# Synthesis and Biological Studies of New 2-Benzoxazolinone Derivatives as Antibacterial Agents
## 2 Materials and Methods
### General Procedure for the Preparation of Hydrazones 8-23
#### 2.3.1 \(N^{\prime}\)-Benzylidene-3-(2-oxobenz[d]oxazol-3(2\(h\))-yl)propanehydrazide (8)
\(N^{\prime}\)-(4-(Dimethylamine)benzylidene)-3-(2-oxobenzo[d]oxazol-3(2\(H\))-yl) propanehydrazide **(16)** Yield 0.43 g (88%), mp 188-190 \({}^{\circ}\)C; \({}^{1}\)H-NMR (400 MHz): $ 2.67, 3.06 (2t, 2H, \(J=6.7\), 6.9 Hz, CH2 CO), 2.94 (s, 6H, N(CH3)), 4.06-4.15 (m, 2H, CH2N), 6.55-6.85 (m, 2H, Har), 7.11 (t, 1H, \(J=7.7\) Hz, Har), 7.17-7.53 (m, 5H, H, Har), 7.80, 7.93 (2s, 1H, N=CH), 11.11 (s, 0.65H, NH), 11.17 (s, 0.35H, NH); \({}^{13}\)C-NMR (101 MHz): $ 30.43, 32.31, 38.03, 38.39.75 (CH2 CO, CH2N, 2 CH3), 109.41, 109.55, 109.61, 111.73, 121.38, 121.45, 122.10, 123.80, 127.99, 128.35, 130.99, 141.95, 141.98, 144.14, 147.23. 151.27, 151.46, 153.60, 165.33, 171.18 (C\({}_{\rm ar}\), N=CH, CO);IR (KBr): \(\
u_{\rm max}\) = 3166, 3061 (NH), 1761 (C=O), 1666 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{19}\)H\({}_{20}\)N\({}_{4}\)O\({}_{3}\) (352.39), %: C, 64.76; H, 5.72; N, 15.90. Found: C, 64.53; H, 5.52; N, 15.73. 2.3.10. N\({}^{\prime}\)-(2-Chloro-5-nitrobenzylidene)-3-(2-oxobenzo[d]oxazol-3(2\(H\))-yl) propanehydrazide (17)  
Yield 0.44 g (82%), mp 202-204 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): \(\delta\) 2.76, 3.15 (2t, 2H, \(J\) = 5.8 Hz, CH\({}_{2}\)CO), 4.01-4.25 (m, 2H, CH\({}_{2}\)N), 6.98-7.38 (m, 4H, Har), 7.78 (t, 1H, \(J\) = 8.1 Hz, H\({}_{\rm Ar}\)), 8.18 (t, 1H, \(J\) = 9.8 Hz, H\({}_{\rm Ar}\)), 8.30, 8.42, 8.46, 8.57 (4s, 2H, H\({}_{\rm Ar}\), N=CH), 11.77 (s, 0.65H, NH), 11.93 (s, 0.35H, NH);  
\({}^{13}\)C-NMR (101 MHz): \(\delta\) 30.32, 32.34, 37.95, 38.08 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 109.39, 109. 57, 120.29, 121.97, 122.16, 123.74, 123.82, 124.91, 130.92, 131.45, 132.69, 137.52, 138.77, 141.88, 146.66, 153.57, 166.57, 172.28 (C\({}_{\rm Ar}\), N=CH, CO);  
IR (KBr): \(\
u_{\rm max}\) = 3104, 3085 (NH), 1778 (C=O), 1674 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{17}\)H\({}_{13}\)CIN\({}_{4}\)O\({}_{5}\) (388.76), %: C, 52.52; H, 3.37; N, 14.41. Found: C, 52.35; H, 3.13; N, 14.23. 2.3.11. 3-(2-Oxobenzo[d]oxazol-3(2\(H\))-yl)-\(N^{\prime}\)-(2,3,4-trimethoxybenzylidene) propanehydrazide (18)  
Yield 0.43 g (77%), mp 150-154 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): \(\delta\) 2.68, 3.07 (2t, 2H, \(J\) = 6.8 Hz, CH\({}_{2}\)CO), 3.75, 3.78, 3.80, 3.82, 3.83 (5s, 9H, 3 OCH\({}_{3}\)), 4.04-4.18 (m, 2H, CH\({}_{2}\)N), 6.82, 6.89 (2d, 1H, \(J\) = 8.9 Hz, H\({}_{\rm Ar}\)), 7.11, 7.22 (2t, \(J\) = 7.8 Hz, H\({}_{\rm Ar}\)), 7.25-7.36 (m, 2H, H\({}_{\rm Ar}\)), 7.39, 7.51 (2d, 2H, \(J\) = 8.8 Hz, H\({}_{\rm Ar}\)), 8.12, 8.25 (2s, 1H, N=CH), 11.27 (s, 0.60H, NH), 11.41 (s, 0.40H, NH);  
\({}^{13}\)C-NMR (101 MHz): \(\delta\) 30.42, 32.32, 38.00, 38.30 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 55.98, 60.46, 61.71, 108.62, 108.67, 109.43, 109.54, 120.22, 121.11, 123.81, 130.97, 139.17, 141.51, 141.96, 152.38, 152.50, 153.59, 154.87, 155.11, 165.63, 171.50 (C\({}_{\rm Ar}\), N=CH, CO);  
IR (KBr): \(\
u_{\rm max}\) = 3181, 3069 (NH), 1778 (C=O), 1671 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{20}\)H\({}_{21}\)N\({}_{3}\)O\({}_{6}\) (399.40), %: C, 60.14; H, 5.30; N, 10.52. Found: C, 59.95; H, 5.13; N, 10.34. 2.3.12. 3-(2-Oxobenzo[d]oxazol-3(2\(H\))-yl)-\(N^{\prime}\)-(3,4,5-trimethoxybenzylidene) propanehydrazide (19)  
Yield 0.46 g (82%), mp 192-194 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): \(\delta\) 2.72, 3.10 (2t, 2H, \(J\) = 6.7 Hz, CH\({}_{2}\)CO), 3.68, 3.80 (2s, 9H, 3 OCH\({}_{3}\)), 4.05-4.23 (m, 2H, CH\({}_{2}\)N), 6.92, 6.95 (2s, 2H, H\({}_{\rm Ar}\)), 7.06-7.34 (m, 4H, H\({}_{\rm Ar}\)), 7.81, 8.02 (2s, 1H, N=CH), 11.40 (s, 0.60H, NH), 11.45 (s, 0.40H, NH);  
\({}^{13}\)C-NMR (101 MHz): \(\delta\) 30.47, 32.24, 38.26 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 55.90, 55.93, 60.10, 104.02, 104.24, 109.29, 109.52, 109.57, 109.62, 122.09, 122.14, 123.75, 123.82, 129.54, 130.96, 128.96, 141.93, 141.97, 143.29, 146.40, 153.12, 153.14, 153.62, 165.95, 171.86 (C\({}_{\rm Ar}\), N=CH, CO);  
IR (KBr): \(\
u_{\rm max}\) = 3190, 3045 (NH), 1766 (C=O), 11,677 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{20}\)H\({}_{21}\)N\({}_{3}\)O\({}_{6}\) (399.40), %: C, 60.14; H, 5.30; N, 10.52.