Studies on the synthesis of orthogonally protected azalanthionines, and of routes towards β-methyl azalanthionines, by ring opening of N-activated aziridine-2-carboxylates
                                
                                    
                                        作者:Keith O'Brien、Keith ó Proinsias、Fintan Kelleher                                    
                                    
                                        DOI:10.1016/j.tet.2014.06.011
                                    
                                    
                                        日期:2014.8
                                    
                                    Orthogonally protected azalanthionines were successfully synthesised by the ring-opening of N-activated aziridine-2-carboxylates with protected diaminopropanoic acids (DAPs). The required DAPs were also prepared by ring-opening of N-activated aziridine-2-carboxylates with para-methoxybenzylamine, but it was found that the choice of aziridine protecting groups dictated both the success of the reaction as well as the regioselectivity of the isolated products. Attempts to extend the methodology to the preparation of the more sterically demanding beta-methyl azalanthionines have, so far, been unsuccessful. (C) 2014 Elsevier Ltd. All rights reserved.