| 摘要 |
The invention relates to the organic chemistry , in particular to the synthesis of 5-anilinpyrazoles, namely to a novel common method for the preparation of previously practically unknown 5-(o-aminoanilino)-3-arylpyrazoles which can find use in technique, medicine, agriculture , and also as original substances for the synthesis of different types of pyrazole-containing compounds. The basis of the invention is a method for the preparation of 5-(o-aminoanilino)-3-arylpyrazoles of the general formula 1 , where R û aromatic radical or cyanetyl group, and Ar û aromatic or heteroaromatic radical. The method is realized on the basis of two-stage reaction. At the first stage the interaction of hydrazoines 2-aroylmethyl-1H-benzimidazoles with trifluoroacetic anhydride the recyclization is performed with formation of 5-(o-trifluroacetaminoaniliono)-3-arylpyrazoles of the general formula 2 . At the second, final stage, deacylation is performed with base, in particular with hydrazine. Yields of 5-(o-trifluoroacetaaminoanilino)-3-arylpyrazoles are of 70-95 %, and 5-(o-aminoanilino)-3-arylpyrazoles are of 85-99 %. The general yield of products is of 68-91 %.
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