Multicomponent synthesis of allomaltol containing 2-aminooxazoles and acid-catalyzed recyclization into substituted furo[3, 2-b]pyrans. (16th July 2022)

• Record Type: Journal Article
• Authors: Komogortsev, Andrey N.; Lichitsky, Boris V.; Karibov, Turan T.; Melekhina, Valeriya G.
• Is Part Of: Tetrahedron. Volume 117/118(2022)
• Publication Date: 2022-07-16
• Subjects: 2-Aminooxazoles -- 3-Hydroxy-4H-pyran-4-one -- Furo[3, 2-b]pyrans -- Multicomponent reactions -- Recyclization; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2022.132836
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: For the first time we elaborated the efficient one-step approach for the preparation of substituted 2-aminooxazoles containing 3-hydroxy-4 H -pyran-4-one moiety. The considered method includes multicomponent condensation of allomaltol derivatives with α-ketoaldehydes and cyanamide. The distinctive feature of the proposed protocol is formation of 2-aminooxazole core in contrast to related previously described approach leading to urea containing condensed furans. The advantages of this synthesis include readily available starting materials, mild reaction conditions, atom economy and easy workup procedure, which can avoid chromatographic purification. Wherein, it was found that obtained 2-aminooxazoles undergo previously unknown acid-catalyzed recyclization into N -(2-aryl-5-methyl-7-oxo-7 H -furo[3, 2- b ]pyran-3-yl)acetamides. The structures of one 2-aminooxazole derivative and one substituted furo[3, 2- b ]pyran were confirmed by X-ray diffraction. Graphical abstract: Image 1 Highlights: Multicomponent reaction of allomaltol derivatives, arylglyoxals and cyanamide. New method for the synthesis of 2-aminooxazoles containing 3-hydroxypyran-4-one unit. One-pot synthetic approach, high atom economy, easy work-up procedure. Previously unknown acid-catalyzed recyclization. Typical structures were confirmed by X-ray crystallographic analysis.