Abstract
Multicomponent domino reactions are an effective modern approach in the synthesis of different types of organic compounds, including biologically active pyrans.Aim. To study the three-component interaction of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide with different hetarenecarbaldehydes and active methylene nitriles in order to synthesize new 2-amino-4H-pyran derivatives, as well as the antimicrobial activity of the compounds obtained.Results and discussion. 2-Amino-4-heteryl-4,6-dihydropyrano[3,2-c][2,1]benzoxathiin-3-carbonitrile 5,5-dioxides were obtained by stepwise and multicomponent reactions of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide with hetarenecarbaldehydes and malononitrile. For the same interaction with ethyl cyanoacetate the reaction selectivity decreased and not only target ethyl 2-amino-4H-pyran-3-carboxylates were obtained, but also triethylammonium salts of bis(1,2-benzoxathiin-2,2-dioxo-4-ol-3-yl)(heteryl)methane. The latter were also purposefully synthesized by the two-component reaction of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide with hetarenecarbaldehydes in the presence of triethylamine. The compounds obtained revealed a higher antimicrobial activity against gram-positive bacteria and fungi compared to the reference drugs.Experimental part. 3-Amino-4-heteryl-4,6-dihydropyrano[3,2-c][2,1]benzoxathiin-3-carbonitrile 5,5-dioxides and triethylammonium 3-[1-(4-hydroxy-2,2-dioxido-1,2-benzoxathiin-3-yl)heteryl]-1,2-benzoxathiin-4-olate 2,2-dioxides were synthesized. The antimicrobial activity of the compounds synthesized was studied by the agar diffusion method.Conclusions. It has been proven that the multicomponent format for the three-component interaction of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide with hetarenecarbaldehydes and active methylene nitriles is more favorable and convenient than the stepwise approach to obtain new derivatives of 2-amino-4H-pyrans. Triethylammonium 3-[(4-hydroxy-2,2-dioxido-2,1-benzoxathiin-3-yl)heteryl]-2,1-benzoxathiin-5-olate 2,2-dioxides have been also synthesized. The antimicrobial properties of the compounds obtained are higher than in the reference drugs, especially against gram-positive bacteria and fungi.
Highlights
2-Amino-4-heteryl-4,6-dihydropyrano[3,2-c][2,1]benzoxathiin-3-carbonitrile 5,5-dioxides were obtained by stepwise and multicomponent reactions of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide with hetarenecarbaldehydes and malononitrile
It has been proven that the multicomponent format for the three-component interaction of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide with hetarenecarbaldehydes and active methylene nitriles is more favorable and convenient than the stepwise approach to obtain new derivatives of 2-amino-4H-pyrans
The results showed a higher antimicrobial activity compared to the reference drugs (Table)
Summary
1. The three-component interaction of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide with different hetarenecarbaldehydes and active methylene nitriles have been studied and described. 2. The utilization of malononitrile led to formation of 2-amino-4H-pyran-3-carbonitriles in moderate and high yields. When using ethyl cyanoacetate three different types of products depending on the initial hetarenecarbaldehyde were obtained, namely the expected ethyl 2-amino-4H-pyran3-carboxylates, the triethylammonium salts of bis-adduct or ethyl 2-cyanoacrylates. 3. The synthesis of the triethylammonium salts was performed by the two-component interaction of 1,2-benzoxathiin-4(3H)-one 2,2-dioxide with hetarenecarbaldehydes in the presence of triethylamine. 4. The study of the antimicrobial properties of the compounds synthesized was performed and revealed a higher activity than in the reference drugs, especially against gram-positive bacteria and fungi. The most active compounds, which may be used in further biological studies, are triethylammonium salts 6a and 6d. Conflict of Interests: authors have no conflict of interests to declare
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