Preparation of porphin,substituted porphin and metal chelates thereof

Abstract

Abstract PREPARATION OF PORPHIN, MESO MONOMETHYL-, MESO DIMETHYL-, MESO TRIMETHYL-, AND MESO TETRAMETHYLPORPHIN, AND THE METAL CHELATES THEREOF IN RELATIVELY LARGE QUANTITIES WITH YIELDS IN THE RANGE OF 1% TO 20% IS ACCOMPLISHED BY CYCLIC CONDENSATION OF A PYRROLE HAVING A PRIMARY OR SECONDARY CARBINOL IN THE 2 POSITION THEREOF TO FORM A METAL CHELATE FOLLOWED BY DEMETALLATION TO FORM PROPHIN OR THE MESO SUBSTITUTED PORPHIN. THE REACTION MIXTURE INCLUDES THE HYDROXYPRYRROLE, A METAL ACETATE, AN ORGANIC ACID AND A POLAR SOLVENT, AND BY (1) CONTROLLING THE PH OF THE BUFFER FORMED BY THE METAL ACETATE AND THE ACID TO BETWEEN 3.2 AND 5.5 BASED ON A WATER SYSTEM, (2) CONTROLLING THE TEMPERATURE OF THE REACTION MIXTURE IN THE RANGE OF 120*C. TO 150*C., AND (3) REDUCING THE SELFPOLYMERIZATION OF THE HYDROXY-PYRROLE BY DROPWISE ADDITION OF A PRECOOLED MIXTURE THEREOF TO A PREHEATED SOLVENT SYSTEM, MUCH IMPROVED YIELDS OF THE METAL CHELATES ARE OBTAINED. ALSO, THE YIELDS OF PROPHIN AND MESO SUBSTITUTED PROPHINS WERE INCREASED BY AN IMPROVED DEMETALLATION PROCEDURE PERMITTING 75% TO 85% YIELDS FROM THE CORRESPONDING METAL CHELATES. VARIOUS METAL ACETATES, SOLVENTS, TEMPERATURE RANGES, RATIOS OF REACTANTS AND REACTION CONDITIONS AND TECHNIQUES ARE DESCRIBED.

Inventors

• 👤 Richard G Yalman

Bibliographic Details