| abstract |
The present invention provides the compounds of formulae ( 3 ) and (1), wherein n is 0 or 1, R 11 and R 12 are the same and are selected from the group consisting of CN, OR 300 , Si(R 301 ) 3 , NHR 302 , NR 303 R 304 , SR 305 and R 306 , or R 11 and R 12 together are selected from the group consisting of (a), (b), and (c) and X is Cl, Br or I, and a process for the preparation of compounds of formula (3) comprising the compounds of formula (1) as key intermediates. |