ИСТИНА

Chlorines are natural macroheterocycles, which hold an important place in modern chemistry. The most famous representative of this compounds, which distributed in nature, is chlorophyll a. Chlorines are widely used in various fields of medicine and technology. Especially these compounds became of special interest for the development of new photosensitizers (PS) for photodynamic therapy due to numerous advantages over synthetic analogs. It has been shown that substitution of chlorins at the pyrrole ring A results in increased photodynamic efficiently of the PS. In particular, introduction of the alkoxide and carbohydrate moieties via the C3-vinyl group of the chlorophyll a derivatives gave rise to the amphiphilic PSs characterized by the high photocytotoxicity compared to those with the substituents in the other positions of the macrocycle. On the other hand, substitution in the C3-vinyl group conjugated with the macrocycle also may affect optical properties of the pigment by shifting the longest absorbing (Qy) maximum. Since this characteristic band is dependent on the transition moment along the y-axis, the modification of the C3-position of the macrocycle can be used for tuning chlorin optical properties. Here we report a facile and efficient procedure for regioselective bromination of the C3 -position of chlorophyll a leading to related bromovinyl derivatives and its subsequent Pd-catalyzed coupling reactions.