JP2001055398A - (+)-estrone derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intermediate capable of giving a (+)-estrone derivative from a dicyclopentadiene derivative with small number of steps in high total yield. SOLUTION: The objective compound of formula (R is a 1-20C alkyl) can be produced by using (-)-tricyclo[5.2.1.02.6]deca-4,8-dien-3-one as a starting substance and carrying out asymmetric Diels-Alder reacting with a 4-vinyl-7- alkoxy-1,2-dihydronaphthalene. The derivative of the compound can be produced by subjecting the product to successive reaction steps.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate which is used as a starting material for a (+)-estrone derivative which is useful as an oral contraceptive starting from a dicyclopentadiene derivative.

[0002]

2. Description of the Related Art (+)-Estron is a compound useful as an oral contraceptive, but its production method is described in a method obtained from nature (US Pat. Nos. 1967350 (1934) and 13059).
No. 92 (1962) is the oldest known, but its efficiency and yield are incomparably low compared to the synthetic method.

In recent years, several synthetic methods of (+)-estrone having a natural configuration have been developed. Posner et al. (J. Am. Chem. Soc., 108 , 1239 (1986)) describe an asymmetric Michael addition reaction between a compound having an AB ring skeleton and a compound having an asymmetrically induced D ring skeleton. Furthermore, C ring skeleton is formed by intramolecular Diels-Alder reaction, and estrone skeleton is constructed with 91-94% diastereoselectivity. However, the overall yield was as low as 6.3%,
The reaction process has also gone through nine steps, which is not efficient.

Also, Taber et al. (J. Org. Chem., 52, 28)
(1987) constructed a β-ketoester having a D-ring skeleton using a camphor derivative as an asymmetric source, coupled this with a benzocyclobutene derivative, and finally constructed a BC ring skeleton at once by an intramolecular cyclization reaction. (+)-Estrone having an optical purity of 91% ee. However,
In this method, the reaction process is also multi-step. Five steps are required to construct the β-ketoester, and three steps are required to synthesize the benzocyclobutene derivative. Further, the target skeleton is obtained in three steps including the bonding between the two. Low yield of cyclization reaction (41%), total yield from β-ketoester precursor
Although the stereoselectivity is relatively good at 9.8%, it is still not an efficient production method.

[0005] That is, prior to the present invention, the supply method of (+)-estrone, which is increasing in demand, was in a situation where it could not be said to be sufficient.

[0006]

In view of the above, the present inventors have conducted intensive studies to achieve the object of obtaining (+)-estrone derivatives efficiently and with good optical purity, and as a result, A method for efficiently obtaining a (+)-estrone derivative using dicyclopentadiene as a starting material has been found. Then, a novel intermediate used in the production method was found.

[0007]

The present invention provides the following formula:

[0008]

Embedded image

(-)-Tricyclo [5.2.
1.0 ^2.6 ] Starting from deca-4,8-dien-3-one (1),

[0010]

Embedded image

(Wherein, R represents an alkyl group having 1 to 20 carbon atoms) 4-vinyl-7-alkoxy-1,2
Performing an asymmetric Diels-Alder reaction with dihydronaphthalene (2),

[0012]

Embedded image

(Wherein R is the same as described above)

[0014]

Embedded image

(Wherein R is as defined above), which is an intermediate used in a process for producing a (+)-estrone derivative, characterized by obtaining a (+)-estrone derivative (4) . In the step of obtaining the (+)-estrone derivative (4) from the compound (3), the following formula

[0016]

Embedded image

[0017]

Embedded image

[0018]

Embedded image

(Wherein R represents an alkyl group having 1 to 20 carbon atoms). The reaction route of this production method is shown by the following formula.

[0020]

Embedded image

The starting material of the present invention, (-)-tricyclo [5.2.1.0 ^2.6 ] deca-4,8-diene-3-
On (1) is obtained by oxidizing dicyclopentadiene with selenium oxide to obtain racemic tricyclo [5.
2.1.0 ^2.6 ] Deca-3-hydroxy-4,6-diene is transesterified with an acylating agent using lipase (Japanese Patent Application No. 1-237546) or hydrolyzed after acetylation. (J. Chem. Soc. Chem. Commun., 198
9, 271) It can be obtained by optical splitting.

The obtained (-)-tricyclo [5.2.
1.02.6] Deca-4,8-dien-3-one (1)
And Schmidt et al. (Liebigs Ann. Chem., 536 , 19
6 (1938); 4-vinyl- obtained in 537 , 246 (1939))
Compound (3) can be obtained by subjecting 7-alkoxy-1,2-dihydronaphthalene (2) to an asymmetric Diels-Alder reaction in the presence of a Lewis acid. As the Lewis acid used here, diethylaluminum chloride is most preferable, but any one that can catalyze the reaction and control the steric configuration, such as titanium tetrachloride and aluminum chloride, can be used. The reaction temperature at this time is -78 ° C
~ -10 ° C, preferably -30 ° C.

As the reaction solvent, a hydrocarbon or a halogen-based solvent can be used, and n-hexane and dichloromethane are particularly preferable. The reaction time varies depending on the treatment amount and the like, but is 12 to 96 hours, preferably 24 to 36 hours. The obtained compound (3) can be methylated with methyl iodide in the presence of a base to give compound (5). The base is particularly preferably potassium t-butoxide, but may be of any type as long as it promotes methylation. As the methylating agent, methyl bromide or methyl chloride can be used.

At this stage, O which is partially obtained as a by-product
The compound (8), which is a -methyl form, is separated by column chromatography or the like, and treated with hydrochloric acid at 0 ° C., whereby the compound (8) can be easily returned to the compound (3). That is, it can be used again as a synthetic intermediate of (+)-estrone. Compound (6) is obtained by treating compound (5) with trifluoroacetic acid and triethylsilane.
Get.

The compound is further subjected to a retro Diels-Alder reaction by heating to obtain a compound (7). Finally,
The unsaturated bond of compound (7) can be reduced by catalytic hydrogenation to obtain the desired (+)-estrone derivative (4). As the reduction catalyst, a contact catalyst such as Raney nickel can be used, and preferably, palladium carbon is used.

[0026]

By using the intermediate described above, the starting material dicyclopentadiene derivative (1)
Thus, the (+)-estrone derivative can be obtained with a small number of steps and with a high overall yield. Taking into account the recovery of compound (8), (+)-estrone can be obtained in better yield.

[0027]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Example 1 (−)-Tricyclo [5.2.1.0 ^2.6 ] deca-4,
1.72 g (11.8 mmol) of 8-dien-3-one (1) and 2.63 g (14.1 mmol) of 4-vinyl-7-methoxy-1,2-dihydronaphthalene (2) were dissolved in 25 ml of dichloromethane. Cooled to ° C. To this solution was added 15 ml (14.1 mmol) of diethylaluminum chloride (0.94 M, n-hexane solution).
l) was added dropwise. After stirring at −30 ° C. for 32 hours, 5% hydrochloric acid was added, and the mixture was further extracted with dichloromethane. Next, the dichloromethane layer was washed with a saturated aqueous solution of sodium bicarbonate and a saturated saline solution in that order, and dried over magnesium sulfate. After distilling off dichloromethane, the residue was subjected to silica gel column chromatography to obtain 3.1 g (yield: 81.5%) of compound (3).

The physical properties of the compound were as follows. [Α] _D ³¹ -168.3 ° _{(c1.01, CHCl 3) IR (} film) νmax 1730, 1605cm -1 1 H-NMR (500MHz, CDCl 3) J, 1.35 (1H, d, J = 8.5H
z) 1.51 (1H, d, J = 7.9Hz), 1.84 (1H, ddd, J = 17.1, 12.2,
4.9Hz), 1.95-2.02 (1H, m), 2.16-2.27 (2H, m), 2.36-2.51
(3H, m), 2.58-2.62 (1H, m), 2.72-2.91 (4H, m), 3.09-3.12
(1H, m), 3.80 (3H, s), 6.15-6.22 (3H, m), 6.66 (1H, d, J
= 8.6 Hz), 7.47 (1H, d, J = 8.6 Hz) MS m / z 332 (M ⁺ ), 266 (100%) Elemental analysis Calculated C ₂₃ H ₂₄ O ₂ : C 83.10, H 7.28 C 83.16, H 7.34.

Example 2 Compound (3) (560 mg, 1.96 mmol) in dimethoxyethane (8 ml)
The solution was added at room temperature with potassium t-butoxide (37.8 mg, 3.37 mm
ol) and stirred for 12 minutes. Under ice cooling, methyl iodide 1.
1 ml (17 mmol) was added dropwise, and after stirring for further 12 minutes, a saturated aqueous sodium hydrogen carbonate solution was added, and the mixture was extracted with ether. The organic layer was washed with saturated saline, dried over magnesium sulfate, the solvent was distilled off, and the residue was subjected to silica gel column chromatography. From the fraction of ether / n-hexane (1/1), 334 mg (yield 57%) of compound (5) and 123 mg (yield 21%) of compound (8) were obtained. Further, the compound (5) was recrystallized from methanol to obtain colorless needles.

The physical properties of the compound were as follows. Mp 161~162 ℃ [α] _D ³¹ +130 DEG _{(c0.665, CHCl 3) IR (} film) νmax 1735, 1606 cm -1 1 H-NMR (90MHz, CDCl 3) J, 1.09 (3H, s), 1.48-2.65
(9H, m), 2.80-3.21 (5H, m), 3.78 (3H, s), 5.81-6.06 (2H,
m) 6.10-6.28 (1H, m), 6.57-6.79 (2H, m), 7.39 (1H, d, J = 8.
3Hz) MS m / z 246 ( M + 100%) Analysis Calculated _{C 24 H 26 O 2: C} 83.20, H 7.56 Found: C 83.21, H 7.78.

Example 3 Compound (5) (304 mg, 0.878 mmol) in dichloromethane (6 ml)
0.68 ml (8.83 mmol) of trifluoroacetic acid and 0.70 ml (4.38 mmol) of triethylsilane were added dropwise to the solution, and the mixture was stirred at room temperature for 20 hours. Add a saturated aqueous solution of sodium hydrogen carbonate under ice-cooling,
The mixture was extracted with dichloromethane, washed with saturated saline, and dried over magnesium sulfate. After evaporating the solvent under reduced pressure, the residue was subjected to silica gel column chromatography to obtain 2.65 mg (yield 87%) of compound (6) from a stream of ether / n-hexane (1/15). . Recrystallization from methanol gave colorless needles.

The physical properties of the compound were as follows. Mp 173~174 ℃ [α] _D ³¹ +126 DEG (c0.96, CHCl ₃₎ IR ^{(Nujol) νmax 1728cm -1 1 H-NMR} (500MHz, CDCl 3) J, 1.07 (3H, s) 1.35-1.48 ( 3H, m), 1.52-1.74 (5H, m), 2.07-2.18 (2H, m),
2.25-2.32 (1H, m), 2.77 (1H, tb, J = 10.4, 4.3Hz), 2.87
-2.98 (3H, m) 3.08 (1H, br, s), 3.24 (1H, dd, J = 10.3, 4.2Hz), 3.77 (3
H, s), 6.02 (1H, dd, J = 5.5,3.0Hz), 6.22 (1H, dd, J =
5.5, 3.0Hz), 6.64 (1H, d, J = 3.0Hz), 6.70 (1H, dd, J = 1
1.0, 2.5 Hz), 7.16 (1H, d, J = 9.1 Hz) MS m / z 348 (M ⁺ ), 282 (100%) Elemental analysis Calculated value C ₂₄ H ₂₈ O ₂ : C 82.72, H 8.10 Actual value : C 82.55, H 8.10.

Example 4 13 mg (0.037 mmol) of diphenyl ether 1 of compound (6)
The ml solution was heated to reflux for 1.5 hours. The resulting product was subjected to silica gel column chromatography to give 8 mg of the enone compound (7) (yield: 76).
%). To a solution of 39 mg (0.14 mmol) of the enone compound in ethanol was added 4 mg of 10% palladium carbon, and the mixture was stirred under a stream of hydrogen.
Stirred for minutes. After filtration through celite, the filtrate was concentrated under reduced pressure.
The residue was subjected to silica gel column chromatography,
33 mg (84% yield) of estrone methyl ether (4) was obtained from a stream of ether / n-hexane (1/6).

The physical properties of the compound were as follows. Mp 174~175.5 ℃ [α] _D ³³ +159 DEG (c0.72, CHCl ₃₎ IR ^{(Nujol) νmax 1735cm -1 1 H-NMR} (90MHz, CDCl 3) J, 0.88 (3H, s) 1.20-2.51 ( 13H, m), 2.72-2.98 (2H, m), 3.77 (3H, s), 6.5
4-6.67 (2H, m), 6.55-6.76 (1H, m), 7.20 (1H, d, J = 8.3H
z) MS m / z 284 (M ⁺ 100%).

Example 5 Compound (8) (melting point: 103-105 ° C., [α] _D ³³ + 215 ° C.
1.0.1, 123 mg of CHCl ₃ ) was dissolved in 5 ml of a 10% HCl-THF (1: 3) mixed solvent at 0 ° C., and the temperature was gradually returned from 0 ° C. to room temperature over 1.5 hours with stirring. The mixture was neutralized by adding a saturated aqueous sodium hydrogen carbonate solution under ice-cooling, extracted with dichloromethane, washed with a saturated saline solution, and dried over magnesium sulfate. After the dichloromethane was distilled off, the residue was subjected to silica gel chromatography to obtain 100 mg (quantitative) of compound (3).

Claims (4)

[Claims] 1. A compound of the general formula (Wherein, R represents an alkyl group having 1 to 20 carbon atoms). 2. A compound of the general formula (Wherein, R represents an alkyl group having 1 to 20 carbon atoms). 3. A compound of the general formula (Wherein, R represents an alkyl group having 1 to 20 carbon atoms). 4. A compound of the general formula (Wherein, R represents an alkyl group having 1 to 20 carbon atoms).