| abstract |
A compound of the formula <IMAGE> I wherein R is =O or <IMAGE> and the rings A and B are selected from the group consisting of <IMAGE> <IMAGE> <IMAGE> and <IMAGE> K is oxo or a protector group of oxo of the formula <IMAGE> n is 2 or 3 and R1 is an ether or ester remainder, K' is oxo or a protector oxime, hydrazone or semicarbazone group and the wavy lines symbolize an isomer mixture, a process for their preparation and their use as intermediates. |