Antibiotic compounds

A compound of structural formula I:

• or a pharmaceutically acceptable salt, ester, enantiomer, diastereomer diasteriomer or mixture thereof,
• wherein:
• R independently represents hydrogen or C1-12 alkyl;
• R1 represents hydrogen, C1-6 alkyl, C3-6 cycloalkyl, or —(CH2)nC5-10 heterocyclyl;
• R2 represents R1 OR1;
• R3 represents —C(O)NR5R6, —C(O)NHC(R7R8)C(O)NR5R6 or C(O)OR5;
• R4 represents
• R4a represents C1-12 alkyl, C(O)H, C(O)C1-12 alkyl, —C(R5)2C5-10 heterocyclyl, —COOR, —(CH2)nC(O)NR5R6, —(CH2)nNR5R6, —(CH2)nC5-10 heterocyclyl, or —(CH2)nP(O)(OR)2, said heterocyclyl optionally substituted with one or more groups of Ra;
• said alkyl optionally substituted with 1 to 6 hydroxy and/or optionally substituted by one or more groups of Ra,
• R5 and R6 independently represent hydrogen, C1-12 alkyl, —(CH2)nC(═CH2)C(O)NH2, —(CH2)nC(═CH2)CN, —(CH2)nC5-10 heterocyclyl, —(CH2)nNR7R8, CHO, —(CH2)nNR(CH2)nNR7R8, —(CH2)nNR(CH2)nC5-10 heterocyclyl, —(CH2)nC6-10 aryl, —(CH2)n(O(CH2)2)1-6R9, or —(CH2)nNHC(O)(CH2)nNR7R8, said aryl, and heterocyclyl optionally substituted with one or more groups of Ra;
• said alkyl optionally substituted with 1 to 6 hydroxy and/or optionally substituted by one or more groups of Ra;
• or
• R5 and R6 together with the nitrogen atom they are attached form a 5 to 10 heterocyclic ring optionally containing 1 to 2 additional heteroatoms selected from the group consisting of N, S and O and optionally substituted with one or more groups of Ra;
• R7 and R8 independently represent hydrogen, —(CH2)nNR5R6, —(CH2)nSR5;
• or —(CH2)nC5-10 heterocyclyl said heterocyclyl optionally substituted with one or more groups of Ra;
• said alkyl optionally substituted with 1 to 6 hydroxy and/or optionally substituted by one or more groups of Ra;
• R9 represents hydrogen, C1-6 alkyl, (CH2)nC5-10 heterocyclyl, or —C(O)OR, CN, OR, said alkyl and heterocyclyl optionally substituted with one or more groups of Ra
• Ra represents hydrogen, halogen, (CH2)nOR, CF3, (CH2)nC(O)OR, (CH2)nC(O)NR7R8, (CH2)nC5-10 heterocyclyl, SO2NR5R6, (CH2)C6-10 aryl, N(R)2, NO2, CN, (C1-6 alkyl)O—, (aryl)O—, (C1-6 alkyl)S(O)0-2—, or C1-12 alkyl, said alkyl, heterocyclyl, and aryl optionally substituted with 1 to 4 groups selected from the group consisting of C1-6 alkyl, (CH2)nOR, (CH2)nN(R)2, and —O—;
• and
• n represent 0-6, and p represents 0, 1 or 2.