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 chromatog raphy on silica gel confirmed the presence of monoenoic and dienoic ho mologues of 1,3-dihydroxy-5-n-alkylbenzene in acetone extracts from ry e 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 deriva tives showed that the breakdown pattern for the monoenoic homologues w as consistent with a double bond in all the homologous chain length at the 8-position. For dienes, the results were not so conclusive, altho ugh the 8- and 11-positions appear to be the favoured ones. It has bee n also shown that rye 5-n-ketoalkylresorcinols contain a previously un observed C17 homologue. All identifications were confirmed by comparis on with synthetically obtained C19:0 and C21:0 5-n-alkylresorcinols an d a 5-n-(2-keto-heptadecyl)resorcinol. Other minor phenolic components present in the acetone extract were identified as homologous 5-n-(2-h ydroxyalkyl)resorcinols.