Antibacterial compounds, pharmaceutical compositions, and methods of treating bacterial infections

A compound according to Formula (II):

• wherein R3, R4, R5, and R6 are each independently selected from the group consisting of an electron pair, H, OH, protected hydroxyl, alkyl, alkenyl, alkynyl, acyl, aryl, heteroaryl, cycloalkyl, phenyl, carbonate ester, a carboxylate, a carboxyl, an ester, a hydroperoxy, a peroxy, an ether, a hemiacetal, a hemiketal, an acetal, a ketal, an orthoester, a methylenedioxy, an orthocarbonate ester, carboxamide, an amine, an imine, an amide, an azide, an azo, a cyanate, a nitrate, a nitrile, an isonitrile, a nitrosooxy, a nitro, a pyridyl, a thiol, a sulfide, sulfinyl, a sulfonyl, a thiocyanate, a carbonothioyl, a phosphate, and heterocycle;
• optionally wherein the alkyl, alkenyl, alkynyl or acyl is substituted with one or more substituents independently selected from the group consisting of halogen, —OH, alkyl, —O-alkyl, NRARB, —S-alkyl, —SO-alkyl, —SO2-alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, and heterocycle;
• wherein RA and RB are each independently selected from hydrogen and C1-4 alkyl;
• wherein X is C or S;
• or a pharmaceutically acceptable salt or ester thereof.