Conversion of 2-Pyrazolines to Pyrazoles Using Bromine
AssigneeE. I. Du Pont de Nemours and Company
InventorPaul Joseph Fagan
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Abstract
This invention relates to a method for preparing a compound of Formula 1 wherein L, R1, R2 and X are as defined in the disclosure, comprising contacting a 2 pyrazoline of Formula 2 with bromine at a temperature of at least about 80° C. (Formula 1) (Formula 2). This invention also discloses preparation of a compound of Formula 3 wherein X, Z, R5, R6, R7, R8a, R8b and n are as defined in the disclosure, using a compound of Formula 1a wherein R10 is as defined in the disclosure, prepared by the aforesaid method for preparing a compound of Formula 1. (Formula 3) (Formula 4).
Claims14
A method for preparing a compound of Formula 1
- wherein
- X is H, halogen, OR3 or an optionally substituted carbon moiety;
- L is an optionally substituted carbon moiety;
- R1 is H or an optionally substituted carbon moiety;
- R2 is H, an optionally substituted carbon moiety, NO2 or SO2R4;
- R3 is H or an optionally substituted carbon moiety;
- and
- R4 is an optionally substituted carbon moiety;
- comprising:
- contacting a 2-pyrazoline of Formula 2
- with bromine at a temperature of at least about 80° C.
Dependencies are inferred from the claim text.