The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 04, 1989
Filed:
Nov. 25, 1987
Colin Hardy, Huddersfield, GB;
Tony R Martin, Huddersfield, GB;
Jerzy Czyzewski, Huddersfield, GB;
Daniel Levin, Huddersfield, GB;
Imperial Chemical Industries PLC, London, GB;
Abstract
A process for preparing a compound of formula (II): ##STR1## or a tautomer or salt thereof in substantially pure form wherein R.sup.1 is C.sub.1-6 alkyl optionally substituted by one or more halogen atoms; R.sup.3 is hydrogen, fluorine, chlorine, bromine or iodine, C.sub.1-6 alkyl, trifluoromethyl or a cyano group; R.sup.4 is hydrogen, fluorine, chlorine, bromine, iodine or trifluoromethyl; R.sup.5 is fluorine, chlorine, bromine, iodine or trifluoromethyl; and R.sup.6 is hydrogen or C.sub.1-4 alkyl; which process comprises nitrating a compound of formula (III): ##STR2## or a salt thereof wherein R.sup.1, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are as defined above, in a solvent which is resistant to nitration under the desired reaction conditions and suitable for purification of the product of formula (II), heating the resultant solution to a temperature sufficient to at least partially dissolve the desired product and impurities and cooling the solution to precipitate the compound of formula (II) in substantially pure form.