Heteroannulation Reaction of α-Aminoketones for the Efficient Synthesis of 4-Imidazolin-2-ones and 2-Thiones

• Published in: Journal of the Brazilian Chemical Society Vol. 33; no. 1; pp. 13 - 27
• Main Authors: Rebollar, Araceli, Bautista, Rafael, Gutierrez, Rsuini U., Espinoza-Hicks, Carlos, Mendieta, Aaron, Zarate-Zarate, Daniel, Martinez-Mora, Eder I., Labarrios-Moran, Ehecatl M., Vazquez, Miguel A., Delgado, Francisco, Tamariz, Joaquin
• Format: Journal Article
• Language: English; Portuguese
• Published: SAO PAULO Soc Brasileira Quimica 2022; Sociedade Brasileira de Química
• Subjects: Chemistry; CHEMISTRY, MULTIDISCIPLINARY; Physical Sciences; Science & Technology; alpha-aminoketones; DESIGN; 4-OXAZOLIN-2-ONES; SERIES; SOLID-PHASE SYNTHESIS; 4-imidazolin-2-ones; AZOLE N-OXIDES; IMIDAZOLE DERIVATIVES; OXIMINO KETONES; CONSTRUCTION; REGIOSELECTIVE SYNTHESIS; 4-imidazolin-2-thiones; INHIBITORS; alpha-oximinoketones; heteroannulation; α-oximinoketones; α-aminoketones
• ISSN: 0103-5053; 1678-4790; 1678-4790
• DOI: 10.21577/0103-5053.20210120

The hydrogenation of alpha-oximinoketones in methanol/HCl afforded alpha-aminoketones, which were applied without purification to the synthesis of 4-imidazolin-2-ones and 2-thiones, including chiral derivatives. The latter two series were obtained in high yields by a heteroannulation reaction of alpha-aminoketones with isocyanates and isothiocyanates, respectively. A double condensation of the alpha-aminoketones with two mol equivalents of the isocyanates produced a series of 4,5-dialkyl-N,3-diaryl-2-oxo-2,3-dihydro-1H-imidazole-1-carboxamides. With isothiocyanates, a single condensation reaction furnished a series of 4,5-dialkyl-1-aryl-1H-imidazole-2(3H)-thiones, which underwent alkylation with alkyl halides to form the corresponding 1-aryl-2-thioalkyl-1H-imidazoles in high yields.