Method for producing 2-(3-pyrazolyl-oxymethylene) nitrobenzenes

  • US 6,133,451 A
  • Filed: 01/27/2000
  • Issued: 10/17/2000
  • Est. Priority Date: 07/30/1997
  • Status: Expired due to Term
First Claim
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1. A process for preparing 2-(3-pyrazolyloxymethylene)nitrobenzene derivatives of the formula I ##STR18## where:

  • R1 is halogen;

    unsubstituted or substituted alkyl or alkoxy;

    R2 is cyano, halogen, alkyl, haloalkyl, alkoxy, alkylthio or alkoxycarbonyl;

    R3 is unsubstituted or substituted alkyl, alkenyl or alkynyl;

    unsubstituted or substituted saturated or mono- or diunsaturated carbocyclyl or heterocyclyl;

    unsubstituted or substituted aryl or hetaryl;

    m is 0, 1 or 2, it being possible for the substituents R2 to be different when m is greater than 1;

    n is 0, 1, 2, 3 or 4, it being possible for the substituents R1 to be different when n is greater than 1;

    by bromination of an o-nitrotoluene of the formula II ##STR19## where R1 has the abovementioned meaning, to give the o-nitrobenzyl bromide of the formula III ##STR20## in the presence of a nonpolar, aprotic solvent and subsequent reaction of the resulting solution of III with a 3-hydroxypyrazole of the formula IV ##STR21## where R2 and R3 have the abovementioned meanings, in the presence of a base, wherein the solution of the o-nitrobenzyl bromide III resulting from the bromination is reacted further with IV, in the solvent used, directly without intermediate isolation of the o-nitrobenzyl bromide III.

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