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On-water synthesis of dipyrromethanes via bis-hetero-diels–alder reaction of Azo- and Nitrosoalkenes with Pyrrole

Publication . Pinho e Melo, Teresa; Lemos, Americo; Pereira, Nelson; Lopes, Susana

An unprecedented one-pot approach to 5-substituted dipyrromethanes based on the hetero-Diels-Alder reaction of azo- and nitrosoalkenes is described. The on-water reaction conditions led to the target compounds in higher yields with significantly shorter reaction times and simpler purification procedures than carrying out the reaction in dichloromethane or in the absence of solvent.

2013Journal article

Open access

Synthesis and anti-cancer activity of chiral tetrahydropyrazolo[1,5-a] pyridine-fused steroids

Publication . Lopes, Susana M. M.; Sousa, Emanuel P.; Barreira, Luísa; F. Marques, C.; Rodrigues, Maria João; Pinho e Melo, Teresa M. V. D.

Regio-and stereoselective synthesis of novel chiral 4,5,6,7-tetrahydropyrazolo [1,5-a]pyridine fused steroids via [8 pi + 2 pi] cycloaddition of diazafulvenium methides with steroidal scaffolds is reported. The biological evaluation of the new family of hexacyclic steroids as anti-cancer agents was also carried out. Hexacyclic steroids bearing a benzyl group at C-22, derived from 16-dehydropregnenolone and 16-dehydroprogesterone, show considerable cytotoxicity against EL4 (murine T-lymphoma) in contrast with the corresponding C-22-unsubstituted derivatives showing low cytotoxicity. Thus, results indicate that the presence of the benzyl group is important to ensure cytotoxicity.

2017-06Journal article

Restricted access