JPS6247190B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel camptothecin derivative and a method for producing the same. To explain in more detail, the present invention is based on the general formula (In the formula, R ¹ is a lower alkyl group, an alkenyl group, or an aralkyl group, R ² is a lower alkyl group, an allyl group, an aralkyl group, or a hydrogen atom, and R ³
is an acyl group or a hydrogen atom) and a method for producing the same. Camptothecin is a deciduous tree (Camptotheca).
acuminata. It is an antitumor substance with a unique mechanism of action, and has been shown to have strong anticancer effects on experimentally transplanted cancers such as murine leukemia L ₁₂₁₀ and rat Walker 256 sarcoma, but it also has toxic effects. Therefore, its usefulness as a drug is currently limited. Therefore, attempts have been made to chemically convert camptothecin into other substances, that is, to convert it into camptothecin derivatives, thereby reducing toxicity while retaining anticancer activity. However, camptothecin itself is poorly soluble in various organic solvents, and camptothecin has resistance to electrophilic substitution reactions due to the heterocycle in its structure. However, there are various obstacles, and the reality is that it is not as easy to obtain new derivatives as planned on paper. The present inventors had previously succeeded in introducing a hydroxyl group into the 5-position of camptothecin, thereby producing various new camptothecin derivatives. Bases that can generate carbanions, such as NaH, BuLi, LDA (lithium diisopropylamide), t-BuOK, and the general formula RX (wherein R is a lower alkyl group, an alkenyl group, or an aralkyl group, and X is a halogen atom or a sulfone) camptothecin or 20-
By reacting with O-acylcamptothecin, we succeeded in introducing a lower alkyl group, alkenyl group, or aralkyl group into the 5-position of a camptothecin compound. Therefore, the present invention relates to the general formula ()
The present invention provides a novel camptothecin derivative represented by and a method for producing the same. The novel camptothecin derivative according to the present invention is
Utilizing its anticancer effect, it has useful uses as medicine and its intermediates. The present invention will be explained in detail below. The novel camptothecin derivative represented by the general formula () provided by the present invention is produced by the production method of the present invention as follows. The production method of the present invention uses camptothecin or 20-
Starting from O-acylcamptothecin, camptothecin (or camptothecin derivatives ) with a base capable of converting the active methylene compound at the 5-position into a carbanion, such as NaH, BuLi, LDA, t-BuOK, and a compound represented by the general formula RX, It is characterized by introducing a lower alkyl group, alkenyl group or aralkyl group into the 5-position of camptothecin (or camptothecin derivative). To introduce one lower alkyl group, alkenyl group, or aralkyl group at the 5-position of camptothecin and 20-O-acylcamptothecin, the above-mentioned base that converts the active methylene at the 5-position into a carbanion is added to camptothecin. Two times the molar amount was used, and the corresponding molar amount was used for camptothecin derivatives protected at position 20, and the general formula
This can be achieved by using the compound represented by RX in a corresponding molar amount or in a small excess amount relative to camptothecin and camptothecin derivatives. To introduce two identical lower alkyl, alkenyl, or aralkyl groups into the 5-position of camptothecin and 20-O-acylcamptothecin, the above-mentioned base was used in a molar amount more than 3 times that of camptothecin, and the 20-position was protected with an acyl group. 2 for camptothecin derivatives
Using more than twice the molar amount, camptothecin and 20-O-
This can be achieved by using at least twice the molar amount of acylcamptothecin. Furthermore, two different lower alkyl groups at the 5-position,
To introduce an alkenyl group or an aralkyl group,
Using the camptothecin derivative having one lower alkyl group, alkenyl group or aralkyl group at the 5-position obtained as described above as a starting material, the above-mentioned base that produces a carbanion at the 5-position and the above-mentioned general formula This can be efficiently achieved by reacting with a compound of RX. The 5-alkyl-camptothecin according to the present invention has diastereomers with respect to the coordination of the alkyl group, alkenyl group, or aralkyl group at the 5-position. These two diastereomers can be separated by subjecting this 5-substituted camptothecin to high performance liquid chromatography. For example, 5-ethyl-camptothecin (a mixture of two diastereomers) was added to a column SI-608 mmφ using 10% acetone-chloroform as a solvent.
×300mm When subjected to high performance liquid chromatography at a flow rate of 5ml/min, the Rt value was 11.3min and the Rt value
Can be separated into each isomer in 12.9min. These two isomers have NMR spectra in which the methine proton at the 5-position and the methyl proton at the 5-position ethyl group are δ5.82, 0.59, ppm and δ, respectively.
It is observed at 5.75, 0.61, and ppm, but there is almost no difference in other hydrogen-based peaks. 5-Ethylcamptothecin produced as described above is observed as two peaks with almost identical area intensities in a high-performance liquid chromatogram, and therefore has a ratio of two diastereomers of approximately 1:1.
It can be seen that it is a mixture of In the production method of the present invention, either camptothecin or a camptothecin derivative can be used as a starting material; When unprotected camptothecin is used, the base is consumed by the hydroxyl group at the 20th position, so more than twice the molar amount of base is required relative to camptothecin. The hydroxyl group at position 20 can be protected by a conventional method, but acylated, especially acetylated, camptothecin derivatives have higher solubility than camptothecin and are easier to perform subsequent operations.
Since it is easy to deacetylate the 20-position if necessary, it is preferable to use a derivative of camptothecin with the hydroxyl group at the 20-position protected as the starting material. That is, after acetylating the 20-position of camptothecin, a reaction is carried out in an aprotic solvent using a base such as NaH, BuLi, and the compound represented by the general formula RX, and the 5-position of camptothecin is
After introducing a lower alkyl group, alkenyl group or aralkyl group at the position, it is preferable to remove the acetyl group at the 20th position by a conventional method, if necessary, to obtain the novel camptothecin derivative of the present invention. The present invention will be further explained below with reference to Examples, but the present invention is not limited to these Examples. Example 1 20-O-acetylcamptothecin (130mg0.33
mmole) in anhydrous DMF (5 ml), add 60% NaH (14.4 mg 0.36 mmole) under a N ₂ stream, and stir for 10 minutes under ice cooling. Add _CH3T (28.0μ
About 0.45 mmole) was added all at once, and stirring was continued for 30 minutes in an ice bath and then for 5 hours at room temperature. DMF was distilled off from this reaction mixture at 60°C under reduced pressure, and the residue was dried under reduced pressure and purified by column chromatography on silica gel (10 g) to obtain 49.5 mg of 5-methyl-20-O-acetylcamptothecin (isolated yield: 38.1%). Starting material (4.7mg3.6
%) will be recovered. mp: 265-269℃ IRν ^KBr _nax cm ^-1 : 2980, 2930, 1755, 1743, 1235
,
790, 760, NMR (CDCl ₃ ) δppm: 0.98 (1.5H, t, J = 8.0
Hz), 1.0 (1.5H, t, J=8.0Hz), 1.90
(1.5H, d, J = 6.0Hz), 1.91 (1.5H, d, J
=6.0Hz), 2.20 (1.5H, s), 2.30 (1.5H,
s), 2.06-2.28 (2H, m), 5.30, 5.62
(two, 1Hs, dxd, J=18.0Hz), 5.70 (1H,
q, J=8.0Hz), 7.10 (1H, s), 7.52-8.10
(4H, m), 8.20 (1H, s) MS m/e: 404 [M ⁺ ] C ₂₃ H ₂₀ N ₂ O ₅ = 404.1372 Example 2 1 ml of 5-methyl-20-O-acetylcamptothecin (30 mg) Suspend in water and add concentrated hydrochloric acid (5 ml) to dissolve. After continued stirring for 36 hours at room temperature, 80
ml of water and extracted with CHCl ₃ (100 ml x 3).
Dry the chloroform layer with magnesium sulfate. When the obtained evaporation residue is recrystallized with ethanol, 5-methylcamptothecin is obtained as pale yellow-white needle crystals (quantitative) mp: 249-255℃ (from methanol) IRν ^KBr _nax cm ^-1 : 3520, 2975 , 2930, 1750, 1655
,
1595, 1160, 1035, 790, 760, NMR (CDCl ₃ ) δppm: 1.04 (1.5H, t, J = 5.9
Hz), 1.06 (1.5H, t, J = 5.9Hz), 1.91
(1.5H, d, J = 6.8Hz), 1.92 (2H, q, J =
5.9Hz), 1.93 (1.5H, d, J = 6.8Hz), 5.28~
5.74 (two 1Hs, dxd, J=16.6Hz), 5.75
(1H, q, J = 6.8Hz), 7.56-8.22 (5H, m),
8.28 (1H, s) MS m/e: 362 [M ⁺ ] C ₂₁ H ₁₈ N ₂ O ₄ = 362.1266 Example 3 20-O-acetylcamptothecin (260mg0.67
mmol) in anhydrous DMF (10 ml) under a stream of _N2.
Add 60% NaH (28.8 mg 0.72 mmole) and stir for 10 minutes under ice cooling. Add CH ₃ CH ₂ I (approximately 72.0μ) to the reaction mixture
Add 0.9 mmole) all at once and continue stirring in an ice bath for 3 hours and then at room temperature for 1 hour. DMF was distilled off from the reaction mixture under reduced pressure at 60°C, and the residue was dried under reduced pressure and purified by silica gel (25 g) column chromatography to obtain 5-ethyl-20
-O-acetylcamptothecin 88.4 mg (isolated yield
38.4) is obtained. Starting material (46.0 mg 17.7%) is recovered. mp:＞300℃(decomposition) IRν ^KBr _nax cm ^-1 :2970, 2930, 2870, 1750, 1730
,
1665, 1620, 1220, 810, 793, 760, NMR (CDCl ₃ ) δppm: 0.61 (1.5H, t, J = 7.5
Hz), 0.67 (1.5H, t, J=7.5Hz), 0.97
(3H, t, J=7.5Hz,) 2.22 (1.5H, s), 2.24
(1.5H, s), 2.00-2.85 (4H, m), 5.31
(0.5H, d, J = 18.0Hz), 5.35 (0.5H, d, J
= 18.0Hz), 5.52 (1H, d, J = 18.0Hz) 5.77
(1H, t, J=3.7Hz), 7.20 (1H, s), 7.66~
8.19 (4H, m), 8.29 (1H, s) MS m/e: 418 [M ⁺ ] C ₂₄ H ₂₂ N ₂ O ₅ = 418.1528 Example 4 In the same manner as in Example 2, 5-ethyl-20- O-
5-Ethylcamptothecin is obtained from acetylcamptothecin. mp: []209-211℃ (diastereomer) []206℃ (diastereomer) IRν ^KBr _nax cm ^-1 : 3420, 2970, 2930, 1745, 1655
,
1605, 1160, 770, NMR (CDCl ₃ ) δppm: [] 0.59 (3H, t, J = 7.3Hz), 1.04 (3H,
t, J = 7.3Hz), 1.89 (2H, q, J = 7.3Hz),
2.23-2.75 (2H, m), 3.73 (1H, s), 5.27,
5.73 (two 1Hs, dxd, J=16.6Hz), 5.82
(1H, t, J=3.4Hz), 7.58~8.21 (4H, m),
7.64 (1H, s) 8.27 (1H, s) [] 0.61 (3H, t, J=7.3Hz), 1.04 (3H,
t, J = 7.8Hz), 1.93 (2H, q, J = 7.8Hz),
2.20-2.87 (2H, m), 3.70 (1H, s) 5.28,
5.73 (two 1Hs, dxd, J=16.6Hz), 5.75
(1H, t, J = 2.7Hz), 7.56~8.20 (4H,
m), 7.66 (1H, s), 8.27 (1H, s) MS m/e: 376 [M ⁺ ] C ₂₂ H ₂₀ N ₂ O ₄ = 376.1423 Example 5 20-O-acetylcamptothecin (100mg0.26
mmole) in anhydrous DMF (5 ml) under a stream of _N2.
Add 60% NaH (12.3 mg 0.31 mmole) and cool on ice for 10 minutes.
Stir for a minute. Add allyl bromide (52.0μ0.60mmole) dropwise to the reaction mixture over 20 minutes in an ice bath.
Continue stirring for 1.5 hours. DMF was distilled off from the reaction mixture under reduced pressure at 60°C, and the residue was dried under reduced pressure and purified by column chromatography using silica gel (10 g) to give 57.1 mg of 5-allyl-20-O-acetylcamptothecin (isolated yield). 63.0%) is obtained. Starting material (17.4 mg 17.4%) is recovered.

[Table] Example 6 20-O-acetylcamptothecin (195mg0.50
mmole) in anhydrous DMF (10 ml) under a stream of _N2.
Add 60% NaH (240 mg 0.60 mmole) and stir for 10 minutes under ice cooling. Benzyl bromide (71.4μ0.60 mmole) was added dropwise to the reaction mixture over about 10 minutes, and stirring was continued for 2 hours in an ice bath. DMF was distilled off from the reaction mixture at 60°C under reduced pressure, and the residue was dried under reduced pressure and purified by column chromatography on silica gel (10 g) to give 200.7 mg of 5-benzyl-20-O-acetylcamptothecin (isolated yield 84.4). %) is obtained. Starting material (2.1 mg 1.1%) is recovered. mp: 152-153℃ IRν ^KBr _nax cm ^-1 : 2920, 1745, 1660, 1613, 1230
,
755, 700, NMR (CDCl ₃ ) δppm: [] 0.96 (3H, t, J = 7.7Hz), 2.21 (2H,
q, J=7.7Hz), 2.20 (3H, s), 3.04 (1H,
dxd, Jgem=13.2Hz Jvic=8.8Hz), 4.17
(1H, dxd, Jgem=13.2Hz, Jvic=2.9Hz),
5.39, 5.73 (two 1Hs, dxd, J=17.6Hz),
5.95 (1H, dxd, Jvic=8.8and2.9Hz), 6.90~
7.35 (5H, m), 7.11 (1H, s), 7.48-8.22
(5H, m), []0.91 (3H, t, J=7.6Hz), 2.18 (2H,
q, J=7.6Hz), 2.18 (3H, s), 3.38 (1H,
dxd, Jgem=13.2Hz, Jvic=7.8Hz), 3.99
(1H, dxd, Jgem=13.2Hz, Jvic=3.4Hz),
5.42, 5.70 (two 1Hs, dxd, J=17.6Hz) 5.94
(1H, dxd, Jvic=7.8and3.4Hz), 6.82~7.16
(5H, m), 7.14 (1H, s), 7.52~8.21 (5H,
m) MS m/e: 480 [M ⁺ ] C ₂₉ H ₂₄ N ₂ O ₅ = 480.1685 Example 7 5-benzyl-20-O-
5-Benzylcamptothecin is obtained from acetylcamptothecin.

【table】

[Table] Example 8 20-O-acetylcamptothecin (100mg0.256
mmole) in anhydrous DMF (5 ml), add 60% NaH (12.3 mg, 0.308 mmole) under a N ₂ stream, and stir for 10 minutes under ice cooling. Benzyl bromide (75.6μ0.635 mmole) was added dropwise to the reaction mixture over about 10 minutes, and stirring was continued for 1 hour in an ice bath. reaction mixture
DMF was distilled off under reduced pressure at 60°C, and the residue was dried under reduced pressure and purified by column chromatography on silica gel (7 g) to give 5,5-dibenzyl-20-O-
93.1 mg (yield 63.7%) of acetylcamptothecin and 26.8 mg (21.8%) of 5-benzyl-20-O-acetylcamptothecin are obtained. 5,5-dibenzyl-20-O-acetylcamptothecin mp: 241-242℃ (decomposition) IRν ^KBr _nax cm ^-1 : 2975, 1760, 1740, 1660, 1605
,
1505, 1245, 1230, 790, 760, 740, 705, NMR (CDCl ₃ ) δppm: 0.75 (3H, t, J = 7.6
Hz), 2.06 (2H, q, J = 7.6Hz), 2.08 (3H,
s), 3.61, 4.38 (two 1Hs, dxd, J=13.2
Hz), 3.74, 4.55 (two 1Hs, dxd, J=13.2
Hz), 5.45, 5.73 (two 1Hs, dxd, J=17.6
Hz), 6.64-6.98 (11H, m), 7.60, 8.01
(4H, m), 8.08 (1H, s) MS m/e: 570 [M ⁺ ] C ₃₆ H ₃₀ N ₂ O ₅ = 570.2154 Example 9 In the same manner as in Example 2, 5,5-dibenzyl-
5,5-dibennzylcamptothecin is obtained from 20-O-acetylcamptothecin. mp: 243-245℃ IRν ^KBr _nax cm ^-1 : 3420, 2925, 1755, 1660, 1590
,
1440, 1235, 1155, 790, 760, 735, 705, NMR (CDCl ₃ ) δppm: 0.86 (3H, t, J = 7.3
Hz), 1.77 (2H, q, J = 7.3Hz), 3.53 (1H,
s), 3.63, 4.51 (two 1Hs, dxd, J=13.7
Hz), 3.71, 4.47 (two 1Hs, dxd, J=13.2
Hz), 5.31, 5.80 (two 1Hs, dxd, J=16.6
Hz), 6.58-6.97 (10H, m), 7.07 (1H, s),
7.64-8.03 (4H, m), 8.11 (1H, s) MS m/e: 528 [M ⁺ ] C ₃₄ H ₂₈ N ₂ O ₄ = 528.2049

Claims (1)

[Claims] 1 General formula, (In the formula, R ¹ is a lower alkyl group, alkenyl group or aralkyl group, R ² is a lower alkyl group, alkenyl group, aralkyl group or a hydrogen atom,
R ³ is an acyl group or a hydrogen atom. ) A camptothecin derivative represented by 2 A base that generates a carbanion at the 5-position of camptothecin or a camptothecin derivative and a general formula RX (wherein R is a lower alkyl group, alkenyl group, or aralkyl group, and X is a halogen atom or a sulfonic acid ester group). A general formula characterized by reacting with camptothecin or a camptothecin derivative using the represented compound (In the formula, R ¹ is a lower alkyl group, alkenyl group or aralkyl group, R ² is a lower alkyl group, alkenyl group, aralkyl group or a hydrogen atom,
R ³ is an acyl group or a hydrogen atom. ) A method for producing a camptothecin derivative represented by