1-Methylimidazolium hydrogen sulfate catalyzed convenient synthesis of 2,5-dimethyl-N-substituted pyrroles under ultrasonic irradiation

Abstract

Ionic liquid [HMIM]HSO4 was found to be an efficient catalyst for the synthesis of N-substituted pyrroles through the reaction of 2,5-hexanedione with amines under ultrasonic irradiation at room temperature. These reactions proceed with good yields under short reaction time. Furthermore, the green catalytic system can be recycled specific times with no decreases in yields and reaction rates.

Protic Ionic Liquids: Evolving Structure–Property Relationships and Expanding Applications

“…519 The optimal amount of the PIL was determined to be 20 mmol %, with higher quantities not increasing the yields. In contrast, the use of the aprotic ILs of BMIm Cl, EMIm Br, or EMIm Cl led only to trace amounts of the product.…”

“…In contrast, the use of the aprotic ILs of BMIm Cl, EMIm Br, or EMIm Cl led only to trace amounts of the product. 519 The formation of 1,2,4-triazoles has been successfully conducted from reacting organoamines and oxadiazoles in protic ILs, as shown in Figure 18. 520 The PILs consisting of the pyridinium cation with either TFA or Ac performed best, with efficiency for arylamines and alkylamines, respectively.…”

Supercritical ethanolysis for biodiesel production from edible oil waste using ionic liquid [HMim][HSO4] as catalyst

“…In order to evaluate if its chemical structure is affected or not by the exposure to scEtOH, despite the change in color, considering that thermal stability under scEtOH is a mandatory request for using as catalyst under this condition [46] ] not exposed to scEtOH (Fig. 2) presents the following signals: 3.86 ppm (s, 3H), 7.64 ppm (t, 1H), 7.69 ppm (t, 1H) and 9.06 ppm (s, 1H).…”

One-pot synthesis, biological evaluation, and docking study of new chromeno-annulated thiopyrano[2,3-c]pyrazoles

“…Recently, methylimidazolium hydrogen sulfate, [Hmim]HSO 4 , has been used successfully in the synthesis of 3,4-dihydropyrimidin-2(1H )-ones/thiones, hydroquin azoline-2,5-diones/thiones [55], and 3,4-dihydropyrimidin-2-(1H )-ones [60]. This halogen-free, less-toxic/carbon-containing protic IL [55,56,[60][61][62][63][64] also mediated synthesis of functionalized pyrroles [63], piperidines [64], pyrazolones [61], and α-aminonitriles [62]. As part of our continued effort and interest in the development of new polyheterocycles [57][58][59][65][66][67], we describe an efficient, one-pot synthesis of new thiopyrano [2,3-c]pyrazole-heterocycles in this work, via the DKHDA approach optimizing the reaction in [Hmim]HSO 4 under microwave irradiation.…”