# 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)
Found: C, 59.90; H, 5.09; 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 Anal. Calcd for C\({}_{15}\)H\({}_{13}\)N\({}_{3}\)O\({}_{3}\)S (315.35), %: C, 57.13; H, 4.16; N, 13.33. Found: C, 56.87; H, 3.85; N, 13.08. 2.3.14. \(N^{\prime}\)-((5-Nitrotiiophen-2-yl)methylene)-3-(2-oxobenzo[d]oxazol-3(2\(H\))-yl) propanehydrazide (**21**)  
Yield 0.44 g (88%), mp 236-238 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): 8 2.75, 3.07 (2t, 2H, \(J\) = 6.7 Hz, CH\({}_{2}\)CO), 4.03-4.21 (m, 2H, CH\({}_{2}\)N), 7.11 (q, 1H, \(J\) = 7.5 Hz, H\({}_{\rm ar}\)), 7.18-7.41 (m, 3H, H\({}_{\rm Ar}\)), 7.47, 7.53 (2d, 1H, \(J\) = 4.3 Hz, H\({}_{\rm ar}\)), 8.09 (dd, 1H, \(J\) = 10.4, 4.7 Hz, H\({}_{\rm ar}\)), 8.11, 8.36 (2s, 1H, N=CH), 11.82 (s, 0.65H, NH), 11.85 (s, 0.35H, NH);  
\({}^{13}\)C-NMR (101 MHz): 8 30.17, 32.308, 37.92, 38.04 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 109.44, 109.56, 122.16, 123.83, 129.06, 129.66, 130.49, 130.93, 136.62, 139.99, 141.99, 146.42, 150.43, 153.57, 166.64, 172.17 (C\({}_{\rm ar}\), N=CH, CO);  
IR (KBr): \(\gamma_{\rm max}\) = 3172, 3108 (NH), 1774 (C=O), 1657 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{15}\)H\({}_{12}\)N\({}_{4}\)O\({}_{3}\)S (360.34), %: C, 50.00; H, 3.36; N, 15.55. Found: C, 49.81; H, 3.05; N, 15.27. 2.3.15. \(N^{\prime}\)-(Furan-2-ylmethylene)-3-(2-oxobenzo[d]oxazol-3(2\(H\))-yl)propanehydrazide (**22**)  
Yield 0.31 g (74%), mp 158-160 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): 8 2.69, 3.03 (2t, 2H, \(J\) = 6.6, 6.9 Hz, CH\({}_{2}\)CO), 4.10 (t, 2H, \(J\) = 6.8 Hz, CH\({}_{2}\)N), 6.59 (s, 1H, H\({}_{\rm ar}\)), 6.81, 6.86 (2d, 1H, \(J\) = 2.7 Hz, H\({}_{\rm ar}\)), 7.05-7.44 (m, 4H, H\({}_{\rm ar}\)), 7.78, 7.80 (2s, 1H, H\({}_{\rm ar}\)), 7.84, 7.98 (2s, 1H, N=CH), 11.37 (s, 0.65H, NH), 11.42 (s, 0.35H, NH);  
\({}^{13}\)C-NMR (101 MHz): 8 30.17, 32.308, 37.92, 38.04 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 109.44, 109.56, 122.16, 123.83, 129.06, 129.66, 130.49, 130.93, 136.62, 139.99, 141.99, 146.42, 150.43, 153.57, 166.64, 172.17 (C\({}_{\rm ar}\), N=CH, CO);  
IR (KBr): \(\gamma_{\rm max}\) = 3176, 3129 (NH), 1761 (C=O), 1669 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{15}\)H\({}_{13}\)N\({}_{3}\)O\({}_{4}\) (299.29), %: C, 60.20; H, 4.38; N, 14.04. Found: C, 59.98; H, 4.14; N, 13.85. 2.3.16. \(N^{\prime}\)-((5-Nitrofuran-2-yl)methylene)-3-(2-oxobenzo[d]oxazol-3(2\(H\))-yl) propanehydrazide (**23**)  
Yield 0.41 g (85%), mp 230-232 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): 8 2.76, 3.08 (2t, 2H, \(J\) = 6.5, 6.8 Hz, CH\({}_{2}\)CO), 4.12 (t, 2H, \(J\) = 6.8 Hz, CH\({}_{2}\)N), 7.07-7.39 (m, 5H, H\({}_{\rm ar}\)), 7.75 (d, 1H, \(J\) = 3.8 Hz, H\({}_{\rm ar}\)), 7.89, 8.06 (2s, 1H, N=CH), 11.82 (s, 0.65H, NH), 11.87 (s, 0.35H, NH);  
\({}^{13}\)C-NMR (101 MHz): 8 30.35, 32.37, 37.73, 38.06 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 109.49, 109.52, 109.58, 114.58, 114.68, 115.38, 122.09, 122.17, 123.86, 130.91, 131.44, 134.36, 141.95, 151.48, 151.60, 151.70, 151.87, 153.59, 166.73, 172.21 (C\({}_{\rm ar}\), N=CH, CO);  
IR (KBr): \(\gamma_{\rm max}\) = 3198, 3063 (NH), 1753 (C=O), 1690 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{15}\)H\({}_{12}\)N\({}_{4}\)O\({}_{6}\) (344.28), %: C, 52.33; H, 3.51; N, 16.27. Found: C, 52.17; H, 3.33; N, 16.03. 2.3.17.