Methods and intermediates for the synthesis of porphyrins
A method of making a porphyrin is carried out by: (a) condensing (i) a 1,9-bis(N,N-)dialkylaminomethyl)dipyrromethane of Formula II: with (ii) a dipyrromethane to produce a reaction product; then (b) oxidizing the reaction product; and then (c) optionally demetallating said reaction product to produce the porphyrin. The reaction is particularly useful for making substituted porphyrins with a wide range of substituents at the A and/or B (the 5 and/or 15) positions.
1. A method of making a compound of Formula II:
wherein:
R a and R b are each independently loweralkyl;
R 1 is H, alkyl or aryl;
R 2 , R 3 , R 4 , and R 5 are each independently selected from the group consisting of H, halo, loweralkoxy, and loweralkylthio; and
A is selected from the group consisting of H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkylalkenyl, cycloalkylalkynyl, aryl, arylalkyl, arylalkenyl, arylalkynyl, alkoxy, halo, mercapto, azido, cyano, hydroxyl, nitro, acyl, alkoxy, alkylthio, amino, alkylamino, arylalkylamino, disubstituted amino, acylamino, acyloxy, amide, sulfonamide, urea, alkoxylacylamino, aminoacyloxy, hydrophilic groups, surface attachment groups, cross-coupling groups and bioconjugatable groups; said method comprising:
reacting a dipyrromethane of Formula IV:
wherein A, R 2 , R 3 , R 4 and R 5 are as given above with an N,N-dialkylmethylammonium halide of Formula V:
wherein R a , R b and R 1 are as given above, and X is halo;
in a polar or nonpolar aprotic solvent selected from the group consisting of methylene chloride, chloroform, tetrahydrofuran, nitromethane, toluene, acetonitrile, and mixtures thereof at a temperature of from room temperature to 100° C. to produce said compound of Formula II.
2. The method of claim 1 , wherein A is a surface attachment group, cross-coupling group or bioconjugatable group.
3. The method of claim 2 , wherein A is an alkene, alkyne, alcohol, thiol, selenyl, phosphono, carboxylic acid, formyl, halo or amine group.
4. The method of claim 1 , wherein R 1 , R 3 , R 4 , and R 5 are each independently selected from the group consisting of H and halo.
5. The method of claim 1 , wherein R 2 , R 3 , R 4 , and R 5 are each H.