Abstract.
This report shows the importance of Principal Component Analysis for grouping types of products observed when alpha
-acylenaminoketones K1-K3 react with four substituted hydrazine nucleophiles in ve organic solvents. The reactions were
carried out with the goal of obtaining substituted pyrazoles and determining which of the carbonyls would preferentially be
attacked by the nucleophile. The reaction products were submitted to GC-MS analysis and the results were subjected to
Principal Component Analysis (PCA). The data set was separated in four groups (scores). The deacetylated pyrazoles P5
were separated from the other pyrazoles by the rst principal component PC1. The second principal component PC2 separated
the pyrazoles P4, derived from nucleophilic attack on the acetyl carbonyl group, from the pyrazoles P6, derived from
nucleophilic attack on the carbonyl bonded to the more bulky group R (loadings analysis). The simultaneous analysis of the
scores-loadings shows the relationship between the mechanisms (types of reaction products-loadings) and the reaction
conditions (solvent, nucleophile). Frontier orbital considerations were also included to complete the analysis.

Keywords.
 

Keywords Plus.
Willgerodt-Kindler Reaction; Organic Synthesis; Pyrazoles; Chemometrics; Strategies; Prediction; Enaminones; Chemistry; Solvents; Example.