Comment on "An unexpected formation of the novel 7-oxa-2-azabicyclo[2.2.1]hept-5-ene skeleton during the reaction of furfurylamine with maleimides and their bioprospection using a zebrafish embryo model" by C. E. Puerto Galvis and V. V. Kouznetsov, Org. Biomol. Chem., 2013, 11, 407Electronic supplementary information (ESI) available: X-ray description for single-crystals 6c and 6h, detailed synthetic procedures and spectral data for compounds 6. CCDC 1547011 and 1547012. For ESI and crystallogra

It has been proved that the reaction between furfuryl amines and N -R-maleimides leads to the formation of aza-Michael addition products - 3-(furylmethylamino)- N -R-pyrrolidine-2,5-diones, instead of 7-oxa-2-azabicyclo[2.2.1]hept-5-enes, as this journal reported previously. It has been proved that the reaction between furfuryl amines and N -R-maleimides leads to the formation of aza-Michael addition products - 3-(furylmethylamino)- N -R-pyrrolidine-2,5-diones, instead of 7-oxa-2-azabicyclo[2.2.1]hept-5-enes, as this journal reported previously.