Synthesis of trifluoromethyl azoles using building blocks.

Trifluoromethyl (CF3) -1, 3- dipolar compounds such as nitrile oxide, imines, ylides, nitrones, and azomethine ylides are applied as the building blocks of various CF3- azoles. Their reactivity, particularly regio- and stereoselectivity of the cycloadditions, is discussed mainly on the basis of the interaction between the frontier orbitals of CF3- dipolar compounds, some of which are calculated by the CNDO/ 2 methods, and those of the dipolarophiles. The initially produced CF3-isoxazoles are utilized as the synthetic intermediates. For example, a variety of CF3-isoxazoloazines are prepared from the condensations of 3-CF3-5-amino-4-methoxycarbonylisoxazoles and the potential of 3-CF3-isoxazolines as the precursors of CF3 -1, 3- aminoalcohols are demonstrated.Moreover, CF3-hydrazides, imidoyl chlorides, and hydrazones are also applied as the building blocks of CF3- tetrahydro-1, 3, 4, 2-oxadiazaphospholes, Reissert analogue salts, and 4-hydroxypyrazoles, respectively.