysis.In addition, can produce a spot of impurity in the hydrolytic process, structure is as follows:
45~50 ℃ of the temperature of reaction of control, the concentration of trifluoroacetic acid can obtain (V) by highly selective 0.8%~1.4%, (V) with (V)
sRatio can reach 95: 5.
(VI): (3R, 4S)-5-acetoxyl group-4-tolysulfonyl oxygen base-3-benzoyloxy-2,2-difluoro valeric acid
In the mixed solvent of triethylamine and chloroform (count triethylamine by volume: chloroform=1: 10~1: 1), (V) be easy to obtain (VI), obtain an extraordinary leavings group PTSO-like this with the Tosyl chloride reaction:
For getting (VII), cyclization provides condition.
(VII): (4R, 5R)-5-acetyl-o-methyl-4-benzoyloxy-3-two fluoro-1-oxos-2-cyclopentanone employing phase-transfer-catalyzed reactions, with Tetrabutyl amonium bromide etc. is phase-transfer catalyst, (count ethyl acetate by volume: water=5: 1~1: 2), intermediate (VI) is finished ring-closure reaction under the salt of wormwood effect at mixed solvent that ethyl acetate and water are formed.Owing to the existence of α-difluoro, strengthened the acidity of the carboxyl of (VI) greatly, reaction can be carried out smoothly, and the hydrolysis of ester can not take place.Phase-transfer catalyst also can be selected n-hexyl tributyl brometo de amonio, tetrabutylammonium chloride, dodecyl tributyl brometo de amonio, crown ether etc. for use.This reaction belongs to the SN2 reaction, in 4 formation cyclizations of (VI), and the counter-rotating that has produced configuration.Obtained the 5R of stereospecificity (VII).The crystallization purifying solvent of intermediate (VII) is a normal hexane.
(VIII): (2R, 3R)-2-acetyl-o-methyl-3-benzoyloxy-4,4-two fluoro-5-hydroxyl tetrahydrofurans
Because; (VII) existence of three acyl groups in needs a hydrogenating reduction reagent that 2 carbonyls are carried out selective reduction, and adopting lithium triethylborohydride among the present invention is catalyzer; in tetrahydrofuran solution, obtained the target product of fine yield under-10 ℃~-5 ℃.Still the impurity that has a spot of other positions to be reduced in addition.Three tert.-butoxy lithium aluminum hydrides, triethoxy lithium aluminum hydride also are available ideal selectivity hydrogenation reagent.Obtained a pair of diastereomer behind the hydrogenating reduction:
The crystallization purifying solvent of intermediate (VIII) is that the mixed solvent of toluene and normal hexane (is counted toluene: normal hexane=1: 5~3: 1) by volume.
(IX): (2R, 3R)-2-acetyl-o-methyl-3-benzoyloxy-4,4-two fluoro-5-tolysulfonyl oxygen base tetrahydrofuran (THF)s
Similar with the formation of (VI), connect an easy leavings group 5 of intermediate (VIII)---tolysulfonyl oxygen base makes (X) form required condensation reaction and carries out easily.Intermediate (IX) synthetic is to be that raw material obtains with the Tosyl chloride reaction in methylene dichloride with intermediate (VIII).
Certainly, because the existence of two kinds of isomer (VIII) (IX) also is the mixture of a pair of diastereomer:
Wherein, only there is (IX)-A can generate the expection product.
(X): (2R, 3R, 5R)-and 2-acetyl-o-methyl-3-benzoyloxy-5-(4 '-aminopyrimidine base-2 '-ketone)-4,4-difluoro tetrahydrofuran (THF)
With cytosine(Cyt) for being dissolved in the hexamethyldisilazane (HMDS), temperature rising reflux 2 hours~4 hours, evaporate to dryness adds after ethyl acetate and methyl-phenoxide dissolve again, the methyl-phenoxide solution reaction with (IX) obtains product.But because the existence of a pair of diastereomer (IX), product (X) is actual to be the mixture of a pair of diastereomer:
The gemcitabine that can access correct three-dimensional arrangement after (X)-A hydrolysis is only arranged.But (X)-B can stay in the mother liquor in crystallisation process and remove by filter.
(XI): (2R, 3R, 5R)-and 2-methylol-3-hydroxyl-5-(4 '-aminopyrimidine base-2 '-ketone)-4,4-difluoro tetrahydrofuran (THF)
(2 '-deoxidation-2 ', 2 '-two fluorouracil nucleosides)---gemcitabine
In the methanol solution, under the catalysis of TERTIARY BUTYL AMINE, two acyl groups in (X) are sloughed in hydrolysis, obtain product (XI).
(XII): hydrochloric acid (2R, 3R, 5R)-and 2-methylol-3-hydroxyl-5-(4 '-aminopyrimidine base-2 '-ketone)-4,4-difluoro tetrahydrofuran (THF)
(2 '-deoxidation-2 ', 2 '-two fluorouracil nucleoside hydrochlorides)---gemcitabine hydrochloride
Behind (XI) deacylated tRNA radical reaction, with concentrated hydrochloric acid regulator solution pH1.5~2, concentrated solution adds entry and acetone successively and finishes the crystallization of product and obtain crude product near doing.Carry out recrystallization with the mixed solution of water and acetone again and obtain the gemcitabine hydrochloride finished product.
Beneficial effect of the present invention
The invention discloses the complete synthesis novel process of a kind of gemcitabine hydrochloride, this method does not relate to the fractionation of enantiomorph, only comprises that the crystallization of twice diastereomer splits, yield height, suitability for industrialized production simple to operate, suitable.
Embodiment
The invention will be further elaborated by the following examples.
Embodiment 1:(1S, 2S)-2-((4R)-2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl)-1-((4S)-2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl)-1 synthetic
After D-N.F,USP MANNITOL 180g is dissolved in 1000ml DMF, add tosic acid 2g, trimethyl orthoacetate 300g, room temperature reaction 24 hours is 15% ammoniacal liquor regulator solution pH to 7.5 with concentration.Filtration, concentrating under reduced pressure filtrate add water 500ml to 100m', stir, and add methylene dichloride 300ml
*3 extractions, the combined dichloromethane layer adds anhydrous sodium sulphate 50g, stirs 2 hours, filters, and obtains the dichloromethane solution of target product.
Embodiment 2:(4S)-and 2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl-4-aldehyde synthetic
In the dichloromethane solution of embodiment 1 gained, gradation adds the 700ml aqueous solution that contains sodium periodate 180g, stirring at room 4 hours, filter, leave standstill the collection dichloromethane layer, behind the anhydrous sodium sulfate drying, be evaporated to absence of liquid outflow in the condenser below 30 ℃.30-100 ℃ of overhead products are collected in 120 ℃ of decompressions of the outer temperature of control, merge distillate, add anhydrous sodium sulphate 50g, stir 2 hours, filter, filtrate concentrating under reduced pressure below 30 ℃ in, get target product 95-100g.
Embodiment 3:(R)-2,2-two fluoro-3-hydroxyl-3-((4S)-2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl) ethyl propionate is synthetic
In the 200ml tetrahydrofuran (THF), add activated zinc powder 45g, warm 45-50 ℃ of 200m1 tetrahydrofuran solution that drips embodiment 2 products therefroms and 104g ethyl bromide difluoride mixture dripped off in about 1 hour in the control, was incubated 2 hours.The TLC detection reaction is complete, reaction solution is dropped to 0 ℃ near after, in the mixture that impouring 200g ice, 400g water and 72g concentrated hydrochloric acid are formed, stirred 30 minutes, after the filtration, use methylene dichloride 160ml
*2 extractions behind the 5% sodium bicarbonate 200ml washing dichloromethane layer, are used the water washing of 150ml saturated common salt once again.Collected organic layer 50g anhydrous sodium sulfate drying filters, and vacuum concentration is to doing.Sherwood oil: ethyl ester=5: 2 is crossed resin column (in advance cinchovatin 3g being adsorbed on the 200g resin dress post) for moving phase, collects the effluent that contains (III)-A, (III)-B, be evaporated to dried, target product (III)-A, (III)-B 92-96g altogether.
Embodiment 4:(R)-2,2-two fluoro-3-benzoyloxy-3-((4S)-2-methoxyl group-2-methyl isophthalic acid, 3-dioxo cyclopentyl) ethyl propionate is synthetic
Behind (III) that obtains with 400ml methylene dichloride dissolving embodiment 3, add the 4gN-methylmorpholine, stirred 0.5 hour, after the dissolving, add triethylamine 100g, attemperation is at 26-30 ℃, drip dichloromethane 40L+ Benzoyl chloride 42g.Dropwise, after the TLC detection reaction is complete, add water 200ml, stirred 15 minutes, left standstill 10 minutes, tell water, organic addition water 200L stirred 15 minutes, left standstill 10 minutes, layering, organic addition anhydrous sodium sulphate 50g stirred 2 hours, filtered, concentrated and do, and got target product 100-105g.
Embodiment 5:(3R, 4S)-5-acetoxy-3-benzoyloxy-2,2-two fluoro-4-hydroxypentanoic acids synthetic
The enriched material that obtains among the embodiment 4 is dissolved in the 600ml acetonitrile, after add 30ml water and trifluoroacetic acid 7g, open steam heating and heat up 50 ℃, insulation reaction 3 hours.Be evaporated to dried, the 300ml recrystallizing methanol.Get target product 65~70g.
Embodiment 6:(3R, 4S)-5-acetoxyl group-4-tolysulfonyl oxygen base-3-benzoyloxy-2,2-difluoro valeric acid synthetic
Embodiment 5 products therefroms are dissolved in chloroform, add triethylamine 20g, control 25 ℃, drip Tosyl chloride 45g, dropwise, be incubated 1 hour.Add hydrochloric acid (concentration is 10%) 200ml, slowly filter, leave standstill, tell organic phase, organic phase washes with water to neutrality, and anhydrous sodium sulphate 30g drying is filtered, and filtrate decompression is concentrated into dried, gets target product 70g.
Embodiment 7:(4R, 5R)-5-acetyl-o-methyl-4-benzoyloxy-3-two fluoro-1-oxo-2-cyclopentanone synthetic
The product that embodiment 6 is obtained is dissolved in the 600ml ethyl acetate, adds salt of wormwood 20g (200ml water), Tetrabutyl amonium bromide 3g, 35~40 ℃ of stirring reactions 5 hours.Filter, filtrate decompression is concentrated into dried.After adding toluene 200ml stirring and dissolving, add normal hexane 200ml, cool to 0-5 ℃, add the small amount of seeds crystallization more than 5 hours.Filter, the washing of 50ml normal hexane, vacuum-drying gets target product 50-53g.
Embodiment 8:(2R, 3R)-2-acetyl-o-methyl-3-benzoyloxy-4,4-two fluoro-5-hydroxyl tetrahydrofurans synthetic
The product that embodiment 7 is obtained is dissolved in the 160ml tetrahydrofuran (THF), cools to-5 ℃, drips lithium triethylborohydride (1mol/L) 80ml, drips off in 3 hours, and back insulation 2 hours adds methyl alcohol 10ml cancellation reaction, adds ethyl acetate 250ml, drips 1N hydrochloric acid adjust pH 5-6.Filter, leave standstill, divide the phase of anhydrating, use 200ml ethyl acetate extraction water more once, methacrylate layer washs once with saturated aqueous common salt 50ml after with 5% sodium hydrogen carbonate solution 50ml washed twice.Anhydrous sodium sulfate drying, filtration open that the concentrating under reduced pressure evaporate to dryness gets enriched material 45-48g below 60 ℃.Add toluene 50ml and normal hexane 100ml and be heated to 55 ℃ of dissolvings, slowly be cooled to 0 ℃, left standstill 5 hours, filter, vacuum-drying gets target product 35~40g.
Embodiment 9:(2R, 3R)-2-acetyl-o-methyl-3-benzoyloxy-4,4-two fluoro-5-tolysulfonyl oxygen base tetrahydrofuran (THF)s synthetic
The product of embodiment 8 gained is dissolved in the 320ml methylene dichloride, adds triethylamine 18g, stirred 15 minutes, be chilled to 0 ℃, keep 0~5 ℃ of dropping to contain the 40ml dichloromethane solution of Tosyl chloride 13g, dropwise, be incubated 1 hour.Be warming up to 20-25 ℃, behind the hydrochloric acid soln adjust pH 6.5 of dropping 1N, leave standstill, divide the phase of anhydrating, organic layer with 5% sodium hydrogen carbonate solution washing once, after use the salt water washing more once, divide anhydrate mutually after, anhydrous sodium sulfate drying, be evaporated to dried, target product 35-40g.
Embodiment 10:(2R, 3R, 5R)-2-acetyl-o-methyl-3-benzoyloxy-5-(4 '-aminopyrimidine base-2 '-ketone)-4,4-difluoro tetrahydrofuran (THF) synthetic
Cytosine(Cyt) 180g is suspended in hexamethyldisilazane 100ml, is warmed up to 120 ℃, reflux 1 hour molten clear after, insulation refluxed 2 hours again.Concentrating under reduced pressure is dried, adds the 240ml ethyl acetate, stirs evaporate to dryness, adds methyl-phenoxide 80ml and is warming up to the solution clarification, with behind 80ml methyl-phenoxide dissolving embodiment 9 products therefroms, opens 120 ℃ of insulations of steam heating intensification 5 hours again.Be cooled to 25 ℃, add the 500ml ethyl acetate, stir, Dropwise 5 60ml 4N hydrochloric acid dropwises, and is warming up to 78 ℃ of insulations 2 hours that reflux.
Filtered while hot, filter cake stirred 30 minutes in 50-60 ℃ of 100ml hot water with 50 ℃ of hot washes again, filtered, and filter cake is used 5% sodium hydrogen carbonate solution adjust pH 7.0 again with 50-60 ℃ of making beating of 100ml water, and filtering drying promptly gets target product 13~15g.
Embodiment 11: and hydrochloric acid (2R, 3R, 5R)-and 2-methylol-3-hydroxyl-5-(4 '-aminopyrimidine base-2 '-ketone)-4,4-difluoro tetrahydrofuran (THF)
Synthesizing of (2 '-deoxidation-2 ', 2 '-two fluorouracil nucleoside hydrochlorides)---gemcitabine hydrochloride
The product that obtains among the embodiment 10 is dissolved in 130ml methyl alcohol, adds the TERTIARY BUTYL AMINE of 2.5ml, 40 ℃ are incubated 5 hours.Obtain containing the methanol solution of intermediate (XI).Drip concentrated hydrochloric acid 8ml, concentrating under reduced pressure is closely dried, add pure water 15ml heating for dissolving become clear after, drip acetone 200ml, stirred crystallization, 0-5 ℃ of insulation 2 hours filtered, the 10L washing with acetone promptly gets crude product 7-7.5g.
Add 40ml water in the crude product, be heated with stirring to 55 ℃ of dissolvings, add gac 0.5g decolouring, filtered while hot, concentrating under reduced pressure slowly drips acetone 150ml to about the 20ml, finishes, and is cooled to 0-5 ℃ of insulation 2 hours.Filter, get white, needle-shaped crystals 5.5-6g, below 50 ℃, vacuum-drying 5 hours gets gemcitabine hydrochloride finished product 5-5.5g.