A convenient synthesis of functionalized tetraphenylchlorins
Abstract
Reaction of metallo-2-nitro-5,10,15,20-tetraphenylporphyrins with ‘active-methylene’ compounds (e.g. malonates, malononitriles) in the presence of base gives access to novel cyclopropachlorins or functionalized trans-chlorins (both characterized by X-ray crystallography) by way of a sequential Michael addition and rare nucleophilic displacement of a secondary nitro group.