Solution-Phase Parallel Synthesis of a Multisubstituted Cyclic Imidate Library (original) (raw)
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Zeitschrift für Naturforschung B, 2015
Ten 1,2,4,5-tetra-substituted imidazole derivatives have been synthesized with a 2-hydroxyethy substituent at the 1-nitrogen atom and potentially electron releasing hydroxy-, methoxy-, dimethylamino- or nitro substituents in various positions on the benzene ring located on the 2-carbon atom. The prototypical derivative with an unsubstituted phenyl ring at the 2-position is also reported. The compounds are obtained in excellent yields (average 86%) via a four-component cyclocondensation reaction of benzil, ethanolamine, and the appropriate aromatic carbaldehyde together with ammonium acetate. The reaction uses a novel ionic liquid catalyst, DEAHS (diethyl ammonium hydrogen sulfate), under solvent-free conditions and a green synthetic protocol. The key advantages of this process are high yield, shorter reaction times and ease of work-up. Furthermore, the products can be purified by a non-chromatographic method and the catalyst is re-usable. All of these newly synthesized compounds hav...
Preparation and Synthetic Applicability of Novel Imidazole-Containing Cyclic Iodonium Salts
2021
The novel approach to the preparation of imidazole-substituted cyclic iodonium salts has been developed via oxidative cyclization of 1-phenyl-5-iodoimidazole using cheap and available Oxone®/H2SO4 oxidative system. The structure of newly prepared compounds has been proved by X-ray monocrystal diffractometry revealing the characteristic surface features for cyclic iodonium salts. The prepared compounds demonstrated the high reactivity in the heterocyclization reactions with elemental sulfur affording benzo[5,1-b]imidazothiazoles with good yields.