Antimicrobial compounds, compositions, and method

A compound having the formula (I) or a pharmaceutically acceptable salt thereof:

• wherein,
• R1 is H or lower alkyl;
• W, Y, and Z are independently selected from H,
• and OR3, so long as only one of W, Y, and Z is
• and R2 and R3 are each independently selected from H or lower alkyl;
• and
• X is H, NO2, N(R4)2, or SO2R5 where R4 is H or lower alkyl, and R5 is H or lower alkyl;
• provided that, where R1 is lower alkyl, W is OR3, R3 is lower alkyl, Y is H, and Z is
• (i) when R2 is H;
• then X is H, NO2, N(R4)2, or SO2R5 where R4 is H or lower alkyl, and R5 is H or lower alkyl;
• and
• (ii) when R2 is lower alkyl;
• then X is N(R4)2 or SO2R5 where R4 is lower alkyl, and R5 is H or lower alkyl.