A simple and novel methodology has been developed for the synthesis of 1,3-bis(carboxymethyl)imidazolium chloride [BCMIM][Cl] salt. The ionic salt [BCMIM][Cl] catalyzed the reaction among arylaldehydes; the substituted 1,3dicarbonyl compounds and urea/thiourea at 80 °C with 5 mol % under neat condition provided the substituted dihydropyrimidin-2(1H)-one/thiones in the synthesis step with yields of up to 96%. In addition, we synthesized the commercially available drug Monastrol by employing this methodology. The new synthesis method employs the benefits of a broad substrate scope, short reaction time, and high atom economy along with low catalyst loading in neat conditions, and is devoid of chromatographic purification. The ionic salt [BCMIM][Cl] was recycled and reused up to six cycles without substantial damage of its catalytic efficiency.

In this study, a highly efficient two-component [3 + 2] cycloaddition reaction of substituted aryl aldehydes with 4toluenesulfonylmethyl isocyanide (TosMIC) in the presence of 2 equiv of potassium phosphate as a base to 5-substituted oxazoles were established in a isopropanol medium under microwave irradiation. However, using 1 equiv of K 3 PO 4 as a base resulted in the diastereoselective synthesis of 4,5-disubstituted oxazolines under identical reaction conditions. The foremost benefits of these protocols are the moderate-to-excellent yields with good functional group compatibility, simple experimental procedure, inexpensive readily available starting materials, nonchromatographic purification, and high bond-forming efficiency. The synthetic manipulation reported herein represents a cleaner route to the sustainable preparation of 5-substituted oxazoles and diastereoselective 4,5disubstituted oxazolines derivatives.

An efficient, novel bifunctional C2-symmetric ionic liquid–supported (S)-proline organocatalyst 7 was developed for a one-pot, five-component reaction involving β-keto esters 8, aryl aldehydes 9, and aryl amines 10, affording highly functionalized tetrahydropyridines 11a–o by simultaneous generation of fives bonds and two stereogenic centers with extraordinary diastereo- and enantioselectivities (up to >99:1 dr, 95:5 er) in isopropanol with high yields (up to 92%). This protocol provides quick access to diverse enantio-enriched, highly functionalized diastereo- and enantioselective tetrahydropyridines in a green medium without any column chromatographic purification. The catalyst was recycled five times without significant loss of its catalytic activity.

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