MASS-SPECTRAL TECHNIQUES FOR THE IDENTIFICATION OF COTTON TERPENOID ALDEHYDES

Mass spectra of four cotton terpenoid aldehydes (TA’s), gossypol, hemigossypolone, heliocide H1(and heliocide H2, have been obtained in positive El and Cl modes and the negative Cl mode. The use of these complimentary modes resulted in the production of molecular ions for each compound in at least one mode. To obtain confirmatory information, several derivatives of these TA’s were prepared and examined by MS. PFA (2,3,4,5,6-pentafluoroaniline) derivatives gave satisfactory molecular ions with the negative ion CI in methane mode. Trimethylsilyl and methoxyamine derivatives gave the expected molecular ions in the positive ion El mode. Hemigossyplone (HGQ) was found to be capable of enolization, because approximately 10% of the tris(trimethylsilyl) species was produced. Although mass spectra for these compounds have previously been reported, mostly in the positive El mode, this present integrated approach should facilitate identification of microquantities of these and other TA’s as obtained from high-pressure liquid chromatography (HPLC) of plant extracts. © 1990, American Chemical Society. All rights reserved.