This report shows the importance of Principal Component Analysis for grouping types of products observed when α-acylenaminoketones K1âK3 react with four substituted hydrazine nucleophiles in five 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 first 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.
这份报告展示了主成分分析在对四种取代
肼亲核试剂与α-酰基
氨基酮K1–K3在五种有机溶剂中反应时观察到的产品类型分组中的重要性。反应的目的是获得取代的
吡唑并确定哪个羰基将优先被亲核试剂攻击。反应产物进行了气相色谱-质谱(GC-MS)分析,结果经过主成分分析(PCA)。数据集被分为四个组(得分)。去乙酰化的
吡唑P5由第一个主成分PC1与其他
吡唑分开。第二个主成分PC2将
吡唑P4(源于对乙酰羰基的亲核攻击)与
吡唑P6(源于对与更大取代基R相连的羰基的亲核攻击)分开(载荷分析)。得分-载荷的同步分析显示了反应机制(反应产物类型-载荷)与反应条件(溶剂,亲核试剂)之间的关系。前沿轨道的考虑也被纳入以完善分析。