Pyrrole → 5,10,15,20-Tetrakis(thiazol-5-yl)porphyrin

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Reaction Steps

A 250-mL three-necked flask equipped with a condenser and charged with propionic acid (60 mL) was heated to reflux. 5-Thiazolecarboxaldehyde (1, 373 mg, 3.30 mmol), pyrrole (230 μL, 3.32 mmol), and an additional 5 mL of propionic acid were added. After 3.5 h at reflux, the mixture was cooled to room temperature while exposed to a stream of air. The solvent was removed in vacuo, the residue was redissolved in CHCl3/MeOH/concentrated NH4OH (6:3:1; 100 mL), and the solvent was removed in vacuo. The residue was adsorbed onto silica gel (3 g) and purified by column chromatography (gradient elution, 1-2% MeOH/CH2Cl2) to provide porphyrin 6 (123 mg, 14%) as a solid: 1H NMR (300 MHz, CDCl3) δ −2.70 (s, 2 H), 8.67 (s, 4 H), 9.02 (s, 8 H), 9.38 (s, 4 H).

Provenance & Evidence