阅读说明：本技术 一种分离卡前列素异构体的方法 (Method for separating carboprost isomer ) 是由 曾维威 鄢舒意 童勇 于 2019-10-31 设计创作，主要内容包括：本发明属于已知化合物异构体分离技术领域,具体公开了一种分离卡前列素异构体的方法。本发明在卡前列素中间体化合物C经格氏反应、内酯还原后,将化合物E中的手性羟基使用拆分试剂右旋樟脑-10-磺酰氯拆分,提前分离异构体,然后经过水解、维蒂希反应得到卡前列素单一构型。本发明分离卡前列素异构体方法操作条件温和,克服了现有技术中需特定硅胶柱层析带来的操作麻烦,周期长,产量低,且分离监控困难的问题。(The invention belongs to the technical field of separation of isomers of known compounds, and particularly discloses a method for separating carboprost isomers. After the carboprost intermediate compound C is subjected to Grignard reaction and lactone reduction, chiral hydroxyl in the compound E is resolved by using a resolving reagent, namely D-camphor-10-sulfonyl chloride, isomers are separated in advance, and then the carboprost single configuration is obtained through hydrolysis and wittig reaction. The method for separating the carboprost isomer has mild operation conditions, and solves the problems of troublesome operation, long period, low yield and difficult separation and monitoring caused by the need of specific silica gel column chromatography in the prior art.)

1. A method for purifying (15S) -carboprost, which comprises the following steps:

(1) reacting compound 1 with a resolving agent to give compound 2:

the compound 1 is an epimer;

the resolving agent is D-camphor-10-sulfonyl chloride;

the molar ratio of the compound 1 to the resolving agent is 1 (1.95-2.15);

(2) hydrolysis of compound 2 under basic conditions gives compound 3:

the alkali is potassium carbonate; the reaction solvent is methanol;

the molar ratio of the compound 2 to the potassium carbonate is 1 (1.0-1.2);

(3) compound 3 is reacted by wittig to give compound 4:

the compound 4 is (15S) -carboprost;

the organophosphorus reagent is 4-carboxybutyl triphenyl phosphonium bromide;

the base is potassium tert-butoxide;

the molar ratio of the compound 3 to the organic phosphine reagent is 1 (1.6-1.8).

2. The method of purifying carboprost according to claim 1,

the specific steps of the step (1) are as follows:

adding the compound 1, dichloromethane and triethylamine into a reaction container, stirring for 0-1 hour, cooling the reaction liquid to-20-20 ℃, then adding a resolution reagent, heating to 20-60 ℃, stirring for reaction for 2-6 hours until the reaction is complete, adding water and separating liquid after the reaction liquid reaches room temperature, washing an organic phase for 2-5 times by using a saturated sodium chloride aqueous solution, then carrying out reduced pressure concentration to obtain a concentrate, and carrying out chromatographic separation on the concentrate layer by using a column chromatography machine to obtain the compound 2.

3. The method of purifying carboprost according to claim 1,

the specific steps of the step (2) are as follows:

adding the compound 2 obtained in the step (1), methanol and potassium carbonate into a reaction container, stirring and reacting at 20-50 ℃ for 2-4h until the compound 2 completely reacts, performing suction filtration, concentrating the filtrate, adding dichloromethane, filtering off insoluble substances, concentrating the mother liquor, and performing chromatographic separation by using a column chromatography column layer to obtain a compound 3.

4. The method of purifying carboprost according to claim 1,

the specific steps of the step (3) are as follows:

adding an organophosphorus reagent into a reaction container under an inert atmosphere, adding tetrahydrofuran, cooling to-20-20 ℃, adding potassium tert-butoxide, controlling the temperature to-20-20 ℃, adding a compound 3, keeping the temperature for reaction for 6-18 hours until the compound 3 completely reacts, adding ethyl acetate, extracting with purified water, leaving a water phase, adjusting the pH of the solution to 4-5 by using a sodium bisulfate solution, extracting by using ethyl acetate, leaving an organic phase, drying by using anhydrous sodium sulfate, distilling under reduced pressure, adding methyl tert-butyl ether and activated carbon into distillation residues, refluxing and stirring for 2 hours, cooling to room temperature, filtering, distilling the filtrate under reduced pressure to obtain a light yellow liquid, namely a compound 4.

Technical Field

The invention relates to the technical field of isomer separation of known compounds, in particular to a method for separating carboprost isomers.

Background

Prostaglandins (abbreviated as PG) are biologically active substances having a wide range of physiological actions, and have actions on endocrine, reproduction, digestion, blood respiration, cardiovascular, urinary and nervous systems, Prostaglandins (PG) are produced by the oxidative metabolism of arachidonic acid in vivo and have a structure of a 20-carbon unsaturated fatty acid consisting of a pentacyclic ring and two side chains, Prostaglandins are few in natural sources, difficult to extract, rapid in vivo metabolism and poor in stability, and scientists have synthesized a series of prostaglandin substances or analogues in a complete manner in succession to meet clinical requirements, wherein carboprost tromethamine is a tromethamine salt solution containing a (15S) -15 methyl derivative of natural prostaglandin F2 α and is suitable for intramuscular injection.

Carboprost is a key intermediate of carboprost tromethamine, wherein the ratio of carboprost to tromethamine is 1: 1.

the carboprost tromethamine is suitable for abortion of 13 weeks to 20 weeks in gestation period, has strong contraction effect on uterine smooth muscle in gestation period, and can obviously increase the biological activity level of cells, and the action mechanism is to increase the tension of the uterine smooth muscle through mechanisms of increasing the concentration of calcium ions in cells, inhibiting adenylate cyclase, directly stimulating gap link formation and the like, so as to further initiate the contraction of myofibrils, enhance uterine contraction and achieve the purpose of stopping bleeding.

The synthesis strategy of carboprost adopts a key intermediate of the colelactone A, and two side chains are respectively connected to the α position and the omega position, as shown in the above, which is also the main method for the industrial production of carboprost tromethamine at present in 1974, Upjohn company (J.Am.chem.Soc.,1974,96,5865) synthesizes (15S) -15 methyl derivatives of prostaglandin F2 α for the first time, and patent WO2008081191 reports a similar synthesis method that in the separation of isomers of carboprost methyl ester H, the isomers are separated by column chromatography, the operation of the column chromatography process is complicated, the productivity is low, and the production cost is high.

In WO2017093770A1, Chromatorex MB type silica gel with the particle size of 40-70um is used for successfully separating carboprost methyl ester H by column chromatography, the yield reaches 57 percent, and the impurities do not exceed 0.5 percent, but the chiral filler of the method is expensive, and highly toxic methyl sulfate or methyl iodide is used for methyl esterification, so that the method is not suitable for industrial production. Patent CN1136938C discloses the separation of carboprost methyl ester H by using a simulated moving bed chromatography (SMBC for short), but the method has high investment on equipment, is not suitable for industrial production, and has separation purity only up to 90%.

At present, high-purity carboprost is generally obtained by column chromatography separation of carboprost methyl ester, but carboprost methyl ester has no ultraviolet absorption at 200nm-280nm, a conventional ultraviolet lamp cannot see a product point, a rapid liquid chromatograph cannot be used for automatic separation, and column chromatography separation isomers have long impurity period, low yield and large solvent consumption, so that the application prospect is limited.

Disclosure of Invention

The applicant has found that the main process for the industrial production of carboprost tromethamine is improved by the existing method for preparing carboprost intermediate compound C (R)₁P-phenylphenyl formyl) is subjected to Grignard reaction and lactone reduction, and then the compound E (R) is obtained₁P-phenylphenyl benzoyl) is resolved by a resolving agent, isomers are separated in advance, and then the carboprost single configuration is obtained through hydrolysis and wittig reaction.

Carboprostic acid has the following structural formula:

the resolving agent is D-camphor-10-sulfonyl chloride.

After the compound E is formed into ester by using a resolving reagent, the obtained ester is (3aR,4R,5R,6aS) -4- ((S, E) -3- (((((((((1S, 4R) -7, 7-dimethyl-2-oxobicyclo [2.2.1] heptyl-1-yl) methyl) sulfonyl) oxy) -3-methyloct-1-en-1-yl) -2-hydroxyhexahydro-2H-cyclopenta [ b ] furan-5- [1,1' -biphenyl ] -4-carboxylic acid ester, the structural formula of which is shown in the specification, the ester has strong ultraviolet absorption, and is favorable for column chromatography separation and separation of carboprost isomers.

The method has mild conditions, and solves the problems of troublesome operation, long period, low yield and difficult monitoring caused by the need of specific silica gel column chromatography in the prior art.

The purification method of carboprost of the invention has the following reaction path:

said compound 1 is equivalent to said compound E.

The compound 1 is an epimer.

The specific purification method is as follows:

(1) reacting compound 1 with a resolving agent to give compound 2:

adding a compound 1 synthesized according to the description of the 0166-th section 0178 of the patent CN108602769A into a reaction vessel, sequentially adding dichloromethane and triethylamine, stirring for 0-1 hour, cooling a reaction solution to-20-20 ℃, then adding a resolution reagent, heating to 20-60 ℃, stirring and reacting for 2-6 hours until the reaction is complete (the compound 1 disappears by TLC detection), adding water and separating after the reaction solution reaches the room temperature, washing an organic phase for 2-5 times by using a saturated sodium chloride aqueous solution, concentrating the organic phase under reduced pressure to obtain a concentrate, and separating by using a column chromatography through a column chromatography to obtain a compound 2; the molar ratio of the compound 1 to the resolving agent is 1 (1.95-2.15).

(2) Hydrolysis of compound 2 under basic conditions gives compound 3:

adding the compound 2 obtained in the step (1), methanol and potassium carbonate into a reaction vessel, stirring and reacting at 20-50 ℃ for 2-4h until the compound 2 completely reacts (the compound 2 disappears detected by TLC), performing suction filtration, concentrating the filtrate, adding dichloromethane, filtering out insoluble substances, concentrating the mother liquor, and performing chromatographic separation by using a column chromatography to obtain a compound 3; the molar ratio of the compound 2 to the potassium carbonate is 1 (1.0-1.2).

(3) Compound 3 is reacted by wittig to give compound 4:

adding an organophosphorus reagent (4-carboxybutyltriphenyl phosphine bromide) into a reaction vessel under an inert atmosphere, adding tetrahydrofuran, cooling to-20-20 ℃, adding potassium tert-butoxide, controlling the temperature to-20-20 ℃, adding a compound 3, preserving the temperature, reacting for 6-18 hours until the compound 3 completely reacts (detecting the compound 3 by TLC to disappear), adding ethyl acetate, extracting by using purified water, retaining a water phase, adjusting the pH of the solution to be acidic by using a sodium bisulfate solution, extracting by using ethyl acetate, retaining an organic phase, drying by using anhydrous sodium sulfate, distilling under reduced pressure, adding methyl tert-butyl ether and activated carbon into a distillation residue, refluxing and stirring for 2 hours, cooling to room temperature, filtering, distilling the filtrate under reduced pressure to obtain a light yellow liquid, namely the compound 4[ (15S) -carboprost. The molar ratio of the compound 3 to the organic phosphine reagent is 1 (1.6-1.8).

Compared with the prior art, the method has the advantages and beneficial effects that:

1. the isomers are separated in advance, so that the problems of troublesome later operation, long period, low yield and difficult separation and monitoring are solved.

2. The resolving agent used in the experiment is simple and easy to obtain, and the operation is simple.

Drawings

Figure 1 is an HPLC diagram of compound 1 prepared in example 1.

Figure 2 is an HPLC profile of compound 4 prepared in example 1.

FIG. 3 shows Compound C (R) as a starting material for preparation of Compound 1 in example 1₁P-phenylbenzoyl) in the HPLC.

The specific implementation mode is as follows:

the applicants will now further describe the synthesis of the present invention in detail with reference to specific examples, but it should be understood that the following examples are only illustrative and not intended to limit the scope of the invention as claimed in the claims.