A Cost-Efficient Method for Unsymmetrical Meso-Aryl Porphyrin Synthesis Using NaY Zeolite as an Inorganic Acid Catalyst

Abstract

Herein we report the synthesis of unsymmetrical meso-aryl substituted porphyrins, using NaY zeolite as an inorganic acid catalyst. A comparative study between this method and the several synthetic strategies available in the literature was carried out. Our method presented a better, more cost-efficient rationale and displayed a significantly lower environmental impact. Furthermore, it was possible to verify the scalability of the process as well as the reutilization of the inorganic catalyst NaY (up to 6 times) without significant yield decrease. In addition, this method was applied to the synthesis of several other unsymmetrical porphyrins, from a low melting point porphyrin to mono-carboxylated halogenated unsymmetrical porphyrins, in yields higher than those found in the literature. Additionally, for the first time, two acetamide functionalized halogenated porphyrins were prepared in high yields. This methodology opens the way to the preparation of high yielding functionalized porphyrins, which can be easily immobilized for a variety of applications, either in catalysis or in biomedicine.

Bioinspired-Metalloporphyrin Magnetic Nanocomposite as a Reusable Catalyst for Synthesis of Diastereomeric (−)-Isopulegol Epoxide: Anticancer Activity Against Human Osteosarcoma Cells (MG-63)

“…This halogenated porphyrin was prepared using reacting pyrrole with the 2,6-difluoro benzaldehyde in equimolar amounts, in a nitrobenzene/acetic acid mixture, according to reported methods [55,60]; characterization data is in agreement with what is previously reported [61].…”

Main Strategies for the Synthesis of meso-Arylporphyrins

“…After thermal activation at 500°C, the zeolite catalyst can be reused without loss of catalytic activity. Using this methodology, Pereira et al [ 212 ] obtained a series of unsymmetrical meso -arylporphyrins, including halo­gen-substituted ones; their yields were almost two times higher than those obtained by the classical nitrobenzene method. The versatility of the proposed methodology using a solid NaY zeolite catalyst was confirmed by the data of [ 213 – 215 ], according to which a number of unsymmetrically substituted por­phyrins were synthesized to create a platform for various biomedical applications, including their use as photosensitizers and diagnostic agents.…”

Overcoming the challenges of infrared photosensitizers in photodynamic therapy: the making of redaporfin

“…32,33 Later, improvements of this nitrobenzene synthetic methodology, using MCM 45 as a reusable Lewis acid catalyst, to activate the aldehyde, allowed us to improve the yields of mono- and di-chlorinated or fluorinated meso-aryl porphyrins. 34,35 The synthesis of these porphyrins was also performed under more sustainable conditions, by using water as the solvent, and microwave irradiation (200 °C) as an alternative reaction activation technique (Scheme 2). 36…”