JP2538231B2 - Process for producing optically active 4-pentene-2-ol derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a compound represented by the general formula (RS) -1 (In the formula, R represents an aliphatic hydrocarbon group having 1 to 7 carbon atoms), the ester (RS) -1 represented by the general formula 2 ^* is asymmetrically hydrolyzed ^. (In the formula, * represents an asymmetric carbon), which is derived from a microorganism belonging to the genus Chromobacterium having stereoselective esterase activity for producing an optically active alcohol (4-penten-2-ol) 2 ^* By reacting with lipase, alcohol which is a hydrolyzate from (RS) -1
2 ^* and the unreacted general formula 1 ^* (In the formula, R is the same as the above), an ester 1 ^* is produced, and each optically active substance is separated and collected. Optically active 4-pentene-2-
The present invention relates to a method for producing an all derivative.

These optically active 4-penten-2-ol derivatives are important compounds as starting materials for pharmaceuticals, agricultural chemicals and the like.

[Conventional technology and problems]

The synthesis of an optically active 4-penten-2-ol derivative is
For example, (1) 4-penten-2-ol racemate is esterified with phthalic anhydride and then optically resolved using brucine [Reference: Sih. JC, Prostagrandins, 13 (5), 831 (1977)],
(2) A method for asymmetrically synthesizing 4-penten-2-ol by reacting optically active allylborane with acetoaldehyde, [literature name: HC Brown et al., Journal of American Chemical Society (J. Am. Chem.So
c.), 105 , 2092 (1983)] are known.

However, the above method is not suitable for production on an industrial scale because the procedure is complicated and expensive reagents must be used.

[Means and Actions for Solving Problems]

The present inventors have made general formula (RS) -1 An enzyme that asymmetrically hydrolyzes the acyl group at the 2-position of the ester (RS) -1 represented by As a result, a lipase derived from a microorganism belonging to Chromobacterium (Chromobacterium) genus (RS) - 1 The asymmetrically hydrolyzing (R) - 2 [(R)-4-penten-2-ol ] And (S) -1 [(S) -4-pentene-2-acylate ] Has been found to have the ability to generate. Also (S)
- 1, if necessary, chemically the alcohol by hydrolysis (S) - 2 [(S)-4-penten-2
Oar ] It can be easily guided to.

The produced 1 ^* and 2 ^* can be separated easily by silica gel column chromatography or by distillation when the carbon chain of the 2-position acyl group is long, and each optically active substance can be collected. it can.

 The present invention will be described in more detail below.

The general formula used as the substrate of the present invention The substituent R of the ester 1 represented by
The aliphatic hydrocarbon groups from 1 to 7 are mentioned. Further, those in which a part of the substituents are substituted with a halogen group, such as a chloromethyl group, can be used.

Raw material (RS) -1 can be synthesized, for example, by the following route.

(RS) -1 is asymmetrically hydrolyzed to give optically active 1 ^*
An example of an enzyme having a stereoselective esterase activity for producing 2 ^* is lipase derived from a microorganism belonging to the genus Chromobacterium. Specifically, for example, Chromobacterium viscosum can be mentioned. Commercially available products of this enzyme include Lipase Toyo (manufactured by Toyo Shuzo Co., Ltd.) and Lipase (manufactured by Calbiochem), which can be used.

In the asymmetric hydrolysis reaction, the substrate (RS) -1 is 2-60% (w /
Suspend in the reaction solution in the range of v) and add the enzyme in an appropriate amount, for example, the weight ratio of the enzyme and the substrate is 1: 1 to 1: 1,000, and the temperature is in the range of 10 ° to 45 ° C, preferably 30 ° C to 40 ° C. It suffices to react in the range of up to ° C. The pH range for the hydrolysis reaction is
It may be 4.0 to 8.5, preferably 6.0 to 7.5, but as the hydrolysis reaction progresses, the pH in the reaction solution tends to the acidic side, so it is carried out in a buffer solution or with a neutralizing agent such as NaON aqueous solution. Is preferably kept in the range 6.0 to 7.5.

The time course of the asymmetric hydrolysis reaction can be determined from the amount of NaOH used to adjust the pH. It is also possible to extract a part of the reaction solution with ether and obtain it by gas chromatography analysis.

Furthermore, the asymmetric hydrolysis reaction can be repeated by, for example, adsorbing and immobilizing an enzyme on a hydrophobic resin or the like.

After hydrolysis, 1 ^* and 2 ^* in the reaction solution can be separated by extracting both 1 ^* and 2 ^* with an organic solvent such as methylene chloride, ether, hexane, ethyl acetate, etc. , Or by separation by silica gel column chromatography, or if the carbon chain of the acyl group of 1 ^* is long, it is distilled to 1 ^* by utilizing the boiling point difference.
2 ^* can be easily separated and collected.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

Production Example of Substrate (1) Preparation of (RS) -4-Penten-2-ol To a solution containing 15.3 g of magnesium powder and 36 ml of anhydrous ether, a solution containing 35.1 g of allyl bromide and 260 ml of anhydrous ether was gradually added, The Grignard reagent is prepared by dropwise addition over about 3 hours and heating for 2 hours.

15.3 g of acetaldehyde was added dropwise to this solution over 1 hour under water cooling. After the dropping, stirring was continued at room temperature for 2-3 hours to complete the reaction. After the reaction, it was washed with 200 ml of ice water. After dehydrating the organic layer with anhydrous magnesium sulfate,
Distillation was performed to obtain highly pure (RS) -4-penten-2-ol 10.0 g (yield 40%).

bp 116 to 118 ° C./760 mmHg ¹ H NMR (90 MHz, CDCl ₃ ) δ (ppm): 1.17 (2H, d, J = 6.6 Hz, CH ₃ −), 2.07−2.45 (3H, m ,, − CH (O _{H) -C H 2 -),} 3.63-4.02 (1H, m, -CH-), 5.06 (2H, d, J-14.9Hz, C H 2 = CH-), 5.53-6.07 (1H, m, CH _{2 = C H -) (2} ) (RS) -4- penten-2-acetate Preparation of (RS) -4-Penten-2-ol 8.6 g, triethylamine 12.0 g and ether 50 ml are added dropwise to a solution containing acetic anhydride 12.0 g at room temperature over 30 minutes. Further, the mixture was reacted under reflux for 10 hours. After the reaction, 50 ml of ice water was used twice, and then saturated NaHCO _{3 was} added.
It was washed once with 50 ml of an aqueous solution. The organic layer was dehydrated with anhydrous magnesium sulfate and then distilled to obtain high-purity (RS)
9.2 g of 4-pentene-2-acetate (yield 72%) was obtained.

bp 73 ° C./68 mmHg ¹ H NMR (90 MHz, CDCl ₃ ) δ (ppm): 1.21 (3H, d, J = 6.3 Hz, C H ₃ CH (O −) −), 2.01 (3H, s, CH ₃ CO -), 2.33 (2H, t , J = 6.3Hz, -CH (O -) - C H 2 -), 4.75-6.03 (4H, m, -C H (O -) - CH 2 -C H = C H ₂ ) (3) (RS) -4-Pentene-2-butyrate Preparation of (RS) -4-Penten-2-ol 8.6 g, triethylamine 12.0 g and ether 50 ml in a solution containing butyric acid chloride 1
2.8 g is added dropwise over 30 minutes under ice cooling. Further, the reaction was carried out at room temperature for 5 hours. After reaction, saturate with 50 ml of ice water twice and then saturate
It was washed once with 50 ml of NaHCO ₃ aqueous solution. The organic layer was dehydrated with anhydrous magnesium sulfate and then distilled to give 9.2 g of highly pure (RS) -4-pentene-2-butyrate (yield 59%).
%) Was obtained.

^{bp 57 ℃ / 12mmHg 1 H NMR} (90MHz, CDCl 3) δ (ppm): 0.94 (3H, t, J = 7.8Hz, C H 3 CH 2 CH 2 CO-), 1.21 (3H, d, J = 6.9 _{Hz, C H 3 CH (O} -) -), 1.42-2.50 (6H, m, CH 3 C H 2 C H 2 CO-, CH (O -) - C H
_{2 -), 4.78-6.03 (4H,} m, -C H (O -) - CH 2 -C H = C H 2) screening substrate (RS Example 1 enzyme) -4-penten-2-butyrate Each 0.1 g,
Enzyme 0.01g (50 species), 0.1M-phosphate buffer (pH7.2) each
Add 2.0 ml of the reaction solution to the test tube and make two each. The top was sealed and shaken on a shaker at 30 ° C. After extraction with 4 ml of ether at each time of 24 hours and 48 hours, the ether layer was dehydrated with anhydrous sodium sulfate, and then subjected to gas chromatography to determine the reaction rate. 24hours,
At each time point of 48 hours, 6 kinds of those having a reaction rate of 20% to 80% were selected and used for the secondary screening.

Example 2 Secondary Screening and Purification Substrate (RS) -4-pentene-2-butyrate 4.0 g each,
0.1M-phosphate buffer solution (pH7.2) 40ml each, 0.1g of each of the 6 enzymes selected in the primary screening was added, and the mixture was stirred with a stirrer at 35 ° C while maintaining the pH at 7.2 with 2N-NaOH aqueous solution.
Asymmetric hydrolysis reaction was performed. NaOH consumption is 50 theoretical
The reaction was terminated when the percentage was reached. After cooling, it was extracted twice with 40 ml of ether each time. This extract was dehydrated with anhydrous sodium sulfate, and then distilled to collect (R) -4-penten-2-ol and (s) -4-pentene-2-butyrate fractions, and their specific optical rotation was measured. The quality was evaluated by measuring the value. The results are shown in Table 1 for the two types of enzymes that have been found to have asymmetric hydrolysis ability.

Example 3 (RS) -4-pentene-2-butyrate 1 as a substrate
5.6g, Lipase Toyo 1.56g, 0.1M-phosphate buffer (pH 7.
2) Asymmetric hydrolysis reaction was carried out in 100 ml at 40 ℃, keeping pH at 7.2 with 2N-NaOH aqueous solution. React for 8 hours,
The reaction was terminated when the consumption of NaOH reached 60% of the theoretical amount. After cooling, it was extracted twice with 100 ml of ether each time. The extract was dehydrated with anhydrous sodium sulfate and then distilled to obtain (R) -4-penten-2-ol and (S) -4-pentene-2-butyrate.

(R) -4-Penten-2-ol: Yield 68% ▲ [α] ²⁰ _D ▼ -3.9 ° (c = 9, Et ₂ O) (S) -4-Pentene-2-butyrate: Yield 53 % ▲ [α] ²⁰ _D ▼ -13.3 ° (c = 9, Et ₂ O) 5N in the obtained (S) -4-pentene-2-butyrate
-About 5 times the molar amount of NaOH aqueous solution was added, and the mixture was stirred overnight at room temperature with a stirrer. After confirming that it is completely hydrolyzed,
(S) -4-Penten-2-ol was extracted with ether, the ether layer was dehydrated with anhydrous sodium sulfate, and then collected by distillation.

(S) -4-Penten-2-ol: 75% yield from (S) -4-pentene-2-butyrate, ▲ [α] ²⁰ _D ▼ + 8.7 ° (c = 1, Et ₂ O) Reference value: HC Brown, Journal of Organic Chemistry (J.Org.Chem.) 49, 4089 (1984),
(S) -4-Penten-2-ol: ▲ [α] ²⁰ _D ▼ +
9.88 ° (c = 9.18, Et ₂ O) R-form ▲ [α] ²³ _D ▼ -9.75 (c = 9.16, Et ₂ O) Example 4 (RS) -4-pentene-2-acetate as a substrate 6.
4g, Lipase Toyo 0.64g, 0.1M-phosphate buffer (pH7.2)
The asymmetric hydrolysis reaction was carried out in 50 ml at 40 ° C. while maintaining the pH at 7.2 with 2N-NaOH aqueous solution. Reaction for 48 hours, NaOH
The reaction was terminated when the amount of consumed water reached 50% of the theoretical amount. After cooling, it was extracted twice with 50 ml of ether each time.
After dehydrating this extract with anhydrous sodium sulfate, only ether was distilled off under normal pressure to obtain a concentrated solution. About 10 ml of this concentrated solution was applied to silica gel column chromatography (column: silica gel C-100, 1.9 cm × 50 cm, developing solution hexane: acetone = 15: 1) to obtain (R) -4-pentene-
The 2-ol and (S) -4-pentene-2-acetate fractions were concentrated and distilled to obtain the desired product.

(R) -4-Penten-2-ol Yield 45%, ▲
[Α] ²⁰ _D ▼ −5.6 ° (c = 9, Et ₂ O) (S) -4-pentene-2-acetate Yield 43%,
▲ [α] ²⁰ _D ▼ -13.2 ° (c = 9, Et ₂ O)

Claims (2)

(57) [Claims] 1. A general formula (RS) -1. (In the formula, R represents an aliphatic hydrocarbon group having 1 to 7 carbon atoms), the ester (RS) -1 represented by the general formula 2 ^* is asymmetrically hydrolyzed ^. (In the formula, * represents an asymmetric carbon) A lipase derived from a microorganism belonging to the genus Chromobacterium having stereoselective esterase activity for producing an optically active alcohol (4-penten-2-ol) 2 ^* By reacting (RS) -1 with the optically active alcohol 2 ^* and the general formula 1 ^*. (In the formula, R and * are the same as above) and optically resolved into an optically active ester 1 ^*, and each optically active substance is separated and collected. -A method for producing a penten-2-ol derivative. 2. The hydrolysis product alcohol 2 ^* is (R)
-4-Pentene-All And the ester 1 ^* on the unreacted side is represented by the general formula (S) -1. The method according to claim 1, wherein R is the same as the above.