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:
Nov. 16, 2010
Filed:
Sep. 19, 2008
Gary David Annis, Landenberg, PA (US);
Gary David Annis, Landenberg, PA (US);
E.I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
A method is disclosed for preparing a 2-substituted-5-oxo-3-pyrazolidinecarboxylate compound of Formula I The method comprises contacting a succinic acid derivative of the formula ROC(O)C(H)(X)C(R)(R)C(O)Y (i.e. Formula II) wherein X and Y are leaving groups and L, R, Rand Rare as defined in the disclosure, with a substituted hydrazine of the formula LNHNH(i.e. Formula III) in the presence of a suitable acid scavenger and solvent. Also disclosed is the preparation of compounds of Formula IV wherein X, R, R, R, R, R, and n are as defined in the disclosure. Also disclosed is a composition comprising on a weight basis about 20 to 99% of the compound of Formula II wherein R, R, R, R, Rand Rare as defined in the disclosure; X is Cl, Br or I; and Y is F, Cl, Br or I; provided that when Rand Rare each H, and X and Y are each Cl then Ris other than benzyl and when Rand Rare each phenyl, and X and Y are each Cl, then Ris other than methyl or ethyl. Also disclosed is a crystalline composition comprising at least about 90% by weight of the compound of the formula ROC(O)C(H)(X)C(R)(R)COH (i.e. Formula VI) wherein Rand Rare H, X is Br and Ris methyl.