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. Author manuscript; available in PMC: 2013 Jul 8.
Published in final edited form as: Tetrahedron. 2012 May 5;68(27-28):5422–5428. doi: 10.1016/j.tet.2012.04.101

Application of Chemoenzymatic Hydrolysis in the Synthesis of 2-Monoacylglycerols

Kyle M Whitten 1, Alexandros Makriyannis 1, Subramanian K Vadivel 1,*
PMCID: PMC3398708  NIHMSID: NIHMS375592  PMID: 22822273

Abstract

The selective biocatalyzed synthesis of 2-monoacylglycerols (2-MAGs) through the use of commercially available immobilized Candida antarctica (Novozym435) and Rhizomucor miehei is explored. Reactions at room temperature result in the formation of a 2-MAG and a corresponding ethyl ester of the fatty acid with immobilized Candida antarctica within 2h with yields ranging from 36%–83%. Similar reaction conditions with immobilized Rhizomucor miehei yielded exclusively the 2-MAG after 24h with yields ranging from 37% to 88%. Yields vary on the acyl group at the sn-2 position and choice of enzyme involved.

Keywords: Cannabinoid, Receptor, Endogenous ligand, 2-Monoacylglycerol, Biocatalysis

Introduction

2-Monoacylglycerols (2-MAGs) exhibit beneficial emulsifying properties that are utilized in the food industry,1,2 and in the administration of pharmaceuticals.3 The polyunsaturated fatty acid (PUFA) occupying the sn-2 position is important in the influence of STGs absorption and digestion.4 The biological effects of fatty acids released from the metabolism of glycerols and amides, or through ingestion, have also been studied.5,6,7 One of the more intensively studied 2-MAGs, 2-arachidonoylglycerol (2-AG, 10b), is a physiologically important lipid signaling molecule acting as a receptor ligand in the endocannabinoid system. Pharmacological properties of 2-AG include hypotension, neuroprotection, and appetite stimulation.8

2-AG and other 2-MAGs in biological systems are usually inactivated/catabolized by the hydrolyzing enzyme monoacylglycerol lipase (MAGL) to produce a fatty acid and glycerol.9 The synthesis and study of 2-MAGs is made difficult due to acyl-migration from the sn-2 to the sn-1 or -3 position (Scheme 1).10,11 This migration is facile and occurs in the presence of acid, base, heat, and protic solvents. 12,13 In the case of 2-AG, acyl migration renders 1-AG, which is incapable of binding to the endocannabinoid receptors.14 Many reported syntheses of 2-MAGs involve multiple laborious steps with unfavorable reaction conditions and work ups that may promote the unwanted acyl migration. An earlier 2-MAG synthesis began with the coupling of the fatty acid to a 1,3-triisopropylsilyl (TIPS) glycerol. The removal of the silyl protecting groups required 24h with the addition of acetic acid and tetrabutylammonium fluoride.15 Another procedure involved coupling of fatty acid with 1,3-benzylideneglycerol and removal of the benzylidene with phenylboronic acid. The reaction resulted in the formation of the mixture of the 1,3- and 1,2-phenylboronate ester which was separated and cleaved with methanol and water.16 A third technique utilizes the ring opening of a glycidal ester with trifluoroacetic acid to produce a triacylglycerol. The 2-MAG was then formed after treatment of the triacylglycerol methanol and pyridine.17

Scheme 1.

Scheme 1

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Application of lipase in the syntheses of 1,3-diacylglycerol, and 1(3)-rac-monoacyl glycerol have been extensively studied and reviewed.18–26 The selectivity and yield are determined by various factors which include amount of enzyme, solvent, temperature and the type of lipase used.27–28 Even though, the preparation of selective 1,3-diacylglycerols have been achieved successfully, it has been a challenging task for the synthesis of 2-acylglycerols mainly due to over hydrolysis and the acyl migration from sn-2 to sn-1 or sn-3 position. Lipase-mediated selective hydrolysis of triglyceride using 1,3-regiospecific lipases, esterification of fatty acids or transesterification of fatty esters with glycerol, and the glycerolysis of triglycerides have been documented in the literature.29–30 Irimescu et al. reported a successful synthesis of various 2-acylglycerols of fatty acids using regiospecfic ethanolysis of symmetrical triglycerides with immobilized Candida antarctica lipase (Novozym 435).22,31 Even though Candida antarctica is not considered as a 1,3-regiospecific enzyme, it has been consistently used for the preparation of 1,3-acylglycerols and ethanolysis of triglycerides.31–32 All existing methods utilize symmetrical (“AAA” type) triglycerides resulting in the formation of corresponding ester as the by product that requires exhaustive purification (Figure 1).

Figure 1.

Figure 1

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Encouraged by this literature, we recently reported a method for the synthesis 2-AG which utilizes a structured glyceride, 1,3-dibutyryl-2-arachidonate (“ABA” type), as a substrate, for we reasoned that the anticipated byproduct, ethyl butyrate, can be easily removed.33 Benefits of this procedure include reactions at ambient temperature, neutral pH, and conservative reaction time. The method is simple and green, as the lipase can be recycled. Nevertheless, a significant amount of ethyl arachidonate formed due to over hydrolysis. Since the reaction is selective and proceeded quickly, it has become a valuable tool for the radiolabelled synthesis of 2-AG.34 The following work extends our method to the synthesis of 2-acylglycerols starting from saturated and unsaturated fatty acids, and alkyl and aryl carboxylic acids.

Results and Discussion

To test the general practicality of our method (Scheme 2), we have synthesized 2-MAGs from various commercially available long-chain carboxylic acids, including those of biological importance. The synthesis began with the enzymatic 1,3-diacyl protection of glycerol by the addition of immobilized Candida antarctica (Novozym 435) to glycerol and vinyl butyrate in anhydrous CH2Cl2 at 0 °C, resulting in the protected glycerol in quantitative yield.32,35 The 1,3-diacylglycerol was then coupled to various medium and long-chain acids through 1-(3-dimethyl-aminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) coupling in a 1:1 mixture of anhydrous THF:CH2Cl2 along with a catalytic amount of 4-dimethylaminopyridine (DMAP) at 0 °C for four hours. This generated the structured triglyceride (“ABA” type) in 67–99% yield.

Scheme 2.

Scheme 2

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For the hydrolysis step, Novozym 435 was added to the triglyceride in a minimal amount of anhydrous ethanol at room temperature. By TLC analysis, it was observed that within one hour the triglyceride had been completely consumed, and a mixture of 2-MAG, mono-protected 2-MAG, and ethyl butyrate was generated. There is no formation of ethyl ester of fatty acid observed during this period. At this point, additional lipase was added to the mixture, which was allowed to stir until all the mono-protected 2-MAG was consumed (1h), affording the 2-MAG. Some significant amount of ethyl ester was observed during this period, and the formation of ethyl ester largely depended on the type of carboxylic acid used. Aryl and unsaturated carboxylic acids showed more resistant towards to over hydrolysis compare to saturated fatty acids.

The separation of 1-MAG and 2-MAG is generally performed on boric acid impregnated TLC plates and silica gel columns.36 Nonimpregnated silica TLC plates do not resolve 1- and 2-MAG. This separation is a necessary step for most 2-MAG syntheses due to the unfavorable synthetic conditions used, which result in formation of considerable 1-MAG as well. In contrast, the highly regiospecific and neutral reaction conditions when using the lipase result in minimal or no 1-MAG formation. Although silica gel purification has been reported to be an inevitable cause of acyl migration in 2-MAG to 1-MAG,37 we did not observe any migration during column chromatography with untreated silica gel. The only required step prior to purification was equilibration of silica gel with hexanes. During chromatography, the highly non-polar ethyl ester byproduct eluted with ethyl butyrate, and the 2-MAG was collected without any acyl migration. It was observed that the lipase- catalyzed hydrolysis reactions involving saturated triglycerides had isolated yields <50%, with the ethyl ester byproduct being the major product, whereas the unsaturated triglycerides had yields in the range of 55–75%, and triglycerides containing phenylalkyl groups had yields >80% (Table 1). It should also be noted that there was no observable difference in rate of reaction or isolated yield from the hydrolysis of a 1,3-diacetylglycerol-protected compound as compared to the 1,3-dibutrylglycerol-protected compound.

TABLE 1.

Structures and Yields of Lipase catalyzed 2-MAGs

Compound No. Triglyceride (a) 2-MAG (b) C. antarctica a R. miehei b
Yield (%) Yield (%)
2 graphic file with name nihms375592t1.jpg graphic file with name nihms375592t2.jpg 47 84
3 graphic file with name nihms375592t3.jpg graphic file with name nihms375592t4.jpg 49 82
4 graphic file with name nihms375592t5.jpg graphic file with name nihms375592t6.jpg 36 80
5 graphic file with name nihms375592t7.jpg graphic file with name nihms375592t8.jpg 75 83
6 graphic file with name nihms375592t9.jpg graphic file with name nihms375592t10.jpg 44 78
7 graphic file with name nihms375592t11.jpg graphic file with name nihms375592t12.jpg 72 83
8 graphic file with name nihms375592t13.jpg graphic file with name nihms375592t14.jpg 63 77
9 graphic file with name nihms375592t15.jpg graphic file with name nihms375592t16.jpg 55 79
10 graphic file with name nihms375592t17.jpg graphic file with name nihms375592t18.jpg 67 75
11 graphic file with name nihms375592t19.jpg graphic file with name nihms375592t20.jpg 63 76
12 graphic file with name nihms375592t21.jpg graphic file with name nihms375592t22.jpg 40 88
13 graphic file with name nihms375592t23.jpg graphic file with name nihms375592t24.jpg 83 40
14 graphic file with name nihms375592t25.jpg graphic file with name nihms375592t26.jpg 83 37
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a

Remaining yield consisted of the ethyl ester of sn-2 acyl group.

b

Remaining yield consisted of intermediate diglyceride.

We also screened other 1,3-specific lipases to investigate whether the transformation can be performed in better yield and selectivity towards the range of substrates and found that lipase from Rhizomucor miehei showed excellent selectivity towards hydrolyzing “ABA” type triglycerides. The reaction proceeded in a similar fashion where the triglyceride was consumed quickly, but hydrolysis of diglycerides took 24h to 48h. Even though the reaction proceeded very slowly compared to Candida antarctica lipase, the R. miehei lipase offered a remarkable improvement in selectivity, providing exclusively 2-acylglycerols in excellent yields without formation of ethyl ester byproduct. The saturated and unsaturated fatty acid triglycerides were hydrolyzed in good yields (75–88%) after 24 h. However, in most of the reactions, some unreacted diglyceride intermediate remained. Allowing the reaction to proceed for an additional 24 h or adding more enzyme did not improve the yield. When unreacted diglyceride that was separated from the 2-MAG after 24 h was subjected to an additional treatment of Rhizomucor miehei lipase the maximal yield once again reached 80% 2-MAG formation. Surprisingly, in contrast to Candida Antarctica lipase, Rhizomucor miehei lipase showed less reactivity towards aryl esters (13 and 14).

Conclusion

Synthesis of 2-MAGs is complicated by the propensity of the acyl group to shift from the sn-2 to the more stable sn-1 or -3 positions, the acyl migration being promoted by heretofore standard reaction conditions. We demonstrate herein that chemoenzymatic hydrolysis of structured triglycerides is a mild and efficient means to synthesize 2-MAGs. The ambient temperature, neutral pH, and lack of caustic work-up are conditions which markedly limit 2-MAG acyl migration. The ability to synthesize 2-MAGs from “ABA” type triglycerides is an important aspect of this current methodology in comparison to utilizing “AAA” type triglycerides. An excess of fatty acid is not required for this method which is important when the preparation of the modified fatty acid involves laborious multistep-synthesis.38–40 This will further enhance the study of structure activity relationships of these biologically important lipid signaling molecules.

Experimental

General Methods

Lipase acrylic resin from Candida antarctica and Lipozyme®, immobilized from Rhizomucor miehei were purchased from Sigma Aldrich (USA). All other reagents were used without prior purification. All reactions were performed under an atmosphere of argon.

All by products, ethyl arachidonate, ethyl butyrate, and all diglycerides were removed during column chromatography. All glycerols were prufied on a Biotage Isolera One using Luknova prepackaged 12g columns equilibrated with hexanes.

Compounds 3a–14a were synthesized following the procedure described for 2a; while compounds 3b–14b were synthesized following the C. antarctica and R. miehei procedures described for 2b.

2-hydroxypropane-1,3-diyl dibutyrate (1)

Immobilized Candida antarctica (750 mg) was added to a solution of glycerol (2.0 g, 21.6 mmol) and vinyl butyrate (6.2 g, 54.0 mmol) in anhydrous CH2Cl2 (10 mL) at 0°C. The resulting mixture was stirred for 3h under argon atmosphere. Then, additional lipase (400 mg) was added to the reaction mixture which was stirred for an additional 2 h at 0°C. The lipase was filtered off, the solvent was evaporated off under reduced pressure, and the residue was chromatographed on silica to yield 1 (5.0 g, 99%) as a colorless oil. Rf = 0.55 (40% ethyl acetate/hexanes). 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 4.20 (dd, J=11.72, 4.39 Hz, 2 H) 4.14 (dd, J=11.72, 5.86 Hz, 2 H) 4.04 – 4.12 (m, 1 H) 2.41 – 2.58 (m, 1 H) 2.33 (t, J=7.32 Hz, 4 H) 1.67 (sxt, J=7.32 Hz, 4 H) 0.96 (t, J=7.57 Hz, 4 H). The 13C NMR spectral data (100 MHz, CDCl3) are in agreement with literature values.32

2-(dodecanoyloxy)propane-1,3-diyl dibutyrate (2a)

EDCI (383 mg, 2.0 mmol), DMAP (19 mg, 0.16 mmol), and 1 (204 mg, 0.88 mmol) were added to a solution of lauric acid (160 mg, 0.80 mmol) in a 1:1 mixture of anhydrous THF/CH2Cl2 (10 mL) at 0 °C. The reaction was allowed to stir for 4h. The reaction was then diluted with CH2Cl2 (15 mL) and H2O (15 mL). The organic layer was separated, dried over MgSO4, and the solvent was removed under reduced pressure. The residue was chromatographed on silica gel (0% to 15% ethyl acetate/hexanes) to yield 2a (221 mg, 67%) as a colorless oil. Rf = 0.50 (15% ethyl acetate/hexanes). 1H NMR (400 MHz, CHLOROFORM-d) δ = 5.24 – 5.31 (m, 1 H) 4.30 (dd, J=12.09, 4.03 Hz, 2 H) 4.16 (dd, J=12.46, 5.86 Hz, 2 H) 2.27 – 2.35 (m, 6 H) 1.57 – 1.70 (m, 6 H) 1.21 – 1.36 (m, 16 H) 0.92 – 0.98 (m, 6 H) 0.88 (t, J=6.60 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.4 (2C), 173.2, 77.4, 69.1, 62.3 (2C), 36.1 (2C), 34.4, 32.1, 29.8, 29.7, 29.6, 29.5, 29.3, 25.1, 22.9, 18.6 (2C), 14.4, 13.9 (2C). IR (neat) cm−1 2926, 2855, 1742, 1460. HRMS for C23H42O6Na (MNa+) 437.2881. Calcd. 437.2879.

1,3-dihydroxypropan-2-yl dodecanoate (2b, utilizing Candida antarctica)

Immobilized Candida antarctica (Novozym 435, 100 mg) was added to a solution of 2a (100 mg, 0.24 mmol) stirred in anhydrous EtOH (1 mL). After the full consumption of 2a (1h, TLC monitoring), additional lipase (100 mg) was added until reaction completion was observed (1h). The reaction mixture was diluted with CH2Cl2 (3 mL), and the lipase was filtered off. The solvent was removed under reduced pressure, and the resulting residue was chromatographed on silica gel (10% to 50% acetone/hexanes) to yield 2b (31mg, 47%) as a white solid. Rf = 0.26 (30% acetone/hexanes). MP = 56–57 °C. 1H NMR (400 MHz, CHLOROFORM-d) δ = 4.93 (quin, J=4.76 Hz, 1 H) 3.84 (br. s., 4 H) 2.38 (t, J=7.69 Hz, 2 H) 2.08 (br. s., 2 H) 1.58 – 1.69 (m, 2 H) 1.20 – 1.37 (m, 16 H) 0.88 (t, J=6.60 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.3, 75.3, 62.8 (2C), 34.6, 32.1, 29.8, 29.7, 29.6, 29.5, 29.3, 25.2 (2C), 22.9, 14.4. IR (neat) cm−1 3352, 2922, 2856, 1730, 1464. HRMS for C15H30O4Na (MNa+) 297.2041. Calcd. 297.2042.

1,3-dihydroxypropan-2-yl dodecanoate (2b, utilizing Rhizomucor miehei)

Lipozyme®, immobilized from Rhizomucor miehei (100mg) was added to a solution of 2a (100 mg, 0.24 mmol) stirred in anhydrous EtOH (1 mL). The reaction was stirred for 24h, diluted with CH2Cl2 (3 mL), and the lipase was filtered off. The solvent was removed under reduced pressure, and the resulting residue was chromatographed on silica gel (10% to 50% acetone/hexanes) to yield 2b (55 mg, 84%) as an oil. All spectral data was consistent with that obtained using the procedure with C. antarctica.

2-(tetradecanoyloxy)propane-1,3-diyl dibutyrate (3a)

347 mg, 99%, colorless oil. Rf = 0.47 (15% ethyl acetate/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 5.32 - 5.22 (m, 1 H), 4.29 (dd, J = 4.4, 11.7 Hz, 2 H), 4.15 (dd, J = 5.9, 11.7 Hz, 2 H), 2.35 - 2.25 (m, 6 H), 1.70 - 1.56 (m, 6 H), 1.36 - 1.19 (m, 20 H), 0.94 (t, J = 7.3 Hz, 6 H), 0.87 (t, J = 6.6 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.4 (2C), 173.2, 69.1, 62.3 (2C), 36.1 (2C), 34.4, 32.2, 29.91, 29.89 (2C), 29.86, 29.7, 29.6, 29.5, 29.3, 25.1, 22.9, 18.6 (2C), 14.4, 13.9 (2C). IR (neat) cm−1 2925, 2854, 1741, 1460. HRMS for C25H46O6Na (MNa+) 465.3195. Calcd. 465.3192.

1,3-dihydroxypropan-2-yl tetradecanoate (3b)

C. antarctica: 34mg, 49%; R. miehei: 57 mg, 82%; white solid. Rf = 0.22 (30% acetone/hexanes). MP = 57–58 °C. 1H NMR (399MHz, CHLOROFORM-d) δ = 4.93 (quin, J = 4.8 Hz, 1 H), 3.89 - 3.78 (m, 3 H), 2.38 (t, J = 7.3 Hz, 2 H), 2.17 - 2.10 (m, 2 H), 1.70 - 1.58 (m, 2 H), 1.38 - 1.19 (m, 20 H), 0.88 (t, J = 7.3 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.3, 75.2, 62.8 (2C), 34.6, 32.2, 29.91, 29.87 (2C), 29.8, 29.7, 29.6, 29.5, 29.3, 25.2, 22.9, 14.4. IR (neat) cm−1 3418, 2926, 2855, 1729, 1466. HRMS for C17H34O4Na (MNa+) 325.2354. Calcd. 325.2355.

2-(palmitoyloxy)propane-1,3-diyl dibutyrate (4a)

309 mg, 84%, colorless oil. Rf = 0.39 (15% ethyl acetate/hexanes). 1H NMR (500MHz, CHLOROFORM-d) δ = 5.30 - 5.25 (m, 1 H), 4.30 (dd, J = 4.2, 12.0 Hz, 2 H), 4.16 (dd, J = 5.9, 11.7 Hz, 2 H), 2.35 - 2.27 (m, 6 H), 1.70 - 1.58 (m, 6 H), 1.34 - 1.21 (m, 24 H), 0.98 - 0.92 (m, 6 H), 0.88 (t, J = 6.8 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.4, 173.2 (2C), 69.1, 62.3 (2C), 36.1, 34.4, 32.2, 29.9 (6C), 29.7, 29.6, 29.5, 29.3, 25.1 (2C), 18.6 (3C), 14.4, 13.9 (2C). IR (neat) cm−1 2924, 1742, 1460. HRMS for C27H50O6Na (MNa+) 493.3503. Calcd. 493.3505.

1,3-dihydroxypropan-2-yl palmitate (4b)

C. antarctica: 25 mg, 36%; R. miehei: 56 mg, 80%; white solid. Rf = 0.27 (30% acetone/hexanes). MP = 64–65 °C. 1H NMR (500MHz, CHLOROFORM-d) δ = 4.93 (quin, J = 4.8 Hz, 1 H), 3.84 (t, J = 4.9 Hz, 4 H), 2.38 (t, J = 7.6 Hz, 2 H), 2.13 - 2.05 (m, 2 H), 1.69 - 1.59 (m, 2 H), 1.38 - 1.20 (m, 24 H), 0.88 (t, J = 7.3 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.3, 75.2, 62.8 (2C), 34.6, 32.2, 29.93, 29.92, 29.89, 29.84, 29.7, 29.6, 29.5, 29.3, 25.2 (2C), 23.3, 22.9, 14.4. IR (neat) cm−1 3320, 2917, 2850, 1730, 1471. HRMS for C19H38O4Na (MNa+) 353.2668. Calcd. 353.2668.

(Z)-2-(hexadec-9-enoyloxy)propane-1,3-diyl dibutyrate (5a)

291 mg, 79%, colorless oil. Rf = 0.50 (15% ethyl acetate/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 5.38 - 5.32 (m, 2 H), 5.31 - 5.24 (m, 1 H), 4.30 (dd, J = 4.4, 11.7 Hz, 2 H), 4.16 (dd, J = 5.9, 12.5 Hz, 2 H), 2.38 - 2.26 (m, 6 H), 2.01 (q, J = 6.6 Hz, 4 H), 1.72 - 1.56 (m, 6 H), 1.39 - 1.20 (m, 16 H), 0.95 (t, J = 7.3 Hz, 6 H), 0.88 (t, J = 7.0 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.3 (2C), 173.1, 130.2, 129.9, 69.1, 62.3 (2C), 36.1 (2C), 34.4, 32.0, 30.0, 29.9, 29.4, 29.3, 29.25, 29.21, 27.5, 27.4, 25.1, 22.9, 18.6 (2C), 14.3, 13.8 (2C). IR (neat) cm−1 3007, 2928, 2856, 1742, 1459. HRMS for C27H48O6Na (MNa+) 491.3347. Calcd. 491.3349.

(Z)-1,3-dihydroxypropan-2-yl hexadec-9-enoate (5b)

C. antarctica: 46 mg, 66%; R. miehei: 58 mg, 83%; colorless oil. Rf = 0.25 (30% acetone/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 5.40 - 5.31 (m, 2 H), 4.92 (quin, J = 4.8 Hz, 1 H), 3.86 - 3.79 (m, 4 H), 2.37 (t, J = 7.7 Hz, 2 H), 2.33 (br. s., 2 H), 2.05 - 1.97 (m, 4 H), 1.63 (quin, J = 7.3 Hz, 2 H), 1.39 - 1.23 (m, 16 H), 0.88 (t, J = 6.6 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.3, 130.3, 129.9, 75.2, 62.6 (2C), 34.6, 32.0, 30.0, 29.9, 29.4, 29.32, 29.30, 29.2, 27.4, 27.4, 25.2, 22.9, 14.3. IR (neat) cm−1 3405, 3008, 2924, 2855, 1736, 1462. HRMS for C19H36O4Na (MNa+) 351.2512. Calcd. 351.2511.

2-(stearoyloxy)propane-1,3-diyl dibutyrate (6a)

300 mg, 85%, colorless oil. Rf = 0.34 (15% ethyl acetate/hexanes). 1H NMR (500MHz, CHLOROFORM-d) δ = 5.30 - 5.24 (m, 1 H), 4.30 (dd, J = 4.4, 11.7 Hz, 2 H), 4.16 (dd, J = 6.1, 12.0 Hz, 2 H), 2.34 - 2.27 (m, 6 H), 1.70 - 1.59 (m, 6 H), 1.35 - 1.20 (m, 28 H), 0.98 - 0.93 (m, 6 H), 0.88 (t, J = 6.6 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.4 (2C), 173.2, 69.1, 62.3 (2C), 36.2 (2C), 34.4, 32.2, 29.9 (4C), 29.89 (3C), 29.86, 29.7, 29.6, 29.5, 29.3, 25.1, 22.9, 18.6 (2C), 14.4, 13.9 (2C). IR (neat) cm−1 2924, 1742, 1460. HRMS for C29H54O6Na (MNa+) 521.3813. Calcd. 521.3818.

1,3-dihydroxypropan-2-yl stearate (6b)

C. antarctica: 32mg, 44%; R. miehei: 56 mg, 78%; white solid. Rf = 0.23 (30% acetone/hexanes). MP = 68–69 °C. 1H NMR (399MHz, CHLOROFORM-d) δ = 4.93 (quin, J = 4.6 Hz, 1 H), 3.88 - 3.82 (m, 4 H), 2.38 (t, J = 7.7 Hz, 2 H), 2.04 (t, J = 5.9 Hz, 2 H), 1.65 (quin, J = 7.3 Hz, 2 H), 1.38 - 1.19 (m, 28 H), 0.88 (t, J = 6.6 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.3, 75.3, 62.8 (2C), 34.6, 32.2, 29.95 (5C), 29.91 (2C), 29.8, 29.7, 29.6, 29.5, 29.3, 25.2, 23.0, 13.8. IR (neat) cm−1 3313, 2916, 2849, 1730, 1472. HRMS for C21H42O4Na (MNa+) 381.2982. Calcd. 381.2981.

(Z)-2-(oleoyloxy)propane-1,3-diyl dibutyrate (7a)

290 mg, 82%, colorless oil. Rf = 0.43 (15% ethyl acetate/hexanes). 1H NMR (500MHz, CHLOROFORM-d) δ = 5.39 - 5.30 (m, 2 H), 5.30 - 5.24 (m, 1 H), 4.30 (dd, J = 4.4, 11.7 Hz, 2 H), 4.15 (dd, J = 6.1, 12.0 Hz, 2 H), 2.36 - 2.25 (m, 6 H), 2.01 (q, J = 6.2 Hz, 4 H), 1.71 - 1.55 (m, 6 H), 1.38 - 1.19 (m, 20 H), 0.95 (t, J = 7.3 Hz, 3 H), 0.88 (t, J = 6.8 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.4 (2C), 173.1, 130.3, 129.9, 69.1, 62.3, 36.1 (2C), 34.4, 32.1, 30.0, 29.9, 29.8, 29.6 (2C), 29.4, 29.3, 29.2, 27.5, 27.4, 25.1, 22.9, 18.6 (3C), 14.4, 13.9 (2C). IR (neat) cm−1 3007, 2925, 1742, 1460. HRMS for C29H52O6Na (MNa+) 519.3658. Calcd. 519.3662.

1,3-dihydroxypropan-2-yl oleate (7b)

C. antarctica: 48 mg, 67%; R. miehei: 60 mg, 83%; colorless oil. Rf = 0.30 (30% acetone/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 5.41 - 5.31 (m, 2 H), 4.92 (quin, J = 4.8 Hz, 1 H), 3.88 - 3.77 (m, 4 H), 2.49 (br. s., 2 H), 2.37 (t, J = 7.7 Hz, 2 H), 2.01 (q, J = 6.4 Hz, 4 H), 1.63 (quin, J = 7.3 Hz, 2 H), 1.40 - 1.19 (m, 20 H), 0.88 (t, J = 6.6 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.4, 130.3, 129.9, 75.1, 62.5 (2C), 34.6, 32.1, 30.0, 29.9, 29.8, 29.6, 29.4, 29.33, 29.31, 27.45, 27.38, 25.2 (2C), 22.9, 14.4. IR (neat) cm−1 3415, 3008, 2923, 2854, 1735, 1464. HRMS for C21H40O4Na (MNa+) 379.2827. Calcd. 379.2824.

2-((9Z,12Z)-octadeca-9,12-dienoyloxy)propane-1,3-diyl dibutyrate (8a)

344 mg, 98%, colorless oil. Rf = 0.38 (15% ethyl acetate/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 5.43 - 5.30 (m, 4 H), 5.29 - 5.24 (m, 1 H), 4.30 (dd, J = 4.4, 11.7 Hz, 2 H), 4.15 (dd, J = 5.9, 11.7 Hz, 2 H), 2.77 (t, J = 6.6 Hz, 2 H), 2.36 - 2.26 (m, 6 H), 2.05 (q, J = 6.6 Hz, 4 H), 1.72 - 1.56 (m, 6H), 1.41 - 1.22 (m, 14 H), 0.95 (t, J = 7.7 Hz, 6 H), 0.89 (t, J = 7.0 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.3 (2C), 173.1, 130.5, 130.2, 128.3, 128.1, 69.1, 62.3 (2C), 36.1 (2C), 34.4, 31.8, 29.8, 29.6, 29.4 (2C), 29.3, 29.2, 27.4, 25.8, 25.1, 22.8, 18.6 (2C), 14.3, 13.9 (2C). IR (neat) cm−1 3008, 2929, 2856, 1741, 1459. HRMS for C29H50O6Na (MNa+) 517.3506. Calcd. 517.3505.

(9Z,12Z)-1,3-dihydroxypropan-2-yl octadeca-9,12-dienoate (8b)

C. antarctica: 45 mg, 63%; R. miehei: 55 mg, 77%; colorless oil. Rf = 0.37 (30% acetone/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 5.44 - 5.30 (m, 4 H), 4.93 (quin, J = 4.8 Hz, 1 H), 3.89 - 3.76 (m, 4 H), 2.77 (t, J = 6.6 Hz, 2 H), 2.38 (t, J = 7.3 Hz, 2 H), 2.13 (t, J = 6.2 Hz, 2 H), 2.05 (q, J = 6.8 Hz, 4 H), 1.69 - 1.59 (m, 2 H), 1.41 - 1.23 (m, 14 H), 0.89 (t, J = 6.6 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.3, 130.5, 130.2, 128.3, 128.1, 75.2, 62.8 (2C), 34.6, 31.8, 29.8, 29.6, 29.4, 29.33, 29.30, 27.4, 25.9, 25.2 (2C), 22.8, 14.3. IR (neat) cm−1 3397, 010, 2926, 2855, 1736, 1459. HRMS for C21H38O4Na (MNa+) 377.2667. Calcd. 377.2668.

(Z)-2-(icos-11-enoyloxy)propane-1,3-diyl dibutyrate (9a)

328 mg, 88%, colorless oil. Rf = 0.42 (15% ethyl acetate/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 5.38 - 5.32 (m, 2 H), 5.30 - 5.24 (m, 1 H), 4.30 (dd, J = 4.4, 11.7 Hz, 2 H), 4.16 (dd, J = 5.9, 12.5 Hz, 2 H), 2.36 - 2.26 (m, 6 H), 2.05 - 1.97 (m, 4 H), 1.71 - 1.57 (m, 6 H), 1.27 (br. s., 24 H), 0.95 (t, J = 7.3 Hz, 6 H), 0.88 (t, J = 6.6 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.3 (2C), 173.1, 130.2, 130.0, 69.0, 62.3 (2C), 36.1 (2C), 34.4, 32.1, 30.0 (2C), 29.8, 29.7, 29.55 (2C), 29.52, 29.51, 29.3, 27.4 (2C), 25.1 (2C), 22.9, 18.6 (2C), 14.4, 13.9 (2C). IR (neat) cm−1 3008, 2925, 2855, 1742, 1459. HRMS for C31H56O6Na (MNa+) 547.3978. Calcd. 547.3975.

(Z)-1,3-dihydroxypropan-2-yl icos-11-enoate (9b)

C. antarctica: 40mg, 55%; R. miehei, 58 mg, 79%; white solid. Rf = 0.24 (30% acetone/hexanes). MP = 32–33 °C. 1H NMR (399MHz, CHLOROFORM-d) δ = 5.38 - 5.32 (m, 2 H), 4.93 (quin, J = 4.8 Hz, 1 H), 3.89 - 3.78 (m, 4 H), 2.38 (t, J = 7.3 Hz, 2 H), 2.20 - 2.12 (m, 2 H), 2.01 (q, J = 6.6 Hz, 4 H), 1.71 - 1.57 (m, 2 H), 1.40 - 1.18 (m, 24 H), 0.88 (t, J = 6.6 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.3, 130.2, 130.0, 75.2, 62.8 (2C), 34.6, 32.1, 30.0 (2C), 29.8, 29.7, 29.7, 29.6 (2C), 29.56, 29.51, 29.3, 27.4, 25.2 (2C), 23.0, 14.4. IR (neat) cm−1 3405, 3008, 2923, 2854, 1737, 1465. HRMS for C23H44O4Na (MNa+) 407.3142. Calcd. 407.3137.

2-((5Z,8Z,11Z,14Z)-icosa-5,8,11,14-tetraenoyloxy)propane-1,3-diyl dibutyrate (10a)

168mg, 98%, colorless oil. Rf = 0.36 (30% ethyl acetate/hexanes). The 1H and 13C spectral data (500 and 100 MHz, CDCl3) are in agreement with literature values.33 IR (neat) 3012, 2931, 1741, 1456. HRMS for C31H50O6Na (MNa+) 541.3502. Calcd. 541.3505.

(5Z,8Z,11Z,14Z)-1,3-dihydroxypropan-2-yl icosa-5,8,11,14-tetraenoate (10b)

C. antarctica: 48mg, 67%; R. miehei: 54 mg, 75%; colorless oil. Rf = 0.30 (30% acetone/hexanes). The 1H and 13C spectral data (500 and 100 MHz, CDCl3) are in agreement with literature values.33 IR (neat) 3420, 2013, 2927, 1736, 1456. HRMS for C23H38O4Na (MNa+) 401.2677. Calcd. 401.2668.

2-((4Z,7Z,10Z,13Z,16Z,19Z)-docosa-4,7,10,13,16,19-hexaenoyloxy)propane-1,3-diyl diacetate (11a)

EDCI (111 mg, 0.58 mmol), DMAP (6 mg, 0.06 mmol), and diacetin (44 mg, 0.25 mmol) were added to a solution of docosahexaenoic acid (75 mg, 0.23 mmol) in anhydrous CH2Cl2 (5 mL) at 0 °C. The reaction was allowed to stir for 4h. Upon completion, the reaction mixture was diluted with CH2Cl2 and H2O. The organic layer was separated, dried over MgSO4, and removed under reduced pressure. The resulting residue was chromatographed on silica gel (0% to 30% ethyl acetate/hexanes) to yield to 11a (111 mg, 99%) as a colorless oil. Rf = 0.55 (30% ethyl acetate/hexanes). 1H NMR (500MHz, CHLOROFORM-d) δ = 5.47 - 5.32 (m, 12 H), 5.30 - 5.21 (m, 1 H), 4.29 (dd, J = 4.4, 11.7 Hz, 2 H), 4.16 (dd, J = 5.9, 12.2 Hz, 2 H), 2.93 - 2.77 (m, 10 H), 2.40 (d, J = 2.9 Hz, 4 H), 2.14 - 2.02 (m, 6 H), 0.98 (t, J = 7.6 Hz, 3 H). The 13C spectral data (100 MHz, CDCl3) and IR data are in agreement with literature values.32 HRMS for C29H42O6Na (MNa+) 509.2880. Calcd. 509.2879.

(4Z,7Z,10Z,13Z,16Z,19Z)-1,3-dihydroxypropan-2-yl docosa-4,7,10,13,16,19-hexaenoate (11b)

C. antarctica: 45 mg, 63%; R. miehei: 63 mg, 76%; colorless oil. Rf = 0.29 (30% acetone/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 5.52 - 5.22 (m, 12 H), 4.92 (quin, J = 4.6 Hz, 1 H), 3.82 (t, J = 5.1 Hz, 4 H), 2.91 - 2.77 (m, 10 H), 2.49 - 2.37 (m, 4 H), 2.22 (t, J = 6.2 Hz, 2 H), 2.07 (quin, J = 7.5 Hz, 2 H), 0.97 (t, J = 7.3 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.5, 132.3 (2C), 129.8 (2C), 128.8, 128.6, 128.5 (2C), 128.3 (2C), 128.1, 127.9, 75.4, 62.6 (2C), 34.4, 25.8 (5C), 23.0 (2C), 20.8. IR (neat) cm−1 3401, 3013, 2663, 1736, 1390. HRMS for C25H38O4Na (MNa+) 425.2666. Calcd. 425.2668.

2-(docosanoyloxy)propane-1,3-diyl dibutyrate (12a)

201 mg, 56%, colorless oil. Rf = 0.48 (15% ethyl acetate/hexanes). MP = 27–28 °C. 1H NMR (399MHz, CHLOROFORM-d) δ = 5.32 - 5.23 (m, 1 H), 4.30 (dd, J = 4.4, 11.7 Hz, 2 H), 4.16 (dd, J = 5.9, 11.7 Hz, 2 H), 2.36 - 2.26 (m, 6 H), 1.71 - 1.57 (m, 6 H), 1.25 (s, 36 H), 0.95 (t, J = 7.3 Hz, 6 H), 0.88 (t, J = 6.6 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.4 (2C), 173.2, 69.1, 62.3 (2C), 36.0 (2C), 34.4, 32.2, 29.95 (9C), 29.91 (2C), 29.88, 29.7, 29.6, 29.5, 29.3, 25.1, 22.9, 18.6 (2C), 14.4, 13.9 (2C). IR (neat) cm−1 2923. 2853, 1742, 1462. HRMS for C33H62O6Na (MNa+) 577.4446. Calcd. 577.4444.

1,3-dihydroxypropan-2-yl docosanoate (12b)

C. antarctica: 32mg, 40%; R. miehei: 70 mg, 88%, white solid. Rf = 0.27 (30% acetone/hexanes). MP = 79–80 °C. 1H NMR (399MHz, CHLOROFORM-d) δ = 4.93 (quin, J = 4.6 Hz, 1 H), 3.88 - 3.81 (m, 4 H), 2.38 (t, J = 7.7 Hz, 2 H), 2.08 (s, 2 H), 1.69 - 1.59 (m, 2 H), 1.38 - 1.19 (m, 36 H), 0.88 (t, J = 6.2 Hz, 3 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.3, 75.2, 62.8 (2C), 34.6, 32.2, 31.8, 29.94 (7C), 29.90 (2C), 29.8, 29.7, 29.6, 29.5, 29.3, 25.2, 22.94, 22.89, 14.4. IR (neat) cm−1 3313, 297, 2850, 1730, 1472. HRMS for C25H50O4Na (MNa+) 437.3610. Calcd. 437.3607.

2-(3-phenylpropanoyloxy)propane-1,3-diyl dibutyrate (13a)

280mg, 98%, colorless oil. Rf = 0.48 (35% ethyl acetate/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 7.33 - 7.25 (m, 2 H), 7.24 - 7.15 (m, 3 H), 5.31 - 5.23 (m, 1 H), 4.28 (dd, J = 4.4, 11.7 Hz, 2 H), 4.13 (dd, J = 5.9, 11.7 Hz, 2 H), 2.96 (t, J = 7.7 Hz, 2 H), 2.66 (t, J = 8.1 Hz, 2 H), 2.34 - 2.24 (m, 6 H), 1.64 (sxt, J = 7.3 Hz, 4 H), 0.94 (t, J = 7.3 Hz, 6 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.3 (2), 172.2, 140.4, 128.7 (2), 128.5 (2), 126.6, 69.4, 62.2 (2), 36.1 (2), 35.9, 31.0, 18.6 (2), 13.9 (2C). IR (neat) cm−1 3027, 2966, 2877, 1737, 1455. HRMS for C20H28O6Na (MNa+) 387.1787. Calcd. 387.1784.

1,3-dihydroxypropan-2-yl 3-phenylpropanoate (13b)

C. antarctica: 38mg, 83%; R. miehei: 8 mg, 40%; white foam. Rf = 0.18 (40% acetone/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 7.36 - 7.28 (m, 2 H), 7.26 - 7.18 (m, 3 H), 4.89 (td, J = 4.5, 9.3 Hz, 1 H), 3.79 - 3.71 (m, 4 H), 3.02 - 2.96 (m, 2 H), 2.77 - 2.70 (m, 2 H), 1.91 - 1.83 (m, 2 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 175.2, 140.4, 128.8 (2), 128.5 (2), 126.7, 75.5, 62.6 (2), 36.1, 31.8. IR (neat) cm−1 3412, 3029, 2935, 2881, 1731, 1454. HRMS for C12H16O4Na (MNa+) 247.0945. Calcd. 247.0946.

2-(5-phenylpentanoyloxy)propane-1,3-diyl dibutyrate (14a)

298mg, 99%, colorless oil. Rf = 0.63 (35% ethyl acetate/hexanes). 1H NMR (500MHz, CHLOROFORM-d) δ = 7.31 - 7.24 (m, 2 H), 7.21 - 7.14 (m, 3 H), 5.31 - 5.23 (m, 1 H), 4.30 (dd, J = 4.4, 11.7 Hz, 2 H), 4.14 (dd, J = 5.9, 11.7 Hz, 2 H), 2.63 (t, J = 7.1 Hz, 2 H), 2.35 (t, J = 6.8 Hz, 2 H), 2.29 (t, J = 6.8 Hz, 4 H), 1.71 - 1.58 (m, 8 H), 0.94 (t, J = 7.3 Hz, 6 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 173.4 (2C), 172.9, 142.2, 128.6 (2C), 128.6 (2C), 126.0, 69.2, 62.3 (2C), 36.1 (2C), 35.8, 34.2, 31.0, 24.7, 18.6 (2C), 13.8 (2C). IR (neat) cm−1 3028, 2965, 2876, 1738, 1454. HRMS for C22H32O6Na (MNa+) 415.2094. Calcd. 415.2097.

1,3-dihydroxypropan-2-yl 5-phenylpentanoate (14b)

C. antarctica: 50mg, 83%; R. miehei: 24mg, 37%; white foam. Rf = 0.26 (40% acetone/hexanes). 1H NMR (399MHz, CHLOROFORM-d) δ = 7.31 - 7.25 (m, 2 H), 7.22 - 7.13 (m, 3 H), 4.92 (td, J = 4.8, 9.5 Hz, 1 H), 3.86 - 3.76 (m, 4 H), 2.64 (t, J = 7.0 Hz, 2 H), 2.41 (t, J = 7.0 Hz, 2 H), 2.17 - 2.11 (m, 2 H), 1.74 - 1.60 (m, 4 H). 13C NMR (100MHz, CHLOROFORM-d) δ = 174.0, 142.2, 128.6 (4C), 126.1, 75.2, 62.7 (2C), 35.8, 34.4, 31.0, 24.7. IR (neat) cm−1 3414, 3027, 2936, 2882, 1731, 1454. HRMS for C14H20O4Na (MNa+) 275.1257. Calcd. 275.1259.

Supplementary Material

01

Acknowledgments

We thank Dr. David Janero for helpful discussions. We thank Dr. Furong Sun at the School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, IL for supplying HRMS data. We would like to acknowledge the financial support for this research from NIDA (R03 DA029184-02).

Footnotes

Supporting Information

1H and 13C NMR spectra for all new compounds reported.

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References

  • 1.Lauridsen J. J Am Oil Chem Soc. 1976;53:400. [Google Scholar]
  • 2.Van Haften J. J Am Oil Chem Soc. 1979;56:831A. [Google Scholar]
  • 3.Pouton CW. Eur J Pharm Sci. 2000;11:S93. doi: 10.1016/s0928-0987(00)00167-6. [DOI] [PubMed] [Google Scholar]
  • 4.Christensen M, Hoy C, Becker C, Redgrave T. Am J Clin Nutr. 1995;61:56. doi: 10.1093/ajcn/61.1.56. [DOI] [PubMed] [Google Scholar]
  • 5.Aberoumand A. World J Fish & Marine Sci. 2010;2:226. [Google Scholar]
  • 6.Czernichow S, Thomas C, Bruckert E. Brit J Nutr. 2010;104:788. doi: 10.1017/S0007114510002096. [DOI] [PubMed] [Google Scholar]
  • 7.Legrand P, Rioux V. Lipids. 2010;45:941. doi: 10.1007/s11745-010-3444-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Lambert DM, Fowler CJ. J Med Chem. 2005;48:5059. doi: 10.1021/jm058183t. [DOI] [PubMed] [Google Scholar]
  • 9.Ortega-Gutiérrez S, Viso A, Cisneros JA. Curr Top Med Chem. 2008;8:231. doi: 10.2174/156802608783498032. [DOI] [PubMed] [Google Scholar]
  • 10.Boswinkel G, Derksen J, van’t Riet K, Cuperus F. J Am Oil Chem Soc. 1996;73:707. [Google Scholar]
  • 11.Lyubachevskaya G, Boyle-Roden E. Lipids. 2000;35:1353. doi: 10.1007/s11745-000-0652-5. [DOI] [PubMed] [Google Scholar]
  • 12.Martin JB. J Am Chem Soc. 1953;75:5483. [Google Scholar]
  • 13.Kingsley PJ, Marnett LJ. Anal Biochem. 2003;314:8. doi: 10.1016/s0003-2697(02)00643-7. [DOI] [PubMed] [Google Scholar]
  • 14.Stelt Mvd, Kuik JAv, Bari M, Zadelhoff Gv, Leeflang BR, Veldink GA, Finazzi-Agrò A, Vliegenthart JFG, Maccarrone M. J Med Chem. 2002;45:3709. doi: 10.1021/jm020818q. [DOI] [PubMed] [Google Scholar]
  • 15.Han L, Razdan RK. Tetrahedron Lett. 1999;40:1631. [Google Scholar]
  • 16.Seltzman HH, Fleming DN, Hawkins GD, Carroll FI. Tetrahedron Lett. 2000;41:3589. [Google Scholar]
  • 17.Stamatov SD, Stawinski J. Tetrahedron. 2005;61:3659. [Google Scholar]
  • 18.Uwe TB. Enzyme Microb Tech. 1995;17:578. [Google Scholar]
  • 19.Berger M, Laumen K, Schneider M. J Am Oil Chem Soc. 1992;69:955. [Google Scholar]
  • 20.Berger M, Schnelder M. J Am Oil Chem Soc. 1992;69:961. [Google Scholar]
  • 21.Piyatheerawong W, Yamane T, Nakano H, Iwasaki Y. J Am Oil Chem Soc. 2006;83:603. [Google Scholar]
  • 22.Irimescu R, Yasui M, Iwasaki Y, Shimidzu N, Yamane T. J Am Oil Chem Soc. 2000;77:501. [Google Scholar]
  • 23.Rosu R, Yasui M, Iwasaki Y, Yamane T. J Am Oil Chem Soc. 1999;76:839. [Google Scholar]
  • 24.Schmid U, Bornscheuer UT, Soumanou MM, McNeill GP, Schmid RD. Biotechnol Bioeng. 1999;64:678. [PubMed] [Google Scholar]
  • 25.Byun HG, Eom TK, Jung WK, Kim SK. Biotechnol Bioproc E. 2007;12:491. [Google Scholar]
  • 26.Waldinger C, Schneider M. J Am Oil Chem Soc. 1996;73:1513. [Google Scholar]
  • 27.Schmid U, Bornscheuer U, Soumanou M, McNeill G, Schmid R. J Am Oil Chem Soc. 1998;75:1527. [Google Scholar]
  • 28.Soumanou MM, Bornscheuer UT, Schmid U, Schmid RD. Biocatal Biotransfor. 1999;16:443. [Google Scholar]
  • 29.Soumanou M, Bornscheuer U, Schmid R. J Am Oil Chem Soc. 1998;75:703. [Google Scholar]
  • 30.Wongsakul S, Prasertsan P, Bornscheuer UT, H-Kittikun A. Eur J Lipid Sci Tech. 2003;105:68. [Google Scholar]
  • 31.Irimescu R, Iwasaki Y, Hou C. J Am Oil Chem Soc. 2002;79:879. [Google Scholar]
  • 32.Magnusson CD, Haraldsson GG. Tetrahedron. 2010;66:2728. [Google Scholar]
  • 33.Vadivel SK, Whitten KM, Makriyannis A. Tetrahedron Lett. 2011;52:1149. doi: 10.1016/j.tetlet.2011.01.047. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Duclos RI, Johnston M, Vadivel SK, Makriyannis A, Glaser ST, Gatley SJ. J Org Chem. 2011;76:2049. doi: 10.1021/jo102277q. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Halldorsson A, Magnusson CD, Haraldsson GG. Tetrahedron. 2003;59:9101. [Google Scholar]
  • 36.Takagi T, Ando Y. Lipids. 1991;26:542. [Google Scholar]
  • 37.Irimescu R, Furihata K, Hata K, Iwasaki Y, Yamane T. J Am Oil Chem Soc. 2001;78:743. [Google Scholar]
  • 38.Li C, Xu W, Vadivel SK, Fan P, Makriyannis A. J Med Chem. 2005;48:6423. doi: 10.1021/jm050272i. [DOI] [PubMed] [Google Scholar]
  • 39.Papahatjis DP, Nahmias VR, Nikas SP, Schimpgen M, Makriyannis A. Chem-Euro J. 2010;16:4091. doi: 10.1002/chem.200902880. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40.Yao F, Li C, Vadivel SK, Bowman AL, Makriyannis A. Bioorg Med Chem Lett. 2008;18:5912. doi: 10.1016/j.bmcl.2008.07.110. [DOI] [PMC free article] [PubMed] [Google Scholar]

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