A series of new fatty N-acyl trihalomethylated pyrazoline derivatives from fatty acid methyl esters was synthesized by the cyclocondensation of respective fatty hydrazides with 4-alkoxy-1,1,1-trialomethyl-3-alquen-2-ones. Efficient and regiospecific cyclizations catalyzed by BF3·MeOH gave the desired products in good to excellent yields and at high purity.
N-acyl hydrazine; FAMEs; 4-alkoxy-1,1,1-trialomethyl-3-alquen-2-ones; N-acyl trialomethylated pyrazoline