Synthesis of 3-cyano-N-confused porphyrin derivatives by silyl cyanide

Creation from Confusion and Fusion in the Porphyrin World─The Last Three Decades of N-Confused Porphyrinoid Chemistry

Confusion is a novel concept of isomerism in porphyrin chemistry, delivering a steady stream of new chemistry since the discovery of N-confused porphyrin, a porphyrin mutant, in 1994. These days, the number of confused porphyrinoids is increasing, and confusion and associated fusion are found in various fields such as supramolecular chemistry, materials chemistry, biological chemistry, and catalysts. In this review, the birth and growth of confused porphyrinoids in the last three decades are described.

Synthesis of 2-(1-Oxo-2,3-Dihydro-1H-Pyrrolizin-2-yl)-2-(Aryl)Acetonitrile Derivatives Via Michael Addition of Trimethylsilyl Cyanide

Several 2-aryl-2-(1-oxo-2,3-dihydro-1 H-pyrrolizin-2-yl)acetonitrile derivatives were synthesised by Michael addition of ( E)-2-arylidene-2,3-dihydro-1 H-pyrrolizin-1-ones with trimethylsilyl cyanide in the presence of tetrabutylammonium fluoride in moderate yields. The structures of all of the products were fully characterised by NMR, IR and high-resolution mass spectrometry, together with X-ray crystallographic analysis.

Synthesis of 6-Aryl-6H-Chromeno[4’,3’:4,5][1,3]Thiazolo[3,2-A]Benzimidazoles from 2-Aryl-3-Nitro-2H-Chromenes and 1H-Benzimidazole-2-Thiol

A number of 6-aryl-6H-chromeno[4’,3’:4,5][1,3]thiazolo[3,2-a]benzimidazole derivatives were synthesised by the reaction of 2-aryl-3-nitro-2H-chromenes with 1H-benzimidazole-2-thiol in the presence of Cu(OAc)2•H2O in moderate yields via successive C-N and C-S bond formations. The structures of all the products were characterised thoroughly by NMR and HRMS spectroscopy together with X-ray crystallographic analysis.

Synthesis of 2H-Chromene-4-Carbonitriles Via Trimethylsilyl Cyanide

A number of 2-aryl-2 H-chromene-4-carbonitriles were synthesised by cyanation of 2-aryl-3-nitro-2 H-chromenes using trimethylsilyl cyanide (TMSCN) in the presence of tetrabutylammonium fluoride (TBAF) in moderate yields via a Michael addition/elimination pathway. The structures of all the products were characterised thoroughly by NMR, IR and HRMS spectroscopy and X-ray crystallographic analysis.

Synthesis of 3-Cyano-21-Nitro-N-Confused Porphyrin Derivatives by Isoamyl Nitrite

The 3-cyano-21-nitro- N-confused porphyrin derivatives were synthesised by the nitration reaction of 3-cyano- N-confused-porphyrin with isoamyl nitrite at room temperature in moderate yield. The reaction took placed regioselectively in 21-position carbon of inverted pyrrole of N-confused porphyrins.