Вивчення трикомпонентної взаємодії етил-1H-2,1-бензотіазин-4(3H)-он 2,2-діоксиду з метиленактивними нітрилами та гетерилкарбальдегідами

• Datum: 2016
• Hauptverfasser: Lega, D. A., Chernykh, V. P., Shemchuk, L. A.
• Format: Artikel
• Sprache: English
• Veröffentlicht: National University of Pharmacy 2016
• Schlagworte: 2; 1-бензотіазин 2; 2-діоксид; гетерилкарбальдегіди; метиленактивні нітрили; 4Н-пірани; трикомпонентна взаємодія; триетиламонієві солі; УДК 54.057; 547.72/73; 547.812; 547.86
• Online Zugang: https://ophcj.nuph.edu.ua/article/view/ophcj.16.876
• Назва журналу: Journal of Organic and Pharmaceutical Chemistry

Some peculiarities of the three-component interaction of 1-ethyl-1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide with active methylene nitriles and heterylcarbaldehydes have been described in this article. It has been found that if malononitrile is used, the products of the three-component reaction are 2-amino-4-heteryl-3-cyano-6-ethyl-4,6-dihydropyrano[3,2-c][2,1]benzothiazine 5,5-dioxides irrespective of the heteryl fragment nature in the initial aldehyde. When using ethyl cyanoacetate (as the active methylene nitrile) in the three-component interaction instead malononitrile the reaction lost its selectivity. In this case, depending on the heterylcarbaldehyde, three different types of products were obtained, namely 2-amino-3-alkoxycarbonyl-4-heteryl-4H-pyranes (for pyridine-3-, pyridine-4-carbaldehydes and furan-2-carbaldehyde), thriethylammonium salt of bis(1-ethyl-1H-2,1-benzothiazin-2,2- dioxo-4-ol-3-yl)(2-thienyl)methane (for thiophen-2-carbaldehyde) or ethyl 2-cyano-3-(1H-indol-3-yl)acrylate (for indol-3-carbaldehyde). Formation of a stable triethylammonium salts was considered as the process competitive with formation of 2-amino-4H-pyranes. It has allowes to propose the modiŸed mechanism of 2-amino-4H-pyranes formation. This mechanism includes the stage of forming triethylammonium salts of bis-adducts. According to this mechanism 2-amino-3-ethoxycarbonyl-4-(2-thienyl)-4H-pyrane without any impurity of bis-adduct could be selectively obtained using the three-component interaction. Triethylammonium salts of bis-adducts were obtained by direct interaction of 1-ethyl-1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide with heterylcarbaldehydes in the presence of equimolar amounts of triethylamine. It has been shown that the three-component interaction of  1-ethyl-1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide with active methylene nitriles and heterylcarbaldehydes is a more  effective tool in order to obtain condensed 2-amino-4-heteryl-4H-pyranes compared to the stepwise approach.