**2. Chemistry**

*Quinazolinone and Quinazoline Derivatives*

**108**

**Figure 1.**

*Biological active drugs containing quinazoline and quinazolinone.*

The chemistry of quinazolines was reviewed by a scientist, Williamson in 1957 and then by Lindquist in 1959 and brought up to date by Armarego in 1963. Quinazolines is stable in cold dilute acid and alkaline solutions, but it is destroyed when these solutions are boiled. *O*-Amino benzaldehyde, ammonia, and formic acid are formed when quinazoline is boiled with hydrochloric acid.

### **2.1 Experimental methods quinazoline based Schiff bases**

Melting points were determined in open capillary tubes and are uncorrected. FT-IR spectra were recorded in KBr pellets on a Perkin-Elmer [8201] spectrometer. 1H NMR spectra were recorded on a Gemini 300-MHz instrument in DMSO-d6 as the solvent and TMS was used as an internal standard. The mass spectra were recorded on SHIMADZU (GCMS-QP 1000 EX) GC-EI-MS spectrometer. Elemental analyses were performed on a Perkin-Elmer 240 CHN elemental analyzer. Purification of the compound was indicated using TLC (ethyl acetate/cyclohexane (0.25 mL:0.25 mL, v/v) as the mobile phase).

#### **2.2 Procedure for preparation of quinazoline based Schiff bases**

In 50 mL of round bottom flask, mixture of 3-amino-2-methyl-3H-quinazolin-4-one (0.01 M) and substituted acteonaphthanones (0.01 M) was dissolved in ethyl alcohol (15 mL). To this reaction mixture acetic acid (0.001 M) was added and resultant reaction mixture was refluxed for 2–3 h. On completion of reaction as monitored by TLC (ethyl acetate:cyclohexane, 0.25 mL:0.25 mL, v/v as the mobile phase) the reaction mixture was work-up using cold water to obtained crud solid product. The separated solid was filtered and recrystallized from ethanol to yield pure Schiff's bases.

• (E)-3-((1-(1-hydroxy-4-iodonaphthalen-2-yl)ethylidene)amino)-2 ethylquinazolin-4(3H)-one.

Appearance: light yellow solid, FT-IR (KBr, ν, cm<sup>−</sup><sup>1</sup> ): 3237, 3065, 2925, 1775, 1628, 1547, 1465, 815, 668. <sup>1</sup> H NMR (300 MHz, DMSO-*d*6, δ, ppm): 12.5 (s, 2H, OH), 6.69–8.29 (m, 9H, ArH), 3.26 (s, 3H, CH3)2.61 (s, 3H, CH3). (MS, EI) *m/z* (%): 453 (M+, 57%).

• (E)-3-((1-(4-bromo-1-hydroxynaphthalen-2-yl)ethylidene)amino)- 2-methylquinazolin-4(3H)-one.

Appearance: light yellow solid, FT-IR (KBr, ν, cm<sup>−</sup><sup>1</sup> ): 3242, 3068, 2933, 1772, 1630, 1549, 1460, 818, 663. <sup>1</sup> H NMR (300 MHz, DMSO-*d*6, δ, ppm): 12.5 (s, 2H, OH), 6.67–8.29 (m, 9H, ArH), 3.26 (s, 3H, CH3)2.61 (s, 3H, CH3). (MS, EI) *m/z* (%): 406 (M+, 69%).

• (E)-3-((1-(4-chloro-1-hydroxynaphthalen-2-yl)ethylidene)amino)- 2-methylquinazolin-4(3H)-one.

Appearance: light yellow solid, FT-IR (KBr, ν, cm<sup>−</sup><sup>1</sup> ): 3247, 3063, 2935, 1774, 1632, 1544, 1462, 816, 665. <sup>1</sup> H NMR (300 MHz, DMSO-*d*6, δ, ppm): 12.5 (s, 2H, OH), 6.68–8.29 (m, 9H, ArH), 3.27 (s, 3H, CH3)2.61 (s, 3H, CH3). (MS, EI) *m/z* (%): 361.5 (M+, 65%).

• (E)-3-((1-(1-hydroxynaphthalen-2-yl)ethylidene)amino)- 2-methylquinazolin-4(3H)-one.

Appearance: light yellow solid, FT-IR (KBr, ν, cm<sup>−</sup><sup>1</sup> ): 3242, 3067, 2937, 1773, 1635, 1546, 1465, 818, 667. <sup>1</sup> H NMR (300 MHz, DMSO-*d*6, δ, ppm): 12.5 (s, 2H, OH), 6.68–8.29 (m, 10H, ArH), 3.25 (s, 3H, CH3)2.62 (s, 3H, CH3). (MS, EI) *m/z* (%): 327(M+, 64%).
