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Lipase-catalyzed selective partial hydrolysis of evening primrose (Oenothera biennisL.) seed oil and borage (Borago officinalisL.) seed oil led to an increase in the level of ?-linolenic acid (GLA; 18:3n-6) in the unhydrolyzed acylglycerols. Thus, in evening primrose oil, the GLA level could be raised from 9.4% in the starting material to 46.5% in the unhydrolyzed acylglycerols by means of a lipase fromCandida cylindracea. Selective hydrolysis of borage oil with Pancreatin led to an increase in the GLA content from 20.4% in the oil to 33.5% in the unhydrolyzed acylglycerols. Partial hydrolysis of borage oil with lipase fromC. cylindracearaised the GLA content of the acylglycerols to 47.8%.

?-Linolenic acid (GLA, all-cis6,9,12-octadecatrienoic acid) has been enriched from fatty acids of borage (Borago officinalisL.) seed oil to 93% from the initial concentration of 20% by lipase-catalyzed selective esterification of the fatty acids withn-butanol in the presence ofn-hexane as solvent. The immobilized fungal lipase preparation, Lipozyme, used as biocatalyst, preferentially esterified palmitic, stearic, oleic and linoleic acids and discriminated against GLA, which was thus concentrated in the unesterified fatty acids fraction. In the absence of hexane, concentrate containing about 70% GLA was obtained. When the reaction conditions, optimized for borage oil fatty acids, were applied to fatty acids of evening primrose (Oenothera biennisL.) oil, concentrates containing 75% GLA were obtained. From both oils, GLA concentrates were prepared efficiently in short reaction times (1–3 h) at 30–60°C. The process can be applied for the production of GLA concentrates for dietetic purposes.

The reaction of methyl (Z)-9,10-epoxy-12-oxoocta-decanoate (2) with ammonium azide, generated in situ from sodium azide and ammonium chloride in aqueous ethanol affords methyl 8-(5-hexylfuran-2-yl)octanoate (1b) in 98% yield. Compound 1b was also prepared in >90% yield by reacting compound 2 with the following Lewis acids: aluminium(III) chloride, tin(IV) chloride, zinc(II) chloride under reflux in benzene or dichloromethane; or at ambient temperature with tin(II) bromide or hydrated tin(II) chloride in dichloroethane.