反应详情

Preparation of hexadecyl cis-9-tetradecenoate, 4 was carried out according to the Scheme 1. Oleic acid methyl ester, 1 (12.0 g, 0.0314 mol) in dichloromethane (100 ml) was cooled to −78 degree. C and ozone gas was bubbled into the reaction mixture for 1 hr. After reaction, the reaction was quenched by adding dimethyl sulphide (DMS, 8 ml) and was stirred for 6 hr at 25° C. The solvents were removed under vacuum and the residue 2 thus obtained (4.25 g, 0.022 mol) was used directly for the preparation of cis-9-myristoleate, 3. n-Pentyl-triphenyl phosphonium salt (11.16 g, 0.027 mol) was taken in 50 ml of dry THF and cooled to 0° C. To this slurry, n-butyl lithium (17.0 ml, 1.6 M in hexane) was added, stirred the reaction mixture for 0.5 hr to obtain an orange solution. 1-Al-methyl nonanoate containing crude product 2 (5.0 g, 0.027 mol) dissolved in dry THF (20 ml) was added to the above contents slowly and allowed the reaction mixture to reach to 25 degree. C and then heated to reflux temperature to reflux for 4 hr. The reaction was monitored by TLC and after completion of the reaction, THF was removed from the reaction mixture under reduced pressure, and to the residue distilled water 825 ml) was added and extracted with ether (25 ml×3 times). The combined ether layer was dried over anhydrous sodium sulphate and solvent was removed and dried under vacuum to get the residue and was purified by column chromatography using hexane and ethyl acetate (98:2) as eluent to get cis-9-myristoleate, 3 (4.2 g, 0.0175 mol) in 65% yield with 66% purity by GC. cis-9-Myristoleate, 3 (4.2 g, 0.0175 mol) was enzymatically transesterified with cetyl alcohol (5.08 g 0.021-mol) in the presence of Lipozyme TL IM (0.930 g, 10 wt % of the total substrate) at 68° C. for 8 hr. The reaction was monitored by TLC and after completion of the reaction, hexane (50 ml) was added and the lipase was separated by filtration and the solvent was evaporated to get the crude product and was purified by column chromatography to obtain hexadecyl cis-9-tetradecenoate, 4 (7.48 g, 0.0166 mol) in 95% yield with 92% purity by GC. The structure of hexadecyl cis-9-tetradecenoate, 4 was confirmed by 1H NMR, IR, and GC-MS.

1. customat 68° C.
2. customfor 8 hr
3. additionwas added
4. customthe lipase was separated by filtration
5. customthe solvent was evaporated
6. customto get the crude product
7. customwas purified by column chromatography