| abstract |
A process for the preparation of a compound of formula (I) in which R1, R2, R3, R4, R5 and R6 are as defined in the description of the invention, comprising the step of reacting the acrylic acid hydrochloride of the compound of formula (II ') in which R1, R2, R3, R4, R5 and R6 are as defined in the description of the invention with aqueous hydroxylamine and optionally converting the formed compound into its acid addition salt. Formula I, Formula II '. |