abstract |
A compound of formula ** Formula ** in which one group R is a hydrogen atom and the other is a hydrogen atom or a C1-3 alkyl group, characterized in that said compound (I) is in the form of a mixture of stereoisomers (4E, 8E), (4Z, 8E) and (4E, 8Z), in which the weight ratio (4E, 8E) / [(4Z, 8E) + (4E, 8Z)] is between 20 / 80 and 1/99, or between 80/20 and 99.5 / 0.5. |