Chemo- and regioselective reactions of 5-bromo enones/enaminones with pyrazoles

Abstract

The reaction of pyrazoles with 5-bromo enones furnished an unexpected series of stable N,O-aminals in a chemo- and regioselective and metal free reaction.

Pyrazole‐Enaminones as Promising Prototypes for the Development of Analgesic Drugs

“…c Synthesis already reported in previous works. [12] Similarly, celecoxib (30 and 100 mg/kg) prevented capsaicin-induced nociception, with I max of 49.2 � 2.8 % at 100 mg/kg dose (Figure 3b). The ID 50 value for the antinociceptive effect of celecoxib was 47.58 (29.15-77.66) mg/kg.…”

“…The alkylation reaction of pyrazoles 2 with the 5-bromo enaminones 4 furnished the pyrazole-enaminones 5, in accordance with the method previously reported. [12] Pyrazoles 5 a-f were previously reported; however, in order to increase the scope for the biological study, a new series of pyrazole-enaminones 5 g-k was synthesized based on structural aspects that could influence the biological activity of the compounds. For this study, we obtained new compounds with the morpholine core, which is a heterocyclic present in known drugs with biological activity.…”

“…B. T. Da Rocha, Prof. S from the chemo-and regioselective N-alkylation reaction of trifluoromethyl pyrazoles, using (E)-4-(amino)-5-bromo-1,1,1trifluoro-but-3-en-2-ones as the alkylating agent. [12] Using the same method reported previously, [12] in this study we synthesized a new series of pyrazole analogs of celecoxib, in order to increase the scope and to analyze their antinociceptive activity. The antinociceptive activity of a new series and the previously obtained compounds were tested in mice using a screening test for new analgesic drugs.…”

“…Using the same method reported previously, [12] in this study we synthesized a new series of pyrazole analogs of celecoxib, in order to increase the scope and to analyze their antinociceptive activity. The antinociceptive activity of a new series and the previously obtained compounds were tested in mice using a screening test for new analgesic drugs.…”

Brominated β-Alkoxyvinyl Trihalomethyl Ketones as Promising Synthons in Heterocyclic Synthesis

“…The structure of 31 enabled the synthesis of novel pyrazoles conjugated with isoxazoles, pyrazoles, and pyrimidine cores. 32 Besides the advantages of using these enones/enaminones as N-alkylating agents, the bromine atom at C5 and an electrophilic carbonyl at C2 favor the preparation of fivemembered heterocycles. Thus, 5-bromo-enone 2 was treated with excess arylamine in a sealed tube for 15 min at 120 °C to furnish a series of 1-aryl-4-(arylamino)-2-(trifluoromethyl)-1H-pyrroles 34 in 86-95% yields (Scheme 8).…”