Studies on the synthesis of orthogonally protected azalanthionines, and of routes towards β-methyl azalanthionines, by ring opening of N-activated aziridine-2-carboxylates
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 β-methyl azalanthionines have, so far, been unsuccessful.
Studies on the synthesis of orthogonally protected azalanthionines, and of routes towards β-methyl azalanthionines, by ring opening of N-activated aziridine-2-carboxylates
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 β-methyl azalanthionines have, so far, been unsuccessful.
Efficient "One-Pot" Synthesis of N-Trityl Amino Acids
A sequential procedure has been developed whereby neutral amino acids 1 were tritylated via their corresponding trimethylsilyl esters 2 to afford, after mild hydrolysis, N-trityl amino acids 3 in high yields and purity.Hydroxy amino acids 4 were preferent