Metathesis syntheses of pheromones or their components

Details Metathesis syntheses of pheromones or their components Metathesis syntheses of pheromones or their components

2001-04-10

2004-02-24

Killos, Paul J. (Department: 1623)

Organic compounds -- part of the class 532-570 series

Organic compounds

Carboxylic acid esters

C560S231000

Reexamination Certificate

active

06696597

ABSTRACT:

TECHNICAL FIELD
The present invention relates to synthetic pheromones or their components and, in particular, to metathesis reactions to produce biologically active compounds and intermediates such as insect sex-attractant pheromones or their components such as E-5-decenyl acetate, the major component of the Peach twig borer pheromone; (5R,6S)-6-acetoxy-5-hexadecanolide, the mosquito oviposition sex attractant pheromone; or E9,Z11-hexadecadienal, the pecan nut casebearer moth pheromone.
BACKGROUND OF THE INVENTION
Insect pests destroy crops and/or spread disease. Common pest control methods involves spraying farmland, orchards, wetlands, forests, or other pest habitats with insecticides. This method is problematic because insecticides are applied directly to crops or watersheds, and this practice is contrary to an increasing preference for organic produce as well as contrary to water quality issues and other environmental concerns. Insecticides are also nondiscriminate killers and kill beneficial insects as well as harmful insects. Finally, the insect pests are becoming increasingly resistant to many of the common insecticides.
An alternative method to control insect populations involves the use of the insect's sex attractant to confuse the male insect and thereby prevent mating and eliminate future insect generations. This technique is called mating pattern disruption. Insect pheromones constitute a relatively new class of compounds that have a number of advantages over conventional insecticides. Insect pheromones are nontoxic and environmentally friendly. They are specific to the target insect and do not adversely affect beneficial insects and, they have not been shown to induce the development of resistance in the target insects. The biggest drawbacks in using mating pattern disruption to control insect populations is the cost of producing the insect pheromone, which is typically far more expensive than that of traditional insecticides. Methods that reduce the production costs of insect pheromones would make mating pattern disruption an economical technique for controlling insect populations and thereby minimize environmental concerns associated with pest control.
In general, common pheromones include a 10- to 18-carbon atom-containing olefin that has a terminal alcohol, aldehyde, or acetate functional group and possess a particular stereo-isomerism. The following background is presented herein only by way of example to a few pheromones for common insect pests, such as the Peach Twig Borer (PTB), which is a major pest in stone fruit orchards, and for pathogen-vectoring mosquitoes of genus Culex, and for the Pecan nutcase bearer.moth, which is a major pest in pecans.
PTB pheromone is an 85:15 ratio of E-5-decenyl acetate and E-5-decenol. Thus production of 5-decenyl acetate, which is the major component of PTB pheromone, is a significant step of the PTB pheromone manufacturing process. The acetate can be subsequently removed by hydrolysis to obtain E-5-decenol, the other component of PTB pheromone. A fast, inexpensive, and high yield process for synthesizing E-5-decenyl acetate is, therefore, desirable.
The following background information concerning the Mosquito Oviposition Pheromone (MOP), another highly sought after insect pest pheromone, is largely derived from Olagbemiro, et al. in “Production of (5R,6S)-6-Acetoxy-5-hexadecanolide, the Mosquito Oviposition Pheromone, from Seed Oil of the Summer Cypress Plant,
Kochia scoparia
(Chenopodiaceae),”
J. Agric. Food Chem
. (1999) 47, 3411. Please refer to this article for greater detail.
Mosquitoes of the genus Culex (Diptera: Culicidae) pose the greatest threat to public health because of their ability to act as vectors of causative agents for diseases such as malaria, dengue, yellow fever, encephalitis, and filariasis, which afflict many millions of people world-wide. Malaria and encephalitis infect the greatest number of people and have the highest mortality levels, affecting approximately one-third the world's 1.5 billion people in 90 countries, mainly in Africa. (AAAS (American Association for the Advancement of Science) “Malaria and Development in Africa”:
AAAS
: Washington, D.C., (1991); Giles et al. “Bruce-Chwatt's Essential Malariology”, 3rd Ed.; Edward Arnold; London UK (1993); and WHO/CTD. “Malaria Prevention and Control,” WHO Report; Geneva (1998).)
Filariasis has infected 3.33% (i.e. ~15 million people) of the 450 million people at risk, with nearly 1 million new cases occurring annually. (Reeves et al. “Natural Infection in Arthropod Vector,”
Epidemiology and Control of Mosquito
-
Borne Arboviruses in California
1943-1987; Reeves, W. G., Ed.; California Mosquito Control Association: Sacramento, Calif. 1990; pp 128-149.) Because of the rapid increase in reported cases of vector caused diseases, efficient techniques for vector surveillance and control are of the utmost importance.
The mosquitoes of
Culex quinquefasciatus
are responsible for the transmission of
Wuchereria bancrofti
, the causative agent of human filariasis and St. Louis encephalitis virus and other arboviruses in the United States. (Reisen et al. “Ecology of mosquito and St. Louis Encephalitis virus in Los Angeles basin of California, 1987-1990
,” J. Med. Entomol
. (1992) 29, 582.) Gravid
Culex quinquefasciatus
females use olfactory cues to locate suitable egg-laying sites. The main cue is the oviposition attractant pheromone ((5R,6S)-6-acetoxy-5-hexadecanolide) which is released by mature egg rafts. (Osgood, C. E. “An oviposition pheromone associated with the egg rafts of
Culex tarsalis,” J. Econ. Entomol
. (1971) 64, 1038; Osgood et al. “An Air-Flow Olfactometer for the Distinguishing between Oviposition Attractants and Stimulants of Mosquitoes,”
J. Econ. Entomol
. (1971a) 64, 1109; and Starratt, A. N.; C. E. Osgood “1,3-Diglycerides from the Eggs of
Culex pipens quinquefasciatus
and
Culex pipens pipens,” Comp. Biochem. Physiol
. (1973) 857.)
The oviposition attractant pheromone ((5R,6S)-6-acetoxy-5-hexadecanolide) produced by female mosquitoes of
Culex quinquefasciatus
is released from apical droplets on the eggs. (Laurence et al. “Erythro-6-acetoxy-5-hexadecanolide the major component of a mosquito oviposition attractant pheromone,”
J. Chem. Soc. Chem. Commun
. (1982) 59-60. (Laurence et al. '82) This attracts other females of this and related species to the vicinity of the laid eggs. (Howse et al. “Insect Pheromones and their Use in Pest Management” Chapman and Hall, 2-6 Boundary Row, London SE1 8HN, UK 1998, p 52.)
New strategies for controlling mosquitoes of
Culex quinquefasciatus
started with the identification of the oviposition attractant pheromone (5R,6S)-6-acetoxy-5-hexadecanolide. (Laurence et al. '82; Laurence et al. “Absolute Configuration of the Mosquito Oviposition Attractant Pheromone 6-acetoxy-5-hexadecanolide,”
J. Chem. Ecol
. (1985) 11,643; and Laurence et al. “An Oviposition Attractant Pheromone in
Culex quinquefasciatus
Say (Diptera, Culicidae),”
Bull. Entomol. Res
. (1985a) 75,283.) Laboratory and field trials, in nine countries and three continents, using synthetic pheromone containing an equal ratio of all four stereoisomers [i.e., (5R,6S), (5S,6S), (5R,6R) and (5S,6R)] of (5,6)-6-acetoxy-5-hexadecanolide (Dawson et al. “Convenient Synthesis of Mosquito Oviposition Pheromone and a Highly Flourinated Analog Retaining Biological Activity,”
J. Chem. Ecol
. (1990) 16, 1779.) have demonstrated the efficacy of the oviposition pheromone in attracting Culex spp. mosquitoes. (Otieno et al. “A Field Trial of the Synthetic Oviposition Pheromone with
Culex quinquefasciatus
Say (Diptera, Culicidae) in Kenya,”
Bull. Entoniol. Res
. (1988) 78, 463.) Despite the presence of the three inactive and unnatural stereoisomers of (5, 6)-6-acetoxy-5-hexadecanolide [i.e., (5S,6S), (5R,6R) and (5S,6R)], the biological activity of the naturally occurring isomer was unaffected. These results demonstrate that an effective, efficacious and inexpensive oviposition attractant pherom

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