Bi-SO3H functionalized ionic liquid based on DABCO as a mild and efficient catalyst for the synthesis of 1,8-dioxo-octahydro-xanthene and 5-arylmethylene-pyrimidine-2,4,6-trione derivatives

Facile and efficient synthesis of xanthenedione derivatives promoted by niobium pentachloride

“…Xanthene derivatives can be prepared by several methods: cyclodehydration (Bekaert et al, 1992), the trapping of benzynes by phenols (Knight & Little, 2001), the palladium-catalysed cyclisation of polycyclic aryltriflate esters (Wang & Harvey, 2002), a simple and efficient procedure for the synthesis of xanthene derivatives through one-pot condensation of 2-naphthol with aryl aldehydes in the presence of niobium pentachloride (Bartolomeu et al, 2014), the condensation of cyclohexane-1,3-diones and aromatic aldehydes in the presence of solid acids (Karami et al, 2013a), amongst others (Horning & Horning, 1946;John et al, 2006;Saini et al, 2006;Zhang & Tao 2008;Zhang & Liu, 2008;Wang et al, 2008;Urinda et al, 2009;Lü et al, 2009;Maleki et al, 2011;Soleimani et al, 2011;Pramanik & Bhar, 2012;Dharma Rao et al, 2012;Karami et al, 2013bKarami et al, , 2013aKarami et al, , 2014Li et al, 2013;Cao et al, 2013;Shirini et al, 2013;Iniyavan et al, *Corresponding author, e-mail: lcsilva@fc.unesp.br 2014; Shirini et al, 2014Shirini et al, , 2015Preetam et al, 2015;Ilangovan et al, 2011). However, some of these methods involve long reaction times, extreme reaction conditions, expensive reagents and unsatisfactory yields, hence the improvement of these syntheses has been the target of several studies.…”

Agar-entrapped sulfonated DABCO: Agelly acidic catalyst for the acceleration of one-pot synthesis of 1,2,4-triazoloquinazolinone and some pyrimidine derivatives

“…The acidic ionic liquid was precisely prepared according to the reported procedure in the article [24] .…”

“…Recently we have reported the preparation of [DABCO] (SO 3 H) 2 (Cl) 2 as an acidic IL and its use in the acceleration of some of the multi-component reactions [24] , although the method is useful but its ability in the adsorption of moisture causes that its efficiency to be reduced. For this reason we motivated to use the above mentioned strategy to prepare, a gel entrapped acidic ionic liquid (GEAIL) by the entrapping of this reagent in agar for the first time.…”

Double Brønsted Acidic Media Immobilized on Carbonized Sugarcane Bagasse (CSCB) as a New and Efficient Solid Acid Catalyst for the Synthesis of Coumarins, Dicoumarols and Xanthenes

“…Versatile heterogeneous catalysts based on ionic liquids have been used to promote the preparation of coumarins and xanthenes, but many of them suffer from disadvantages such as expensive reagents and difficult synthesis route, long reaction times and use of hazardous materials. So, introduction of a new methodology using an inexpensive and green support for the synthesis of a novel solid acid catalyst is still in demand.…”