Table 17. Chemical Structures and Observed MIC Values against the AcrAB-TolC Efflux Pump Overexpressor E. coli AG102 Strain of 2-Substituted Benzothiazoles 52a–n.

compd	R	X	Y	MIC (μg/mL)a	E. coli AG102 combination with CIP	MIC (μg/mL)b
ciprofloxacin (15, CIP)				0.125
52a	H			256	CIP + 24a	0.03
52b	OCH2(CH2)C2H5			64	CIP + 24b	0.5
52c	C2H5			128	CIP + 24c	0.016
52d	OCH3		CH2	256	CIP + 24d	0.008
52e	F		CH2	128	CIP + 24e	0.03
52f	CH3		CH2	512	CIP + 24f	0.004
52g	H		CH2	256	CIP + 24g	0.125
52h	F	CH2	CH2	256	CIP + 24h	0.03
52i	F	CH2		128	CIP + 24i	0.03
52j	Br	CH2		128	CIP + 24j	0.03
52k	NO2	CH2		128	CIP + 24k	0.06
52l	C2H5	CH2		64	CIP + 24l	0.06
52m	H	CH2		256	CIP + 24m	0.016
52n	H		C2H4	512	CIP + 24n	0.004

^aObserved MIC values of compounds tested alone.

^bObserved MIC values of CIP tested in combination with each compound.