abstract
A novel sapphyrin derivative was obtained from the reaction between a free-base sapphyrin and dimethyl acetylenedicarboxylate (DMAD). The formation of the new compound involved a double aza-Michael addition of two pyrrolic NH groups to a DMAD molecule, with the formation of a disubstituted ethano bridge. The NMR spectral data reveal a product with an unsymmetrical structure; DFT calculations provided support for a structure in which the ethano bridge links two adjacent pyrrole units. The present study provides a seemingly unprecedented example of an N,N'-dinucleophile reacting with DMAD to form a heterocyclic compound in which the two N-atoms are linked to the two sp(3) carbon atoms derived from a substituted acetylene.
keywords
1,3-DIPOLAR CYCLOADDITION REACTIONS; DIELS-ALDER REACTIONS; BARRELENE-FUSED CHLORINS; EXPANDED PORPHYRINS; DIMETHYL ACETYLENEDICARBOXYLATE; MESO-TETRAARYLPORPHYRINS; PHOTOPHYSICAL PROPERTIES; AZOMETHINE YLIDES; ORGANIC-SYNTHESIS; O-XYLYLENE
subject category
Chemistry
authors
Figueira, F; Marques, I; Farinha, ASF; Tome, AC; Cavaleiro, JAS; Silva, AMS; Sessler, J; Felix, V; Tome, JPC
our authors
Flávio Alberto da Silva Figueira
Junior Researcher
Igor Oliveira Marques
Junior Researcher
Vítor Félix
Associate Professor with Aggregationacknowledgements
Thanks are also due to FCT/MEC for financial support to the QOPNA (FCT UID/QUI/00062/2013), CICECO-Aveiro Institute of Materials (FCT UID/CTM/50011/2013), iBiMED - Institute of Bio-medicine (FCT UID/BIM/04501/2013) and CQE (FCT UID/QUI/0100/2013) research units through national funds and, when applicable, co-financed by FEDER, within the PT2020 Partnership Agreement, and also to the Portuguese NMR Network. The work in Austin was supported by the National Science Foundation (grant CHE-1402004) and the Robert A. Welch Foundation. F. F. and I. M. thank FCT for their doctoral fellowships SFRH/BD/46788/2008 and SFRH/BD/87520/2012, respectively. The authors are also grateful to Dr. Monica Valega for help with the HPLC experiments.