abstract |
A method for the production of compounds of the formula (I), wherein R1, R2, R3, R4, R5 and R6 have the meanings as indicated in claim 1, comprising the reaction of a compound of the formula (II), wherein R1, R2, R3, R4 have the meanings as indicated above, with a compound of the formula (III), wherein R5, R6 have the meanings as indicated above. |