Boron-containing tetrapyrroles

Abstract

The recent advances in the synthesis of carborane and boronic ester-substituted tetrapyrroles (porphyrins, porphyrazines, and phthalocyanines) are reviewed together with their possible utilization as agents for photodynamic therapy (PDT) and boron neutron capture therapy of cancer (BNCT) as well as dual PDT/BNCT sensitizers.

Synthesis and properties of novel polymeric metal-free and metallophthalocyanines containing peripherally long 1,2-bis[(3-oxapropyl)oxa]benzene derivatives

“…28,54 While compounds 3 and 4 exhibit melting points at 115 and 330 • C (Figure 4), respectively, no melting point is observed for the metallophthalocyanine polymers (5)(6)(7)(8). The main degradation step is visible between 350 and 450 • C with about 22%-84% weight loss for all samples (3)(4)(5)(6)(7)(8) in the TGA/DTG measurements. The initial decomposition temperature is reduced in the order of 4 > 8 > 5 > 6 > 7 > 3 (Table 2).…”

“…Low-molecular weight phthalocyanines 1,2 and their polymeric derivatives 3,4 are attracting great attention because of their high thermal and chemical stability, 5 high gas sensitivity, 6,7 excellent semiconducting behavior, 1,2,6,7 and biological importance due to their similar molecular structure to metalloporphyrins. 1,2,8 The attention to the usage of phthalocyanines is increasing in many fields such as dyestuffs, 9 electric conductors, 10 catalysts, 1,2 electrocatalysts, 3,4,11 electrochemically active layers, 12 cathode materials in Li-batteries, 13 photovoltaic or photogalvanic elements, 14 and sensitizers for photodynamic therapy of cancer (PDT). 15,16 Metal-free and metallophthalocyanines containing single phthalocyanine cores are mostly prepared via cyclotetramerization reaction of phthalic acid derivatives, such as o-benzonitrile or phthalic anhydride derivatives or 1,3-diminiisoindoline derivatives, under different reaction conditions in the absence or presence of metals or metal salts, in high yields.…”

In Vivo Application of Carboranes for Boron Neutron Capture Therapy (BNCT): Structure, Formulation and Analytical Methods for Detection

“…From the beginning of 1990, Miura and colleagues explored the potential of lipophilic porphyrins containing boron for in vivo applications [43,[113][114][115][116][117][118][119][120][121][122][123][124][125][126][127]. Since then, significant progress has been made in the development of a series of porphyrin-based drugs [128,129], also complexed with metals such as Zn and Cu. The incorporation of these metal atoms into porphyrins can influence their biological activity and allow the use of radionuclides (i.e., 64 Cu) for tracing and quantifying the boron distribution during in vivo treatment.…”