CEREAL GRAIN RESORCINOLIC LIPIDS - MONO AND DIENOIC HOMOLOGS ARE PRESENT IN RYE GRAINS

Analyses (UV, IR, H-1-NMR, MS) of the main phenolic fractions isolated by sequential separation on normal-phase and by argentation chromatography on silica gel confirmed the presence of monoenoic and dienoic homologues of 1,3-dihydroxy-5-n-alkylbenzene in acetone extracts from rye grains. Conversion of mono and dienoic homologue dimethyl ethers to the cis-diols with osmium tetroxide, transformation of the diol to the acetonide with acetone and subsequent MS analysis of resulting derivatives showed that the breakdown pattern for the monoenoic homologues was consistent with a double bond in all the homologous chain length at the 8-position. For dienes, the results were not so conclusive, although the 8- and 11-positions appear to be the favoured ones. It has been also shown that rye 5-n-ketoalkylresorcinols contain a previously unobserved C17 homologue. All identifications were confirmed by comparison with synthetically obtained C19:0 and C21:0 5-n-alkylresorcinols and a 5-n-(2-keto-heptadecyl)resorcinol. Other minor phenolic components present in the acetone extract were identified as homologous 5-n-(2-hydroxyalkyl)resorcinols.