Unconventional Method for Synthesis of 3‑Carboxyethyl-4-formyl(hydroxy)-5-aryl‑N‑arylpyrazoles

An alternative highly regioselective synthetic method for the preparation of 3,5-disubstituted 4-formyl-N-arylpyrazoles in a one-pot procedure is reported. The methodology developed was based on the regiochemical control of the cyclocondensation reaction of β-enamino diketones with arylhydrazines. Structural modifications in the β-enamino diketone system allied to the Lewis acid carbonyl activator BF3 were strategically employed for this control. Also a one-pot method for the preparation of 3,5-disubstituted 4-hydroxymethyl-N-arylpyrazole derivatives from the β-enamino diketone and arylhydrazine substrates is described.本文报道了一种具有高区域选择性的替代合成方法，可通过一锅法制备3,5-二取代-4-甲酰基-N-芳基吡唑类化合物。所开发的方法基于β-烯胺二酮与芳基肼的环缩合反应的区域化学调控：通过对β-烯胺二酮体系进行结构修饰，并辅以路易斯酸羰基活化试剂三氟化硼（BF3），从策略层面实现了对该反应的精准控制。此外，本文还报道了一种以β-烯胺二酮与芳基肼为底物，通过一锅法制备3,5-二取代-4-羟甲基-N-芳基吡唑衍生物的方法。