A series of 9-(acylamino)doxycycline derivatives has been prepared. These analogs exhibit good activity against both tetracycline sensitive and tetracycline resistant Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria that are encoded with the efflux and ribosomal resistance gene factors. N,N-Dialkylglycylamido derivatives possessed the highest activity. Replacement of glycine moiety with other amino acids did not further enhance the activity.
α-Azido Esters in Depsipeptide Synthesis: C–O Bond Cleavage during Azido Group Reduction
作者:Chuda Raj Lohani、Jacob Soley、Braden Kralt、Michael Palmer、Scott D. Taylor
DOI:10.1021/acs.joc.6b02309
日期:2016.12.2
these cases, C–O bondcleavage occurred via either triazole formation and/or hydrolysis of the ester bond in the iminophosphorane intermediate to give betaines. The mechanism that dominated for C–O bondcleavage depended upon the phosphine that was used for azido group reduction. C–O bondcleavage during reduction of the azido group in the peptide was minimized by performing the reduction with PBu3 in