[Hmim][HSO] ionic liquid (IL) and bio-renewable sources as chitosan (CHT) and chondroitin sulfate (CS) were used to yield hydrogel-based materials (CHT/CS). The use of IL to solubilize both polysaccharides was considered an innovative way based on "green chemistry" principle, aiming the production of CHT/CS blended systems. CHT/CS hydrogels were carried out in homogeneous medium from short dissolution times. The hydrogels were characterized and achieved with excellent stabilities (in the 1.2-10pH range), larger swelling capacities, as well as devoid of cytotoxicity towards the normal VERO and diseased HT29 cells. The CHT/CS hydrogels carried out in [Hmim][HSO] could be applied in many technological purposes, like medical, pharmaceutical, and environmental fields.

Efficient and regioselective synthesis of isoxazoles was demonstrated through cyclocondensation of β-enamino diketones with hydroxylamine: four of the six possible regioisomers were obtained.

No abstract

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.

An efficient one-pot method is described for the highly regioselective synthesis of α-ketoamide N-arylpyrazoles from secondary β-enamino diketones. For this, the key intermediate, 4-acyl 3,5-dihydroxypyrrolone, was generated in situ and underwent bimolecular nucleophilic substitution at C-5 by arylhydrazine, with subsequent heterocyclization at the carbonyl carbon of the acyl group. This strategy allowed for regiochemical control of α-ketoamide N-arylpyrazoles from β-enamino diketones and arylhydrazines.