Synthesis of Porphyrins Di‐ and Tetra‐Functionalized with Nucleobases

Abstract

AbstractA library composed of ten porphyrins bearing nucleobases is prepared, following two strategies: substitution or Sonogashira cross‐coupling reactions. The former strategy led to the synthesis of four porphyrins (T2−Po1, A2−Po1, C2−Po1 and P2−Po1) bearing nucleobases (NBs) at two trans meso‐positions. These 4 porphyrins were obtained by reacting 5,15‐di(4‐(bromomethyl)phenyl)‐10,20‐dimesitylporphyrin (Po1) with thymine (T), adenine (A), cytosine (C) and 2‐amino‐6‐chloropurine (P), a precursor of guanine (G), respectively in the presence of a suitable base. A fifth porphyrin, 5,15‐di(N9‐methylphenylguanine)‐10,20‐dimesitylporphyrin (G2−Po1) was obtained by hydrolysis of P2−Po1. A thymine tetra‐functionalized porphyrin was also synthesized following the same strategy starting from T and 5,10,15,20‐tetrakis[4‐(bromomethyl)phenyl]porphyrin (Po2). The second strategy based on Sonogashira cross‐coupling reactions between 5,15‐dibromo‐10,20‐dipentylporphyrin (Po3) and ethynyl‐substituted nucleobases resulted in four rigid porphyrins (U2−Po3, C2−ZnPo3, A2−ZnPo3, and G2−ZnPo3).