Microwave assisted N-propargylation of imidazole using alkaline promoted carbons
2003; Elsevier BV; Volume: 240; Issue: 1-2 Linguagem: Inglês
10.1016/s0926-860x(02)00456-8
ISSN1873-3875
AutoresVanesa Calvino Casilda, A.J. López-Peinado, J.L.G. Fierro, Rosa María Martín Aranda,
Tópico(s)Asymmetric Hydrogenation and Catalysis
ResumoTwo basic activated carbons (Na+ and Cs+-Norit) have been used as catalysts in the synthesis of N-propargyl imidazole. The effect of the microwave irradiation has been studied. Under the experimental conditions used higher yields and selectivities of N-propargyl imidazole than those obtained using other basic media were reached. The carbons were characterized by thermal analysis, nitrogen adsorption and X-ray photoelectron spectroscopy. Most of the basic sites in the promoted carbons have 13.3≤pKa≤16.5. The order or basicity is Na+-Norit<Cs+-Norit. The basicity enhancement is directly connected with the size of the alkaline cation. The yield of the N-propargyl imidazole presents a maximum for 0.04 g of Cs+-Norit at 300 W in only 3 min of microwave irradiation.
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