1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)-based ionic liquids (ILs) has exhibited a high catalytic activity in the aza-Michael reactions compared to conventional catalysts and with imidazole-based ILs. In the present work DBU-based ILs showed high catalytic potential for aza-Michael addition of aromatic amines to 2-cyclohexen-1-one under solvent-free condition. Electrospray ionization-mass spectrometry (ESI-MS) and density functional theory studies have been carried out to provide an effective activation mode of DBU-based ILs in aza-Michael addition. Our results show that both the presence of the acid hydrogen in the IL and the ability of the anion to carry out a hydrogen bond with the −NH2 group of the arylamine are fundamental for the reaction catalysis. The catalytic model proposed can be used for the rational development of new ILs with excellent catalytic properties.

In this work a series of 28 novel pyrazolo[3,4-d]pyridazin-7-ones were synthesized and tested against Leishmania amazonensis (strain WHOM/BR/75/JOSEFA) in promastigote and axenic amastigote forms. Five compounds were active against both cellular forms with IC50 (inhibitory concentration growth of 50%) values of 20.2, 11.7, 16.2, 29.5 and 40.3 µM for promastigote and 17.4, 25.2, 3.84, 21.8 and 22.7 µM for axenic amastigote. All compounds were studied by the Lipinski rule, cytotoxicity both in silico and in vitro to fibroblast line (L929) and macrophages (J774A1), and the most active compound showed a selectivity index of 59.9.

The present study describes the synthesis, assessment of the anticholinesterase activity and the inhibition type of novel cis- and trans-3-arylaminocyclohexyl N,N-dimethylcarbamates. In vitro inhibition assay by Ellman's method with human blood samples showed that carbamates were selective for butyrylcholinesterase (BuChE) with compound concentration that inhibits 50% of enzyme activity (IC50) between 0.11 and 0.18 mmol L-1. cis- and trans-3-(4-Methoxyphenylamino)cyclohexyl N,N-dimethylcarbamate hydrochloride were the most active for BuChE, showing that the presence of methoxyl group enhanced the anticholinesterase activity. The enzyme kinetics studies indicate a noncompetitive inhibition against acetylcholinesterase (AChE) and mixed type inhibition for BuChE. Molecular modeling studies confirm the ability of carbamates to bind both the active and peripheral sites of the BuChE.

Este trabalho descreve a síntese de 1,4'-bipirazóis inéditos pela da reação de ciclocondensação de novas β-dimetilaminoenonas com as monoidrato de hidrazina, tert-butil hidrazina, fenil hidrazina, carboximetilhidrazina. Os produtos foram obtidos com alta regiosseletividade em rendimentos de bons a moderados (50-80%). A técnica de cristalografia de raios-X foi utilizada para a elucidação da regiosseletividade da formação dos produtos. 1,4'-Bipirazolilisoxazóis também foram descritos.

Novel 1,4'-bipyrazoles were synthesized via highly regioselective cyclocondensation reactions of β-dimethylaminoenones with hydrazine monohydrate, tert-butylhydrazine hydrochloride, phenylhydrazine hydrochloride or carboxymethylhydrazine. X-ray diffraction technique was used in the elucidation of the regiochemistry of the β-dimethylaminoenaminones and of the 1,4'-bipyrazoles. 1,4'-Bipyrazolylisoxazoles were also reported.

Este trabalho descreve a reação de ciclocondensação de 3-amino-5-metil-1H-pirazol com 1,1,1-tricloro-4-alcóxi-3-alquen-2-onas [CCl3C(O)CH=C(R¹)OR, onde R¹/R = H/Me, Me/Et, Et/Me, Pr/Et, Bu/Me, iso-Bu/Me] e β-dimetilaminovinil cetonas [R²C(O)CH=CHNMe2, onde R² = Ph, Ph-4-Me, Ph-4-F, Ph-4-Cl, Ph-4-Br, Ph-4-NO2, fur-2-il, tien-2-il, pirrol-2-il, pyrid-2-il], em refluxo de ácido acético para a obtenção de uma série de catorze pirazolo[1,5-a]pirimidinas. Os produtos foram obtidos em bons rendimentos (65-98%). Este trabalho apresenta ainda uma metodologia simples e seletiva para a obtenção de 3-bromo-pirazolo[1,5-a]pirimidinas, com rendimentos de 70-98%.

The reaction of 3-amino-5-methyl-1H-pyrazole with 1,1,1-trichloro-4-alkoxy-3-alken-2-ones [CCl3C(O)CH=C(R¹)OR, where R¹/R = H/Me, Me/Et, Et/Me, Pr/Et, Bu/Me, iso-Bu/Me] or β-dimethylaminovinyl ketones [R²C(O)CH=CHNMe2, where R² = Ph, Ph-4-Me, Ph-4-F, Ph-4-Cl, Ph-4-Br, Ph-4-NO2, fur-2-yl, thien-2-yl, pyrrol-2-yl, pyrid-2-yl], in acetic acid under reflux for 16 hours, furnished highly regioselective the halomethylated pyrazolo[1,5-a]pyrimidines and aryl[heteroaryl]pyrazolo[1,5-a]pyrimidines, respectively. A protocol for the bromination reaction at the 3-position pyrazolo[1,5-a]pyrimidines also was investigated.