Conversion of 2-Pyrazolines to Pyrazoles Using Bromine

摘要

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, R^8a, R^8b 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).