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 BF 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.
A series of 60 4‐aminomethyl 5‐aryl‐3‐substituted isoxazoles were synthesized by an efficient method and evaluated in vitro against
Leishmania amazonensis
and
Trypanosoma cruzi
, protozoa that cause the neglected tropical diseases leishmaniasis and Chagas disease, respectively. Thirteen compounds exhibited a selective index greater than 10. The series of 3‐
N
‐acylhydrazone isoxazole derivatives bearing the bithiophene core exhibited the best antiparasitic effects.
Invited for this month's cover picture is the group of Prof. Fernanda Andreia Rosa at the State University of Maringá (Brazil). The cover picture shows the contribution of the SINTHET research group to the synthesis and discovery of new antiprotozoal compounds. The synthetic methodology allowed the construction of 60 new isoxazole derivatives with structural variations on the 3‐, 4‐, and 5‐positions. The authors acknowledge Ms. Jeniffer do Nascimento Ascencio Camargo and Ms. Julia Caroline Manzano Willig for the Cover picture creation. Read the full text of their Full Paper at 10.1002/open.202100141.
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