Synthesis and Physicochemical Properties of [(1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy]-thiophen-5-yl-substituted Tetrapyrazinoporphyrazine with Magnesium(II) Ion

Tetrapyrazinoporphyrazine with peripheral menthol-thiophenyl substituents was synthesized using Linstead conditions and purified by flash column chromatography. The optimized synthetic and purification procedures allowed us to obtain a new macrocycle with 36% yield. Tetrapyrazinoporphyrazine derivative was characterized by UV-Vis and NMR spectroscopy, as well as MS spectrometry. Complex NMR studies using 1D and 2D NMR techniques allowed the analysis of the bulky menthol-thiophenyl substituted periphery of the new macrocycle. Further, photochemical stability and singlet oxygen quantum yield were determined by indirect method with diphenylisobenzofuran. The new tetrapyrazinoporphyrazine revealed low generation of singlet oxygen with a quantum yield of singlet oxygen formation at 2.3% in dimethylformamide. In turn, the macrocycle under irradiation with visible light presented very high stability with quantum yield for photostability of 9.59 x 10(-6) in dimethylformamide, which figures significantly exceed the border for its classification as a stable porphyrinoid (10(-4)-10(-5)).

Automated summary

In this study, a new tetrapyrazinoporphyrazine derivative with peripheral menthol-thiophenyl substituents was successfully synthesized and purified with a 36% yield. Characterization of the derivative was done using UV-Vis, NMR, and MS spectroscopy, with further analysis of its structure through complex NMR studies. The new tetrapyrazinoporphyrazine exhibited low singlet oxygen generation, but showed high stability under visible light irradiation.