Divergent synthesis of polysubstituted isoxazoles, isoxazoline N-oxides, and dihydroisoxazoles by a one-pot cascade reaction

Rouf, Abdul
ŞAHİN, Ertan
Tanyeli, Cihangir
An efficient one-pot synthesis of a new class of 3,4,5-trisubstituted isoxazoline N-oxides/isoxazoles and dihydroisoxazoles is developed by a green approach from aromatic and aliphatic aldehydes by controlling the reaction conditions. Aldehydes were reacted with ethyl nitroacetate in the presence of DABCO as a catalyst under ultrasonication. In aromatic aldehydes, isoxazoline N-oxides were obtained exclusively when the reaction was carried out at 40 degrees C, but raising the temperature to 80 degrees C isoxazoles were formed selectively. Aliphatic aldehydes, on the other hand, gave a mixture of isoxazoline N-oxides and dihydroisoxazoles where the ratio of these depended on the bulk of the aliphatic chain on the aldehyde. This is the first method for the synthesis of aliphatic 4-substituted-3,5-bis(ethoxycarbonyl)isoxazoline N-oxides and 4-substituted-3,5-bis(ethoxycarbonyl)-dihydroisoxazoles with good to excellent yields.


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Citation Formats
A. Rouf, E. ŞAHİN, and C. Tanyeli, “Divergent synthesis of polysubstituted isoxazoles, isoxazoline N-oxides, and dihydroisoxazoles by a one-pot cascade reaction,” TETRAHEDRON, pp. 331–337, 2017, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/39824.