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Possible fatty acyl pheromone precursors in Spodoptera littoralis . Search for 11‐ and 12‐hydroxytetradecanoic acids in the pheromone gland
Author(s) -
Navarro Isabel,
Fabriàs Gemma,
Camps Francisco
Publication year - 1997
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-997-0052-x
Subject(s) - spodoptera littoralis , chemistry , pheromone , fatty acid , methanol , gas chromatography , organic chemistry , mass spectrometry , stereochemistry , chromatography , biology , noctuidae , botany , lepidoptera genitalia
Lipidic extracts of Spodoptera littoralis pheromone glands submitted to acid methanolysis using: (i) sulfuric acid/methanol/benzene (0.1∶4∶2, by vol) at 90°C for 1 h; (ii) 12 N HCl/methanol (1∶2; vol/vol) at 90°C for 1 h, or (iii) 14% BF 3 ‐MeOH at 90°C for 1 h did not reveal the presence of either 11‐ or 12‐hydroxytetradecanoic acid in the extracts, as concluded from the gas chromatography‐mass spectrometry analyses. Under the above methanolysis conditions, a synthetic sample of methyl (14, 14, 15‐ 2 H 3 ) 12‐hydroxytetradecanoate remained unaltered. These results may indicate that formation of ( E )‐11‐tetradecenoic acid from tetradecanoic acid does not occur in the pheromone gland by dehydration of an intermediate hydroxyacid. Acid methanolysis of a lipidic extract using BF 3 ‐MeOH led to the formation of a mixture of methoxy fatty acid methyl esters, identified by gas chromatography‐mass spectrometry. These methoxy derivatives should arise from BF 3 ‐catalyzed addition of methanol to the double bond of the natural monounsaturated fatty acyl derivatives present in the gland. Thus, under the same conditions, a synthetic sample of methyl (Z)‐11‐tetradecenoate was partially transformed into methyl 11‐methoxytetradecanoate and methyl 12‐methoxytetradecanoate. This reaction might be a useful alternative procedure to obtain methoxy derivatives of olefins, which are very helpful for the structural characterization of the parent alkenes.