Lipoamide → Hexadecyl cis-10-tetradecenoate

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Reaction Steps

Preparation of hexadecyl cis-10-tetradecenoate, 8 was carried out according to the Scheme 2. Methyl undecenoate, 5 (10.21 g, 0.0515 mol) in dichloromethane (150 ml) was cooled to −78° C. and ozone gas was bubbled into the reaction mixture for 1 hr. The reaction was quenched by adding dimethyl sulphide (DMS, 5 ml) and was stirred for 6 hr at 25° C. The solvents were removed under vacuum and the residue 6 thus obtained was used directly further preparation of cis-10-myristoleate, 7. n-Butyl-triphenyl phosphonium bromide salt (10.0 g, 0.0251 mol) was taken in dry THF (50 ml) and cooled to 0° C. To this slurry, n-Butyl lithium (17.0 ml, 1.6 M in hexane) was added and stirred for 0.5 hr. 1-Al-methyl deaconate containing crude product 6 (5.01 g, 0.025 mol) dissolved in dry THF (50 ml) was added slowly to the above contents and allowed the reaction mixture to warm to roam temperature and then heated to reflux temperature to reflux for 4 hr. THF was removed from the reaction product under reduced pressure, and to the residue distilled water (25 ml) was added and extracted with ether (25 ml×3 times). The combined ether layer was dried over anhydrous sodium sulphate and solvent was evaporated and dried under vacuum to get the product and was further purified by column chromatography using hexane and ethyl acetate (98:2) as eluent to obtain cis-10-myristoleate, 7 (3.35 g, 0.014 mol) in 56% yield with 97% purity by GC. cis-10-Myristoleate, 7 (3.35 g, 0.014 mol) was enzymatically transesterified with cetyl alcohol (4.07 g, 0.0168 mol) in the presence of Lipozyme TL IM (0.745 g, 10 wt % of the total substrate), at 65° C. for 8 hr. The reaction was monitored by TLC and after completion of 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-10-tetradecenoate, 8 (5.55 g, 0.0123) in 88% yield with 95% purity by GC. The structure of hexadecyl cis-10-tetradecenoate, 8 was confirmed by 1H NMR, IR, and GC-MS.

Provenance & Evidence