Syntheses of water-soluble cationic porphyrins and chlorins

Abstract

Reactions of vinylchlorins and vinylporphyrins with N,N-dimethylmethyleneammonium iodide (“Eschenmoser's Reagent”) gives Mannich adducts in which substitution (with CH 2NMe 2) has taken place on the terminal carbon of the vinyl group to yield a trans-3-(N,N-dimethylaminomethyl)prop-1-enyl derivative. Under no circumstances was meso substitution observed. Use of zinc(II) vinylchlorins or zinc(II) vinylporphyrins afforded the corresponding zinc(II) trans-vinyl adducts at a significantly faster rate than the metal-free substrates. Reaction of Eschenmoser's reagent with deuteroporphyrin-IX dimethyl ester ( 29) (which possesses two peripherally unsubstituted positions) produces the bis-(N,N-dimethylaminomethyl) product ( 30). Treatment of the dimethylamino chlorins and porphyrins with methyl iodide, in all cases, gives an excellent yield of the corresponding quaternary ammonium iodides, and these compounds are highly water-soluble.