Abstract:
A method for producing optically active glycol derivatives by biochemical resolution which comprises contacting a racemic ester of the general formula 1 ##STR1## (wherein R 1  is an aliphatic hydrocarbon group of 1 to 16 carbon atoms, R 2  is an aliphatic hydrocarbon group of 1 to 8 carbon atoms, and R 3  is an aromatic hydrocarbon group such as phenyl, tolyl or naphtyl) with a microorganism- or animal organ-derived enzyme having stereoselective hydrolytic activity to asymmetrically hydrolyze said racemic ester of general formula 1 to produce an optically active alcohol of general formula 2* ##STR2## (wherein R 1  and R 3  have the same meanings as defined above) and an unreacted ester of the general formula 1* ##STR3## (wherein R 1 , R 2  and R 3  have the same meanings as defined hereinbefore), separating the optically active compounds from each other, hydrolyzing said ester of general formula 1* to give an optically active glycol derivative which is antipodal to the alcohol of general formula 2* and, then, isolating the same optically active glycol derivative. The invention provides a method for producing optically active glycol derivatives, which is expedient, does not require costly reagents and is suited to commercial scale production.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method for producing optically active glycol derivatives by biochemical resolution which comprises contacting a racemic ester of the general formula 1 ##STR4## (wherein R 1  is an aliphatic hydrocarbon group of 1 to 16 carbon atoms, R 2  is an aliphatic hydrocarbon group of 1 to 8 carbon atoms, and R 3  is an aromatic hydrocarbon group such as phenyl, tolyl or naphthyl) with a microorganism- or animal organ-derived enzyme having stereoselective hydrolytic activity to asymmetrically hydrolyze said racemic ester of general formula 1 to produce an optically active alcohol of general formula 2* ##STR5## (wherein R 1  and R 3  have the same meanings as defined above) and an unreacted ester of the general formula 1* ##STR6## (wherein R 1 , R 2  and R 3  have the same meanings as defined hereinbefore) and, then, isolating the respective optically active compounds. 
     In another aspect, the present invention further comprises a method for producing an optically active glycol derivative which comprises hydrolyzing said ester of general formula 1* to give an optically active glycol derivative which is antipodal to the alcohol of general formula 2* and, then, isolating the same optically active glycol derivative. 
     2. Description of the Prior Art 
     The optically active glycol derivatives mentioned above are versatile starting materials for the production of various optically active pharmaceutical products, agricultural chemicals and so on. 
     Taking 1-p-tosyloxy-2-propanol ##STR7## which corresponds to R 1  =methyl and R 3  =tolyl, as an example, it can be easily converted to propylene oxide ##STR8## and this optically active propylene oxide  can be further converted to various physiologically active substances [Uchimoto et al: Tetrahedron Letters, 3641 (1977), synthesis of (R)-recifeiolide from (R)-propylene oxide; and W. Seidel &amp; D. Seebach: Tetrahedron Letters 23, 159 (1982), synthesis of grahamimycin A 1  from (R)-propylene oxide] 
     Further, in the case of 1-p-tosyloxy-2-tridecanol ##STR9## which corresponds to R 1  =undecyl (C 11  H 23 ) and R 3  =tolyl, it can be easily converted to 1,2-epoxytridecane ##STR10## which, in turn, can be converted to δ-n-hexadecalactone ##STR11## an insect pheromone [J. L. Coke &amp; A. B. Richon: Journal of Organic Chemistry 22, 3516 (1976); and Fujisawa et al: Tetrahedron Letters 26, 771 (1985)]. 
     These optically active glycol derivatives can be respectively synthesized, for example, by means of an optically active acid after conversion to an amine or by esterifying lactic acid or 3-hydroxybutyric acid from a fermentation process, reducing the ester with a reducing agent such as lithium aluminum hydride to give 1,2-propanediol or 1,2-butanediol and introducing a sulfonic acid group into the 1-position [B. Seuring: Helvetica Chimica Acta 60, 1175 (1977)]. 
     However, these methods are disadvantageous in that complicated procedures are involved or costly reagents must be employed, and are not suitable for commercial scale production. Therefore, the establishment of an expedient method for production of such optically active compounds has been earnestly awaited. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a commercially advantageous method for producing optically active glycol derivatives which is expedient and does not require costly reagents. 
     Other objects and advantages of the present invention will become apparent as the following detailed description of the invention proceeds. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention in one aspect thereof relates to a method for producing an optically active glycol derivative by biochemical resolution which comprises contacting a racemic ester of the general formula 1 ##STR12## (wherein R 1  is an aliphatic hydrocarbon group of 1 to 16 carbon atoms, R 2  is an aliphatic hydrocarbon group of 1 to 8 carbon atoms, and R 3  is an aromatic hydrocarbon group) with a microorganism- or animal organ-derived enzyme having stereoselective hydrolytic activity to asymmetrically hydrolyze said racemic ester of general formula 1 to produce an optically active alcohol of general formula 2* ##STR13## (wherein R 1  and R 3  have the same meanings as defined above) and an unreacted ester of the general formula 1* ##STR14## (wherein R 1 , R 2  and R 3  have the same meanings as defined hereinbefore) and, then, isolating the respective optically active compounds. 
     In another aspect, the present invention is directed to a method for producing an optically active glycol derivative which comprises hydrolyzing the ester of general formula 1* obtained in the first-mentioned process to give an optically active glycol derivative which is antipodal to the compound of general formula 2* and, then, isolating the same compound. 
     The present inventors conducted an intensive research to obtain an optically active compound by esterifying the hydroxyl group in the 2-position of an alcohol of the general formula 2 ##STR15## and permitting an enzyme having stereoselective hydrolytic activity to act on the resulting ester of general formula 1 for asymmetric hydrolysis of the ester bond. As a result, the inventors have found that certain enzymes derived from microorganisms belonging to the genera Pseudomonas, Chromobacterium, Aspergillus, Mucor, Rhizopus and so on and certain enzymes derived from animal organs such as the livers and pancreas of bovine, equine, swine, and other species of animals are respectively able to asymmetrically hydrolyze the above-mentioned ester 1 to give an unreacted ester (S)-1 having the general formula: ##STR16## and an alcohol (R)-2 having the general formula: ##STR17## 
     Further, the optically active ester 1* can be easily hydrolyzed, if necessary, into the alcohol 2* by refluxing 1* in methanol. 
     The products 1* and 2* can be easily separated from each other by silica gel column chromatography, for instance, so that the respective optically active compounds can be independently recovered. 
     The method according to the present invention will now be described in further detail. 
     In the ester of the general formula 1: ##STR18## which is used as the substrate in the present invention, the substituent groups R 1 , R 2  and R 3  may for example be as follows. R 1  is an aliphatic hydrocarbon group containing 1 to 16 carbon atoms, such as methyl, ethyl, propyl, butyl, isopropyl, undecyl, etc., preferably, being an aliphatic hydrocarbon containing 1 to 4 carbon atoms and R 2  may for example be an aliphatic hydrocarbon group, an unsubstituted or substituted alicyclic hydrocarbon group, or an unsubstituted or substituted phenyl or benzyl group, although an aliphatic hydrocarbon group of 1 to 8 carbon atoms is preferred from the standpoint of the enzymatically hydrolytic activity. Further, the aliphatic hydrocarbon group may be substituted by halogen and/or hydroxy groups. R 3  is an aromatic hydrocarbon group such as tolyl, phenyl, naphthyl and so on. These aromatic hydrocarbon groups may have halogen and/or hydroxy groups as substituents. 
     The starting material 1 can be synthesized, for example, by the following two routes of synthesis. ##STR19## 
     The enzyme may be any enzyme having stereoselective hydrolytic activity to asymmetrically hydrolyze the racemic ester 1 to give (S)-1 and (R)-2. Thus, for example, there may be mentioned the enzymes derived from Pseudomonas fluorescens, Chromobacterium viscosum, Aspergillus niger, Rhizopus delemar, Rhizopus javanicus, Rhizopus japonicus and so on. The enzymes derived from animal organs can also be used and the organs may be the pancreas, liver, etc. of bovine, equine, swine and other species of animals. Examples of commercial preparations of such enzymes that can be utilized include Lipoprotein Lipase Amano 3, Lipase AP-6, Lipase M-AP-10, Lipase D, Lipase F-AP15 and pancreatic digesting enzyme TA (all available from Amano Pharmaceutical Co., Ltd.), Saiken 100 (manufactured by Nagase Sangyo Co., Ltd.), Lipase (Carbiochem Co.), Steapsin (Wako Pure Chemical Industries, Ltd.) and so on. 
     The asymmetric hydrolysis reaction is conducted in the following manner. The substrate racemic ester 1 is suspended in the reaction medium at a concentration of 2 to 80 w/v percent and, then, the enzyme is added in a suitable proportion, for example in an enzyme-to-substrate weight ratio of 1:1 through 1:1000. The reaction is carried out at a temperature of 10° to 40° C., preferably in the range of 25° to 35° C. and its progress is monitored by high performance liquid chromatography (HPLC) to determine the residual amount of the substrate and the amount of product alcohol 2. The reaction is terminated when the molar ratio of 1* to 2* in the reaction system is 50:50. The pH range for this hydrolysis reaction is pH 4 to 8.5, preferably pH 6 to 7.5, but as the pH of the reaction system leans to the acidic side with the progress of reaction, this reaction is preferably carried out in a buffer solution or while the pH of the system is controlled at pH 6 to 7.5 by the addition of a neutralizing agent such as an aqueous solution of sodium hydroxide. 
     Depending on the types of substituents on the substrate ester, the reaction may not proceed smoothly. In such instances, the substrate may be dissolved in a suitable solvent such as dioxane, acetone, tetrahydrofuran or the like and, then, suspended in the reaction medium or if the melting point of the substrate is not so high, an elevated reaction temperature may be used for the enzymatic conversion. 
     Furthermore, by immobilizing the enzyme, the above asymmetric hydrolysis reaction may be conducted in repeated runs. 
     Following the hydrolysis reaction, the compound 1* and 2* in the reaction mixture can be separated from each other in the following manner. For example, both compounds 1* and 2* are extracted with a solvent such as methylene chloride, ethyl acetate, or the like and the extract is concentrated and subjected to silica gel chromatography. In this manner, 1* and 2* are easily separated from each other. The optically active ester 1* thus fractionated can be directly concentrated to give the ester with high optical purity. Hydrolysis of this ester in dilute hydrochloric acid at room temperature or refluxing thereof in methanol converts 1* into the alcohol 2* having the corresponding optical activity. 
    
    
     EXAMPLES 
     The following examples are intended to illustrate the present invention in further detail and should by no means be construed as limiting the scope of the invention. 
     EXAMPLE 1 OF PRODUCTION OF THE SUBSTRATE 
     Production of (RS)-2-butanoyloxy-1-p-toluenesulfonyloxypropane 1a 1  ##STR20## 
     In 200 ml of methylene chloride were dissolved 38 g of 1,2-propanediol and 44 g of pyridine and, then, 95 g of p-toluenesulfonyl chloride was added gradually over a period of 15 minutes. The reaction was further conducted at room temperature for 72 hours. The reaction mixture was washed twice with one volume of water each, dehydrated over anhydrous sodium sulfate, and concentrated under reduced pressure. The concentrate was crystallized from toluene-hexane (100 ml-100 ml), filtered, and dried in vacuo to give colorless crystals of (RS)-1-p-toluenesulfonyloxy-2-propanol 2a ##STR21## (54 g). 
     Melting point: 49.5°-50° C. 
     The  1  H NMR (90 MHz) spectrum and elemental analysis of the above product were as follows. 
       1  H NMR (90 MHz, CDCl 3 ), δ (ppm): 1.16 (3H, d, CH 3  (OH)--), 2.33 (1H, broad, OH), 2.35 (3H, s, CH 3  --Ar), 3.70-4.18 (3H, m, --CH(OH)CH 2  O--), 7.34, 7.80 (4H, 2d, Ar--H) 
     Elemental analysis: Calcd. for C 10  H 14  O 4  S: C, 52.16; H, 6.13. Found: C, 52.41; H, 6.21. 
     In 200 ml of methylene chloride were dissolved 11.5 g of compound 2a and 6 g of triethylamine. Under ice-cooling, 6 g of butyryl chloride was added dropwise to the above solution over a period of 15 minutes and the reaction was further conducted at room temperature for 3 hours. 
     After butanoylation was confirmed by HPLC, the reaction mixture was washed twice with one volume of a saturated aqueous solution of sodium carbonate and concentrated under reduced pressure. The above procedure gave a syrup of (RS)-2-butanoyloxy-1-p-toluenesulfonyloxypropane (1a 1 ) in a yield of 13 g. 
     The  1  H NMR (90 MHz) spectrum and elemental analysis of the above product were as follows. 
       1  H NMR (90 MHz, CDCl 3 ) δ (ppm): 0.82-1.08 (3H, t, CH 3  --CH 2  --), 1.16-1.83 (5H, m, CH 3  CH(O--)--, CH 3  CH 2  CH 2  --), 2.10-2.33 (2H, t, CH 3  CH 2  CH 2  --), 2.45 (3H, s, CH 3  --Ar), 4.05 (2H, d, --CH(O--)CH 2  O--), 4.86-5.22 (1H, m, --CH(O--)--), 7.35, 7.77 (4H, 2d, Ar--H). 
     Elemental analysis: Calcd. for C 14  H 20  O 5  S: C, 55.98; H, 6.71. Found: C, 55.73; H, 6.77. 
     EXAMPLE 2 OF PRODUCTION OF THE SUBSTRATE 
     Production of (RS)-2-acetyloxy-1-p-toluenesulfonyloxypropane 1a 2  ##STR22## 
     Using 2a, triethylamine and acetyl chloride, the substrate compound 1a 2  was produced in accordance with Example 1 of Production. 
     Description: Colorless crystals. 
     Melting point: 39.5°-40.0° C. 
       1  H NMR (90 MHz, CDCl 3 ) δ (ppm): 1.23 (3H, d, CH 3  CH(O--)--), 1.95 (3H, s, CH 3  CO--), 2.45 (3H, s, CH 3  --Ar--), 4.03 (2H, d, --CH 2  --), 4.82-5.17 (1H, m, --CH--), 7.33, 7.77 (4H, 2d, Ar--H). 
     Elemental analysis: Calcd. for C 12  H 16  O 5  S: C, 52.93; H, 5.92. Found: C, 53.08; H, 5.99. 
     EXAMPLE 3 OF PRODUCTION OF THE SUBSTRATE 
     Production of (RS)-2-butanoyloxy-1-p-toluenesulfonyloxybutane 1b ##STR23## 
     Using 1,2-butanediol, pyridine and p-toluenesulfonyl chloride, (RS)-1-p-toluenesulfonyloxy-2-butanol 2b ##STR24## was prepared in the same manner as Example 1 of Production. 
     Description: Colorless crystals. 
     Melting point: 59°-60° C. 
       1  H NMR (90 MHz, CDCl 3 ) δ (ppm): 0.79-1.05 (3H, t, CH 3  CH 2  --), 1.30-2.10 (2H, m, CH 3  CH 2  --), 2.15 (1H, d, OH), 2.45 (3H, s, CH 3  --Ar), 3.60-4.12 (3H, m, --CH(OH)CH 2  O--), 7.30, 7.76 (4H, 2d, Ar--H) 
     Elemental analysis: Calcd. for C 11  H 16  O 4  S: C, 54.08; H, 6.60. Found: C, 54.29; H, 6.75. 
     Using 2b, triethylamine and butyryl chloride, the substrate compound 1b was produced in accordance with Example 1 of Production. 
     Description: a syrup. 
       1  H NMR (90 MHz, CDCl 3 ) δ (ppm): 0.73-1.07 (6H, m, CH 3  CH 2  CH(O--)--, CH 3  CH 2  CH 2  CO--), 1.35-1.80 (4H, m, CH 3  CH 2  CH(O--)--, CH 3  CH 2  CH 2  CO--), 2.08-2.33 (2H, m, CH 3  CH 2  CH 2  CO--), 2.45 (3H, s, CH 3  --Ar), 4.04 (2H, d, --CH(O--)CH 2  O--), 4.76-5.03 (1H, m, --CH(O--)--), 7.30, 7.75 (4H, 2d, Ar-H) 
     Elemental analysis: Calcd. for C 15  H 22  O 5  S: C, 57.30; H, 7.05. Found: C, 56.95; H, 6.89. 
     EXAMPLE 4 OF PRODUCTION OF THE SUBSTRATE 
     Production of (RS)-2-butanoyloxy-1-p-toluenesulfonyloxyheptane 1c ##STR25## 
     Using 1,2-heptanediol, pyridine and p-toluenesulfonyl chloride, (RS)-1-p-toluenesulfonyloxy-2-heptanol 2c ##STR26## was prepared in the same manner as Example 1 of Production. 
     Description: a syrup. 
       1  H NMR (90 MHz, CDCl 3 ) δ (ppm): 0.70-1.75(11H, m, C 5  H 11  --), 2.45(3H, s, CH 3  --Ar--), 2.90(1H, s, OH), 3.67(2H, d, --CH 2  O--), 4.30-4.70 (1H, m, --CH--), 7.30, 7.77(4H, d--d, Ar--H). 
     Elemental analysis: Calcd. for C 14  H 22  O 4  S: C, 58.72, H, 7.74. Found: C, 58.70, H, 7.71. 
     Using 2c, triethylamine and butyryl chloride, the substrate compound 1c was produced in accordance with Example 1 of Production. 
     Description: a syrup. 
       1  H NMR (90 MHz, CDCl 3 ) δ (ppm): 0.70-2.33(18H, m, C 5  H 11 , C 3  H 7  --), 2.42(3H, s, CH 3  --Ar), 3.85(2H, m, --CH 2  O--), 4.52-4.80(1H, m, --CH--), 7.26, 7.76(4H, d--d, Ar--H). 
     Elemental analysis: Calcd. for C 18  H 28  O 5  S: C, 60.65, H, 7.92. Found: C 60.71, H, 7.94. 
     EXAMPLE 5 OF PRODUCTION OF THE SUBSTRATE 
     Production of (RS)-2-butanoyloxy-1-p-toluenesulfonyloxyhexadecane 1d ##STR27## 
     Using 1,2-hexadecanediol, pyridine and p-toluenesulfonyl chloride, (RS)-1-p-toluenensulfonyloxy-2-hexadecanol 2d ##STR28## was prepared in the same manner as Example 1 of Production. 
     Description: a syrup. 
       1  H NMR (90 MHz, CDCl 3 ) δ (ppm): 0.75-1.73(29H, m, C 14  H 29  --), 2.00(1H, S, OH), 2.45 (3H, s, CH 3  --Ar), 3.67(2H, d, --CH 2  O--), 4.40-4.70 (1H, m, --CH--), 7.26, 7.76(4H, d--d, Ar--H). 
     Elemental analysis: calcd. for C 23  H 40  O 4  S: C, 66.95, H, 9.77. Found: C, 66.99, H, 9.82. 
     Using 2d, triethylamine and butyryl chloride, the substrate compound 1d was prepared in accordance with Example 1 of Production. 
     Description: a syrup. 
       1  H NMR (90 MHz, CDCl 3 ) δ (ppm): 0.80-2.27(36H, m, C 14  H 29  --, C 3  H 7  --), 2.44(3H, s, CH 3  --Ar), 3.90-4.27(1H, m, --CH 2  O--), 4.56-4.79(2H, m, --CH--), 7.27, 7.73(4H, d--d, Ar--H). 
     Elemental analysis: Calcd. for C 27  H 46  O 5  S; C, 67.18, H, 9.60. Found: C, 67.25, H, 9.67. 
     EXAMPLES 1 TO 16 
     A 20 ml test tube equipped with a cap was charged with 100 mg of the substrate compound 1a 1  or 1b, 10 mg of the enzyme and 5 ml of 0.1M phosphate buffer (pH 7.25) and shaken at 33° C. for 48 hours. To the reaction mixture was then added 10 ml of ethyl acetate to extract the unreacted ester (1a 1  or 1b) and the hydrolysate (2a or 2b). The ethyl acetate layer was dehydrated, filtered, and subjected to high performance liquid chromatography using a chiral column to determine the yield and optical purity of the alcohol. The results are shown in Table 1. 
     The conditions of analysis and the retention time values were as follows. 
     Liquid chromatography 
     Column: Chiral CEL OC (Nippon Bunko). 
     Developer solvent system: hexane-isopropyl alcohol =95:5. 
     Flow rate: 2.5 ml/min. 
     Detection: UV, 235 nm. 
     Retention times: 
     (RS)--1a 1  : 10.7 minutes 
     (S)--2a: 32.1 minutes 
     (R)--2a: 27.4 minutes 
     (RS)--1b: 8.4 minutes 
     (S)--2b: 19.8 minutes 
     (R)--2b: 17.6 minutes. 
     Incidentally, as to compounds 1a 1  and 1b, the R-form and the S-form have the same retention time and are, therefore, not separated from each other. 
     
                                           TABLE 1__________________________________________________________________________                       The percentage of                       product alcohol                                 OpticalExample                 Sub-                       relative to added                                 purityNo.  Enzyme   Origin    strate                       substrate, max. 50%                                 (% e.e.)__________________________________________________________________________1    Lipoprotein         Pseudomonas                   1a.sub.1                       50        &gt;99lipase Amano 3          fluorescens2    Lipase   Chromobacterium                   &#34;   27        &gt;99         viscosum3    Lipase AP-6         Aspergillus                   &#34;   3         &gt;99         niger4    Lipase M-AP-10         Mucor sp. &#34;   5         &gt;995    Lipase D Rhizopus delemar                   &#34;   15        &gt;996    Lipase F-AP 15         Rhizopus javanicus                   &#34;   13        &gt;997    Saiken 100         Rhizopus japonicus                   &#34;   8         &gt;998    Pancreatic         Swine pancreas                   &#34;   9          72digestingenzyme TA9    Lipoprotein         Pseudomonas                   1b  50        &gt;99lipase Amano 3         fluorescens10   Lipase   Chromobacterium                   &#34;   32        &gt;99         viscosum11   Lipase AP-6         Aspergillus                   &#34;   9         &gt;99         niger12   Lipase M-AP-10         Mucor sp. &#34;   18        &gt;9913   Lipase D Rhizopus delemar                   &#34;   30        &gt;9914   Lipase F-AP 15         Rhizopus japonicus                   &#34;   17        &gt;9915   Saiken 100         Rhizopus japonicus                   &#34;   11        &gt;9916   Pancreatic         Swine pancreas                   &#34;   11         60digestingenzyme TA__________________________________________________________________________ 
    
     EXAMPLE 17 
     The reaction was conducted using Lipoprotein lipase Amano 3 which possessed the highest hydrolytic activity among the lipases in Examples 1 to 16. 
     To 30 ml of 0.1M phosphate buffer (pH 7.25) were added to 3.0 g of the substrate 1a 1  and 0.03 g of Lipoprotein lipase Amano 3 and the asymmetric hydrolysis reaction was conducted at 33° C. with stirring for 4 hours, while the reaction system was controlled at pH 7.25 using an 1N aqueous solution of NaOH. The reaction mixture (30 ml) was extracted twice with 60 ml portions of methylene chloride and the methylene chloride layers were combined, dehydrated over anhydrous sodium sulfate and concentrated under reduced pressure. The concentrate was subjected to silica gel column chromatography (Wakogel C-200, L/D=40/1.5 cm, developer solvent: hexane-acetone=12-6:1, v/v) and the fractions corresponding to the ester (S)-1a 1  and the alcohol (R)-2a were recovered and concentrated under reduced pressure. The above procedure gave 1.15 g of (S)-1a 1  (yield 77%) and 0.91 g of (R)-2a (yield  79%). 
     The above (R)-2a was further recrystallized from ether-hexane to obtain 0.70 g (theoretical yield based on (RS)-1a 1  :61%). 
     The optical rotation values of the two compounds were as follows. 
     (S)-1a 1  : [α] D   20  -10.0° (c=2.0, chloroform). 
     (R)-2a: [α] D   20  -12.6° (c=2.0, chloroform). 
     The literature value: B. Seuring et al (Helvetica Chimica Acta 60, 1175 (1977): (S)-2a: [α] D  =+11.3° (c=1.1, chloroform). 
     Then, the ester (S)-1a 1  was refluxed in methanol for 3 hours, whereby it was converted into the alcohol (S)-2a. The reaction mixture was concentrated under reduced pressure to remove the methanol and the concentration residue was washed with a saturated aqueous solution of sodium hydrogen carbonate, extracted with methylene chloride, dehydrated and concentrated to give (S)-2a in a yield of about 75%. The optical rotation value of this product was as follows. 
     (S)-2a: [α] D   20  +12.6° (c=2.0, chloroform). 
     EXAMPLES 18 AND 19 
     Using 1a 2  or 1b, the asymmetric hydrolysis reaction was conducted and (S)-1a 2  and (R)-2a or (S)-1b and (R)-2b were respectively separated and isolated as in Example 17. The results are shown in Table 2. 
     
                                           TABLE 2__________________________________________________________________________Example   (S)-ester        (R)-alcoholNo.  Substrate     Yield (%).sup.( *.sup.d)            [α].sub.D.sup.20( *.sup.a)                 % e.e..sup.( *.sup.b)                      Yield (%)                            [α].sub.D.sup.20                                % e.e.__________________________________________________________________________17   1a.sub.1     39     -10.0°                 &gt;99  31    -12.6°                                &gt;9918     1a.sub.2.sup.( *.sup.c)     35     -13.0°                 &gt;99  40    -12.0°                                &gt;9919   1b   40     -18.3°                 &gt;99  40     -9.4°                                &gt;99__________________________________________________________________________ Conditions of reaction: 3.0 g of the substrate and 0.03 g of Lipoprotein lipase Amano 3 in 30 ml of 0.1 M phosphate buffer (pH 7.25). The reaction was conducted at 33° C. for 4 hours. .sup.(*.sup.a) [α].sub.D.sup.20 (c = 2.0, chloroform) .sup.(*.sup.b) Each ester was hydrolyzed by refluxing in methanol and the resulting alcohol was assayed by high performance liquid chromatography using a chiral column. .sup.(*.sup.c) Reaction temperature: 40° C. .sup.(*.sup.d) The percentage of ester or alcohol is calculated from adde substrate (max. 50%). 
    
     EXAMPLES 20 AND 21 
     Using 1c, and 1d, the asymmetric hydrolysis reaction was performed. The hydrolysis proceeded approximately 70% based on (RS)-1c and 1d. All other preparations were performed according to Example 17. The results are shown in Table 3. 
     
                       TABLE 3______________________________________    Ester         AlcoholExample  Sub-    Yield (%).sup.( *.sup.d)                     [α].sub.D.sup.20                            Yield (%)                                    [α].sub.D.sup.20No.    strate  (C = 4, Methanol)                          (C = 4, Methanol)______________________________________20     (RS)-1c 24         -0.95°                            58       0.74°21     (RS)-1d 21         -0.92°                            60      -0.85°______________________________________ Conditions of reaction: 3.0 g of the substrate and 0.3 g of Lipoprotein lipase Amano 3 in 30 ml o 0.1 M phosphate buffer (pH 7.25). The reaction was conducted at 33.degree C. for 4 hours. .sup.(*.sup.d) The percentage of ester or alcohol is calculated from adde substrate (max. 50%).