Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
1999-12-23
2001-03-27
Robinson, Allen J. (Department: 1616)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
Reexamination Certificate
active
06207695
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to chiral fungicidal compositions, and to methods for using the chiral fungicidal compositions to prevent and treat fungal diseases in plants, including the seeds of plants and in plant produce and crops.
BACKGROUND OF THE INVENTION
Fungicides have well-known commercial value in protecting desirable plants from the development of fungal diseases. However, fungicides can be toxic to the plants to which they are applied as well as to beneficial organisms. Thus, it is desirable to maximize the efficacy of fungicides in order to minimize such detrimental effects on plants.
A wide variety of chemical compounds, differing in chemical structure, mechanism of activity, and preferred mode of application, are useful as fungicides. Exemplary types of chemical compounds useful as fungicides include chlorobenzenes and related compounds, quinones, dicarboximides, and systemic fungicides including sulphonamides, benzimidazoles, thiophanates, aminopyrimidines, piperazines, pyridines, imidazoles, and triazoles. These and other fungicidal compounds are described in R. J. Cremlyn,
Agrochemicals,
pp. 157-216, John Wiley & Sons, New York, N.Y. (1991).
The fungicide 1-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy)ethyl]-1H-imidazole, known as Imazalil, is an imidazole fungicide. It is used, for example, to control powdery mildews in cucumbers, marrows and ornamentals, and Fusarium in seed potatoes. It is also used as a seed dressing for control of diseases in cereals such as, for example, Fusarium and Helminthosporium spp. Imazalil is also active against storage diseases, such as, for example, Penicillium, Gloeosporium, Phomopsis, and Phoma spp., of citrus fruit, pome fruit, bananas, and seed potatoes. Furthermore, Imazalil is active against benzimidazole-resistant strains of plant pathogenic fungi (
The Pesticide Manual,
Datix International Ltd., Bungay, Suffolk, The Bath Press, Bath, 1995).
Imazalil is presently used in its racemic form, and there is heretofore no reported use of a single enantiomer of Imazalil as a fungicide and no suggestion for such use. There remains a need for more highly effective fungicides with an improved balance between fungitoxicity and phytotoxicity. It is also desirable to reduce the costs associated with the use of fungicides. The present invention is directed to these, as well as other, important ends.
SUMMARY OF THE INVENTION
One embodiment of the present invention provides a method for inhibiting the growth of fungus on a plant comprising applying to the locus of the plant a fungicidally effective amount of the (S)-enantiomer of 1-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy)ethyl]-1H-imidazole, substantially free of the (R)-enantiomer.
In another embodiment of the present invention a fungicidal composition comprises the (S)-enantiomer of 1-[2-(2,4-dichlorophenyl)-2-(propenyloxy)ethyl]-1H-imidazole, substantially free of the (R)-enantiomer, and an agriculturally acceptable carrier.
In certain preferred embodiments, the amount of the (S)-enantiomer is at least about 90% by weight of the 1-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy)ethyl]-1H-imidazole present in a fungicidal composition, based on the total weight of active ingredient in the fungicidal composition.
The present invention provides an effective method for controlling and/or inhibiting the growth of fungi in association with plants. As used herein, fungi “in association with” include fungi on or in a plant, on plant seeds, on crops or on plant produce. Such fungi which interfere with the growth, development, or reproduction of a plant are also comprehended hereby. The invention also provides new and effective fungicidal compositions for use in preventing and controlling fungal diseases in plants, seeds, produce, etc. These as well as other aspects of the present invention are described in more detail below.
The present invention is directed to chiral fungicidal compositions, and to methods for using the chiral fungicidal compositions to prevent and treat fungal diseases in plants including the seeds of plants and in plant produce and crops. In some preferred embodiments, the chiral fungicidal compositions comprise 1-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy)ethyl]-1H-imidazole, also known, and referred to alternately herein, as Imazalil.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In accordance with the present invention, there are provided chiral fungicidal compounds having formula (I):
wherein: R
1
, R
2
, and R
3
are, independently, H, F, Cl, Br, I, OH, SH, NH
2
, or NO
2
; R
4
is C
1
-C
6
alkyl, C
1
-C
6
alkenyl, C
1
-C
6
alkynyl, or allyl, and agriculturally acceptable salts thereof, enriched in the (S)-enantiomer and, preferably substantially free of the (R)-enantiomer.
The present invention also provides compositions in which at least about 70% by weight, (which is also, in this case, mole percent) based on the total weight of active ingredient in the composition, is present as the (S)-enantiomer. It is preferred that at least about 80 percent by weight of the (S)-enantiomer is present in the compositions of the present invention. More preferably at least about 85 percent by weight of the (S)-enantiomer is present. Still more preferably at least about 90 percent, even more preferably at least about 95 percent, and still more preferably at least about 99 percent of the (S)-enantiomer is present in the compositions of the present invention. “Active ingredient”, as used herein, refers to fungicidally active compounds and can include one or more other fungicidal or other active compounds known in the art. It is preferred that at least one of R
1
, R
2
, R
3
be a halogen, preferably Cl. It is also preferred that the phenyl moiety be 2,4-dichloro. R
4
is preferably allyl. In highly preferred embodiments of the present invention, the compound is (S)-1-[2-(2,4-dichlorophenyl)-2-(propenyloxy)ethyl]1H-imidazole, also referred to as (S)-Imazalil.
The (R)- and (S)-enantiomers of Imazalil were synthesized by stereospecific synthesis from (R)-2-chloro-1-(2′,4′-dichlorophenyl)-1-ethanol and (S)-2-chloro-1-(2′,4′-dichlorophenyl)-1-ethanol, respectively. The enantiomeric purity of these compounds was determined by chiral derivatization and GC analysis of the halohydrin intermediates. Mosher's Acid Chloride (&agr;-methoxy-&agr;-trifluoromethylphenylacetyl chloride), is a well-known chiral derivatizing agent. It has been successfully employed for the derivatization and chiral analyses of a number of alcohols and amines. It is commercially available in both enantiomeric forms and does not require any additional reagents for the derivatizations when purchased in the acid chloride form. Mosher's Acid Chloride exhibits marked stability toward racemization even under severe conditions of acidity, basicity, and temperature. Another advantage of using Mosher's Acid derivatives for chiral analyses are their inherent volatility, which allows lower molecular weight derivatives to be analyzed by gas chromatography. Mosher's Acid Chloride has been used as a derivatizing agent for the chiral analysis of the reduction product of 2,2′,4′-trichloroacetophenone with diisopinocampheylchloroborane (DIP-Cl). Brown et al.,
J. Org. Chem.,
1988, 53, 2916. After derivatization, diastereomeric Mosher's esters were analyzed on a Supelcowax glass capillary GC column for the direct determination of enantiomeric excess.
The present invention also provides methods for inhibiting the growth of one or more species of fungi on or in a plant. Such methods include application of a fungicidally effective amount of a composition of the present invention to the locus of the plant. “Inhibition” of the growth of fungi, as used herein, is intended to include prevention of growth, halting of growth, slowing of growth, and/or killing of one or more species of fungi. Thus, the fungicidal method of the invention includes preventative, protective, prophylactic, systemic and eradicative
Lewis Craig M.
Lin Sue L.
Matcham George W.
Nelson Richard A.
Thomas Norman W.
Celgene Corporation
Robinson Allen J.
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
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