Data on the reactions of pyridazine, pyrimidine, pyrazine, triazine, oxazine, thiazine, oxadiazine, and thiadiazine aldoximes, ketoximes, and amidoximes and their derivatives are reviewed. The synthesis of new heterocycles based on the oximes of six-membered heterocyclic compounds with two and three heteroatoms is considered separately. The principal results of research into the biological activity of these oximes and their ethers are also presented.The oximes of six-membered heterocyclic compounds with two and three heteroatoms are widely used as intermediates in fine organic synthesis. Their production methods and structural features were examined in the review [1]. In this article we discuss the reactions of pyridazine, pyrimidine, pyrazine, triazine, oxazine, thiazine, oxadiazine, and thiadiazine aldoximes, ketoximes, and amidoximes and their derivatives. Methods for the synthesis of new heterocyclic systems from the derivatives of these oximes are considered in a separate section. In the last section some results from investigation of the biological activity of the ethers of these oximes are considered.
A series of novel Shiff bases (1a-h) was synthesized by condensation of pyridinecarboxaldehydes (1-4) with 3-and 4-trifluoromethylanilines (5, 6) in the presence of molecular sieves (4 Å ). It was found that AlCl 3 and AlBr 3 catalyzed the addition of Me 3 SiCN to the C=N bond of the imines obtained, whereas the other Lewis acids studied (YCl 3 , LaCl 3 , ZnI 2 ) were not active. The reactivity of the imines in the title reaction, on the whole, correlated with their basicity. Besides the addition giving the expected a-amino nitriles (2a,b,d-f,h), an unusual reaction leading to unsaturated nitriles (3a-h) was observed. The structures of saturated and unsaturated products 2d and 3c were determined by X-ray diffraction.
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