Pentaatomic heteroaromatic cations. 18. Acylation of pyrrole and N-methylpyrrole with 1,3-benzoxathiolium tetrafluoroborates. A high-yield method for the synthesis of diacylpyrroles

Ligand‐Based Storage of Protons and Electrons in Dihydrazonopyrrole Complexes of Nickel

“…As a starting point for these studies, we wanted access to diacyl pyrrole synthons which would be amenable to condensation with N‐based nucleophiles. These compounds are readily accessible through benzoxthiolium mediated acylation chemistry, and we have initially targeted tolyl‐substituents as functional groups that provide reasonable steric protection to prevent arm rotation. The synthesis of the dihydrazonopyrrole ligand Tol,Ph DHPyH 3 ( 1 , Tol,Ph DHPyH 3 =2,5‐bis((2‐phenylhydrazono)( p ‐tolyl)methyl)‐pyrrole) was carried out by condensation of PhN 2 H 3 with this diacyl pyrrole to provide the ligand 1 as a mixture of two isomers ( 1 a and 1 b , Scheme ).…”

“…All runs were collected in fluorescence mode and were referenced to Ni foil at 8.333 keV.D ata collected was processed using Athena software. [12] Synthesis of 2,5-ditolylacylpyrrole [9] This procedure can be carried out under aerobic conditions. 2-Hydroxythiophenol (10 mL, 0.063 mol) and p-toluic acid (8.6 g, 0.063 mol) were dissolved in POCl 3 (100 mL) in a2 50 mL roundbottom flask and heated with stirring to 110 8Cf or 10 min, turning ad eep red color.T he reaction was cooled to room temperature and HBF 4 ·Et 2 O( 30 mL) was added, followed by dry ether (200 mL), resulting in precipitation of the benzoxathiolium salt as ay ellow powder.T he powder was collected by vacuum filtration and used without further purification (yield:1 8g).…”

“…13 C{ 1 H} NMR (125 MHz, CDCl 3 ,R T): d = 166.6, 157. 9,147.1,140.2,139.1,138.4,138.1,135.3,131.0,129.1,129.1,128.7,128.7 (2C,overlapping),128.5,128.0,128.0,127.8,127.3,126.1,122.7,122.2,110.5,21.3,21.2,20.6 ppm. Anal.…”

Classic highlights in porphyrin and porphyrinoid total synthesis and biosynthesis

“…Similar approaches, [3+1]-condensations and reactions of bilanes with aldehydes have likewise been used for the synthesis of the so-called A 2 B 2 porphyrins, notably of the type 212. 101,102 Several approaches have also been developed for members of the A x or ABCD series. In most cases, however, these have been targeted at specific types of porphyrin, such as meso-formyl derivatives 103 and a survey of the developments in the last decade has been provided.…”

Porphyrin–Ryleneimide Hybrids: Tuning of Visible and Near-Infrared Absorption by Chromophore Desymmetrization

“…To circumvent these problems, we used a multistep approach shown in Scheme . First, the reaction of acenaphtho­pyrrole 4 and 2-tolyl 1,3-benzo­xathiolium tetrafluoro­borate , afforded the masked diketone 5 , which was hydrolyzed to yield the diacyl pyrrole 6 . The latter intermediate was reduced with NaBH 4 in THF/CH 3 OH, and the resulting crude acenaphtho­pyrrole dicarbinol was condensed with 1 equiv of diamide pyrrole 7 .…”