Table 5.

One-pot three-component synthesis and antibacterial activity of coumarin substituted thiazolyl-3-aryl-pyrazole-4-carbaldehydes 25.

Compound	R	R1	R2	Yield 25 (%)	MIC (μg/mL)
					EC	KP	PV	MRSA	BS	BC
25a	H	H	H	84	135	150	133	150	132	145
25b	H	Cl	H	80	134.6	129	130	150	129.5	138.6
25c	Cl	Cl	H	75	119.6	118	131.5	115	123	117
25d	H	Br	H	80	118.1	116.8	124	116	125	129
25e	Br	Br	H	85	115.6	119	120	116.8	118	119
25f	H	Benzo	H	78	132.8	150	150	135	122.8	138.9
25g	H	Cl	Cl	77	126.3	117.4	130.7	134	112.2	110.8
25h	Cl	Cl	Cl	73	110.9	105	113	112.5	110.7	112
25i	H	Br	Cl	83	117.5	115	127.5	122.9	119.7	115
25j	MeO	H	Cl	82	125.3	129	132.3	139	132.6	126
25k	H	H	Me	77	132.5	150	150	150	150	135
25l	H	Br	Me	82	134.6	124	121.8	138.1	125	126
25m	Cl	Cl	Me	81	101.3	100.9	105	115.6	98.2	100.1
25n	Br	Br	Me	85	86.5	79.1	100.7	105.9	92.4	72.8
25o	MeO	H	Me	82	132.7	150	142	150	150	136
Gentamycin b	--	--	--	--	2	4	4	22	45	10
Ampicillin b	--	--	--	--	10	-- c	-- c	4	5	4

^a Reaction conditions: 3-(2-bromoacetyl)coumarin derivative 22 (1 mmol), thiosemicarbazide 23 (1 mmol), substituted acetophenone 24 (1 mmol), DMF (5 mL), POCl₃ (5 mmol), 0–60 °C, 5–6 h. ^b Positive control for the study. ^c Not determined. EC (Escherichia coli), KP (Klebsiella pneumoniae), PV (Proteus vulgaris), MRSA (Methicillin-resistant Staphylococcus aureus), BS (Bacillus subtilis), and BC (Bacillus cereus).