Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2003-10-10
2004-12-14
Dentz, Bernard (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06831179
ABSTRACT:
CROSS REFERENCES TO RELATED APPLICATIONS
This application claims the benefit of PCT/IN01/00092, in the name of Ashwin Champraj Shroff, entitled “A Process For The Stereoselective Preparation Of Insecticide 6,7,8,9,10-10-Hexahalo-1,5,5A,6,9,9A-Hexahydro-6,9-Methano-2,4,3-Benzodioxathiepin-3-Oxide,” filed on Apr. 24, 2001.
A process for the stereoselective preparation of insecticide 6,7,8,9,10,10-hexahalo-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide.
6,7,8,9,10,10-hexahalo-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide are of the formula I:
wherein X may be a halogen such as fluorine, chlorine or bromine.
PRIOR ART
U.S. Pat. No. 2,799,685 describes unsaturated polycyclic sulfites of the general formula II:
wherein X may be hydrogen or halogen or alkyl group and Y may be hydrogen or alkyl group, and their derivatives containing two hydrogen atoms in 5,6-positions. These compounds are reported to exhibit insecticidal activity. The process for the preparation of these compounds comprises heating a diol of the general formula III:
wherein X and Y are each as defined above, with thionyl chloride under heating optionally in an inert organic solvent. The product is reported to be a mixture of two isomers. The desired isomer may be resolved from the mixture, for instance by fractional crystallisation using petroleum ether.
U.S. Pat. No. 3,251,856 describes a process for the resolution/separation of the two isomers viz &agr; and &bgr;-isomers of 6,7,8,9,10,10-hexahalo-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide, commonly known as endosulfan of the formula IA:
The resolution process comprises contacting the endosulfan isomeric mixture with a halogenated hydrocarbon solvent at 40-50° C. followed by cooling the mixture to 20-25° C. The resulting insoluble portion in the mixture is reported to predominantly contain the high melting isomer viz &bgr;-isomer of endosulfan whereas the solution portion when subjected to evaporation results in a residue which is reported to predominantly contain the low melting isomer viz &agr;-isomer of endosulfan. The &agr; and &bgr;-isomers so obtained may be purified by crystallisation from alcohol.
Both the isomers of endosulfan are reported to exhibit different insecticidal properties. For instance, in short exposure periods, &agr;-endosulfan is more effective against flies than &bgr;-endosulfan. In the case of fruit flies
Drosophila melanogaster,
the killing times (LT
50
) with the use of &agr;-endosulfan and &bgr;-endosulfan are in the ratio 1:3 respectively. Insecticidal effectiveness or efficacy of &agr;-endosulfan against wood boring insects is more as compared to &bgr;-endosulfan. Insecticidal effectiveness limit per m
3
wood with the larvae of the house longhorn beetle
Hylotupes bajulus L
is more in the case of &bgr;-endosulfan as compared to &agr;-endosulfan (Mater. Org. 1983, 18(2), 81-91, Kuelune Helmut et al; CA 100: 134245a). Both the isomers differ in insecticidal persistence and biodegradability. &agr;-Endosulfan decomposes rapidly by soil microorganisms when compared to &bgr;-endosulfan (Karachi Univ J. Sci; 1985, 13(2), 191-7, Akhtar Shahida et al; CA 107: 91836u). &agr;-Endosulfan is degradable by both bacteria and fungi, whereas &bgr;-endosulfan is degradable mainly by bacteria (Int. J Environ. Stud, 1981, 16 (3-4), 171-80, El Beit, I O D et al; CA 94: 151865c). &bgr;-endosulfan has greater half life than &agr;-endosulfan under varying environmental conditions (J. Environ. Sci. Health, Part B, 1995, B30 (2), 221-32, Ceron J J et al; CA 122: 180980p). Therefore, treatment with &bgr;-endosulfan is particularly preferred to achieve desired efficacy over a long term.
The &agr; and &bgr;-isomers of endosulfan are reported to be obtained in the average isomeric ratio of about 2:1 (U.S. Pat. No. 3,251,856). Due to the different in the physical, chemical and biological properties of &agr; and &bgr;-endosulfan and &agr; and &bgr;-benzodioxathiepin compounds in general, it is advantageous to have increased quantity of the desired stereoisomer in the isomeric mixture depending upon the intended specific application of the benzodioxathiepin compound. In order to obtain required quantity of a desired isomer of the benzodioxathiepin compound, correspondingly large quantities of the substrate viz the diol compound is required. Therefore, the above process is uneconomical. Besides, it also generates the undesired isomer in the ratio 2:1 and its efficiency is low.
OBJECTS OF THE INVENTION
An object of the invention is to provide a process for the stereoselective preparation of 6,7,8,9,10,10-hexahalo-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide having insecticidal activity, which results in increased quantity of the desired stereoisomer in high purity without using additional quantity of starting material.
Another object of the invention is to provide a process for the stereoselective preparation of 6,7,8,9,10,10-hexahalo-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide having insecticidal activity, which is economical.
Another object of the invention is to provide a process for the stereoselective preparation of 6,7,8,9,10,10-hexahalo-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide having insecticidal activity, which is efficient.
Another object of the invention is to provide a process for the stereoselective preparation of 6,7,8,9,10,10-hexahalo-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide having insecticidal activity, without using any foreign reagent which may introduce impurity to the product.
REFERENCES:
patent: 2799685 (1957-07-01), Frensch et al.
patent: 3251856 (1966-05-01), Schlichting
patent: 2505707 (1976-08-01), None
Chemical Abstract No. 100: 134245a.
Chemical Abstract No. 107: 91836u.
Chemical Abstract No. 94: 151865c.
Chenical Abstract No. 122: 180980.
English translation of Kuhne et al., Mater Org. vol. 18, No. 2, pp. 81-91 (1983).
Akhter and Siddiqui, Kar. Univ. J. Sc., vol. 13, No. 2, pp. 191-197 (1985).
Beit et al., Int. J. Environ. Stud., vol. 16, No. 3-4, pp. 171-180 (1981).
Ceron and Camera, J. Environ. Sci. Health, vol. B30, No. 2, pp. 221-232 (1995).
Purohit Abhijit Premvallabh
Shroff Ashwin Champraj
Vadodaria Sanjay Dhirajlal
Dentz Bernard
Excel Industries Limited
Greenblum & Bernstein P.L.C.
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