Efficient synthesis of aryldipyrromethanes in water and their application in the synthesis of corroles and dipyrromethenes

Abstract

In this paper, we describe the efficient and selective synthesis of aryldipyrromethanes in aqueous medium by acid-catalyzed (HCl) condensations of aromatic aldehydes with 3 equivalents of pyrrole at room temperature. The precipitated aryldipyrromethanes can be isolated directly from the reaction mixture in an essentially pure state by simple filtration. Time control seems to be essential to avoid significant formation of the tripyrromethane analogue and the reaction time is strongly dependent on the nature of the aromatic aldehyde. A one-pot synthesis of several aryldipyrromethenes and various novel meso-aryl-substituted trans-A 2 B-corroles was also achieved starting from the obtained aryldipyrromethanes. Trichloroacetic acid was the preferred acid catalyst for the preparation of meso-triarylcorroles from the condensation of 5-(2,6-dichlorophenyl)dipyrromethane with more reactive aldehydes, while trifluoroacetic acid was preferred for less reactive substrates.

C*-BODIPYs: Exploring a New Strategy to Transfer Chirality towards BODIPY Chiroptics

“…Therefore, we decided to use a dipyrrin without substituents at positions 3,5 (α to the nitrogen), to diminish the sterical hindrance near the boron-complex site (see 4 in Scheme 2 ). Since the F -BODIPY precursor of dipyrrin 4 is not commercially available, we prepared the required 4 from the corresponding aldehyde and pyrrole, following a standard procedure used in synthesis of F -BODIPY (see Scheme 2 ) [ 16 ]. Having 4 in hand, its reaction with I pc2 BCl ( 2 ) in the presence of triethylamine finally led to C* -BODIPY 5 with a 65% yield.…”

Suzuki–Miyaura cross-coupling reaction on copper-trans-A2B corroles with excellent functional group tolerance

“…The first step in the synthesis of 3 ( Scheme 1 ) was the HCl-catalyzed condensation of pyrrole with pentafluorobenzaldehyde in water/MeOH to give the 5-pentafluorophenyldipyrromethane 2 in 85% yield. 20 …”

Synthesis of BODIPY dyes through postfunctionalization of the boron dipyrromethene core

“…54 However, a convenient, water-based, HCl-catalyzed protocol for the synthesis of 5-aryldipyrromethane 20 has been described, avoiding polymerization by precipitation of the formed dipyrromethane 20 from the aqueous solution. 55 In this protocol, a large excess of pyrrole is not required, making this reaction better suited for large-scale synthesis in water as an inexpensive and environmentally benign ('green') solvent. Because dipyrromethanes 20 are generally unstable and sensitive to light, air and acid, it is best to use them immediately after preparation.…”