A facile synthesis and antibacterial activity of novel pyrrolo[3,4-b]quinolin-2(3H)-yl)benzamides

Figures & data

Figure 1. Some important pyrrolo[3,4-b]quinoline-containing drugs.

Scheme 1. Synthetic route for the synthesis of pyrrolo[3,4-b]quinolin-2(3H)-yl)benzamide derivatives.

Table 1. Synthesis of pyrrolo[3,4-b]quinolin-2(3H)-yl)benzamides 9a–g.

Entry	Product	Yield (%)	Time (min)
1		95	110
2		90	60
3		92	120
4		93	90
5		87	60
6		84	60
7		87	90

Table 2. Antibacterial activity of 9a–g determined by measuring the diameter of inhibition zone.

Compound	Zone of inhibition (mm)
	Enterococcus			Staphylococcus			Escherichia coli
Conc. in mg/disc	0.5	0.25	0.125	0.5	0.25	0.125	0.5	0.25	0.125
9a	11	10	08	10	12	10	08	12	10
9b	10	09	09	09	11	09	10	11	08
9c	08	10	08	09	11	10	08	10	09
9d	07	10	08	09	10	09	07	10	08
9e	09	07	07	10	07	07	10	09	07
9f	09	10	08	08	11	09	09	10	08
9g	08	10	08	08	10	08	08	10	07
DMSO^a	00			00			00
PE^b	10			12			15
S^c	11			13			12

^aDMSO: dimethyl sulfoxide.

^bPE: Penicillin.

^cS: streptomycin.

Figure 2. The experimental methodology to perform twofold serial dilution with solid modification. The procedure involves preparing twofold dilutions of the antimicrobial agent (e.g. 0.125, 0.25, 0.5, 1 and 2 mg/mL) in a MHA dispensed in 6-well plate (step 1 and 2). Then, each well is inoculated with a microbial inoculum prepared adjusted to 2 McFarland scale (step 3). After well-mixing, the inoculated 6-well plate are incubated at ∼37°C for 24 h.

Figure 3. Growth inhibition effect of compound 9a. The experiments were carried out in triplicate and error bars indicate standard error of the mean.