Synthesis and Antimicrobial Activity of Some New Quinazolin-4(3H)-one Derivatives

Figures & data

Table 1.  Crystallization solvents, melting points, yield percentages, molecular formulas, and molecular weights of compounds 4–24.

Compound	Cryst. solv.	M.P. (°C)	Yield (%)	Mol. Formula (Mol. wt.)
3	DMF	248–50	71	C16H12IN3OS2 (453.32)
4	EtOH	225–27	86	C16H13IN4OS (436.27)
5	EtOH	231–33^a	85^a	C17H15IN4OS (450.3)
6	EtOH	202–04	88	C18H15IN4OS (462.31)
7	EtOH	215–17	85	C22H17IN4OS (512.37)
8	EtOH	197–99	85	C21H15IN4OS (498.34)
9	DMF	221–23^a	90	C23H16IN3O2S2 (557.43)
10	DMF	246–48	92	C23H15BrIN3O2S2 (636.32)
11	DMF	232–34	95	C23H15ClIN3O2S2 (591.87)
12	DMF	208–10	95	C23H15IN4O4S2 (602.42)
13	DMF	197–99	80	C24H18IN3O2S2 (571.45)
14	AcOH	236–38	56	C23H14IN3OS2 (539.41)
15	AcOH	254–56	56	C23H13BrIN3OS2 (586.24)
16	AcOH	239–41	55	C23H13ClIN3OS2 (573.86)
17	AcOH	213–15	50	C23H13IN4O3S2 (584.41)
18	AcOH	207–09	50	C24H16IN3OS2 (553.44)
19	EtOH	240–42	70	C15H12IN5OS (437.26)
20	DMF	274–76	84	C17H14IN5O2S (479.29)
21	DMF	277–79	85	C18H16IN5O2S (493.32)
22	DMF	283–85	83	C23H18IN5O2S (555.39)
23	DMF	288–90	83	C22H16IN5O2S (541.36)
24	DMF	262–64	80	C23H18IN5O2S (555.39)

^aReported: 246–48 °C, 68% (Sami, 2001).

Scheme 1.  Reagents: a, CS₂/KOH; b,(CH₃)₂SO₄; c, RNCS/C₂H₅OH; d, ArCOCH₂X/(CH₃)₂CHOH; e, C₂H₅ONa/C₂H₅OH; f, NH₂NH₂.H₂O/C₂H₅OH; g, RCOC1/pyridine.

Table 2.  Antimicrobial activity of compounds (200 μ g/8 mm disk), the broad-spectrum antibacterial drug ampicillin trihydrate (100 μ g/8 mm disk) and the antifungal drug Clotrimazole (100 μ g/8 mm disk) against S. aureus ATCC 19433 (SA), B. subtilis ATCC 6633 (BS), E. coli ATCC 25922 (EC), P. aeruginosa ATCC 27853 (PA), and C. albicans ATCC 753 (CA).

	Diameter of growth inhibition zone (mm)^a
Compound	SA	BS	EC	PA	CA
1	10	13	10	10	10
2	10	–	–	–	–
3	12	–	–	–	–
4	22	22	18	17	15
5	21	21	16	13	12
6	21	20	14	13	12
7	11	10	10	9	–
8	11	10	10	9	9
9	10	–	–	–	–
10	9	–	–	–	–
11	11	–	–	–	–
12	11	–	–	–	–
13	10	–	–	–	–
14	11	–	–	–	–
15	11	–	–	–	–
16	11	–	–	–	–
17	9	–	–	–	–
18	8	–	–	–	–
19	22	21	15	13	12
20	22	22	16	17	18
21	22	22	18	16	18
22	20	20	15	13	12
23	15	13	9	–	–
24	20	20	15	13	13
Ampicillin	22	22	25	19	NT
Clotrimazole	NT	NT	NT	NT	23

^a(–), inactive, no inhibition zone. (NT), not tested.

Table 3.  The minimal inhibitory concentrations (MIC, μg/mL) of indicated compounds, the broad spectrum antbacterial drug ampicillin trihydrate, and the antifungal drug clotrimazole against S. aureus ATCC 19433 (SA), B. subtilis ATCC 6633 (BS), E. coli ATCC 25922 (EC), P. aeruginosa ATCC 27853 (PA) and C. albicans ATCC 753 (CA).

	MIC μ g/mL)
Compound	SA	BS	EC	PA	CA
4	12.5	12.5	50	100	100
5	25	100	100	200	200
6	50	50	200	200	400
19	50	100	200	200	200
20	50	50	400	200	400
21	12.5	12.5	50	50	200
22	50	50	200	200	200
24	50	50	200	200	400
Ampicillin	< 6.25	< 6.25	< 6.25	< 6.25	NT
Clotrimazole	NT	NT	NT	NT	12.5

NT, not tested.

G A Sami. (2001). Synthesis of some new substituted quinazoline derivatives and their antimicrobial screening. SPJ 9:72–84.

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