beraprost prodrug

Abstract

This invention discloses a prodrug of beraprost, as shown in Formula I below. This invention provides a class of prodrugs of beraprost, which solves the defects of beraprost sodium such as short elimination half-life and multiple dosing times, reduces the dosage and frequency of administration, and improves the efficacy and safety of the drug.

Description

Technical Field

[0001] This invention belongs to the field of biomedicine, specifically relating to beraprost prodrugs, their pharmaceutical compositions and uses. Background Technology

[0002] Pulmonary hypertension (including pulmonary arterial hypertension, PAH) is a group of diseases characterized by increased pulmonary vascular resistance and right ventricular failure. Patients diagnosed with PAH have a short survival rate and high mortality rate, making it a malignant disease. Prostaglandins in the body activate adenylate cyclase by interacting with prostaglandin receptors on platelets or vascular smooth muscle, thereby increasing intracellular cAMP concentration and dilating blood vessels. Exogenous prostaglandin derivatives can specifically bind to prostaglandin receptors, relaxing vascular smooth muscle, reducing pulmonary artery pressure, and inhibiting pulmonary vascular remodeling and in situ thrombosis; they can be used to treat peripheral vascular disease and pulmonary hypertension.

[0003] Beraprost is a PGI2 prostaglandin analogue, a racemic mixture used medicinally as a sodium salt. It consists of four stereoisomers in equal amounts. In vitro studies on human platelets have confirmed that the optical isomer esuberaprost (beraprost-314d) is the most pharmacologically active isomer. The relative binding affinity of the four isomers varies by about 100 times (Kajikawa N et al., Arzneimittelforschung 1989). In 1992, Toray Industries of Japan applied for approval to market the drug in Japan (trade name: Dorner, "プロサィリン"). The company also applied for patent protection in October 1992 for its use in treating metastatic cancer (US5496850A), and in February 1996 for its use in treating pulmonary heart disease (US6046233A). Subsequently, it was jointly developed by Toray Industries, Kaken, and Yamanouchi, and in 1994, it was approved by Yamanouchi of South Korea. In South Korea, beraprost sodium tablets were approved for the treatment of peripheral vascular disease. Subsequently, a Japanese-developed version was approved for the treatment of pulmonary hypertension (brand name: Procylin). In China, in 2003, beraprost sodium tablets from Yamanouchi Pharmaceutical Co., Ltd. of Japan were approved for import registration (brand name: Dena). In 2008, domestically produced beraprost sodium tablets from Beijing Taide Pharmaceutical Co., Ltd. were approved for marketing as a generic drug (brand name: Kaina, 20 micrograms / tablet), achieving good results in the clinical treatment of pulmonary hypertension in China.

[0004] Betaprostol was the first prostaglandin drug marketed for pulmonary hypertension (Melian EB and Goa KL, Drugs, 2002), followed by other prostaglandin drugs such as enoprostol, treprostinil, etc. Due to their unique mechanism of action, prostaglandin drugs have always been the first-line clinical drugs for the treatment of pulmonary hypertension (Zhai Zhenguo et al., Chinese Guidelines for the Diagnosis and Treatment of Pulmonary Hypertension (2021 Edition), Chinese Medical Journal, 2021; Klinger JR et al., American Guidelines for the Treatment of Pulmonary Hypertension 2019, CHEST, 2019; Fukuda K et al., Japanese Guidelines for the Treatment of Pulmonary Hypertension (JCS 2017 / JPCPHS 2017), Circ.J, 2019).

[0005] Currently, only beraprost and treprostol are available for oral administration of prostaglandin drugs. Treprostol is approved for marketing in lyophilized form for injection, injection solution, inhalation solution, and extended-release tablets, but it is mainly administered via injection in clinical practice. The only commonly used oral formulation is beraprost tablets. Beraprost is rapidly absorbed on an empty stomach, but due to its short elimination half-life, it requires frequent dosing, which can lead to unstable blood drug concentrations and affect patient adherence (requiring up to 3-4 doses per day). This is the main reason why the drug has not yet been approved for marketing in Europe and the United States. To address this deficiency, Japan has approved a long-acting oral beraprost sodium extended-release tablet (TR-100STP, brand name Careload, 60 mcg / tablet) for once-daily dosing, significantly improving patient adherence.

[0006] Betaprostol is also being used to treat metastatic malignant tumors (developed by United Therap, USA), atherosclerosis (developed by Kaken Pharma, Japan), hypertension (developed by Kaken Pharma and United Therap, respectively), diabetic neuropathy (developed by Kaken Pharma, Japan), as well as nephritis, vascular dementia (CN 112691109A), alcoholic fatty liver (HK1219665A), and other diseases. These research efforts are currently underway.

[0007] Due to the high selectivity of betaprostadine for the IP receptor, it has a significant therapeutic advantage over other prostacyclins. Scientists from various countries have been exploring different ways to improve this drug. For example, the betaprostadine sodium extended-release tablet Careload was successfully launched in Japan. United Therapeutics in the United States was licensed to develop the betaprostadine optical device Esuberaprost for the treatment of pulmonary hypertension. However, the Phase III clinical trial, which used a superiority trial design based on treprostine, failed to meet the primary endpoint, leading to the termination of the project in April 2019.

[0008] Exploring suitable prodrug pathways to further improve the in vivo metabolism of beprostol, and achieving long-lasting effects through prodrug administration while reducing dosage and frequency, is a better way to address the current clinical deficiencies of beprostol.

[0009] This invention relates to a series of beraprost prodrugs that can be slowly broken down into beraprost in the body to achieve a long-lasting effect. The active substance also specifically binds to receptors to relax vascular smooth muscle and exert pharmacological effects. Summary of the Invention

[0010] Objective of the invention: To address the shortcomings of beraprost sodium, such as its short elimination half-life and the need for frequent clinical dosing, this invention provides an acetal prodrug of beraprost. This type of beraprost prodrug compound can be slowly degraded in vivo to beraprost sodium, achieving a long-lasting effect, and can be used to treat various diseases such as pulmonary hypertension.

[0011] Technical solution: To achieve the above objectives, a prodrug of beraprost, as described in this invention, is provided as follows:

[0012]

[0013] R1 is hydrogen or C. 1-4 alkyl;

[0014] R2 is C 1-6 Alkyl, C 3-7 cycloalkyl, C 1-6 Amine, hydroxyl or C 1-6 Alkoxy;

[0015] n is 0, 1, 2, 3 or 4;

[0016] m is 1 or 2;

[0017] X is carbon or phosphorus;

[0018] Preferably, compound R1 is hydrogen, methyl, or isopropyl; R2 is selected from methyl, ethyl, n-propyl, isopropyl, tert-butyl, cyclopropyl, cyclohexyl, hydroxy, methoxy, ethoxy, propoxy, methylamino, ethylamino, butylamino, or 2-methylpropyl-1-amine; and n is 0, 1, 2, or 3.

[0019] Furthermore, the compound comprises any of the following structures:

[0020]

[0021]

[0022] The beraprost prodrug of the present invention includes its use as a procyclosporine analogue.

[0023] Its application in the preparation of drugs for treating various diseases, including pulmonary hypertension, chronic vascular occlusive disease, myocardial infarction, kidney disease, peripheral vascular diseases such as occlusive arteriosclerosis, ophthalmic diseases (such as diabetic retinopathy, glaucoma, etc.), osteoporosis, thromboangiitis obliterans, and thromboembolic diseases.

[0024] Another technical solution of this application provides a pharmaceutical composition comprising a prodrug of beraprost and a pharmaceutically acceptable carrier.

[0025] The carrier is any one or a mixture of two or more of the following: sustained-release agent, excipient, filler, binder, wetting agent, disintegrant, absorption promoter, adsorbent carrier, surfactant, and lubricant.

[0026] The pharmaceutical composition is any one of an inhaled formulation, a topical formulation, an oral formulation, and an injectable formulation.

[0027] The oral preparation is any one of granules, capsules, and tablets.

[0028] Beneficial effects: Compared with the prior art, the present invention has the following advantages: The present invention provides a prodrug of beraprost, which solves the defects of beraprost sodium such as short elimination half-life and multiple dosing times, reduces the dosage and frequency of administration, and improves the efficacy and safety of the drug. Attached Figure Description

[0029] Figure 1 The value represents the mean pulmonary artery pressure (mPAP) of rats in the intervention group, control group, and model group of compound 5 described in this invention. Detailed Implementation

[0030] The present invention will be further described below with reference to the embodiments.

[0031] Example 1

[0032]

[0033] Synthesis route:

[0034]

[0035] Synthesis of Compound 1

[0036] Beraprost (20 mg), potassium iodide (25 mg), and potassium carbonate (21 mg) were dissolved in 10 mL of acetonitrile. After stirring at room temperature for 10 min, methyl chloroacetate (15 mg) was slowly added, and the mixture was reacted at 80 °C for 8 h. The reaction was then stopped, the solvent was evaporated, dichloromethane was added, and the mixture was washed twice with water and once with saturated brine. The organic phase was concentrated, and after column chromatography, it was concentrated, dissolved in THF / water, and 2N HCl was added. The mixture was stirred at room temperature, and the reaction was monitored by TLC until complete. The solvent was evaporated, and the mixture was purified by HPLC to obtain Example 1, with a yield of 31%. 1 HNMR(300MHz, Methanol-d4)δ7.00(dd,J=7.9,1.4Hz,2H),6.74(t,J=5.8Hz,1H),6.21(s,2H),5.60–5.41(m,2H),5.17–5.14(m,1H),4.10–4.03(m,3 H),3.47(t,J=5.2Hz,1H),2.69–2.50(m,4H),2.24–2.21(m,7H),2.18(s,3 H),2.10–1.97(m,3H),1.83(d,J=7.1Hz,4H),0.98(d,J=5.7Hz,3H).ESI-MS m / z:493.2[M+Na] + .

[0037] Example 2

[0038]

[0039] Compound 2 can be prepared by replacing methyl chloroacetate with methyl chloropropionate using the synthesis method described in Example 1. 1HNMR(300MHz,Methanol-d4)δ6.98(d,J=7.2Hz,2H),6.73(t,J=5.8Hz,1H),6. 20(s,2H),5.66–5.45(m,2H),5.20–5.15(m,1H),4.12–4.06(m,3H),3.44(t,J= 5.2Hz,1H),2.71–2.55(m,4H),2.34–2.24(m,9H),2.18(s,3H),2.11–2.02(m,3 H),1.87(d,J=6.8Hz,4H),1.23(t,J=5.3Hz,3H),0.98(d,J=5.7Hz,3H).ESI-MS m / z:485.3[M+H] + .

[0040] Example 3

[0041]

[0042] Compound 3 can be prepared by replacing methyl chloroacetate with ethyl 1-chloroacetate using the synthesis method described in Example 1. 1 HNMR(300MHz, Methanol-d4)δ7.44–7.40(m,1H),6.99(d,J=7.2Hz,2H),6.79(t,J=5.6Hz,1H),5.69–5.46(m,2H),5.24–5.18(m,1H),4.20–4.11(m, 3H),3.45(t,J=5.2Hz,1H),2.70–2.59(m,4H),2.34–2.24(m,7H),2.18(s ,3H),2.15–2.04(m,3H),1.87–1.76(m,7H),0.98(d,J=5.7Hz,3H).ESI-MS m / z:507.2[M+Na] + .

[0043] Example 4

[0044]

[0045] Compound 4 can be prepared by replacing methyl chloroacetate with ethyl 1-chloropropionate using the synthesis method described in Example 1. 1HNMR(300MHz,Methanol-d4)δ7.47–7.42(m,1H),7.01(d,J=7.4Hz,2H),6.82(t ,J=5.8Hz,1H),5.72–5.49(m,2H),5.28–5.21(m,1H),4.21–4.12(m,3H),3.43( t,J=5.2Hz,1H),2.72–2.61(m,4H),2.35–2.26(m,9H),2.18(s,3H),2.18–2.06 (m,3H),1.83–1.74(m,7H),1.23(t,J=5.3Hz,3H),0.99(d,J=5.5Hz,3H).ESI-MS m / z: 521.3 [M+Na] + ..

[0046] Example 5

[0047]

[0048] Compound 5 can be prepared by replacing methyl chloroacetate with chloromethyl isobutyrate using the synthesis method described in Example 1. 1 HNMR(300MHz,Methanol-d4)δ7.04(d,J=7.7Hz,2H),6.78(t,J=5.8Hz,1H),6. 26(s,2H),5.65–5.42(m,2H),5.22–5.18(m,1H),4.15–4.08(m,3H),3.49(t,J= 5.2Hz,1H),2.77–2.59(m,2H),2.26–2.24(m,7H),2.17(s,3H),2.18–1.99(m,3 H),1.84(d,J=7.1Hz,4H),1.12(d,J=6.5Hz,6H),0.96(d,J=5.8Hz,3H).ESI-MS m / z:521.3[M+Na] + .

[0049] Example 6

[0050]

[0051] Compound 6 can be prepared by replacing methyl chloroacetate with methyl neopentanoate using the synthesis method described in Example 1. 1HNMR (300MHz, Methanol-d4) δ7.03 (dd, J=7.8, 1.4Hz, 2H), 6.73 (t, J=5.8Hz, 1 H),6.20(s,2H),5.58–5.40(m,2H),5.15–5.12(m,1H),4.07–4.00(m,3H),3.4 4(t,J=5.2Hz,1H),2.64–2.47(m,4H),2.26–2.21(m,5H),2.18(s,3H),2.11–2 .00(m,3H),1.83(d,J=7.1Hz,4H),1.27(s,9H),0.97(d,J=5.6Hz,3H).ESI-MS m / z:513.3[M+H]+.

[0052] Example 7

[0053]

[0054] Compound 7 can be prepared by replacing methyl chloroacetate with methyl chlorobutyrate using the synthesis method described in Example 1. 1 HNMR(300MHz, Methanol-d4)δ7.05(dd,J=7.8,1.4Hz,2H),6.73(t,J=5.8Hz,1H),6.25(s,2H),5.63–5.45(m,2H),5.21–5.18(m,1H),4.15–4.08(m,3H ),3.48(t,J=5.2Hz,1H),2.66–2.52(m,4H),2.26–2.24(m,7H),2.18(s,3H) ,2.12–1.97(m,3H),1.83–1.81(m,6H),0.98(dd,J=5.7,1.6Hz,6H).ESI-MS m / z:499.3[M+H] + .

[0055] Example 8

[0056]

[0057] Compound 8 can be prepared by replacing methyl chloroacetate with ethyl 1-chlorobutyrate using the synthesis method described in Example 1. 1HNMR(300MHz, Methanol-d4)δ7.05(d,J=7.0Hz,2H),6.79(t,J=5.7Hz,1H),6.00–5.55(m,3H),5.24–5.19(m,1H),4.20–4.11(m,3 H),3.44–3.39(m,1H),2.69–2.55(m,4H),2.29–2.25(m,7H),2.17–1.97(m,6H),1.89–1.75(m,9H),0.99(d,J=5.7Hz,6H).ESI-MS m / z:513.3[M+H] + .

[0058] Example 9

[0059]

[0060] Compound 9 can be prepared by replacing methyl chloroacetate with 1-chloroethyl isobutyrate using the synthesis method described in Example 1. 1 HNMR(300MHz,Methanol-d4)δ7.36–7.24(m,2H),7.07(q,J=5.8Hz,1H),6.26(s ,2H),4.57(dd,J=5.0,1.0Hz,1H),4.15–4.08(m,2H),3.49(d,J=0.9Hz,1H),2. 93–2.77(m,2H),2.66–2.52(m,5H),2.34–2.24(m,2H),2.07(s,3H),1.89(s,3H ),1.84(d,J=7.1Hz,1H),1.12(d,J=12.5Hz,6H),0.96(d,J=8.8Hz,3H).ESI-MS m / z:535.3[M+Na] + .

[0061] Example 10

[0062]

[0063] Compound 10 can be prepared by replacing methyl chloroacetate with 1-chloroethyl neopentanoate using the synthesis method described in Example 1. 1 H NMR(300MHz, Methanol-d4)δ7.04(d,J=7.7Hz,2H),7.00(dt,J=5.8,3.0Hz,1H),5.89–

[0064] 5.48(m,3H),5.20–5.12(m,1H),4.22–4.17(m,2H),3.49(t,J=5.2Hz,1H),2.91–2.72(m,2H),2.66(dq,J=12.5,2.0Hz ,1H),2.52–2.38(m,2H),2.38–2.18(m,3H),1.94–1.80(m,6H),1.13(d,J=12.8Hz,9H),1.01(d,J=8.8Hz,3H).ESI-MS m / z:549.3[M+Na] + .

[0065] Example 11

[0066]

[0067] Compound 11 can be prepared by replacing methyl chloroacetate with 1-chloroethylcyclohexane carboxylate using the synthesis method described in Example 1. 1 H NMR(300MHz, Methanol-d4)δ7.49–7.20(m,2H),7.07(ddt,J=7.5,2.0,1.1Hz,1H),5.84(d,J=46.5Hz,2H) ,5.53(s,1H),4.57(dd,J=5.0,1.0Hz,1H),4.19(d,J=4.9Hz,1H),3.58(d,J=1.1Hz,1H),2.92–2.74(m,2H ),2.66(dq,J=12.4,2.0Hz,1H),2.46(dq,J=12.5,2.0Hz,1H),2.39–2.22(m,4H),2.16(d,J=13.0Hz,1H), 1.96–1.79(m,7H),1.75–1.65(m,5H),1.63–1.48(m,4H),1.12–1.08(m,2H),0.96(d,J=5.8Hz,3H).ESI-MS m / z:553.3[M+Na] + .

[0068] Example 12

[0069]

[0070] Compound 12 can be prepared by replacing methyl chloroacetate with 1-chloro-2-methylpropyl isobutyrate using the synthesis method described in Example 1. 1H NMR (300MHz, Methanol-d4) δ7.40–7.20 (m, 2H), 7.00 (d, J = 7.3Hz, 1H), 5.88 (s, 1H), 5.8 0(d,J=27.1Hz,2H),4.57(dd,J=5.0,1.0Hz,1H),4.19(d,J=4.9Hz,1H),3.58(d,J=1.0Hz ,1H),2.93–2.74(m,2H),2.66(dq,J=12.5,2.0Hz,1H),2.53–2.40(m,2H),2.37–2.21(m ,4H),2.01(s,1H),1.92–1.70(m,5H),1.24(d,J=24.9Hz,6H),1.12–0.94(m,9H).ESI-MS m / z:541.3[M+H] + .

[0071] Example 13

[0072]

[0073] Synthesis route

[0074]

[0075] Synthesis of Compound 13

[0076] Methylamine (2 mmol) was dissolved in dichloromethane. At 0°C, N,N,N',N'-tetramethyl-1,8-naphthyldiamine (2.2 mmol) was added and stirred for 2 min. Then, methyl chloroformate (2.2 mmol) was added dropwise, and the reaction was allowed to proceed overnight at room temperature. The reaction was confirmed to be complete by TLC. The solution was washed twice with water and once with saturated brine, dried over anhydrous sodium sulfate, and the solvent was evaporated to dryness. The prepared compound (0.2 mmol), beraprost sodium (0.1 mmol), and DIPEA (0.2 mmol) were dissolved in dichloromethane and stirred at room temperature for two hours. The reaction was confirmed to be complete by TLC. The solution was washed twice with water and once with saturated brine, dried over anhydrous sodium sulfate, concentrated by column chromatography, dissolved in THF / water, and then 2N HCl was added. The reaction was stirred at room temperature, confirmed to be complete by TLC, dried over anhydrous sodium sulfate, and purified by HPLC to obtain compound 13 in 45% yield. 1HNMR(300MHz, Methanol-d4)δ7.32–7.24(m,2H),7.07(dt,J=5.8,3.7Hz,1H),5.84(d,J=13.9Hz,2H),5.38–5.13(m,2H),4.19(d,J=4.9Hz,1H), 3.44(s,1H),2.90–2.76(m,2H),2.72–2.56(m,4H),2.51–2.38(m,4H),2 .28(d,J=13.0Hz,1H),1.93–1.82(m,6H),0.96(d,J=7.8Hz,3H).ESI-MS m / z:486.3[M+H] + .

[0077] Example 14

[0078]

[0079] Compound 14 can be prepared by referring to the synthesis method of Example 13. 1 H NMR(300MHz, Methanol-d4)δ7.35–7.24(m,2H),7.03(dt,J=5.8,3.7Hz,1H),5.85(d,J=29 .5Hz,2H),5.39–5.08(m,2H),4.57(dd,J=5.0,1.0Hz,1H),4.19(d,J=4.9Hz,1H),3.44(d,J =0.9Hz,1H),3.32–3.06(m,2H),2.85(qd,J=12.4,0.9Hz,2H),2.61(dq,J=12.4,2.0Hz,1H ),2.54–2.36(m,4H),2.28(d,J=13.0Hz,1H),2.07–1.81(m,6H),1.08–1.00(m,6H).ESI-MS m / z:500.3[M+H] + .

[0080] Example 15

[0081]

[0082] Compound 15 can be prepared by referring to the synthesis method of Example 13. 1H NMR(300MHz, Methanol-d4)δ7.35–7.20(m,2H),6.99(dt,J=6.0,3.6Hz,1H),5.85(d,J=29.5Hz,2H),5 .42–5.09(m,3H),4.57(dd,J=5.0,1.0Hz,1H),4.11(dd,J=4.9,3.0Hz,1H),3.51–3.23(m,3H),2.85(qd ,J=12.4,0.9Hz,2H),2.70(dq,J=12.5,2.0Hz,1H),2.55(dq,J=12.3,1.9Hz,1H),2.51–2.35(m,3H),2 .28(d,J=13.0Hz,1H),2.06–1.81(m,6H),1.55(q,J=12.3Hz,2H),1.00–0.97(m,J=62.1Hz,6H).ESI-MS m / z:536.3[M+Na] + .

[0083] Example 16

[0084]

[0085] Compound 16 can be prepared by referring to the synthesis method of Example 13. 1 H NMR(300MHz,Methanol-d4)δ7.04(d,J=7.8Hz,2H),6.98(t,J=5.8Hz,1H),5.9 4–5.56(m,3H),5.38–5.10(m,2H),4.69–4.59(m,2H),4.24(d,J=4.9Hz,1H),3 .75–3.21(m,3H),2.95–2.72(m,2H),2.66(dq,J=12.5,2.0Hz,1H),2.57–2.34 (m,4H),2.28(d,J=13.0Hz,1H),2.08–1.81(m,7H),1.11–0.73(m,9H).ESI-MS m / z:528.3[M+H] + .

[0086] Example 17

[0087]

[0088] Synthesis route

[0089]

[0090] Beraprost sodium (0.1 mmol), 1,2-ethylene glycol monoacetate (0.11 mmol), DCC (0.2 mmol), and DMAP (0.02 mmol) were dissolved in dichloromethane and reacted overnight. The reaction was confirmed to be complete by TLC. The solvent was evaporated, concentrated by column chromatography, dissolved in THF / water, and 2N HCl was added. The mixture was stirred at room temperature and the reaction was confirmed to be complete by TLC. The solvent was evaporated, and the mixture was purified by HPLC to give compound 17. 1 H NMR (300MHz, Methanol-d4) δ7.36–7.22(m,2H),7.01(dt,J=5.8,3.1Hz,1H),5.84(d,J=13.9Hz,2H),4.61(d,J=58.5Hz,3H),4.40–4.11(m,5H),3.52 –3.25(m,2H),2.96–2.77(m,2H),2.61(dq,J=12.5,2.0Hz,1H),2.54–2.38 (m,4H),2.28(d,J=13.0Hz,1H),2.16–1.73(m,9H),0.96(d,J=7.8Hz,3H).

[0091] ESI-MS m / z: 485.3 [M+H] + .

[0092] Example 18

[0093]

[0094] Compound 18 can be prepared by referring to the synthesis method of Example 17. 1 H NMR (300MHz, Methanol-d4) δ7.35–7.21(m,2H),7.00(t,J=7.2Hz,1H),5.85(d,J=29.5Hz,2H),4.71–4.49(m,3H),4.30–4.08(m,6H),2.86(q d,J=12.3,0.9Hz,2H),2.61(dq,J=12.4,2.0Hz,1H),2.54–2.39(m,4H),2.36–2.15(m,3H),2.05–1.79(m,9H),0.99(d,J=7.2Hz,3H).ESI-MS m / z:521.3[M+Na] + .

[0095] Example 19

[0096]

[0097] Compound 19 can be prepared by referring to the synthesis method of Example 17.1 H NMR(300MHz, Methanol-d4)δ7.15(d,J=7.8Hz,2H),7.01(dt,J=5.2,3.4Hz,1H),5.85(d,J=29.5Hz,2H),4.65–4.51(m,2H),4.33–3 .95(m,6H),2.86(qd,J=12.3,0.9Hz,2H),2.76–2.50(m,2H),2.48–2.22(m,4H),2.07–1.79(m,13H),1.01(d,J=7.2Hz,3H).ESI-MS m / z:513.3[M+H] + .

[0098] Example 20

[0099]

[0100] Compound 20 can be prepared by referring to the synthesis method of Example 17. 1 H NMR (300MHz, Methanol-d4) δ7.30–7.21(m,2H),7.07(t,J=6.2Hz,1H),5.85(d,J=29.5Hz,2H),4.64–4.52(m,2H),4.35–4.10( m,6H),2.89(dd,J=12.4,1.0Hz,1H),2.87–2.54(m,2H),2.53–2.18(m,7H),2.08–1.80(m,6H),1.09(d,J=55.1Hz,6H).ESI-MS m / z:521.3[M+Na] + .

[0101] Example 21

[0102]

[0103] Compound 21 can be prepared by referring to the synthesis method of Example 17. 1H NMR (300MHz, Methanol-d4) δ7.35–7.21(m,2H),7.05(ddt,J=5.8,3.7,1.0Hz,1H),5.85(d,J=29.5Hz,2H),4.73–4.52(m,3H),4.43–4.05(m,6 H),2.86(qd,J=12.3,0.9Hz,2H),2.72–2.51(m,2H),2.51–2.39(m,4H),2.28(d,J=13.0Hz,1H),2.10–1.78(m,6H),1.42–0.92(m,9H).ESI-MS m / z:513.3[M+H] + .

[0104] Example 22

[0105]

[0106] Compound 22 can be prepared by referring to the synthesis method of Example 17. 1 H NMR (300MHz, Methanol-d4) δ7.21(d,J=5.0Hz,2H),7.01(dt,J=5.2,3.0Hz,1H),5.85(d,J=29.5Hz,2H),4.72–4.54(m,3H),4.35–4.02(m, 6H),2.86(qd,J=12.3,0.9Hz,2H),2.76–2.51(m,2H),2.51–2.34(m,5H),2.34–2.12(m,3H),2.07–1.77(m,6H),1.10–0.97(m,6H).ESI-MS m / z:535.3[M+H] + .

[0107] Example 23

[0108]

[0109] Compound 23 can be prepared by referring to the synthesis method of Example 23. 1H NMR(300MHz, Methanol-d4)δ7.09(d,J=7.4Hz,2H),6.99(dt,J=7.3,2.1Hz,1H),5.85(d,J=29.5Hz,2H),4.68–4.50(m,3H),4.30 –3.99(m,6H),2.96–2.74(m,2H),2.66(dq,J=12.4,2.0Hz,1H),2.57–2.21(m,6H),2.07–1.70(m,10H),1.38–0.83(m,9H).ESI-MS m / z:563.3[M+Na] + .

[0110] Example 24

[0111]

[0112] Referring to the synthesis method of Example 13, chloromethyl chloroformate was replaced with 1-chloroethyl chloroformate to obtain compound 24. 1 H NMR(300MHz, Methanol-d4)δ7.11(d,J=7.4Hz,2H),7.00(dt,J=5.9,3.2Hz,1H),5.96–5.72(m,3H),4.73–4.48(m,3H),4.29–4.14(m ,2H),2.94–2.74(m,2H),2.74–2.57(m,4H),2.56–2.37(m,2H),2.37–2.22(m,3H),2.14–1.64(m,9H),1.00(d,J=5.1Hz,3H).ESI-MS m / z:500.2[M+H] + .

[0113] Example 25

[0114]

[0115] Compound 25 can be prepared by referring to the synthesis method of Example 17. 1H NMR (300MHz, Methanol-d4) δ7.34–7.24(m,2H),7.01(t,J=7.0Hz,1H),5.85(d,J=29.5Hz,2H),4.70–4.49(m,3H),4.38–4.09(m,6H),2.8 6(qd,J=12.3,0.9Hz,2H),2.77–2.56(m,4H),2.56–2.37(m,4H),2.28(d,J=13.0Hz,1H),2.08–1.81(m,6H),0.99(d,J=5.1Hz,3H).ESI-MS m / z:522.2[M+Na] + .

[0116] Example 26

[0117]

[0118] Compound 26 can be prepared by referring to the synthesis method of Example 17. 1 H NMR(300MHz,Methanol-d4)δ7.14(d,J=7.4Hz,2H),7.01(dt,J=4.7,2.5Hz,1 H),5.85(d,J=29.5Hz,2H),4.64–4.51(m,2H),4.34–4.03(m,6H),2.86(qd,J= 12.3,0.9Hz,2H),2.75–2.68(m,4H),2.55(dq,J=12.3,1.9Hz,1H),2.51–2.3 6(m,3H),2.29–2.18(m,3H),2.05–1.84(m,6H),0.98(d,J=5.2Hz,3H).ESI-MS m / z:536.3[M+Na] + .

[0119] Example 27

[0120]

[0121] Compound 27 can be prepared by referring to the synthesis method of Example 17. 1H NMR (300MHz, Methanol-d4) δ7.16 (d, J=7.0Hz, 2H), 7.02 (ddt, J=6.0, 4.1, 1.1Hz, 1H), 5.85 (d, J=29.5Hz, 2H), 4.74–4. 59(m,2H),4.31–4.10(m,6H),3.00–2.57(m,6H),2.55–2.20(m,5H),2.08–1.72(m,10H),0.98(d,J=5.8Hz,3H).ESI-MS m / z:528.3[M+H] + .

[0122] Example 28

[0123]

[0124] Synthesis method

[0125]

[0126] Beraprost sodium (0.1 mmol) and potassium carbonate (0.2 mmol) were dissolved in DMF, and dibenzylchloromethyl phosphate (0.11 mmol) was added dropwise. The mixture was stirred overnight at room temperature, and the reaction was confirmed to be complete by TLC. Water was added, and the mixture was extracted with ethyl acetate. The organic phase was collected, dried over anhydrous sodium sulfate, purified by column chromatography, and concentrated to obtain a solid. The solid was dissolved in methanol, and 10% Pd / C was added. The mixture was stirred at room temperature for one hour under H2 conditions. The mixture was filtered through diatomaceous earth, and the filtrate was concentrated to obtain compound 28. The compound was dissolved in THF / water, and 2N HCl was added. The mixture was stirred at room temperature, and the reaction was confirmed to be complete by TLC. The solvent was evaporated, and the compound was purified by HPLC. 1 H NMR(300MHz, Methanol-d4)δ7.41–7.24(m,2H),7.00(dt,J=7.2,3.1Hz,1H),5.85(d,J=29.5Hz,2H),5.15–4.92(m,2H),4.77–4.45 (m,3H),4.06(dd,J=125.3,5.1Hz,2H),2.93–2.36(m,7H),2.28(d,J=13.0Hz,1H),2.06–1.78(m,6H),0.98(d,J=5.6Hz,3H).ESI-MS m / z:531.2[M+Na] + .

[0127] Example 29

[0128]

[0129] Compound 29 can be prepared by referring to the synthesis method of Example 28. 1H NMR(300MHz, Methanol-d4)δ7.38–7.19(m,2H),7.04(dt,J=7.3,2.1,1.0Hz,1H),5.85(d,J=29.5Hz,2H),5.16–4.92(m,2H),4.57(dd,J=5.0,1.0Hz, 1H),4.32–4.04(m,2H),3.90(s,6H),2.91–2.51(m,4H),2.50–2.39(m,3H) ,2.28(d,J=13.0Hz,1H),2.05–1.75(m,6H),0.99(d,J=5.7Hz,3H).ESI-MS m / z:559.2[M+Na] + .

[0130] Example 30

[0131]

[0132] Compound 30 can be prepared by referring to the synthesis method of Example 28. 1 H NMR (300MHz, Methanol-d4) δ7.37(t,J=7.5Hz,1H),7.24(dd,J=7.5,2.0Hz,1H),7.07(ddt,J=7.5,2.0,1.1Hz,1H),5.85(d,J=29.5Hz,2H),5 .26–4.94(m,2H),4.63–4.53(m,2H),4.30–4.02(m,6H),2.96–2.63(m,3H),2.55–2.23(m,5H),2.07–1.84(m,6H),1.18–0.94(m,9H).ESI-MS m / z:565.3[M+H] + .

[0133] Example 31

[0134]

[0135] Compound 31 can be prepared by referring to the synthesis method of Example 28. 1H NMR (300MHz, Methanol-d4) δ7.46–7.20(m,2H),7.12(ddt,J=7.5,2.0,1.0Hz,1H),5.84(d,J=46.5Hz,2H),4.94–4. 62(m,3H),4.38–4.05(m,6H),2.95–2.60(m,3H),2.52–2.09(m,5H),2.09–1.76(m,6H),1.76–0.89(m,12H).ESI-MS m / z:601.3[M+Na] + .

[0136] Example 32

[0137]

[0138] Compound 32 can be prepared by referring to the synthesis method of Example 28. 1 H NMR(300MHz, Methanol-d4)δ7.38(t,J=7.5Hz,1H),7.24(dd,J=7.5,2.0Hz,1H), 7.12(ddt,J=7.5,2.0,1.0Hz,1H),5.84(d,J=46.5Hz,2H),4.89–4.63(m,3H),4. 30–4.02(m,6H),2.99–2.74(m,2H),2.66(dq,J=12.4,2.0Hz,1H),2.46(dq,J=12 .5,2.0Hz,1H),2.37–2.12(m,4H),2.05–1.79(m,7H),1.43–0.70(m,15H).ESI-MS m / z: 607.3 [M+H] + .

[0139] Example 33

[0140]

[0141] Compound 33 can be prepared by referring to the synthesis method of Example 28. 1H NMR (300MHz, Methanol-d4) δ7.37(t,J=7.5Hz,1H),7.24(dd,J=7.5,2.0Hz,1H),7.12(ddt,J=7.5,2.0,1.0Hz,1H),5.84(d,J=46.5Hz,2H),4 .93–4.73(m,2H),4.39–4.08(m,10H),3.05–2.74(m,2H),2.74–2.35(m ,4H),2.35–2.12(m,2H),2.12–1.78(m,6H),1.20–0.94(m,9H).ESI-MS m / z:601.3[M+H] + .

[0142] Example 34

[0143]

[0144] Compound 34 can be prepared by referring to the synthesis method of Example 28. 1 H NMR (300MHz, Methanol-d4) δ7.40–7.19(m,2H),7.12(ddt,J=7.5,2.0,1.0Hz,1H),5.84(d,J=46.5Hz,2H),4.94–4.64(m,3H),4.32–4.07(m,8H ),4.00–3.84(m,2H),2.93–2.77(m,2H),2.56(ddq,J=98.7,12.5,2.0Hz,2H),2.43–2.11(m,6H),2.10–1.79(m,6H),1.24–0.97(m,9H).ESI-MS m / z:615.3[M+Na] + .

[0145] Example 35

[0146]

[0147] Compound 35 can be prepared by referring to the synthesis method of Example 28. 1H NMR(300MHz,Methanol-d4)δ7.38(t,J=7.5Hz,1H),7.24(dd,J=7.5,2.0Hz,1H) ,7.12(ddt,J=7.5,2.0,1.0Hz,1H),5.84(d,J=46.5Hz,2H),4.86–4.64(m,3H),4 .36–4.10(m,8H),4.07–3.88(m,2H),2.96–2.76(m,2H),2.56(ddq,J=98.7,12. 5,2.0Hz,2H),2.29–2.11(m,2H),2.10–1.70(m,10H),1.20–0.97(m,9H).ESI-MS m / z: 629.3 [M+Na] + .

[0148] Example 36

[0149]

[0150] Compound 36 can be prepared by referring to the synthesis method of Example 1. 1 H NMR(300MHz, Methanol-d4)δ7.37–7.18(m,2H),7.07(t,J=7.3Hz,1H),5.85( d,J=29.5Hz,2H),5.41–5.10(m,2H),4.66–4.50(m,3H),4.31–3.98(m,2H),2. 93–2.76(m,2H),2.66(dq,J=12.5,2.0Hz,1H),2.54–2.34(m,6H),2.28(d,J= 13.0Hz,1H),2.11–1.75(m,6H),1.57–1.22(m,8H),1.12–0.96(m,6H).ESI-MS m / z:541.3[M+H] + .

[0151] Example 37

[0152]

[0153] Compound 37 can be prepared by referring to the synthesis method of Example 1. 1H NMR (300MHz, Methanol-d4) δ7.37(t,J=7.5Hz,1H),7.24(dd,J=7.5,2.0Hz,1H),7.07(dt,J =7.5,2.0Hz,1H),5.84(d,J=46.5Hz,2H),5.42–5.11(m,2H),4.81–4.63(m,2H),4.32–4.12( m,2H),2.97–2.76(m,2H),2.66(dq,J=12.5,2.0Hz,1H),2.46(dq,J=12.5,2.0Hz,1H),2.42 –2.12(m,6H),1.94–1.79(m,5H),1.50(s,2H),1.37–1.16(m,8H),1.12–0.95(m,6H).ESI-MS m / z:555.3[M+H] + .

[0154] Example 38

[0155]

[0156] Compound 38 can be prepared by referring to the synthesis method of Example 1. 1 H NMR (300MHz, Methanol-d4) δ7.37(t,J=7.5Hz,1H),7.24(dd,J=7.5,2.0Hz,1H),7.12(dt ,J=7.5,2.4Hz,1H),5.84(d,J=46.5Hz,2H),5.45–5.13(m,2H),4.94–4.62(m,3H),4.38– 4.10(m,2H),2.97–2.75(m,2H),2.66(dq,J=12.5,2.0Hz,1H),2.46(dq,J=12.5,2.0Hz,1 H),2.39–2.11(m,6H),1.92–1.80(m,5H),1.39–1.22(m,10H),1.13–20.95(m,6H).ESI-MS m / z:569.3[M+H] + .

[0157] Pharmacodynamic Test Example 1: Pharmacokinetic Experiment of Compounds from Examples of the Invention

[0158] 1. Experimental Apparatus and Materials: High-speed refrigerated centrifuge, vortex mixer (Vortex Genius3), high-speed centrifuge (Eppendorf 5415D), disposable syringes, pipettes (Eppendorf), male SD rats used in the experiment were all purchased from Yangzhou University, EDTA-K2 vacuum blood collection tubes, and physiological saline. All rats in the oral administration group were fasted for 12 hours before administration, but had free access to water and food during the administration period.

[0159] 2. Experimental Procedure: Compound 5 was dissolved in DMSO / solutol / water (10 / 10 / 80) to prepare a clear solution, which was then administered by gavage at a dose of 25 mg / kg. For tail vein administration, the dose of Compound 5 was 5 mg / kg. Blood samples of 0.5 mL were continuously collected from the fundus venous plexus at 2 min, 10 min, 30 min, 1 h, 2 h, 3 h, 5 h, 8 h, 12 h, 16 h, and 24 h after tail vein administration and added to heparin tubes. Blood samples of 0.5 mL were continuously collected from the fundus venous plexus at 5 min, 15 min, 30 min, 1 h, 2 h, 3 h, 5 h, 8 h, 12 h, 16 h, and 24 h after gavage administration and added to heparin tubes. The samples were centrifuged at 8000 rpm at 4 °C for 10 min, and 0.15 mL of the supernatant plasma was collected and stored at -20 °C for LC-MS / MS analysis. Data were analyzed using a WinNolin non-compartmental model to obtain key pharmacokinetic parameters. The experimental results are shown in the table below, which displays the pharmacokinetic parameters of some compounds in the examples of this experiment:

[0160]

[0161] As can be seen from the pharmacokinetic data of the compounds in the above examples, compared with the peak concentration of beraprost sodium at 30 min and the elimination half-life at about 40 min (Chinese J of New Drugs 2019,28(14):1713-1717), the peak concentration time and elimination half-life of the compounds in the examples are significantly improved.

[0162] Example 2 of efficacy test: In vivo test in rats with hypoxic pulmonary hypertension

[0163] 1. Experimental instruments and materials: HX-200 animal ventilator; all male SD rats used in the experiment were purchased from Yangzhou University. All control groups were raised under normal conditions, while the model group and the test compound group were raised in a low-pressure hypoxic chamber (50 kPa pressure, 10% oxygen concentration).

[0164] 2. Experimental Procedure: The compound in the example was dissolved in DMSO / solutol / water (10 / 10 / 80) to prepare a clear solution. Starting from the second day of hypoxia, the intervention group was administered the compound via gavage at a dose of 5 mg / kg. All rats were weighed weekly, and their survival status was recorded. Pulmonary artery pressure was measured after four weeks. Rats were anesthetized with chloral hydrate (100 g / L) (3 mL / kg), fixed in a supine position, and tracheotomized. They were then assisted with ventilation using a small animal ventilator (60 breaths / min, tidal volume 5 mL, I:E ratio 4:5). The left third rib was freed, and a catheter with one end connected to a tension transducer was inserted into the pulmonary artery. Mean pulmonary artery pressure (mPAP) was recorded using a BL-420E biomechanical experimental system. Pleural and peritoneal fluid were examined and collected. Finally, blood was drawn from the abdominal aorta to euthanize the rats.

[0165] The experimental results are shown in the table below, illustrating the activity of this experiment. Compared with the control group, the mPAP level in the model group rats was significantly increased, and treatment with compound 5 significantly reduced the mPAP level in the model animals.

[0166] Group (n) Mean pulmonary artery pressure (mmHg) Right ventricular systolic pressure (mmHg) Control group (4) 13.01±0.76 26.12±3.03 Model group (4) 25.84±5.82 56.33±15.21 Test group "Compound 5" (4) 16.56±3.46 36.11±7.12

[0167] For those skilled in the art, this disclosure is not limited to the foregoing illustrative embodiments and can be embodied in other specific forms without departing from its essential attributes. Therefore, it is intended that all aspects be considered illustrative rather than restrictive, that references be made to the appended claims rather than the foregoing embodiments, that references be made only to the appended claims and not to the foregoing examples, and that all variations falling within the meaning and scope of claim equivalence are therefore intended to be included herein.

[0168] All patents, patent applications, and references listed in this specification are incorporated herein by reference in their entirety. In case of inconsistencies, this disclosure, including its definitions, will be considered more persuasive.

Claims

1. A prodrug of beraprost as shown in Formula I: R1 is hydrogen or C. 1-4 alkyl; R2 is C 1-6 Alkyl, C 1-6 amino or C 1-12 alkoxy; n is 0, 1, 2, 3 or 4; m is 1 or 2; X represents carbon or phosphorus.

2. The beraprost prodrug according to claim 1, characterized in that, R1 is hydrogen, methyl, or isopropyl; R2 is selected from methyl, ethyl, n-propyl, isopropyl, tert-butyl, methoxy, ethoxy, propoxy, methylamino, ethylamino, butylamino, 2-methylpropyl-1-amine; n is 0, 1, 2, or 3.

3. The beraprost prodrug according to claim 1, characterized in that, The beraprost prodrug comprises any of the following structures:

4. The use of a beraprost prodrug according to any one of claims 1 to 3 as a procyclosporine analogue.

5. The use of a beraprost prodrug according to any one of claims 1 to 3 in the preparation of a medicament for treating pulmonary hypertension, chronic vascular occlusive disease, myocardial infarction, kidney disease, occlusive arteriosclerosis, ophthalmic disease, osteoporosis, thromboangiitis obliterans, and thromboembolic diseases.

6. A pharmaceutical composition, characterized in that... The invention comprises a prodrug of beraprost as described in any one of claims 1 to 3 and a pharmaceutically acceptable carrier.

7. The pharmaceutical composition according to claim 6, characterized in that, The carrier is any one or a mixture of two or more of the following: sustained-release agent, excipient, filler, binder, wetting agent, disintegrant, absorption promoter, adsorbent carrier, surfactant, and lubricant.

8. The pharmaceutical composition according to any one of claims 6 to 7, characterized in that, The pharmaceutical composition is any one of an inhaled formulation, a topical formulation, an oral formulation, and an injectable formulation.

9. A pharmaceutical composition according to claim 8, characterized in that, The oral preparation is any one of granules, capsules, and tablets.

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