A method for deuterating a camptothecin intermediate cd ring derivative

Abstract

The present application relates to a kind of camptothecin intermediate CD ring derivative deuterated method, and its application in preparation deuterated camptothecin derivative and antibody conjugated drug (ADC).According to the method of the present application, deuterated CDE ring can be prepared with milder reaction conditions, efficiently, simply, cost controllable and scaled, which is of great significance for promoting the research and development of deuterated camptothecin ADC drug.

Description

Technical Field

[0001] This invention belongs to the field of medicinal chemistry and organic synthesis technology, specifically relating to a new synthetic route for a key intermediate of deuterated camptothecin—the deuterated CDE ring (three-membered ring)—and its application in the preparation of deuterated camptothecin derivatives and antibody-drug conjugates (ADCs). Background Technology

[0002] Camptothecin (CPT) is a pentacyclic quinoline alkaloid derived from the bark of the camptotheca tree. It effectively induces tumor cell apoptosis by inhibiting the formation of a ternary complex between topoisomerase I (TOP I) and DNA. Several camptothecin derivatives (such as irinotecan, topotecan, and beloteccan) have been successfully used clinically to treat various solid tumors. However, traditional camptothecin drugs suffer from poor water solubility, unsatisfactory distribution in vivo, and significant toxic side effects, limiting their wider application.

[0003] In recent years, the development of antibody-drug conjugate (ADC) technology has provided new opportunities for the application of camptothecin-based drugs. ADCs achieve precise delivery to tumor cells by linking highly active camptothecin compounds (such as SN-38 and DXd) to targeting antibodies, thereby improving efficacy while reducing systemic toxicity. For example, ADC drugs such as IMMU-132 (Sacituzumabgovitecan) and DS-8201a (Trastuzumab deruxtecan) have demonstrated significant therapeutic effects in clinical practice.

[0004] Deuteration, as a drug structure modification strategy, significantly improves the pharmacokinetic properties of compounds by replacing hydrogen atoms with their isotope deuterium atoms. This includes extending half-life, reducing metabolic rate, and decreasing the formation of toxic metabolites. Furthermore, deuterated compounds exhibit better stability during in vivo metabolism, making them particularly suitable for the design of target drugs in antibody-drug conjugates (ADCs). They can be rapidly metabolized and cleared after release from the antibody, further reducing off-target toxicity.

[0005] In the synthesis of camptothecin compounds, the CDE ring (i.e., the three-membered ring structure) is a key intermediate for constructing its core framework. CN201910712589.0 discloses a method for synthesizing a racemic CDE ring, which uses 6-chloro-2-methoxynicotinic acid as a starting material to obtain a three-membered ring compound through multiple steps. However, this route does not involve deuteration modification and cannot be directly used for the preparation of deuterated camptothecin.

[0006] On the other hand, CN117105948A discloses a class of dideuterated camptothecin derivatives and their preparation methods, which involve a step of introducing deuterium atoms during the synthesis process (such as deuteration using a deuterating reducing agent).

[0007]

[0008] However, this route still has the following limitations: The synthesis steps are lengthy: multiple reaction steps are required to construct the deuterated CDE ring structure, limiting the overall yield; the deuteration steps are inefficient: some deuteration reaction conditions are harsh, making it difficult to control the deuteration rate and affecting the deuteration purity of the final product; the raw materials and reagents are costly: the use of various deuteration reagents (such as sodium deuterated borohydride, deuterated methanol, etc.) increases the preparation cost; and it is not conducive to large-scale production: some reaction conditions (such as low temperature, anhydrous and oxygen-free environments) require sophisticated equipment and complex process control.

[0009] Therefore, developing a new synthetic route that is efficient, simple, cost-controllable, and suitable for large-scale preparation of deuterated CDE rings is of great significance for promoting the research and development of deuterated camptothecin-based ADC drugs. Summary of the Invention

[0010] To address the aforementioned problems, the inventors of this invention discovered through extensive experiments that using CD ring derivatives as raw materials, the deuterated CDE ring structure obtained as a deuterated camptothecin intermediate after deuteration and cyclization is easy to control the deuteration rate and has mild reaction conditions with high yield. Based on this, the present invention was completed.

[0011] One object of the present invention is to provide a method for the deuteration of CD ring derivatives of camptothecin intermediate.

[0012] Another object of the present invention is to provide the application of the method in the preparation of deuterated camptothecin derivatives and antibody-drug conjugates (ADCs).

[0013] According to one aspect of the present invention, a method for deuteration of a camptothecin intermediate CD ring derivative is provided, the method comprising:

[0014] Where R is Or hydrogen; S1) XY-D is reacted with deuterium and acetic anhydride in acetic acid or deuterated acetic acid in the presence of a catalyst to obtain XY-E.

[0015] In some embodiments, step S1 is carried out at a temperature of 50-70°C for 4-20 hours.

[0016] In some embodiments, the catalyst is selected from Raney nickel, palladium on carbon, platinum on carbon, platinum oxide, and wherein the mass-to-volume ratio of XY-D, acetic anhydride, acetic acid, or deuterated acetic acid is 1:(3.0-5.0 CV):(1.0-3.0 CV); the amount of catalyst added relative to the weight of XY-D is 0.1-1 m / m.

[0017] Here, CV represents the mass-volume ratio, which is measured in g for solid substances and in ml for liquid substances. That is, relative to 1 g XY-D, the amount of acetic anhydride used is 3.0-5.0 ml, and the amount of acetic acid or deuterated acetic acid used is 1.0-3.0 ml; m / m indicates the weight ratio or mass ratio, which is dimensionless.

[0018] In some embodiments, the method further includes:

[0019] Where R is Or hydrogen; S2) React XY-E with acetic acid or deuterated acetic acid to obtain XY-F.

[0020] In some implementations, step S2 is performed in the presence of NaNO2.

[0021] In some embodiments, step S2 is performed in an ice bath for 0.5-3 hours, then at room temperature for 2-4 hours, and then at 40-70°C for 3-7 hours to obtain XY-F.

[0022] In some embodiments, in step S2, the mass-volume ratio of XY-E, acetic anhydride, acetic acid, or deuterated acetic acid is 1:(5.0-10.0 CV):(1.0-5.0 CV); the amount of NaNO2 added relative to XY-E is 3.0-10.0 eq (i.e., the molar ratio of XY-E to NaNO2 is 1:3-10).

[0023] According to one embodiment of the present invention, the method further includes:

[0024] Where R is Or hydrogen; S3) Cyclate XY-F to obtain XY-G.

[0025] In some embodiments, step S3 is carried out in an organic solvent under alkaline conditions, wherein the alkaline reagent is selected from one or more of lithium hydroxide, sodium hydroxide, potassium carbonate, and potassium hydroxide, and the organic solvent is selected from one or more of methanol and ethanol.

[0026] In some embodiments, step S3 involves reacting in an ice bath for 1-3 hours, then adding hydrochloric acid or sulfuric acid to adjust the pH to 2-3, and stirring at room temperature for 1-3 hours to obtain XY-G.

[0027] In some embodiments, in step S3, the molar ratio of XY-F to the alkaline reagent is 1:(2.0-10.0).

[0028] According to one embodiment of the present invention, the method further includes:

[0029] S4) Deprotect XY-G to obtain XY-DCDE.

[0030] In some embodiments, step S4 is carried out in the presence of an acidic reagent selected from hydrochloric acid, sulfuric acid, or trifluoroacetic acid.

[0031] In some embodiments, step S4 involves reacting at room temperature for 8-16 hours to obtain XY-DCDE.

[0032] The mass-to-volume ratio of XY-G and acidic reagent is 1:(3.0-10.0 CV).

[0033] According to one embodiment of the present invention, steps S1) and S2) can be performed continuously without intermediate separation.

[0034] According to one embodiment of the present invention, the preparation method is specifically shown in the following formula: Where R is Or hydrogen.

[0035] According to another aspect of the invention, the above method is provided for use in the preparation of deuterated camptothecin derivatives and antibody-drug conjugates (ADCs).

[0036] Beneficial effects According to the method of the present invention, deuterated CDE rings can be prepared efficiently, simply, cost-controllably, and on a large scale under milder reaction conditions, which is of great significance for promoting the research and development of deuterated camptothecin-based ADC drugs. Detailed Implementation

[0037] The present invention will be described below through embodiments, which are merely illustrative in nature and are not intended to limit the invention or its uses. Furthermore, this document is not limited to the foregoing prior art or the invention itself, or to any theory described in the following specific embodiments or examples.

[0038] In this invention, unless otherwise specified, all raw materials and reagents used are obtained by commercial purchase or by methods disclosed in the prior art.

[0039] Example 1 Synthesis of XY-D026E:

[0040] XY-026D (5.0 g, 1.00 eq, purchased from Yantai Xianhua Chemical Technology Co., Ltd.), acetic anhydride (21 ml), deuterated acetic acid (7 ml), and anhydrous Raney nickel catalyst (1.5 g, 0.3 m / m) were added to a 250 ml three-necked flask. The mixture was purged with deuterium three times and reacted overnight at an internal temperature of approximately 60°C (external temperature 60-65°C). The solution was light green. TLC monitoring confirmed complete reaction of the reactants (DCM:MEOH = 20:1, Rf = 0.6). The mixture was filtered through diatomaceous earth, and the filter cake was washed with approximately 5 ml of acetic anhydride. The filtrate was concentrated under reduced pressure, and the crude product was purified by column chromatography (0-3% methanol in DCM) to obtain a white solid, XY-D026E (3.0 g, yield 56%). LC-MS: (ESI) + )m / z 648.2[M+H + ].

[0041] 1 H NMR (CDCl3): δ 7.76 (d, J = 8.4 Hz, 2H), 7.32 (d, J = 8.0 Hz, 2H), 7.03-7.01 (m, 1H), 6.69 (s, 1H), 4.45-4.02 (m, 9H), 3.55-3.50 (m, 1H), 3.26-3.20 (m, 1H), 2.73-2.64 (m, 1H), 2.59-2.51 (m, 1H), 2.43-2.40 (m, 5H), 2.05-1.92 (m, 6H), 1.74-1.67 (m, 1H), 1.27 (t, J = 7.2 Hz, 3H), 0.87 (t, J = 7.2Hz, 3H).

[0042] Example 2 Synthesis of XY-D026F:

[0043] XY-D026E (3.0 g) obtained in Example 1 was placed in a 250 ml three-necked flask (thermometer, desiccant tube), and acetic anhydride (35 ml) and deuterated acetic acid (15 ml) were added. The flask was placed in an ice bath, and after the internal temperature reached 5°C, NaNO2 (3.5 g, 6.0 eq) was added in 5 batches (a brown gas was emitted, and the mixture became a light green turbidity). After the addition was complete, the mixture was reacted in an ice bath for 1 hour, and then at room temperature for 3 hours (the system turned into a yellow-green turbidity). TLC monitoring showed that the starting material (DCM:MEOH=20:1, Rf=0.2) disappeared. The system was heated to an internal temperature of about 55°C and reacted for 5 hours. The solvent was removed by rotary evaporation, and the concentrate was extracted with ethyl acetate (30 ml) and water (30 ml). The organic phase was concentrated to a foamy yellow solid.

[0044] Add ethyl acetate (5 ml) to the concentrate and stir. Heat to reflux until dissolved. Add tert-butyl methyl ether (15 ml) and stir at 75°C for 1 hour. Allow to cool naturally to room temperature. Filter the suspension and wash with tert-butyl methyl ether (5 ml). Dry the filter cake to obtain a white solid XY-D026F (2.0 g, yield 65%). LC-MS: (ESI) + )m / z 649.2[M+H + ].

[0045] 1 H NMR (CDCl3) δ: 7.74 (d, J = 8.4 Hz, 2H), 7.33 (d, J = 8.4 Hz, 2H), 6.76 (s, 1H), 4.44-4.04 (m, 9H), 3.62-3.55 (m, 1H), 3.26-3.20(m, 1H), 2.69-2.59 (m, 1H), 2.49-2.27 (m, 6H), 2.04-1.90 (m, 6H), 1.71-1.67 (m, 1H), 1.22(t, J = 7.2 Hz, 3H), 0.89 (t, J = 7.6 Hz, 3H).

[0046] Example 3 Synthesis of XY-D026F (one-step method):

[0047] Add XY-026D (5.0 g, 1.00 eq), anhydrous acetic anhydride (21 ml), deuterated acetic acid (7 ml), and Raney nickel catalyst (2.5 g, 0.3 m / m) to a 250 ml three-necked flask. React at 30-80 °C under deuterium atmosphere until TLC shows complete disappearance of the starting material. Filter with diatomaceous earth and rinse the filter cake with acetic anhydride (approximately 5 ml).

[0048] The mother liquor was placed in a 250 ml three-necked flask (thermometer and desiccant), placed in an ice bath, and after the internal temperature reached 5°C, NaNO2 (3.5 g, 6.0 eq) was added in 5 batches (a brown gas was emitted, and the mixture became a light green turbidity). After the addition was complete, the mixture was reacted in an ice bath for 1 hour, then at room temperature for 3 hours (the system turned into a yellow-green turbidity). TLC monitoring showed that the starting material (DCM:MEOH=20:1, Rf=0.2) disappeared. The system was then heated to an internal temperature of approximately 55°C and reacted for 5 hours. The solvent was removed by rotary evaporation, and the concentrate was extracted with ethyl acetate (30 ml) and water (30 ml). The organic phase was concentrated until a foamy yellow solid was formed.

[0049] Add ethyl acetate (5 ml) to the concentrate and stir. Heat to reflux until dissolved. Add tert-butyl methyl ether (15 ml) and stir at 75°C for 1 hour. Allow to cool naturally to room temperature. Filter the suspension and wash with tert-butyl methyl ether (5 ml). Dry the filter cake to obtain a white solid XY-D026F (2.5 g, yield 46%). LC-MS: (ESI) + )m / z 649.2[M+H + ].

[0050] 1 H NMR (CDCl3) δ: 7.74 (d, J = 8.4 Hz, 2H), 7.33 (d, J = 8.4 Hz, 2H), 6.76 (s, 1H), 4.44-4.04 (m, 9H), 3.62-3.55 (m, 1H), 3.26-3.20(m, 1H), 2.69-2.59 (m, 1H), 2.49-2.27 (m, 6H), 2.04-1.90 (m, 6H), 1.71-1.67 (m, 1H), 1.22(t, J = 7.2 Hz, 3H), 0.89 (t, J = 7.6 Hz, 3H).

[0051] Example 4 Synthesis of XY-D026G:

[0052] XY-D026F (3.5 g, 1.0 eq) obtained in Example 2 was added to a 250 mL reaction flask, followed by methanol (70 mL). After the system dissolved, 35 mL of an aqueous solution of lithium hydroxide monohydrate (1.13 g, 5.0 eq) was added under ice bath conditions, and the reaction was allowed to proceed for 2 hours.

[0053] TLC monitoring showed that the raw material was no longer present, indicating complete hydrolysis. Under ice bath conditions, 2M hydrochloric acid (15 ml) was added dropwise to pH 2-3. After stirring at room temperature for 2 hours, LCMS and TLC showed that the product was entirely the target product. 10% sodium bicarbonate (10 ml) was added to adjust the pH to 6-7. The product was then extracted four times with 40 ml of DCM:MEOH (10:1). The organic phases were combined, dried, and evaporated to dryness. The mixture was then slurried with 5 ml of tert-butyl methyl ether and filtered to obtain a white solid XY-D026G (1.6 g, yield 95.8%).

[0054] LC-MS: (ESI) + )m / z 310.2[M+H + ].

[0055] 1 H NMR (DMSO- d 6) δ: 6.46 (s, 1H), 6.36 (s, 1H), 4.21 – 4.02 (m, 4H), 3.97 (t, J = 6.8 Hz, 2H), 2.36 (dd, J = 7.6, 6.0 Hz, 2H), 1.76 (q, J = 7.3Hz, 2H), 0.80 (t, J = 7.3 Hz, 3H).

[0056] Example 5 Synthesis of XY-D026G (another reactant):

[0057] XY-D026F-dep (35 g), methanol (450 mL), and potassium carbonate (13 g) were added to a 1 L reaction flask. Oxygen was bubbled in, and the mixture was stirred at 20–30°C for 2 h. When the starting material was depleted by TLC, the mixture was cooled to 10–20°C and slowly acidified to pH 6 with 1M sulfuric acid aqueous solution (150 mL). Methanol was removed under reduced pressure, and the mixture was concentrated to approximately 200 mL. The mixture was cooled to 20°C, and water (100 mL) was added. The aqueous solution was extracted twice with dichloromethane (350 mL and 100 mL), and the dichloromethane phases were combined and washed once with water (100 mL). Dichloromethane was removed from the organic phase under reduced pressure to obtain a crude solid. Ethanol (1.5 mL) and MTBE (15 mL) were added to the crude product, and the mixture was stirred for 1 h. The mixture was filtered to obtain a white solid XY-D026G (14 g, 45% yield).

[0058] LC-MS: (ESI) + )m / z 310.2[M+H + ].

[0059] 1 H NMR (DMSO-d 6) δ: 6.46 (s, 1H), 6.36 (s, 1H), 4.21 – 4.02 (m, 4H), 3.97 (t, J = 6.8 Hz, 2H), 2.36 (dd, J = 7.6, 6.0 Hz, 2H), 1.76 (q, J = 7.3Hz, 2H), 0.80 (t, J = 7.3 Hz, 3H).

[0060] Example 6 Synthesis of XY-DCDE:

[0061] Under nitrogen protection, XY-D026G (1.5 g, 1.0 eq) obtained in Example 4 and 80% trifluoroacetic acid (6.0 mL) were added to a 50 mL reaction flask. The starting materials were completely dissolved, and the reaction was stirred at room temperature for 12 hours. After the reaction was completed by TLC, the solvent was removed under reduced pressure (using 20 mL of ethanol three times). Ethanol (5 mL) and tert-butyl methyl ether (10 mL) were added to the reaction system, and the mixture was stirred and stirred for 1 hour. The mixture was filtered, washed with tert-butyl methyl ether (10 mL), and dried to obtain a white solid XY-DCDE (1.05 g, yield 81.3%).

[0062] LC-MS: (ESI) + )m / z 266.2[M+H + ].

[0063] 1 H NMR (DMSO- d 6) δ: 6.85 (s, 1H), 6.51 (s, 1H), 4.13 (t, J = 6.5 Hz,2H), 2.89 (dd, J = 7.1, 5.7 Hz, 2H), 1.78 (qt, J = 9.4, 4.8 Hz, 2H), 0.80 (t,J = 7.3 Hz, 3H).

[0064] Example 7 Except that acetic acid was used instead of deuterated acetic acid, the reaction was carried out in the same manner as in Example 1 to obtain compound XY-D026E. Then, using XY-D026E prepared in this Example 7, compound XY-DCDE was prepared according to the methods of Examples 2, 4 and 6.

[0065] Example 8 Except that acetic acid was used instead of deuterated acetic acid, the reaction was carried out in the same manner as in Example 2 to obtain compound XY-D026F. Then, using XY-D026F prepared in this Example 8, compound XY-DCDE was prepared according to the methods of Examples 4 and 6.

[0066] Example 9 Except that acetic acid was used instead of deuterated acetic acid, the reaction was carried out in the same manner as in Example 1 to obtain compound XY-D026E. Then, except that XY-D026E prepared in this Example 9 was used and acetic acid was used instead of deuterated acetic acid, the reaction was carried out in the same manner as in Example 2 to obtain compound XY-D026F. Then, using XY-D026F prepared in this Example 9, compound XY-DCDE was prepared according to the methods of Examples 4 and 6.

[0067] Experimental Example Deuteration rate determination method (HRMS method): High-resolution mass spectrometry (HRMS) was performed on the compounds prepared in the examples using an IonSpec 4.7 Tesla FTMA mass spectrometer (ESI ionization source). The peak areas of undeuterated compounds (A0), compounds substituted with one deuterium (A1), and compounds substituted with two deuteriums (A2) were measured, according to: The deuteration rate was calculated using the formula, and the results of the peak area and deuteration rate are listed in the table below:

[0068] Based on the results of the above embodiments and experimental examples, it can be seen that the method of the present invention can prepare deuterated CDE rings efficiently, simply, cost-controllably, and on a large scale under milder reaction conditions; moreover, when using deuterated acetic acid as a reagent, the deuteration rate of the prepared deuterated CDE rings is higher.

[0069] Surprisingly, the results of Examples 1, 6, and 7 show that although deuterated acetic acid is not a deuterating agent, its use in step S1 significantly affects the deuteration rate of the final product. However, the results of Examples 1, 6, and 8 show that, unlike in Example 7, the use of deuterated acetic acid in step S2 does not significantly affect the deuteration rate of the final product. These results demonstrate the complexity of the actual deuteration reaction mechanism.

Claims

1. A method for deuteration of a CD ring derivative of camptothecin intermediate, the method comprising: Where R is Or hydrogen; S1) XY-D is reacted with deuterium and acetic anhydride in acetic acid or deuterated acetic acid in the presence of a catalyst to obtain XY-E, and Where R is Or hydrogen; S2) Reaction of XY-E with acetic acid or deuterated acetic acid yields XY-F, wherein, Step S2 is performed in the presence of NaNO2.

2. The method according to claim 1, wherein, Step S1 involves reacting at 50-70°C for 4-20 hours.

3. The method according to claim 1, wherein, The catalyst is selected from Raney nickel, palladium on carbon, platinum on carbon, and platinum oxide, wherein the mass-volume ratio of XY-D, acetic anhydride, acetic acid, or deuterated acetic acid is 1:(3.0-5.0 CV):(1.0-3.0 CV); the amount of catalyst added relative to the weight of XY-D is 0.1-1 m / m.

4. The method according to claim 1, wherein, Step S2 involves reacting in an ice bath for 0.5-3 hours, then at room temperature for 2-4 hours, and finally at 40-70°C for 3-7 hours to obtain XY-F.

5. The method according to claim 1, wherein, In step S2, the mass-volume ratio of XY-E, acetic anhydride, acetic acid, or deuterated acetic acid is 1:(5.0-10.0 CV):(1.0-5.0 CV); the amount of NaNO2 added relative to XY-E is 3.0-10.0 eq.

6. The method according to claim 1, wherein, The method further includes: Where R is Or hydrogen; S3) Cyclize XY-F to obtain XY-G, wherein step S3 is carried out in an organic solvent under an alkaline reagent, the alkaline reagent being selected from one or more of lithium hydroxide, sodium hydroxide, potassium carbonate and potassium hydroxide, and the organic solvent being selected from one or more of methanol and ethanol.

7. The method according to claim 6, wherein, Step S3 involves reacting in an ice bath for 1-3 hours, then adding hydrochloric acid or sulfuric acid to adjust the pH to 2-3, and stirring at room temperature for 1-3 hours to obtain XY-G.

8. The method according to claim 6, wherein, In step S3, the molar ratio of XY-F to alkaline reagent is 1:(2.0-10.0).

9. The method according to claim 6, wherein, The method further includes: S4) Deprotect XY-G to obtain XY-DCDE, step S4 is carried out in the presence of an acidic reagent selected from hydrochloric acid, sulfuric acid or trifluoroacetic acid.

10. The method according to claim 9, wherein, Step S4 involves reacting at room temperature for 8-16 hours to obtain XY-DCDE. The mass-to-volume ratio of XY-G and acidic reagent is 1:(3.0-10.0 CV).

11. The method according to claim 1, wherein, Steps S1) and S2) are performed consecutively without intermediate separation.

12. The use of the method according to any one of claims 1-11 in the preparation of deuterated camptothecin derivatives and antibody-drug conjugates.

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