Bi‐SO₃H Functionalized Ionic Liquid Based on DABCO: New and Efficient Catalyst for Facile Synthesis of Dihydropyrimidinones

Abstract

A simple and efficient method for the one-pot Biginelli condensation reaction of aldehydes,β-dicarbonyl compounds, and urea or thiourea employing [DABCO](SO3H)2Cl2as a novel ionic liquid catalyst is described.

Synthesis of 2 H- indazolo[2,1- b ]phthalazine-1,6,11(13 H )-triones using 1,4-disulfo-1,4-diazabicyclo[2.2.2]octane-1,4-diium dihydrogen sulfate {DABCO(HSO 3 ) 2 (HSO 4 ) 2 } as a new ionic liquid catalyst

“…2) while in the 1 H NMR spectrum of Cl) 2 the hydrogen of SO 3 H can be observed at 7.32 ppm[17].This observation confirm the preparation of…”

“…After the addition was completed, the reaction mixture was stirred for 2 h, and then stood for 5 min, and then CH 2 Cl 2 was decanted. The residue was washed with dry diethylether (3 × 50 mL) and dried under vacuum to give [DABCO](HSO 3 ) 2 (Cl) 2 as a white solid in 98% yield [17]. At the second step and in a round-bottomed flask (100 mL) equipped with a gas inlet tube for conducting HCl gas to room temperature and washed with water for the separation of the catalyst.…”

Introduction of a novel nanosized N-sulfonated Brönsted acidic catalyst for the promotion of the synthesis of polyhydroquinoline derivatives via Hantzsch condensation under solvent-free conditions

“…To highlight the merits of our newly developed procedures, we have compared our results for the synthesis of ethyl 2,7,7trimethyl-5-oxo-4-phenyl-1,4,5,6,7,8-hexahydroquinoline-3carboxylate using NS-[C 4 (DABCO-SO 3 H) 2 ]$4Cl as catalyst with other results reported in the literature and also N-sulfonated DABCO ([DABCO](SO 3 H) 2 (Cl) 2 ). 52 As it showed in Table 3, the newly developed method avoids some of the disadvantages associated with the other procedures such as long reaction time, large excesses of reagents, harsh reaction conditions and bad conditions for catalyst preparation.…”

Introduction of Two New Brønsted Acidic Ionic Liquids for the Formamide and Formamidine Derivatization of Amines

“…[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] In continuation of these studies and in order to overcome the previously mentioned restrictions on the synthesis of formamides and N, N'-diaryl formamidines, we motivated to report new and straightforward one-pot procedures to obtain these compounds using [DABCO] (HSO 3 ) 2 (Cl) 2 and [DABCO](HSO 3 ) 2 (HSO 4 ) 2 as newly reported efficient ionic liquid catalysts. [31,32] First of all, to optimize the amounts of the catalysts, solvent and temperature, the reaction of 4-chloroaniline (1 mmol), and formic acid (1 mmol) was selected as the model for the preparation of formamides and studied in the presence of different amounts of [ formamidines from the condensation of amines and triethyl orthoformate. In order to optimize the reaction conditions, the condensation of 4-chloroaniline (2 mmol) with triethyl orthoformate (1 mmol) was studied in the presence of [DABCO] (HSO 3 ) 2 (Cl) 2 and [DABCO](HSO 3 ) 2 (HSO 4 ) 2 , and the results are tabulated in Table 1.…”