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.
Cyclic peptides as selective tachykinin antagonists
作者:Brian J. Williams、Neil R. Curtis、Alexander T. McKnight、Janet J. Maguire、Stephen C. Young、Daniel F. Veber、Raymond Baker
DOI:10.1021/jm00053a001
日期:1993.1
Twenty homodetic cyclic peptides based on the C-terminal sequence of substance P were prepared (Table I) by a combination of solid-phase techniques and cyclizations using azide coupling Incorporation of dipeptide mimics based on substituted gamma-lactams were used in some cases to restrict their conformational mobility. Five of these cyclic peptides were shown to have high tachykinin antagonist activity (pA2 > 6) at NK-2 receptors (rat vas deferens). The two most potent of this series, XVII, cyclo(Gln-Trp-Phe-Gly-Leu-Met) (pA2 = 8.1), and I cyclo(Gln-Trp-Phe-(R)Gly[ANC-2]Leu-Met) (pA2 = 6.7), were selective for NK-2 receptors compared with the other tachykinin receptors (Table II).