Method for producing chlorobenzoxazolene

A process for preparing chlorobenzoxazoles of the formula (I),

• in which R1, R2 and R4 are each, independently of one another, H, halogen, CN, NO2, C1-C5-alkyl, C1-C5-alkoxy, aryl or aryloxy, where each of the 4 lastmentioned radicals is unsubstituted or substituted, and
• in case (a) R3=H, halogen, CN, NO2, C1-C5-alkyl, C1-C5-alkoxy, aryl or aryloxy, where each of the 4 lastmentioned radicals is unsubstituted or substituted, or
• in case (b) R3=chlorine,
• which comprises reacting benzoxazoles of the formula (II),
• in which R1, R2 and R4 are as defined in formula (I) and R3 in case (a) is as defined in formula (I) and R3 in case (b) is hydrogen,
• in the presence of an acidic catalyst with a chlorinating agent to give the monochlorination product (I) or in case (b) with an excess of the chlorinating agent to give the dichlorination product (I) in which R3=chlorine.