70686-42-9Relevant academic research and scientific papers
Reductive Ring Opening of N-Benzoylaziridine by Anthracene Hydride (Anion of 9,10-Dihydroanthracene) via Base-Induced Fragmentation of the Intermediate Carbonyl Adduct
Stamm, Helmut,Mall, Thomas,Falkenstein, Reinhard,Werry, Juergen,Speth, Dieter
, p. 1603 - 1607 (2007/10/02)
As previously reported reaction of anthracene hydride (AH-) or of its oxa analogue xanthenyl anion (X-), with N-benzoylaziridines 1a,b can result in amidoethylation (2a,b and 3a,b) of the carboanion, in reductive opening (4a,b) of the aziridine ring, and in attack on the carbonyl group of 1a,b.We now show with 1a that both the rate of ring opening and the amount of reductive opening are significantly enhanced by an excess of AH-Li+ while the initially formed (90percent) carbonyl adduct 6a survives with a defict of AH-Li+.Both effects due to carbanion excess are absent with X-Li+ but are much stronger with AH-Na+.These results point to a rapid process that is triggered off by deprotonation at position 10 of the carbonyl adduct 6.A concerted or subsequent homolytic fragmentation is proposed to generate the ketyl 5 of 1, followed by homolytic ring opening of 5 to yield the radical 12, which is reduced to the carbanion 14.The latter forms 4 by capturing a proton from dihydroantracene.Inaccessibility of reductive ring opening for a trialkylacetyl-activated aziridine is demonstrated again (18).
Reactions with Aziridines, 45. - Arene Hydrides, 5 Reversibility of Carbonyl Attack on N-Benzoylaziridines Prior to Ring Opening by Carbanions. - Strong Influence of the Gegen Ion
Mall, Thomas,Stamm, Helmut
, p. 1349 - 1352 (2007/10/02)
A previous report had shown that anthracene hydride AH- or the xanthenyl anion X-, respectively, at first add to the carbonyl group of N-benzoylaziridines since high yields of benzoyl dihydroanthracene 3 or benzoyl xanthene 11 were obtained when in early stages the reaction was quenched with protons.The respective intermediate carbonyl adducts 2 and 10 had been considered to be precursors of products resulting from homolysis of the aziridine ring.It is now shown that quenching of the reaction between AH- or X- and N-benzoylaziridines 1a, b with methyl iodide or aroyl chlorides results in substantial yields of products derived from either AH- (or X-) or 1a,b.This indicates that 2 (or 10) are in equilibrium with AH- (or X-) and 1a, b.Study of the gegen ion influence with X- revealed that the equilibrium concentrations of 10-Na+ were much lower than those of 10-Li+ while simultaneously the ring opening of 1a was distinctly faster with X-Na+ than with X-Li+.This finding suggests that, contrary to the previous assumption, the equilibrium concentrations, of X- and 1a are responsibile for the (homolytic) ring opening.
