POSSIBLE FATTY ACYL PHEROMONE PRECURSORS IN SPODOPTERA-LITTORALIS - SEARCH FOR 11-HYDROXYTETRADECANOIC AND 12-HYDROXYTETRADECANOIC ACIDS INTHE PHEROMONE GLAND

Lipidic extracts of Spodoptera littoralis pheromone glands submitted t o acid methanolysis using: (i) sulfuric acid/methanol/benzene (0.1:4:2 , by vol) at 90 degrees C for 1 h; (ii) 12 N HCl/methanol (1:2, vol/vo l) at 90 degrees C for 1 h, or (iii) 14% BF3-MeOH at 90 degrees C for 1 h did not reveal the presence of either 11- or 12-hydroxytetradecano ic acid in the extracts, as concluded from the gas chromatography-mass spectrometry analyses. Under the above methanolysis conditions, a syn thetic sample of methyl (14,14,14-H-2(3)) 12-hydroxytetradecanoate rem ained unaltered. These results may indicate that formation of (E)-11-t etradecenoic acid from tetradecanoic acid does not occur in the pherom one gland by dehydration of an intermediate hydroxyacid. Acid methanol ysis of a lipidic extract using BF3-MeOH led to the formation of a mix ture of methoxy fatty acid methyl esters, identified by gas chromatogr aphy-mass spectrometry. These methoxy derivatives should arise from BF 3-catalyzed addition of methanol to the double bond of the natural mon ounsaturated fatty acyl derivatives present in the gland. Thus, under the same conditions, a synthetic sample of methyl (Z)-11-tetradecenoat e was partially transformed into methyl 11-methoxytetradecanoate and m ethyl 12-methoxytetraderanoate. This reaction might be a useful altern ative procedure to obtain methoxy derivatives of olefins, which are ve ry helpful for the structural characterization of the parent alkenes.