Beneficial effects of salts on an acid-catalyzed condensation leading to porphyrin formation

A Facile and Reliable Method for the Synthesis of Tetrabenzoporphyrin from 4,7‐Dihydroisoindole

“…Indeed, the addition of a highly hygroscopic salt, namely, anhydrous tetrabutylammonium chloride, resulted in full suppression of tarring and desired dipyrromethane 7 was formed in near-to-quantitative yield. The action of salt, which binds the liberated water, is probably similar to the well-known salt effect in the formation of porphyrinogens, described by Lindsey et al, [29] though, as far as we know, this effect was never employed in dipyrromethane chemistry. Besides, unlike the salt effect of Lindsey, which is delivered by a lot of various salts, in our reaction simple salts such as NaCl or Na 2 SO 4 aryloctahydrotetrabenzoporphyrin 10, which is cleanly aromatized to 5,15-diaryltetrabenzoporphyrin 11.…”

Phenyl Substituted Porphyrins. Part 4. Acylation of Hydroxyphenylporphyrins

“…The attempts to synthesize these pophyrins by Lindsey method [19][20][21][22][23][24] did not lead to the desired result. Nevertheless, isomeric porphyrins 1 were obtained by two-stage scheme through 5-methoxyphenyl-10,15,20-triphenylporphyrins 10 with following demethylation of the porphyrin mixture by boron tribromide [25] and its chromatographic separation.…”

Asymmetric Cyclopropanation of Olefins Catalyzed by a Chiral Cobalt(II) Porphyrin

“…25 Cobalt(II) tetramesitylporphyrin (CoTMP, 6) was synthesized from the reaction of the porphyrin ligand 5 with excessive Co(OAc) 2 ·4H 2 O in boiling mixture of CHCl 3 -MeOH and it was purified via column chromatography (aluminum oxide, neutral, hexane/CHCl 3 , gradient elution from 10:0.2 to 10:1). 26 The chiral Halterman porphyrin ligand (7) was prepared according to the literature.…”