TWI441632B - Muricatacin analogues, process for synthesizing the same, and use thereof - Google Patents

Description

Saponin analog and its synthesis method and use

The present invention relates to a muricatacin derivative, and more particularly to a saponin derivative which is cytotoxic to esophageal cancer cells.

Panic acid saponin is a fat-soluble compound isolated from the seeds of Soursop (scientific name Annona muricata ) and belongs to an acetogenin. Studies have shown that saponin is cytotoxic to a variety of human cancer cell lines, such as human cell carcinoma cell line (KB cell line), human lung cancer cell line (K549 cell line), human breast cancer cell line (MCF-7 cell line). ), human chronic myeloid leukemia cell line (K562 cell line) and the like.

A variety of different biosynthetic methods are currently available for the synthesis of saponin or its derivatives and analogs. However, these methods often face problems such as cumbersome steps, low yields, and/or high costs. For example, Tsai et al., in 1999, disclosed a method for the preparation of a hydroxylated saponin derivative. The method has nine steps, the reaction time is nearly 60 hours, and the reaction temperature of the different steps is -78 ° C to 180. Between °C, and the total yield is only 5.5% (Tsai, SH et al. (1999) Synthesis of a hydroxylated muricatacin analog related to squamocin, Tetrahedron Letters, 40 (10), p. 1975-1976). From the point of view of industrial mass production, the reaction steps are complicated and long, and the temperature rise and cool during the reaction process will increase the production cost; while the low yield will lead to a decrease in the yield.

In view of the above, there is a need in the related art to provide a novel preparation method of the saponin derivative which overcomes one or more of the problems and disadvantages described above. Further, such a saponin derivative preferably has a biological activity similar to that of saponin.

SUMMARY OF THE INVENTION The Summary of the Disclosure is intended to provide a basic understanding of the present disclosure. This Summary is not an extensive overview of the disclosure, and is not intended to be an

One aspect of the present invention relates to a method for preparing a saponin and a derivative thereof according to the following formula (1),
(1),
Wherein n = a positive integer of 7-11, and R ₁ is hydroxy or ethoxylated. In one embodiment, the method requires only six reaction steps to prepare the saponin or its derivative, and the total reaction time of each step is within 20 hours, which is much shorter than the prior art. In addition, each reaction step in the preparation method can be carried out at 20-30 ° C, without complicated heating and cooling control, and the equipment and labor costs required in the preparation process can be reduced. Further, according to an embodiment of the present invention, the overall yield of the method can be up to about 50%, which is much higher than the yield of the prior art for the preparation of the saponin or other saponin derivatives.

According to an embodiment of the present invention, the method can be used to prepare a saponin derivative represented by the following formula (7), and the method comprises the following steps (a) to (f):
(a) D-lyxose is isopropylideated to form a compound represented by formula (2)
(2) ;
(b) The compound represented by the formula (2) is subjected to a Wittig olefination to produce a compound represented by the formula (3).
(3);
(c) subjecting a compound represented by formula (3) to oxidative cleavage to produce a compound represented by formula (4)
(4);
(d) The compound represented by the formula (4) is subjected to a deterrent reaction to give a compound represented by the formula (5)
(5);
(e) hydrogenating a compound represented by formula (5) to give a compound represented by formula (6)
(6) ; and
(f) The compound represented by the formula (6) is lactonized to give a compound represented by the formula (7)

According to another embodiment of the present invention, the saponin derivative represented by the following formula (7) can be prepared, and the method further comprises the step (g) of acetylating the compound represented by the formula (7). Production of a compound of formula (8)

In one embodiment, the compound of the above formula (1) has n=10, so that the compound represented by the formula (7) synthesized has a structure represented by the formula (7-1):

In another embodiment, the compound of formula (8) produced by acetylation of a compound of formula (7-1) has the structure shown in formula (8-1):

According to an embodiment of the present invention, the above steps (a) and (g) can be carried out using concentrated acid as a catalyst, respectively.

According to an embodiment of the present invention, the reagents for the deuteration reaction of the above steps (b) and (d) are brominated (triphenyl) C _7-11 alkyl phosphine and Ph ₃ P=CHCO ₂ E, respectively.

According to an embodiment of the present invention, the above-described oxidation step (c) the cleavage reaction using any one selected from _4, HIO ₄ and Pb (OAc) ₄ in the group consisting of NaIO oxidant performed. In a specific example, the oxidizing agent is NaIO ₄ .

According to an embodiment of the invention, the above steps (a) to (f) are carried out at about 20-30 °C.

Another aspect of the present invention relates to a novel saponin derivative (such as a compound of the above formula (7-1) or (8-1)) synthesized according to the above preparation method of the present invention, and the test results show that the novel Litchi saponin derivatives can inhibit the proliferation of esophageal cancer cells. This property has not been found in the saponin or other known saponin derivatives.

Accordingly, another aspect of the present invention is directed to a pharmaceutical composition for treating esophageal cancer.

According to an embodiment of the present invention, the pharmaceutical composition comprises a therapeutically effective amount of the saponin derivative represented by the formula (7-1) or (8-1); and a pharmaceutically acceptable adjuvant.

The basic spirit and other objects of the present invention, as well as the technical means and implementations of the present invention, will be readily apparent to those skilled in the art of the invention.

The description of the embodiments of the present invention is intended to be illustrative and not restrictive. The features of various specific embodiments, as well as the method steps and sequences thereof, are constructed and manipulated in the embodiments. However, other specific embodiments may be utilized to achieve the same or equivalent function and sequence of steps.

The scientific and technical terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention pertains, unless otherwise defined herein. In addition, the singular noun used in this specification covers the plural of the noun in the case of no conflict with the context; the plural noun of the noun is also included in the plural noun used. Also, words such as "at least one" and "one or more" are used herein to include one, two, three or more.

Although numerical ranges and parameter boundaries are used to define a broad range of the present invention, the relevant values of the specific embodiments are presented as precisely as possible. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. As used herein, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range. Alternatively, the term "about" means that the actual value falls within the acceptable standard deviation of the average, depending on the considerations of those of ordinary skill in the art to which the invention pertains. Except for the experimental examples, or unless otherwise explicitly stated, all ranges, quantities, values, and percentages used herein are understood (eg, to describe the amount of material used, the length of time, the temperature, the operating conditions, the quantity ratio, and the like. Are all modified by "about". Therefore, unless otherwise indicated to the contrary, the numerical parameters disclosed in the specification and the appended claims are intended to be At a minimum, these numerical parameters should be understood as the number of significant digits indicated and the values obtained by applying the general carry method.

According to the preparation method of one aspect of the present invention, a novel mirror image-isolated pure hydroxy-γ-lactone (enantiomerically pure hydroxy-) is efficiently produced by using D-lyxose as a starting material through asymmetric synthesis. Γ-lactone) and a derivative thereof having the structure represented by the following formula (1):
(1),
Wherein n = a positive integer of 7-11, and R1 is hydroxy or ethoxylated.

According to an embodiment of the present invention, the compound represented by the formula (7) can be produced from D-lyxose by only six steps by this method, and the total yield can be up to about 50%. The structural formula (7) is as follows:
(7),
Where n = a positive integer of 7-11. Here, a method for producing a compound represented by the formula (7) according to an embodiment of the present invention will be described with reference to Fig. 1.

First, in the step (a), the starting material D-(-)-lyxose and acetone are subjected to O-isopropylidenation under the catalysis of a catalyst to form the formula (2). The compound shown. Catalysts that can be used to catalyze the isopropylation of sugars include, but are not limited to, concentrated H ₂ SO ₄ , a mixture of anhydrous zinc chloride (ZnCl ₂ ) and phosphoric acid (H ₃ PO ₄ ), anhydrous copper sulfate. (anhydrous copper(II) sulfate), ferric chloride (FeCl ₃ ), pyridiniump-toluenesulfonate (PPTS), iodine, HY zeolite (Zeolite HY), montmorillonite clay And vanadyl triflate (VO(OTf) ₂ · xH ₂ O). In an embodiment of the invention, concentrated sulfuric acid is used as the catalyst.

Thereafter, in the step (b), the compound represented by the formula (2) is subjected to a deuteration reaction to give an olefin-based compound represented by the formula (3). Deterrent reaction means reacting a reactant (for example, a compound represented by formula (2)) with a deuteration reagent (for example, (triphenyl)alkylphosphonium bromide) in the presence of a suitable base to form An olefinic compound and triphenylphosphine oxide. In a particular example, the deuterium reaction reagent used is (triphenyl) dodecylphosphine bromide. Base species suitable for use with detergency reagents include, but are not limited to, potassium hexamethyldisilazide (KHMDS), sodium hexamethyldisilazide (NaHMDS), Lithium hexamethyldisilazide (LiHMDS), n-butyllithium, isobutyllithium and potassium tert-Butoxide (t-BuOK). In one embodiment, the salt selected is KHMDS.

Next, the step (c) is carried out, and the compound represented by the formula (3) is oxidatively cleaved with an appropriate oxidizing agent to produce a compound represented by the formula (4). The compound represented by the formula (3) is a diol compound, and an oxidizing agent suitable for oxidative cleavage of the diol compound includes, but not limited to, periodic acid (HIO ₄ ), sodium periodate (NaIO ₄ ). Or lead (IV) acetate, Pb (OAc) ₄ ). The oxidizing agent used in a particular embodiment is sodium periodate.

Next, in the step (d), the compound represented by the formula (4) is subjected to a deuteration reaction with a C ₂ alkylene compound (C ₂ -ylide) to give a compound represented by the formula (5). In a particular embodiment of the present invention, the reaction K Ti agent used for the Ph ₃ P = CHCO ₂ Et. This step will simultaneously produce isomers with two different stereo configurations of E- and Z-, so the compound represented by formula (5) is a stereoscopic form containing two stereo configurations of E- and Z- The form of the mixture exists. In a particular example, the E-configuration compound is present in an amount of about 3.2 times the Z-configuration compound content.

Then, the reaction is carried out to the step (e), and the compound represented by the formula (5) is reduced to a compound represented by the formula (6) under the environment of hydrogen and a suitable catalyst. Suitable hydrogenation catalysts such as palladium on carbon (Pd/C), nickel (Ni), palladium (Pd), platinum (Pt), palladium hydroxide (Pd(OH) ₂ ) or triphenylphosphine chloride ((Ph ₃ P) ₃ RhCl).

Finally, in step (f), a one-pot reaction deprotection and intramolecular lactonization is performed to produce a compound represented by the formula (6). ) the compound shown. The deprotection of the alkyl ester is generally carried out using an acid or a base such as acid (HCl), trifluoroacetic acid (THA) or pyridiniump-toluenesulfonate (PPTS). By way of illustration and not limitation, in one embodiment of the invention, concentrated HCl is used to remove the ethyl ester (Et) functional group of the compound of formula (7). As for the intramolecular lactonization reaction, it is mostly carried out by using an acid or a suitable catalyst.

This method utilizes an asymmetric synthetic methodology, so that the image-isomerized pure hydroxy-γ-lactone can be synthesized simply and efficiently (as shown in formula (7)). Further, when the lychee saponin and the derivative thereof are prepared according to the above method, the crude product or the mixture can be subjected to the next preparation step without purification or separation of the product in some steps, and the time and money cost required for the preparation can be greatly saved. . Furthermore, the reaction carried out in each step of the method can be carried out at about 20-30 ° C without complicated heating and cooling steps, which not only reduces the complexity of the process, but also reduces the equipment and equipment required in the preparation process. Labor costs. It is understood by those of ordinary skill in the art that the temperature of the reaction system may be unnecessarily reduced when the reagent is added before the start of each reaction step to avoid the thermal energy that is instantaneously released by the addition of the reagent destroying the reactants. Additionally, in accordance with an embodiment of the present invention, the overall yield of the process can be up to about 50%, which is much higher than the yield of the prior art for the preparation of the saponin or other saponin derivatives.

Further, this compound can be further prepared into other saponin derivatives. For example, according to another embodiment of the present invention, the compound represented by the formula (7) can be acetylated to form a compound of the formula (8).
(8).

In another aspect, the present invention provides a novel saponin derivative (shown in the above formula (1)).

According to an embodiment of the present invention, the structural formula of the above-mentioned saponin derivative is represented by the following formula (7-1):
(7-1).

According to another embodiment of the present invention, the structural formula of the above-mentioned saponin derivative is represented by the following formula (8-1):
(8-1).

The present invention also encompasses the medical use of the saponin derivative (shown in the above formula (1)). Specifically, the present invention unexpectedly finds that the saponin derivative (particularly the compound represented by the formula (7-1) and the formula (8-1)) is capable of inhibiting the expansion of esophageal cancer cells; therefore, the present invention One aspect relates to a pharmaceutical composition for treating esophageal cancer, particularly esophagus squamous cell carcinoma (also known as esophagus epidermoid carcinoma).

According to an embodiment of the invention, the pharmaceutical composition comprises a therapeutically effective amount of a compound of formula (7-1) or formula (8-1), and a pharmaceutically acceptable adjuvant.

Various embodiments are set forth below to clarify some aspects of the present invention so that those skilled in the art can practice the invention. Therefore, these examples should not be construed as limiting the scope of the invention. The present invention is based on the description herein, and can be applied without excessive derivation. All documents mentioned herein are considered to be fully incorporated into this specification.

Example 1 Preparation of a compound of the formula (7-1)

(4S,5R)-(+)-5-Hydroxy-4-octalactone ((4S,5R)-(+)-5-hydroxy-4-octadecanolide).

Example 1.1 Preparation of a compound of formula (2)

D-(-)-esaose (0.586 g, 3.90 mmol) was suspended in dry acetone (19.5 mL, 0.2 M) and stirring was continued. Concentrated sulfuric acid (22 μL, 0.39 m) at 0 ° C Moor) was dropped into the suspension and stirred for 10 minutes. Thereafter, stirring was continued for 2 hours at room temperature (about 24-26 ° C, the same applies hereinafter) until a clear reaction solution was obtained. The reaction mixture was then neutralized with solid barium hydroxide (Ba(OH) ₂ ) at 0 °C. The solid was filtered off using a short Celite pad, then the celite pad was rinsed with 15 ml of ethyl acetate and the filtrate was collected. The filtrate was concentrated under reduced pressure to give a colorless residue. The residue was subjected to flash chromatography using a molar ratio of 2:1 of ethyl acetate and n-hexane as an eluent to obtain a white solid (formula (2)) of 0.637 g. This is a single alpha-isomer of 2,3-O-isopropylidene-α-D-lyxofuranose with a yield of 86%.
(2)

R _f = 0.5 (ethyl acetate); mp = 81-83 ° C; [α] 21 D +28.0 (c = 1.2, CHCl 3); FT-IR (neat) v max 3398, 2985, 2941, 1646, 1540, 1456, 1375, 1210, 1057, 861, 578, 513 cm ^-1 ; ¹ H NMR (300 MHz, CDCl ₃ ): δ 5.44 (d, J = 2.1 Hz, 1H), 4.83 (dd, J = 6.0 , 3.9 Hz, 1H), 4.64 (d, J = 6.0 Hz, 1H), 4.28 (dd, J = 9.0, 4.8 Hz, 1H), 4.01-3.88 (m, 2H), 2.70 (d, J = 2.1 Hz , 1H), 2.28 (dd, J = 7.2, 4.8 Hz, 1H), 1.47 (s, 3H), 1.32 (s, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ 112.6 (C), 100.7 ( CH), 85.6 (CH), 80.1 (CH), 80.0 (CH), 60.9 (CH ₂ ), 25.8 (CH ₃ ), 24.5 (CH ₃ ); HRMS-ESI [M + Na] ⁺ Calcd for C ₈ H ₁₄ O ₅ Na 213.0738, Found 213.0733.

Example 1.2 Preparation of a compound of the formula (3-1)

Treatment of brominated (triphenyl) dodecylphosphine (dodecyl) at 0 ° C with potassium hexamethyldisilazide (KHMDS) (3.47 mmol, 0.5 M dissolved in toluene) Triphenyl)phosphornium bromide) (1.755 g, 3.47 mmol), the reaction mixture was kept at 0 ° C for 1 hour; then the compound of formula (2) obtained in Example 1.1 (188 mg, 0.99 mmol) The solid was quickly added to the solution and stirred at 0 ° C for 10 minutes. The reaction mixture was then stirred at room temperature for 6 hours. Cold water was carefully added to the above reaction at 0 ° C, and the mixture was extracted with ethyl acetate, then dried and evaporated under reduced pressure to give a yellow powder. Using hexane and ethyl acetate (1:4 v/v) as the eluent, the slurry was subjected to flash column chromatography to obtain 0.865 g of a white solid (the compound of formula (3-1). ), this is (4S,5R)-2,2-dimethyl-4-((1R)-1,2-dihydroxyethyl)-5-((1Z)-1-trienyl)- 1,3-dioxolane ((4S,5R)-2,2-dimethyl-4-
((1R)-1,2-dihydroxyethyl)-5-((1Z)-1-tridecenyl)-
The Z-stereoisomer of 1,3-dioxolane) has a yield of 81%.
(3-1)

R _f = 0.2 (ethyl acetate: n-hexane = 1:4 (v/v)); mp = 63-65 °C; [α] ²⁸ _D –35.9 (c = 1.1, CHCl ₃ ); FT-IR ( Neat)v _max 3432, 2924, 2854, 1742, 1655, 1464, 1378, 1215, 1059, 882, 721, 514 cm ^-1 ; ¹ H NMR (300 MHz, CDCl ₃ ): δ 5.74-5.50 (m, 2H ), 5.00 (t, J = 7.5 Hz, 1H), 4.13 (t, J = 4.8 Hz, 1H), 3.68-3.54 (m, 3H), 2.57 (bs, 1H), 2.36 (bs, 1H), 2.17 -1.97 (m, 2H), 1.51 (s, 3H), 1.39, (s, 3H), 1.25 (bs, 20H), 0.87 (t, J = 5.1 Hz, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ 135.8 (CH), 124.6 (CH), 108.5 (C), 77.7 (CH), 73.0 (CH), 69.9 (CH), 64.3 (CH ₂ ), 31.9 (CH ₂ ), 29.6 (CH ₂ ) , 29.6 (CH ₂ ), 29.5 (CH ₂ ), 29.4 (CH ₂ ), 29.3 (CH ₂ ), 29.2 (CH ₂ ), 27.7 (CH ₂ ), 27.3 (CH ₃ ), 24.9 (CH ₃ ), 22.6 (CH ₂ ), 14.1 (CH ₃ ); HRMS-ESI [M + Na] ⁺ Calcd for C ₂₀ H ₃₈ O ₄ Na 365.2662, Found 365.2667.


Example 1.3 Preparation of a compound of the formula (4-1)

The diol compound of formula (3-1) in Example 1.3 (102 mg, 0.30 mmol) was dissolved in EtOH/H 2 O (1 mL, 2:1 (v/v)); at 0 ° C Sodium periodate (127 mg, 0.60 mmol) was added in one portion and stirring was continued for 10 minutes, then the ice bath was removed. Thereafter, stirring was continued for 3 hours at room temperature. After the starting material was consumed, the reaction mixture was filtered to remove the solid component, and the filtrate was concentrated in vacuo to give a syrup of formula (4-1) (86 mg), (4S, 5R). )-2,2-dimethyl-4-carbamimido-5-((1Z)-1-trienyl)-1,3-dioxocyclopentane ((4S,5R)-2,2 -Dimethyl-4-formyl- 5-((1Z)-1-tridecenyl)-1,3-dioxolane), yield 93%.
(4-1)

R _f = 0.2 (ethyl acetate: n-hexane = 1:1 (v/v)); [α] ²⁷ _D -29.7 (c = 0.3, CHCl ₃ ); FT-IR (neat) v _max 2986, 2925, 1738, 1658, 1463, 1377, 1242, 1217, 1161, 1065, 868, 799, 722 cm ^-1 ; ¹ H NMR (300 MHz, CDCl ₃ ): δ 9.43 (d, J = 3.3 Hz, 1H), 5.63 -5.54 (m, 1H), 5.24 (t, J = 11.1 Hz, 1H), 5.08 (t, J = 7.8 Hz, 1H), 4.25 (dd, J = 7.8, 3.3 Hz, 1H), 2.08-1.89 ( m, 2H), 1.50 (s, 3H), 1.33 (s, 3H), 1.18 (bs, 18H), 0.79 (t, J = 6.3 Hz, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ 199.3 (CH), 136.1 (CH), 122.7 (CH), 110.5 (C), 82.1 (CH), 74.5 (CH), 31.6 (CH ₂ ), 29.4 (CH ₂ ), 29.4 (CH ₂ ), 29.3 (CH ₂ ), 29.2 (CH ₂ ), 29.1 (CH ₂ ), 28.9 (CH ₂ ), 28.9 (CH ₂ ), 27.8 (CH ₂ ), 27.1 (CH ₃ ), 25.0 (CH ₃ ), 22.4 (CH ₂ ) , 13.8 (CH ₃ ); HRMS-ESI [M + Na] ⁺ Calcd for 333.2400, Found 333.2388.

Example 1.4 Preparation of a compound of the formula (5-1E) and formula (5-1Z)

The aldehyde primary product of formula (4-1) (398 mg, 1.28 mmol) prepared in Example 1.3 was dissolved in dry CH ₂ Cl ₂ (7.8 mL, 0.165 M) at 0 ° C To this solution was added 940 mg (2.56 mmol) of methyl (triphenylphosporanilidine) acetate, and stirring was continued at 0 ° C for 10 minutes. The resulting solution was stirred at room temperature for 3 hours, and concentrated under reduced pressure to remove solvent. The above slurry residue was purified using EtOAc / n-hexane (1:20 v/v) as eluent to afford 400 mg of yd. This product contains the E- and Z-stereoisomers of the compound of the formula (5-1) (ca. 3.2: 1.0), wherein the compound 5-1E is (4S, 5R)-2, 2-dimethyl 4-(1E)-ethoxycarbonylvinyl)-5((1Z)-1-trienyl)-1,3-dioxocyclopentane ((4S,5R)-2,2- Dimethyl-4-
((1E)-ethoxycarbonylethenyl)-5-((1Z)-1-
Tridecenyl)-1,3-dioxolane); and compound 5-1Z is (4S,5R)-2,2-dimethyl-4-(1Z)-ethoxycarbonylvinyl)-5-((1Z) -1-trienyl)-1,3-dioxolane ((4S,5R)-
2,2-Dimethyl-4-((1Z)-ethoxycarbonylethenyl)-
5-((1Z)-1-tridecenyl)-1,3-dioxolane).
(5-1)

R _f = 0.5 (ethyl acetate: n-hexane = 1:20 (v/v)); FT-IR (neat) v _max 2925, 2854, 1719, 1644, 1466, 1370, 1188, 1049, 874, 721, 508 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ): δ (5-1E) 6.78 (dd, J = 15.6, 5.6 Hz, 1H), 6.03 (dd, J = 15.6, 1.6 Hz, 1H), 5.71-5.61 (m, 1H), 5.32-5.24 (m, 1H), 5.07-5.02 (m, 1H), 4.69 (dt, J = 4.8, 1.6 Hz, 1H), 4.18 (q, J = 7.2 Hz, 2H), 2.18-1.92 (m, 2H), 1.53 (s, 3H), 1.40 (s, 3H), 1.39-1.25 (m, 18H), 0.86 (t, J = 6.8 Hz, 3H); (5- 1Z) 6.19 (dd, J = 12.0, 8.0 Hz, 1H), 5.84 (dd, J = 12.0, 1.6 Hz, 1H), 5.56-5.50 (m, 1H), 5.22-5.16 (m, 1H), 5.07- </ RTI></RTI><RTIgt; (s, 3H), 1.39-1.25 (m, 18H), 0.86 (t, J = 6.8 Hz, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ) δ 165.9 (C), 144.0 (CH), 135.5 ( CH), 135.0 (CH), 125.1 (CH), 124.6 (CH), 122.6 (CH), 121.2 (CH), 119.1 (CH), 109.2 (C), 77.2 (CH), 75.4 (CH), 74.6 ( CH), 74.2 (CH), 60.4 (CH ₂ ), 60.3 (CH ₂ ), 31.6 (CH ₂ , 31.5 (CH ₂ ), 29.6 (CH ₂ ), 29. 4 (CH ₂ ), 29.3 (CH ₂ ), 29.3 (CH ₂ ), 29.2 (CH ₂ ), 29.0 (CH ₂ ), 28.7 (CH ₂ ), 28.1 (CH ₂ ), 27.8 (CH ₂ ), 27.6 ( CH ₂ ), 27.5 (CH ₂ ), 25.4 (CH ₃ ), 22.6 (CH ₂ ), 14.2 (CH ₃ ), 14.1 (CH ₃ ); HRMS-ESI [M + Na] ⁺ Calcd for C ₂₃ H ₄₀ O ₄ Na 403.2819, Found 403.2820.

Example 1.5 Preparation of a compound of formula (6-1)

The compound of the formula (5-1) (400 mg, 1.05 mmol) was dissolved in 5.3 ml of ethyl acetate, and activated 10% Pd/C (38 mg) was added at room temperature. The reaction mixture was stirred under a hydrogen atmosphere (60 psi) at room temperature for 1 hour, and the reaction was monitored by TLC (ethyl acetate: n-hexane = 1:1 (v/v), Rf = 0.7). The short diatomaceous earth disk was filtered and the celite pad was rinsed with ethyl acetate (15 ml). The filtrate was concentrated under vacuum, and without further purification, a saturated ester compound was obtained (yield of formula (6-1); (4S,5R)-2,2-dimethyl-4-methoxy Carbonylethyl-5-tridecyl-1,3-dioxocyclopentane, (4S,5R)-2,2-Dimethyl-4-methoxy carbonylethyl-5-tridecyl-1,3-dioxolane) Yield 99 %.
(6-1)

R _f = 0.25 (ethyl acetate: n-hexane = 1:20 (v/v)); [α] ²⁸ _D -14.5 (c = 0.9, CHCl ₃ ); FT-IR (neat) v _max 3539, 2917, 2849, 1737, 1465, 1370, 1182, 1065, 877, 718 cm ^-1 ; ¹ H NMR (400 MHz, CDCl ₃ ): δ 4.12 (q, J = 6.8, 2H), 4.10-40.0 (m, 2H) , 2.60-2.30 (m, 2H), 1.80-1.60 (m, 2H), 1.40 (s, 3H), 1.31 (s, 3H), 1.24 (bs, 24H), 0.86 (t, J = 6.6 Hz, 3H ¹³ C NMR (100 MHz, CDCl ₃ ): δ 173.5 (C), 107.5 (C), 77.9 (CH), 76.8 (CH), 60.3 (CH ₂ ), 32.0 (CH ₂ ), 30.9 (CH _{2 )} ), 30.8 (CH ₂ ), 29.7 (CH ₂ ), 29.7 (CH ₂ ), 29.7 (CH ₂ ), 29.6 (CH ₂ ), 29.6 (CH ₂ ), 29.5 (CH ₂ ), 29.4 (CH ₂ ), 26.4 (CH ₂ ), 25.4 (CH ₂ ), 22.7 (CH ₂ ), 28.6 (CH ₃ ), 25.9 (CH ₃ ), 14.2 (CH ₃ ), 14.1 (CH ₃ ); HRMS-ESI [M + Na] ⁺ Calcd for C ₂₃ H ₄₄ O ₄ Na 407.3132, Found 407.3134.

Example 1.6 Preparation of a compound of formula (7-1)

The ethyl ester compound of formula (6-1) (60 mg, 0.16 mmol) was dissolved in tetrahydrofuran (THF) / H ₂ O (3.9 mL, 10:3 v/v) at 0 ° C Concentrated hydrochloric acid (0.65 mL, 7.80 mmol) was added to this solution and stirred for 10 min. Then, the reaction mixture was stirred at 30 ° C for 3 hours, after which the mixture was diluted with diethyl ether (Et ₂ O) and then neutralized with saturated aqueous sodium hydrogen carbonate (NaHCO ₃ ). Thereafter, the neutralized aqueous layer was extracted with diethyl ether; the organic layer was washed with brine, dried over magnesium sulfate (MgSO ₄ ) and evaporated. The residue was chromatographed on a silica gel column (ethyl acetate: n-hexane = 1:3) to give 41 mg of white solid (yield 88%) which is represented by formula (7-1) ( 4S,5R)-(+)-5-Hydroxy-4-octalactone ((4S,5R)-5-Hydroxy-4-octadecanolide).
(7-1)

R _f = 0.2 (ethyl acetate: n-hexane = 1:3 (v/v)); mp = 48-50 ° C; [α] ²⁸ _D +10.0 (c 0.4, CHCl ₃ ); FT-IR (neat v _max 3539, 3413, 2954, 2917, 2848, 2360, 2341, 1757, 1460, 1189 cm ^-1 ; ¹ H NMR (300 MHz, CDCl ₃ ): δ 4.44 (td, J = 7.2 Hz, 1H), 4.00-3.90 (m, 1H), 2.70-2.40 (m, 2H), 2.40-2.00. (m, 2H), 1.86 (s, 1H), 1.70-1.40 (m, 2H), 1.26 (bs, 22H) , 0.88 (t, J = 6.0 Hz, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ): δ 177.6 (C), 82.9 (CH), 71.3 (CH), 31.9 (CH ₂ ), 31.8 (CH ₂ ), 29.7 (CH ₂ ), 29.6 (CH ₂ ), 29.6 (CH ₂ ), 29.5 (CH ₂ ), 29.5 (CH ₂ ), 29.5 (CH ₂ ), 29.32 (CH ₂ ), 28.7 (CH ₂ ), 25.6 (CH ₂ ), 22.7 (CH ₂ ), 21.0 (CH ₂ ), 14.1 (CH ₃ ); HRMS-ESI [M + Na] ⁺ Calcd for C ₁₈ H ₃₄ O ₃ Na 321.2400, Found 321.2400.

Example 2 Preparation of a compound of the formula (8-1)

The compound of the formula (7-1) (149 mg, 0.5 mmol), 4-dimethylamino pyridine (DMAP) (7 mg, 0.05 mmol) and imidazole (41) Mg, 0.6 mmol, placed in a baked single-necked original flask and evacuated to a vacuum system for 1 hour. After 1 hour, the plug was sealed with a serum plug and a nitrogen balloon was inserted in the ice bath. Under normal conditions, anhydrous dichromromethane (2.5 ml, 0.2 M) was added, and after stirring for 5 minutes, acetic acid anhydride (56 μL, 0.6 mmol) was slowly added to the reaction mixture, which was stirred under ice bath. After 10 minutes, it was moved to room temperature for 12 hours. After completion of the reaction, the reaction was neutralized with a 1 N aqueous solution of hydrochloric acid in an ice bath, and the solution was poured into a separating funnel, and the organic layer was washed with distilled water. Finally, an appropriate amount of anhydrous magnesium sulfate (magnesium sulfate) was added to the organic layer to remove water, and the magnesium sulfate was removed by suction filtration, and the solvent was concentrated under reduced pressure to give 163 mg of a white solid (the compound of formula (8-1)). (4S,5R)-(+)-5-Ethyloxy-4-octadecanolide ((4S,5R)-5-Acetoxy-4-octadecanolide), the yield was 96%.
(8-1)

Rf = 0.6 (ethyl acetate: n-hexane = 1:1 (v/v)); mp = 41 ° C; [α] ²⁴ _D +32.0 (c 0.12, CHCl ₃ ); FT-IR (neat) v _max 2924 , 2855, 1782, 1461, 1371, 1234, 1178, 1029 cm-1; ¹ H NMR (300 MHz, CDCl ₃ ): δ 5.11-5.06 (m, 1H), 4.55-4.50 (m, 1H), 2.61-2.46 (m, 2H), 2.30-2.21 (m, 1H), 2.17-2.09 (m, 1H), 2.07 (s, 3H) ), 1.62-1.52 (m, 2H), 1.24 (s, 20H), 0.89 (t, J = 6.6 Hz, 3H); ¹³ C NMR (100 MHz, CDCl ₃ ): δ176.6 (C), 170.2 ( C), 79.9 (CH), 73.6 (CH), 31.9 (CH ₂ ), 30.0 (CH ₂ ), 26.7 (CH ₂ ), 29.6 (CH ₂ ), 29.6 (CH ₂ ), 29.5 (CH ₂ ), 29.4 (CH ₂ ), 29.4 (CH ₂ ), 29.3 (CH ₂ ), 28.1 (CH ₂ ), 25.1 (CH ₂ ), 22.8 (CH ₂ ), 22.7 (CH ₂ ), 21.0 (CH ₃ ), 14.1 (CH) ₃ ); HRMS-ESI [M+Na] ⁺ Calcd for C ₂₀ H ₃₆ O ₄ Na 363.2506, Found 363.2506.

Example 3 Evaluation of Antitumor Effects of Compounds of Formula (7-1) and (8-1)

The CE48T cell line is an esophageal cancer cell derived from a patient with male esophageal squamous cell carcinoma (also known as esophageal epidermoid cell carcinoma). In this example, a CE48T cell line (providing a source) was used for the in vitro test, by discussing the formula (7- 1) The cytotoxicity of the compound of the formula (8-1) on the CE48T cell line to evaluate whether the compounds have an anti-esophageal effect.

CE48T cells were cultured in Dulbecco's modified Eagle's medium (DMEM) and added with 10% fetal calf serum (FCS), 100 units/ml of penicillin, 100 μg/ml. Streptomycin and 2 mM L-glutamic acid were maintained at 37 ° C in a humid environment (5% CO ₂ and 95% air).

At the beginning of the experiment, CE48T cells were treated with compounds of formula (7-1) or formula (8-1) at a concentration of 0.01-0.05 mg/ml for 24 hours, and the control group was either DMSO or no lactone. The ring of the saponin derivative (as shown in the formula (9)) was treated, and thereafter, the survival rate of each group of cells was calculated. The results are shown in Figure 2.
(9)

As can be seen from Fig. 2, the two compounds of formula (7-1) and (8-1) exhibited dose-dependent cytotoxicity at doses of 10-50 μg/mL, respectively. The IC50 of the compounds of formula (7-1) and (8-1) for CE48T cell lines was calculated to be 20 and 25 μg/mL, respectively. In terms of cell type, CE48T cells treated with a compound of formula (7-1) or (8-1) at 30 μg/mL showed significant cell type changes after 24 hours of treatment. The above results show that for esophageal cancer cells, either the compound of the formula (7-1) or the compound of the formula (8-1) can effectively inhibit the proliferation of esophageal cancer cells.

In contrast, no significant cytotoxicity was observed in the control group treated with DMSO or the compound of the formula (9).

This experimental example demonstrates for the first time that a derivative of the saponin (for example, a compound of the formula (7-1) or the formula (8-1)) is cytotoxic to esophageal cancer cells, and thus the compound can be used as a pharmaceutical composition for treating esophageal cancer. The active ingredient.

Although the embodiments of the present invention are disclosed in the above embodiments, the present invention is not intended to limit the invention, and the present invention may be practiced without departing from the spirit and scope of the invention. Various changes and modifications may be made thereto, and the scope of the invention is defined by the scope of the appended claims.

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates a method for preparing an individual saponin or a derivative thereof according to an embodiment of the present invention;

Figure 2 illustrates the cell viability of CE48T cells treated with the lycopene saponin analog of the present invention, in accordance with one embodiment of the present invention.

Claims (10)

A method for preparing the saponin of the formula (7), Wherein n = 7-11 is a positive integer; the method comprises the steps of: (a) subjecting D-lyxose to a isopropylidenation reaction to form a compound of formula (2) (b) The compound represented by the formula (2) is subjected to a Wittig olefination to produce a compound represented by the formula (3). (c) subjecting a compound represented by formula (3) to oxidative cleavage to produce a compound represented by formula (4) (d) The compound represented by the formula (4) is subjected to a Wittig olefination reaction to produce a compound represented by the formula (5). (e) hydrogenating a compound represented by formula (5) to give a compound represented by formula (6) And (f) the compound represented by the formula (6) is lactonized to give a compound represented by the formula (7). A method for preparing the saponin of the formula (8), Wherein n = 7-11 is a positive integer; the method comprises the steps of: (a) subjecting D-lyxose to a isopropylidenation reaction to form a compound of formula (2) (b) The compound represented by the formula (2) is subjected to a Wittig olefination to produce a compound represented by the formula (3). (c) subjecting a compound represented by formula (3) to oxidative cleavage to produce a compound represented by formula (4) (d) The compound represented by the formula (4) is subjected to a Wittig olefination reaction to produce a compound represented by the formula (5). (e) hydrogenating a compound represented by formula (5) to give a compound represented by formula (6) (f) the compound represented by the formula (6) is lactonized to give a compound represented by the formula (7); And (g) acetylating the compound represented by the formula (7) to give a compound of the formula (8). The method according to claim 1 or 2, wherein the step (a) and the step (g) are respectively carried out using a concentrated acid as a catalyst. The method of claim 1 or 2, wherein the reagents for the deuteration reaction in step (b) and step (d) are (triphenyl) C7-11 alkylphosphine bromide and Ph ₃ P=CHCO _{2 respectively.} Et. The method of claim 1 or 2, wherein the oxidative cleavage of step (c) is carried out using any oxidizing agent selected from the group consisting of NaIO4, HIO4 and Pb(OAc)4. The method of claim 1, wherein each step is carried out at 20-30 °C. A saponin derivative as shown in formula (7-1): A pharmaceutical composition for treating esophageal cancer comprising a therapeutically effective amount of a saponin derivative as claimed in claim 7; and a pharmaceutically acceptable adjuvant.
A saponin derivative represented by the formula (8-1):
(8-1).
A pharmaceutical composition for treating esophageal cancer comprising a therapeutically effective amount of a saponin derivative as claimed in claim 9; and a pharmaceutically acceptable adjuvant.