| abstract |
New compounds of the formula: ##STR1## wherein R 1 represents a hydrogen atom or an alkanoyl group containing from 1 to 4 carbon atoms, R 2 and R 3 each represent a hydrogen atom or a C 1 -C 4 alkyl group, and R 4 represents a hydroxy or methoxy group in the 6-position or 7-position, have been found to be useful in therapy, and more particularly in the treatment of cardiovascular diseases and Parkinson's disease. |