| abstract |
A compound of the formulas (IA), (1 B), (XA), (XB), (YA) or (YB) where R 'represents where R "represents hydrogen, hydroxy, alkoxy of 1 to 7 atoms of carbon, alkanoyloxy of 1 to 8 carbon atoms, or R5R4N-CO-O-, wherein R4 and R5 are independently alkyl of 1 to 7 carbon atoms or phenyl which is substituted or unsubstituted by a substituent selected from alkyl of 1 to 7 carbon atoms, alkoxy of 1 to 7 carbon atoms, halogen and trifluoromethyl and wherein R4 is additionally hydrogen; or R4 and R5 together represent alkylene of 3 to 6 carbon atoms; in free form or in the form of an addition salt pharmaceutically acceptable acid. |