JPH0369912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Background and Summary of the Invention The present invention relates to a novel bruceolide derivative represented by the following formula and a method for producing the same. (In the formula, R ₁ represents hydrogen, a t-butyldimethylsilyl group, a methoxyethoxymethyl group, or a methoxymethyl group, and R ₂ represents hydrogen or a C ₅ to C ₁₈ straight chain α,
Indicates a β-unsaturated carboxylic acid residue. However, R ₁ = R ₂
Excludes compounds represented by =H. ) The antitumor effects of various natural products and compounds derived from natural products have long attracted attention, and a small number of these have already been put into practical use, but they all have advantages and disadvantages in terms of efficacy, toxicity, etc. The current situation is that there is nothing that can be said to be completely satisfying. Quassinoids, which include the bruceolide compound that is the subject of the present invention, are also the active ingredient of Brucea antidysenterica Mill, a plant of the Bitteraceae family that has been used in the treatment of cancer in Ethiopia. Discovery (Kupchan et al., J.Org.Chem., 38 , 178
(1973); British Patent No. 1440094), natural products such as bruceantarin, brucein B, dihydrobruceantin, brucein D, brucein E, and bruceoside A were produced from the same plant and plants of the same genus. or artificial congener compounds derived from them have been clarified (in addition to the above publications,
40, 648 (1975); Ibid. 46 , 1138 (1981); J.Pharm.
Sci. 68 , 883 (1979)). However, the present inventor discovered that brusatol has two fewer carbon atoms in the carboxylic acid residue bonded to the 15th carbon position than the above-mentioned bruceantin ().
Below formula, J.Org.Chem, 33 , 429 (1963)). As a result of conducting research to create more effective anticancer substances, we directly created a bruceolide derivative (formula (') below) obtained by chemically removing the 15-position ester group of the above compound (). It has been found that a novel bruceolide derivative represented by the following formula () can be obtained by re-esterification with a chain α,β-unsaturated carboxylic acid residue. [(In the formula, R ₁ is a t-butyldimethylsilyl group,
A methoxyethoxymethyl group or a methoxymethyl group, _R2 represents a residue of a _C5 to _C18 linear α,β-unsaturated carboxylic acid. ) However, compounds represented by R-R=H are excluded. ] However, the actual reaction is carried out, for example, according to the following steps. That is, for example, brusatol () extracted and isolated from the seeds of Bruceajavanica Merr. (Chinese name: B. gall) or B. sumatrana according to a conventional method, such as t-butyldimethyl. Etherification in a conventional manner with an etherification agent such as silyl chloride, chloromethyl methoxyethyl ether (MEMCl) or chloromethyl methyl ether (MOMCl) gives the compound (). Here, the hydroxyl group at the 3-position of the compound () is converted to an ether group to form the compound (), and the hydroxyl group at the 15-position of the compound (') is selectively converted into a C ₅ to C ₁₈ linear chain α, β. - This is to introduce an unsaturated carboxylic acid. When compound () is solvolyzed using IN potassium methoxide/methanol solution, compound (') from which the 15-position ester residue is removed is obtained.
Next, this compound (') is esterified with an acid chloride of a desired _C5 to _C18 linear α,β-unsaturated carboxylic acid and potassium carbonate, resulting in a compound () in which the hydroxyl group at position 15 is re-esterified. is obtained. Finally, acid hydrolysis of this compound () with an acetonitrile solution of hydrofluoric acid or a methanol solution of P-toluenesulfonic acid yields the corresponding compound () with a free hydroxyl group at the 3-position. In the above compounds, the substituent R ₂ in the compound and refers to a residue of a C ₅ to _{C 18} linear α,β-unsaturated carboxylic acid as described above, and specific examples thereof include, for example, trans or cis -2-pentenoic acid, trans or cis-2-hexenoic acid, trans or cis-2-heptenoic acid, trans or cis-2-octenoic acid, trans or cis-
2-nonenoic acid, trans or cis-2-decenoic acid, trans or cis-2-undecenoic acid, trans or cis-2-dodecenoic acid, trans or cis-2-tridecenoic acid, trans or cis-2-tetradecenoic acid, trans or cis-
2-pentadecenoic acid, trans or cis-2-
These include residues of hexadecenoic acid, trans or cis-2-heptadenoic acid and trans or cis-2-octadecenoic acid. (B) Effect of the compound of the invention The compound of the invention (') is an important intermediate of the compound (), and the compound of the invention () has strong antitumor activity against murine leukemia P388. Furthermore, its toxicity is lower than that of the well-known brusatol (2007), so its future development as a new antitumor drug is expected. The toxicity ^*2 and life extension rate (ILS%) ^*3 of representative compounds belonging to compound () are shown below in Table 1. [Table] [Table] (C) Physicochemical constants of the compounds of the present invention, etc. The physicochemical constants of the compounds of the present invention are shown in Tables 2 to 4 below.
Shown as [Table] [Table] [Table] [Table] *Consistent with the numbers in the examples.
[Table] [Table] *Consistent with compound numbers in Examples.
[Table] [Table] *Consistent with compound numbers in Examples.
(D) Production example of the compound of the present invention (1) Production of 3-O-t-butyldimethylsilyl brusatol (2) ~ Dissolve 16 g of brusatol (compound (1) ~) in 640 ml of dimethylformamide, 15.76 g of dimethylsilyl chloride and 15.76 g of imidazole
g was added thereto, and the mixture was stirred at room temperature overnight. Approximately 2 parts of water was added to the reaction mixture to stop the reaction, and the mixture was extracted four times with ether. The ether layer was washed once with water, then twice with saturated brine, and then dried over anhydrous magnesium sulfate. Kieselgel 60 (manufactured by Merck, 70-230 mesh) made by suspending the above ether extract in chloroform
It was loaded onto a column with a diameter of 5 cm packed with 150 g, and eluted with a mixture of chloroform and methanol (20:1). From the eluate, crude 3-O-t-butyldimethylsilylbrusatol (compound (2) ~) was extracted. Obtained 20g. This crude product was recrystallized from benzene to obtain 16.62 g (yield: 85%) of colorless needles. (2) Production of 3-O-t-butyldimethylsilylbruceolide (3) 4.94 g of compound (2) was added to 99 ml of 1N potassium methoxide/methanol solution and stirred. Although 2 dissolved once, it immediately precipitated as a white precipitate, and after 20 minutes, it became a transparent liquid again. After that, 9
Stirring was continued for a minute, followed by neutralization using a methanol solution of hydrochloric acid. Next, potassium chloride precipitated from the reaction solution was filtered off, and methanol was distilled off under reduced pressure.
(The potassium chloride precipitated during distillation was also filtered out each time.)
The residue was loaded onto a column with a diameter of 3.0 cm packed with a suspension of 100 g of Kieselgel 60 (mentioned above) suspended in ethyl acetate, and when eluted with ethyl acetate, the desired 3-O-t-butyldimethyl ~3.69 g of silyl bruceolide (3) was obtained. Yield 86%. (3) 3-O-t-butyldimethylsilyl-15-O
Production of -2'-pentenoyl bruceolide (4) Dissolve ~550 mg of compound (3) in 50 ml of methylene chloride,
1.5 g of potassium carbonate and 1.2 g of 2-pentenoyl chloride were added, and the mixture was stirred at room temperature for 6 days. Thereafter, 2N hydrochloric acid was added to the reaction solution to stop the reaction, and the mixture was extracted four times with ether. The extract was washed once each with saturated aqueous sodium bicarbonate, water, and saturated brine, and then dried over anhydrous magnesium sulfate.
This dry ether solution was purified by column chromatography using Kieselgel 60 (solvent: chloroform/methanol) and preparative thin layer chromatography (Kieselgel 60F _25A 0.5 mm, solvent: chloroform/methanol).
-O-t-butyldimethylsilyl-15-O-2'-
Pentenoyl bruceolide (compound (4) ~), 166 mg
was obtained with a yield of 34%, in addition to 125 mg of raw material (3) ~
was recovered. (4) 3-O-t-butyldimethylsilyl-15-O
-Production of -2'-hexenoylbruceolide (5) - Dissolve 550 mg of compound (3) in 50 ml of methylene chloride,
1.5g of potassium carbonate and 2-hexenoyl chloride
1.2 g was added and reacted at room temperature for 3 days. The reaction product is treated, extracted and purified in the same manner as in Example (3) to obtain the desired 3-O-t-butyldimethylsilyl-15-O-
2′-hexenoylbruceolide (5) ~101mg is 16%
was obtained in a yield of . (5) 3-O-t-butyldimethylsilyl15-O-
Production of 2′-heptenoylbruceolide (6) ~ Dissolve 550 mg of compound (3) in 50 ml of methylene chloride,
1.5 g of potassium carbonate and 1.63 g of 2-heptenoyl chloride were added to this, and the mixture was reacted at room temperature for 8 days. The reaction product was treated, extracted and purified in the same manner as in the previous example (3), resulting in the desired 3-O-t-butyldimethylsilyl-15-O-2'-heptenoylbruceolide 136
mg (yield 35%), in addition to raw material (3) - 125 mg
was recovered. (6) 3-O-t-butyldimethylsilyl-15-O
-Production of 2'-octenoyl bruceolide (7) ~ 550 mg of compound (3) ~ was reacted with 1.30 g of 2-octenoyl chloride for 4 days in the same manner as in Example (3), and the reaction product was reacted in the same manner as in the same example. When processed, the desired 3-O-t-
Butyldimethylsilyl-15-O-2'-octenoylbruceolide (7) ~ 51% yield (yield 198 mg)
In addition, 230 mg of starting compound (3) was recovered. (7) 3-O-t-butyldimethylsilyl-15-O
-Production of -2'-decenoylbruceolide (8) - Dissolve 500 mg of compound (3) in 30 ml of methylene chloride,
To this were added 2.49 g of potassium carbonate and 1.24 g of 2-decenoyl chloride, and the mixture was stirred at room temperature overnight. The reaction product was treated and purified in the same manner as in the previous example (3), and the desired 3-O
~101 mg of -t-butyldimethylsilyl-15-O-2'-decenoylbruceolide (8) was obtained. Yield 16%. (8) 3-O-t-butyldimethylsilyl-15-O
-Production of -2'-tridecenoylbruceolide (9) - Dissolve 555 mg of compound (3) in 50 ml of methylene chloride,
1.6 g of potassium carbonate and 1.6 g of 2-tridecenoyl chloride were added and reacted with stirring at room temperature for 4 days.
The reactant was treated and purified in the same manner as in the previous example (3), and the objective 3
-O-t-butyldimethylsilyl-15-O-2'-
~128 mg of tridecenoyl bruceolide (9) was obtained.
Yield 17%. (9) 15-O-2'-pentenoylbruceolide (10) ~
Production of Compound (4) - 260 mg was dissolved in acetonitrile-47% hydrofluoric acid mixture (10:1) and stirred at room temperature for 5 hours. Next, water was added to the reaction solution and extracted with ether, and the ether layer was washed with saturated brine and dried over magnesium sulfate. The residue obtained by distilling off the solvent from this dry ether solution was loaded into a chromatography column in which 20 g of Kieselgel 60 (Merck's 70-230 mesh) was suspended in chloroform and filled in a column with a diameter of 1.5 cm. Elution with a methanol mixture (100:1) yields the desired 15-O
−2′-pentenoylbruceolide (10) 122mg is 57
% yield. (10) Production of compounds (11~, 12~, 13~ and 15~) The following compounds (11~, 12~) were prepared from compounds (5~, 6~, 7~ and 9~) in the same manner as in Example (9). ~, 13~ and
15~) were synthesized. The results are shown in Table 5 below. [Table] (11) 15-O-2'-decenoylbruceolide
(14) Production of ~ Dissolve ~101 mg of compound (8) in 5 ml of methanol, and
0.5 ml and 270 mg of P-toluenesulfonic acid were added, and the mixture was stirred at room temperature overnight. After completion of the reaction, methanol was removed under reduced pressure, water was added to the residue, and the mixture was extracted five times with chloroform. The chloroform portion was first washed twice with water and then once with saturated brine, dried over magnesium sulfate, and then the solvent was distilled off. The residue was subjected to silica gel chromatography using Kieselgel 60reinst (Art7754, manufactured by Merck) and eluted with a benzene/ethyl acetate solvent to obtain the desired 15-O-2'-
~80 mg of decenoyl bruceolide (14) was obtained. Yield 93%. (12) Production of 3-O-methoxyethoxymethyl brusatol (16) 106 mg of sodium hydride (50% oil) was dispersed in 50 ml of tetrahydrofuran, and 300 mg of brusatol (1) was added at room temperature. Cool the solution in ice, drop 276 mg of chloromethyl methoxyethyl ether dissolved in a small amount of tetrahydrofuran,
It was then stirred at room temperature overnight. After completion, water was added to the reaction mixture and tetrahydrofuran was removed under reduced pressure.
After acidifying the residue with an aqueous potassium hydrogen sulfate solution,
Extraction was performed five times with methylene chloride, and the extract was washed twice each with water and saturated brine, and dried over magnesium sulfate. When the residue obtained by removing the solvent from the methylene chloride solution is purified by silica gel chromatography (Kieselgel 60 (Merck 70-230 mesh), benzene-ethyl acetate system), the desired 3-O-methoxyethoxymethylbrusatol (16) ~ 223mg is 83
% yield and an additional 68 mg of raw material (1) was recovered. (13) 3-O methoxymethylbrusatol (17) ~
Disperse 23 mg of sodium hydride (50% oil) in 20 ml of tetrahydrofuran, add a solution of 55 mg of brusatol (1) in tetrahydrofuran under ice cooling, and after stirring for 1 hour, drop a solution of 42 mg of chloromethyl methyl ether in tetrahydrofuran. The mixture was further stirred at room temperature for 2 hours. Then, saturated brine was added to the reaction solution to stop the reaction, and tetrahydrofuran was distilled off under reduced pressure, followed by extraction with ether four times. The ether solution was washed twice with saturated saline, dried over magnesium sulfate, and then treated in the same manner as in Example (12) above to obtain the desired 3-O-methoxymethylbrusatol.
(17) ~60 mg was obtained. Yield quantitative. (14) Production of 3-O-methoxyethoxymethylbruceolide (18) ~ Dissolve ~50 mg of compound (16) in 0.8 ml of 1N potassium methoxide/methanol solution, and cool to room temperature.
Stirred for 25 minutes. After neutralizing the reaction mixture by adding a methanol solution of hydrochloric acid, precipitated potassium chloride was filtered off. The residue obtained by concentrating the solution under reduced pressure is directly loaded onto preparative thin layer chromatography and purified.
3-O-methoxyethoxymethylbruceolide
(18) ~24.6 mg was obtained. (15) 3-O-methoxymethylbruceolide
(19) Production of ~ Compound (17) ~ 52.3 mg was dissolved in 0.90 ml of 1N potassium methoxide/methanol solution, and heated to 25 ml at room temperature.
After stirring for a minute, the same purification treatment as in Example (14) was performed to obtain 24.6 mg of the desired 3-O-methoxymethylbruceolide (19). Yield 55%. (16) 3-O-methoxyethoxymethyl-15-O
-Production of -2'-decenoylbruceolide (20) ~30 mg of compound (18) was added to 2-
After reacting with 60 mg of decenoyl chloride for 3 days and treating the reaction product in the same manner as in the same example, the desired 3-O-
10 mg of methoxyethoxymethyl-15-O-2'-decenoylbruceolide (20) was obtained. (17) Production of 3-O-methoxymethyl-15-O-2'-decenoylbruceolide (21) 24.6 mg of compound (19) was added to 24.6 mg in the same manner as in the previous example (3).
- reacted with 60 mg of decenoyl chloride for 3 days,
The reaction product was treated in the same manner as in the same example to obtain 8 mg of the desired 3-O-methoxymethyl-15-O-2'-decenoylbruceolide (21). (18) 15-O-2'-decenoylbruceolide
(14) Production of Compound (20) - 10 mg was dissolved in 0.5 ml of dry methylene chloride, 21 mg of zinc bromide was added, and the mixture was stirred at room temperature for 1 hour. The reaction mixture was purified by preparative thin layer chromatography to obtain ~3 mg of the desired 15-O-2'-decenoylbruceolide (14). (19) 15-O-2'-decenoylbruceolide
Production of (14) - 8 mg of compound (21) was dissolved in a hydrogen chloride-methanol solution and stirred at room temperature for 1 hour. The reaction mixture was purified by preparative thin layer chromatography to obtain the desired
5 mg of 15-O-2'-decenoylbruceolide (14) was obtained.

Claims (1)

[Claims] 1. General formula (In the formula, R ₁ represents hydrogen, t-butyldimethylsilyl group, methoxyethoxymethyl group, or methoxymethyl group, and R ₂ represents hydrogen or a C ₅ to C ₁₈ linear α,β-unsaturated carboxylic acid residue. However, R ₁
A novel bruceolide derivative represented by the following formula (excluding compounds represented by =R ₂ =H). 2 General formula (In the formula, R ₁ represents a t-butyldimethylsilyl group, a methoxyethoxymethyl group, or a methoxymethyl group.)
The hydroxyl group at position 15 is esterified with the residue of a _C5 to _C18 linear α,β-unsaturated carboxylic acid to form the general formula (In the formula, R ₁ represents a t-butyldimethylsilyl group, a methoxyethoxymethyl group, or a methoxymethyl group, and R ₂ represents a C ₅ to _{C 18} linear α,β-unsaturated carboxylic acid residue.) 15β-carboxylic acid ester represented by the formula, and then hydrolyzed to give the general formula (In the formula, _R2 represents a _C5 to _C18 linear α,β-unsaturated carboxylic acid residue.)