Direct synthesis of magnesium porphine via 1-formyldipyrromethane

The reaction of 1-formyldipyrromethane (100 mM) in toluene at 115 degrees C containing DBU (10 mol equiv) and MgBr2 (3 mol equiv) in the presence of air affords the magnesium chelate Mg(II) porphine in 30-40% yield. The advantages of the new method include simplicity, high concentration, chromatography-free purification, gram-scale synthesis, and avoidance of the poorly soluble free base porphine. Mg(II) porphine exhibits good solubility in common organic solvents and is a valuable core scaffold for derivatization.