Rolland M. Waters

Reimer-Tiemann adducts as potential insect antifeedant agents Reviewing the structure-activity relationship theory of the antifeedant, warburganal

Structure-activity relationships of naturally occurring enedials with antifeedant activity againstSpodoptera species have been extended via the synthesis and bioassay of a series of Reimer-Tiemann adducts. The activities attributed to the different chemical structures of these and other analogs interacting with the chemoreceptor site have been observed; a three-pronged mode of substrate binding via aromatic pyrrole formation, Michael addition of free sulfhydryl moieties, and van der Waals interactions of the A ring has been postulated to account for these observations.

Improvement of the Attractiveness of Spodoptera Littoralis Sex Pheromone, and its Possible Use in Safety Belts around Cultivated Areas to Control the Pest in Israel

A comparison of the field attractiveness of five samples of American-synthesized and one sample of Japanese-synthesized (Z,E)-9,11-tetradecadien-1-01 acetate (9,11-TDDA), the sex pheromone of Spodoptera littoralis Boisd. and S. litura (F.), showed that traps baited with one of the American-produced samples and the Japanese product were equally effective in attracting and capturing S. littoralis males in cotton and alfalfa fields of Israel. Optimum captures were obtained for periods up to three months with 4800 mug of 9,11-TDDA plus 8 mg of an antioxidant; higher doses were not advantageous. Paper squares were superior to two types of rubber septa and to closed polyethylene vials as dispensers for the pheromone; the polyethylene vials were least effective. In terms of numbers of moths captured, open polyethylene vials were as effective as paper dispensers when both were baited with 9-11-TDDA plus antioxidant. Admixture of (Z,E)-9,12-tetradecadien-1-o1 acetate (9,12-TDDA) with 9,11-TDDA was antagonistic at ratios of 1:20 and 1:50, but ratios from 1:500 to 1:1600 were synergistic, increasing moth catches up to 2.5-fold. Pheromone traps placed in Caesarea sand dunes located at least 3 km from the nearest host area captured larger numbers of males than traps placed in cultivated areas. It is therefore recommended that safety belts of pheromone traps, about 500 m apart, be used around cultivated areas to prevent invasion of the pest from outside and to attract males present inside such areas, thus reducing both the male population and mating through mass trapping and disruption of sex communication.

Synthesis of attractants for oriental fruit flyDacus dorsalis Hendel using a catalytic organocopper coupling reaction

A general synthetic approach to various catechol derivatives was developed using a copper-catalyzed cross-coupling reaction of 1,2-dimethoxy-4-brornomethyl, 1-ethoxy-2-methoxy-4-bromomethyl- and 2-ethoxy-1-methoxy-4-bromomethylbenzenes with Grignard reagents. Dilithium tetrachlorocuprate was an acceptable catalyst in the dimethoxy series, whereas copper(I) iodide in THF-HMPA was a superior catalyst in all cases due to decreased side reactions, i.e., reduction and reductive coupling. Methyl-substituted analogs of methyl eugenol, a potent attractant of Oriental fruit fly,Dacus dorsalis Hendel, were synthesized by this method and evaluated for attractancy in field tests.

Moth responses to selectively fluorinated sex pheromone analogs

Partially fluorinated analogs of the European corn borer (Ostrinia nubilalis) female sex pheromone, 11-tetradecenyl acetate (97:3Z:E), having mono- and trifluorsubstitutions at the terminal carbon of the pheromone chain, mimicked the biological activity of the pheromone, while analogs with fluorine at either side of the double bond and a pentafluoro analog were essentially inactive. Comparison of the pheromonal activity of these analogs with the previously reported activity of similarly fluorinated pheromones in five other species of moths revealed an unpredictable relationship between fluorine substitution pattern and pheromone-mimicking activity. Fluorine substitution patterns that rendered pheromonal analogs biologically inactive in the European corn borer had no detrimental influence upon pheromonal activity in other species and the converse was also true. This is evidence that the relative importance of electronic qualities of sites within a pheromone molecule differ from species to species. Furthermore, it indicates that the biochemical components (pheromone receptor proteins, binding proteins, and enzymes) that make up moth olfactory chemosensory systems must also vary structurally from species to species, despite the fact that they are involved in olfactory sensing of compounds having very similar chemical structure.

A Nuclear Magnetic Resonance (NMR) Method for the Determination of the cis/trans Isomeric Content of Chlorprothixene

Proton NMR spectroscopy was applied to the assignment of the isomeric identity of commercially available chlorprothixene. Nuclear Overhauser effect studies confirmed that the clinically useful isomer is the cis (Z) configuration. An NMR method for determining the isomeric content of chlorprothixene was developed based on integration of the ratio of areas of signal strength of the cis-N-methyl in comparison to the trans-N-methyl resonances.

The relative attractiveness of several synthetic formulations of Spodoptera littoralis1 / pheromone to male moths

Abstract Formulations of six samples of (Z,E)‐9,11‐tetradecadien‐l‐ol acetate (9,11‐TDDA), the sex pheromone of Spodoptera littoralis Boisd., synthesized at Beltsville and a sample synthesized in Japan by another method were compared for attractiveness in the fields of Israel. The Japanese sample was 20–50% more attractive than the others, despite the fact that it was contaminated with the (E,E)‐isomer, which was shown to delay optimum attraction in the Beltsville samples (but not in the Japanese sample) during the first 4–5 nights of exposure. Beltsville 9,11‐TDDA freed of the (E,E)‐isomer was still somewhat inferior to the Japanese pheromone in attractive power. A component present only in the Japanese sample and observable by capillary column gas chromatography was at first believed to be (Z,E)‐8,10‐tridecadien‐l‐ol acetate, but total synthesis of the compound showed this not to be the case; it was neither attractive per se nor synergistic with 9,11‐TDDA of Beltsville origin. (Z,E:)‐9,12‐Tetradecadien‐...

1H NMR chemical shift studies of pregn-5-ene-3β,20(R)-diol and pregn-5-ene-3β-ol,20-one d-glucopyranoside derivatives

Abstract The 1 H NMR chemical shift and J value data of a series of pregn-5-ene-3β,20( R )-diol/pregn-5-ene-3β-ol, 20-one d -glucopyranosides and d -glucopyranoside derivatives are reported because of their relevance to the structure determination of pregnenediol tri- and diglucosides on tobacco hornworm eggs. Effects of various substituents at the 3β- and 20( R )-positions of the pregn-5-ene nucleus upon chemical shifts of selected protons on the pregn-5-ene nucleus are discussed. Chemical shifts of selected protons on the d -glucopyranoside nucleus/nuclei are also discussed. Differentiation between the pregn-5-ene substitution points, between anomeric glucose configurations and between anomeric protons on β- d -glucosides at 3β and 20( R ) is demonstrated. A COSY NMR analysis of the Manduca peracetylated triglucoside is utilized to show the interaction of the three anomeric β- d -glucoside protons and to distinguish the dissimilar one.