Patent ID: 8889826

Claim:
An antibiotic compound of the formula: or a pharmaceutically acceptable salt thereof, wherein: A is selected from R′—(C═O)-(p-aminophenylacetyl)-, R′—(C═O)-Lys-, R′—(C═O)-Phe-, R′—NH—(C═O)—, R′—NH(C═S)—, R′—SO 2 —, R′—(C═NH)—, R′—O—CH 2 —(C═O)—, R′—, R′-alkyl, R′—P(O)OH, R′—O—(C═S)—, R′—NH—(C═NH)—, and R′—(C═S)—; R′ is selected from aryl, heteroaryl, alkyl, alkenyl, heterocyclyl and cycloalkyl, wherein each aryl, heteroaryl, alkyl, alkenyl, heterocyclyl and cycloalkyl is optionally substituted with one or more groups selected from halogen, (C 1 -C 20 ) alkyl, aryl, heteroaryl and aryloxy; x and y are each independently 0 or 1; z is 1; X1 is selected from Dab, Phe, Ala, Lys and Gly; X2 is Thr; X3 is Dab; and R 6 , R 7 and R 10 are each independently selected from isopropyl, benzyl, isobutyl, sec-butyl, 1-hydroxy-1-ethyl, and hydroxymethyl.