| 摘要 |
FIELD: organic chemistry, chemical technology, agriculture, pharmacy. ^ SUBSTANCE: invention relates to a method for preparing chlorobenzoxazoles of the formula (I): ^ wherein R1, R2 and R3 are determined as in cl. 1; in the case (a) R3 means hydrogen, halogen atom, cyano-, nitro-group, halogenalkyl with 1-5 carbon atoms, halogenalkoxy-group with 1-5 carbon atoms, alkyl with 1-5 carbon atoms, alkoxy-group with 1-5 carbon atoms, phenyl or phenoxy-group; or in the case (b) R3 means chlorine atom. Method involves interaction of benzoxazoles of the formula (II) given in the invention description with chlorinating agent in the presence of acid catalyst to form the monochlorinated product (I), or in the case (b) with excess of chlorinating agent to form dichlorinated product (I) wherein R3 means chlorine atom. Chlorobenzoxazoles are used as intermediate substances for synthesis of biologically active compounds, agents for protection of plants and pharmaceuticals preparations. Invention provides selective synthesis of chlorobenzoxazoles with high yields. ^ EFFECT: improved preparing method. ^ 10 cl, 7 ex |
