JP3359722B2 - Methotrexate derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel methotrexate derivative, and more particularly, to a novel methotrexate derivative useful as an antirheumatic agent.

[0002]

BACKGROUND OF THE INVENTION Methotrexate has long been used as a therapeutic agent for leukemia, but in 1951 Gubner et al. Used aminopterin for rheumatoid arthritis (RA) and psoriasis. , Has been noted as a remedy for RA and has been used mainly in Europe and the United States. More recently, detailed studies of dosage and administration have revealed that low-dose methotrexate therapy has relatively few side effects and exhibits excellent efficacy. However, since side effects such as liver damage and pulmonary fibrosis caused by taking methotrexate cannot be ignored, there is a demand for a drug with less side effects and excellent efficacy.

[0003] So far, as a methotrexate derivative to N ¹⁰ is alkyl groups other than methyl groups are introduced, for example, the following formula

Embedded image (J. Med. Chem., 22, 862 (197)
9)) and expressions

Embedded image (J. Med. Chem., 25, 877 (198)
2)), etc., but did not show satisfactory activity.

The inventor of the present invention has intensively studied for a methotrexate derivative of this type which has a better balance between efficacy and side effects as an antirheumatic agent, and has accomplished the present invention.

[0005]

The present invention provides a compound represented by the following general formula (I):

Embedded image (Wherein R ₁ and R ₂ may be the same or different and each represent a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms) and a salt thereof. The present invention also provides an antirheumatic agent containing this compound as an active ingredient.

The compounds of the present invention are described in WO92 / 3436 as a general formula of the general concept,
Examples of actual production are unknown novel compounds not described in the literature, and are synthesized, for example, as follows.

Embedded image (Wherein R ₁ and R ₂ may be the same or different and each represent a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms;
Represents a protecting group, and X represents a halogen atom. )

The reaction for obtaining the compound of the general formula (3) from the compound of the general formula (1) and the compound of the general formula (2) is carried out by a commonly used amide bond forming reaction. Is suspended in an acid halogenating agent such as thionyl chloride and oxalyl chloride, and in the presence of a catalytic amount of dimethylformamide or the like, an acid halide obtained by stirring at room temperature is dissolved in a solvent such as dichloromethane. The reaction is carried out by adding an aqueous solution of the compound of the formula (2) under ice-cooling or water-cooling, and stirring at room temperature in the presence of an inorganic salt such as potassium carbonate, sodium hydroxide, sodium hydrogen carbonate and the like.

In the formula, examples of the protecting group represented by A include amino-protecting groups such as an acyl group, and preferably include a carbobenzoxy group, a tosyl group, and an acetyl group. The compound of the general formula (1) is described in, for example, International Publication WO92.
/ 9436.

The compound of the general formula (3) is deprotected by a conventional method and converted into a compound of the general formula (4). For example, when the protecting group is a carbobenzoxy group or a tosyl group,
A compound of the general formula (3) is added to a solution of anisole and phenol dissolved in a hydrogen bromide-acetic acid solution.
It is carried out by stirring at 0 ° C., preferably at room temperature. Also,
When the protecting group is a carbobenzoxy group, the compound of the formula (3) is dissolved in a solvent such as methanol, ethanol or acetic acid, palladium-carbon is added, and the mixture is stirred at room temperature under a hydrogen atmosphere. You may.

The reaction for obtaining the compound of the general formula (6) from the compound of the general formula (4) and the compound of the general formula (5) is performed by converting the compound of the general formula (4) and the compound of the general formula (5) to dimethylacetamide or the like. The reaction is carried out by stirring at 0 ° C. to 100 ° C., preferably at 50 ° C. to 70 ° C. in a solvent such as dimethylformamide. In particular, when R ₁ and R ₂ are hydrogen atoms, an alkaline aqueous solution such as a 1N aqueous sodium hydroxide solution is added to a solvent such as methanol or ethanol, and the temperature is reduced from 0 ° C. to 6 ° C.
The desired product is obtained by stirring at 0 ° C., preferably at 15 ° C. to 35 ° C. In the formula, examples of the halogen atom represented by X include a bromine atom and a chlorine atom.

The compound of the present invention can also be synthesized by the following method.

Embedded image (In the formula, R ₁ , R ₂ , and R ₃ may be the same or different and represent a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms, and X represents a halogen atom.)

The reaction for obtaining the compound of the general formula (8) from the compound of the general formula (5) and the compound of the general formula (7) is performed by converting the compound of the general formula (4) and the compound of the general formula (5) into a compound of the general formula (5) The reaction is performed in the same manner as in the reaction for obtaining the compound of 6). The compound of the general formula (7) is described, for example, in International Publication WO92 / 9436.
The method is described in Japanese Patent Publication No. The reaction for obtaining the compound of the general formula (6) from the compound of the general formula (8) and the compound of the general formula (2) is carried out by a commonly used amide bond forming reaction.

The compound of the present invention can be obtained as a salt by a conventional method. Examples of the salt to be used include hydrochloride, hydrobromide, hydroiodide, sulfate, inorganic acid salts such as phosphate, succinate, malonate, acetate,
Organic acid salts such as maleate, fumarate, citrate, gluconate, mandelate, benzoate, salicylate, methanesulfonate, benzenesulfonate, p-toluenesulfonate, and sodium salts , Potassium salt,
Examples thereof include metal salts such as magnesium salts, preferably inorganic salts or organic acid salts, and more preferably hydrobromide salts or methanesulfonic acid salts.

The drug containing the compound of the present invention can be administered orally or parenterally.
Local administration into the joint cavity or the like is preferred. The dose varies depending on the patient's weight, symptoms, etc., but is usually 0.01 to 1
00 mg / day / person is preferred. Examples of the dosage form of the drug containing the compound of the present invention include liquids such as injections, tablets, capsules, powders and the like.

The compound of the present invention represented by the general formula (I) is useful as an antirheumatic agent because it has an excellent balance between antirheumatic activity and toxicity as compared with methotrexate and existing methotrexate derivatives.

[0016]

The compounds of the present invention will be described below in more detail with reference to Examples, but the present invention is not limited by these Examples.

[0017]

Reference Example 1 Synthesis of N- (4-carbobenzoxy-3,4-dihydro-2H-1,4-benzothiazine-7-carbonyl) -L-α-aminoadipic acid dimethyl ester 4-carbobenzoxy- 3,4-dihydro-2H-1,
Thionyl chloride (10 ml) was added to 4-benzothiazine-7-carboxylic acid (2.0 g), and the mixture was stirred at room temperature for 2 hours. Next, the reaction solution was concentrated to dryness under reduced pressure. The obtained solid was dissolved in dichloromethane (25 ml), and an aqueous solution (25 ml) of dimethyl L-α-aminoadipate hydrochloride (1.4 g) and then potassium carbonate (3.4 g) were sequentially added to this solution. And stirred overnight. The reaction solution was poured into a saturated aqueous solution of sodium hydrogen carbonate, and organic substances were extracted with chloroform. Further, the chloroform layer was washed with 1N hydrochloric acid, dried over sodium sulfate, and the solvent was distilled off under reduced pressure. The obtained residue was subjected to silica gel column chromatography, and chloroform:
Using methanol = 100: 1, the title compound (2.35
g) was obtained.

¹ H NMR (CDCl ₃ , δ value) 1.6-2.1 (4H, m), 2.37 (2H, t, J
= 7.1 Hz), 3.20 (2H, m), 3.67 (3
H, s), 3.78 (3H, s), 3.98 (2H,
m), 4.77 (1H, m), 5, 23 (2H, s),
6.75 (1H, d, J = 7.3 Hz), 7.36 (5
H, m), 7.48 (2H, m), 7.63 (1H,
d, J = 1.5 Hz)

[0019]

Reference Example 2 N- (3,4-dihydro-2H-1,4-
Synthesis of benzothiazine-7-carbonyl) -L-α-aminoadipic acid dimethyl ester A solution of anisole (15 g) in 30% hydrogen bromide-acetic acid (2
00ml), the compound of Reference Example 1 (14.8 g) was added,
Stirred at room temperature for 4 hours. Then, a large amount of ether was added to the reaction solution, and a red-brown oily substance precipitated. The oily substance was suspended in chloroform except for most of the ether layer,
The suspension is washed with a saturated aqueous sodium hydrogen carbonate solution,
Extracted with chloroform. The chloroform layer was dried over sodium sulfate, and the solvent was distilled off under reduced pressure to obtain the title compound (7.6 g).

¹ H NMR (CDCl ₃ -CD ₃ OD, δ
Value) 1.6-2.0 (4H, m), 2.40 (2H, t, J
= 6.8 Hz), 3.01 (2H, m), 3.68 (5
H, m), 3.78 (3H, s), 4.65 (1H,
m), 6.50 (1H, d, J = 8.8 Hz), 7.4
1 (2H, m), 7.51 (1H, d, J = 2.0H
z)

[0021]

Example 1 N- (1-((2,4-diamino-6-pteridinyl) methyl) -3,4-dihydro-2H-1,
Synthesis of 4-benzothiazine-7-carbonyl) -L-α-aminoadipic acid dimethyl ester The compound of Reference Example 2 (7.6 g) and 6-bromomethyl-
2,4-Diaminopteridine hydrobromide isopropanol adduct (8.2 g) was added to dimethylacetamide (12
0 ml) and stirred at 60 ° C for 13 hours. After cooling, the reaction solution was poured into a saturated aqueous solution of sodium hydrogen carbonate, and extracted with a mixed solvent of chloroform: methanol = 10: 1. After the organic layer was dried over sodium sulfate, the solvent was distilled off under reduced pressure. The obtained residue was subjected to silica gel column chromatography, and chloroform: methanol = 10: 1 was used as the elution solvent to give the title compound (5.8 g).

¹ H NMR (CDCl ₃ -CD ₃ OD, δ
Value) 1.6-2.0 (4H, m), 2.39 (2H, t, J
= 7.1 Hz), 3.17 (2H, m), 3.68 (3
H, s), 3.76 (3H, s), 3.94 (2H,
m), 4.66 (1H, m), 4.79 (2H, s),
6.70 (1H, d, J = 8.8 Hz), 7.42 (2
H, m), 7.62 (1H, d, J = 2.4 Hz),
8.67 (1H, s)

[0023]

Example 2 N- (1-((2,4-diamino-6-pteridinyl) methyl) -3,4-dihydro-2H-1,
Synthesis of 4-benzothiazine-7-carbonyl) -L-α-aminoadipic acid The compound of Example 1 (5.8 g) was treated with ethanol (300 m
l), 1N aqueous sodium hydroxide solution (32.2 ml) was added at 35 ° C, and the mixture was stirred at room temperature overnight. Then the reaction was evaporated to dryness under reduced pressure. The obtained solid is washed with water (1
00 ml), adjusted to pH = 3.7 with 1N hydrochloric acid, and allowed to stand in a cool place for 2 hours. The deposited precipitate is collected by filtration,
The title compound (4.5 g) was obtained.

¹ H NMR (DMSO-d ₆ , δ value) 1.5-1.9 (4H, m), 2.21 (2H, t, J
= 7.1 Hz), 3.15 (2H, m), 3.96 (2
H, m), 4.30 (1H, m), 4.76 (2H,
s), 6.78 (1H, d, J = 8.8 Hz), 7.4.
4 (1H, m), 7.60 (1H, s), 8.17 (1
H, d, J = 7.8 Hz), 8.65 (1H, s)

[0025]

Example 3 N- (1-((2,4-diamino-6-pteridinyl) methyl) -3,4-dihydro-2H-1,
Synthesis of 4-benzothiazine-7-carbonyl) -L-α-aminoadipic acid hydrobromide (2/3 hydrate) The compound (100 mg) obtained in Example 2 was brominated by 2.4%. It was suspended in hydrogen acid (10 ml) and dissolved by heating to 60 ° C. in a hot water bath. Next, it was filtered with a cotton plug, and the filtrate was cooled to room temperature and left overnight. The precipitated needle-like crystals were collected by filtration, and dried by heating under vacuum to obtain the title compound (92 mg).

¹ H NMR (DMSO-d ₆ , δ value) 1.42-1.90 (4H, m), 2.21 (2H,
t, J = 7.3 Hz), 3.19 (2H, m), 3.9
7 (2H, m), 4.26 (1H, m), 4.84 (2
H, s), 6.76 (1H, d, J = 8.9 Hz),
7.44 (1H, dd, J = 2.2 Hz, 8.8H
z), 7.62 (1H, d, J = 1.97 Hz), 8.
23 (1H, d, J = 8.2 Hz), 8.80 (1H,
s) Elemental analysis: C: 43.76 H: 4.31 N: 1
8.73 S: 5.12 Br: 13.43 Calculated C: 43.73 H: 4.37 N: 1
8.54 S: 5.31Br: 13.22 Molecular formula _{C 22 H 24 N 8 O 6} S · HBr · 2/3
H ₂ O

[0027]

[Test Example] Growth inhibition test of synovial cells derived from rheumatic patients 2.5 × 10 ³ synovial cells derived from RA patients were treated with various concentrations of test drugs together with 96-well culture pl.
ate. 3 days after the start of culture
1 μCi of ³ H-UdR was added thereto, and the cells were further cultured for 2 days. After the culture was completed, the uptake of ³ H-UdR into the cells was measured with a scintillation counter. The following drugs were used.

Embedded image The results are shown in FIG. As is clear from FIG. 1, it was confirmed that the compound of the present invention has a superior synovial cell growth inhibitory action as compared with the control compound.

[0028]

The compound of the present invention represented by the general formula (I) has an excellent antirheumatic activity and is less toxic than methotrexate, so that it is useful as an antirheumatic agent.

[Brief description of the drawings]

FIG. 1 shows the cell proliferation rate at each concentration of a test drug.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C07D 475/08 A61K 31/505 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A compound of the general formula (I) (Wherein R ₁ and R ₂ may be the same or different and each represent a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms) and a salt thereof. 2. An antirheumatic agent comprising as an active ingredient at least one of the compound represented by the general formula (I) according to claim 1 and a salt thereof.