# 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)  
Yield 0.35 g (81%), mp 170-172 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): \(\delta\) 2.72, 3.10 (2t, 2H, \(J\) = 6.7 Hz, CH\({}_{2}\)CO), 4.01-4.19 (m, 2H, CH\({}_{2}\)N), 7.11 (t, 1H, \(J\) = 6.8 Hz, H\({}_{\rm ar}\)), 7.22 (t, 1H, \(J\) = 6.8 Hz, H\({}_{\rm ar}\)), 7.26-7.46 (m, 5H, Har), 7.50-7.67 (m, 2H, H\({}_{\rm ar}\)), 7.94, 8.09 (2s, 1H, N=CH), 11.41 (s, 0.65H, NH), 11.48 (s, 0.35H, NH);\({}^{13}\)C-NMR (101 MHz): $ $ 30.40, 32.30 37.99, 38.24 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 109.43, 109.55, 109.59, 122.12, 123.80, 126.71, 127.03, 128.76, 129.77, 130.98, 134.03, 141.98, 143.30, 146.40, 153.60, 166.03, 171.86 (C\({}_{\rm ar}\), N=CH, CO);  
IR (KBr): \(\
u_{\rm max}=3183,3064\) (NH), 1772 (C=O), 1667 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{17}\)H\({}_{15}\)N\({}_{3}\)O\({}_{3}\) (309.32), %: C, 66.01; H, 4.89; N, 13.58. Found: C, 65.91; H, 4.63; N, 13.33. 2.3.2. \(N^{\prime}\)-(4-Fluorobenzylidene)-3-(2-oxobenzo[d]oxazol-3(2H)-yl)propanehydrazide (9) Yield 0.4 g (87%), mp 180-182 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): $ 2.72, 3.11 (2t, 2H, \(J=6.8\) Hz, CH\({}_{2}\)CO), 4.13-4.20 (m, 2H, CH\({}_{2}\)N), 7.12 (t, 1H, \(J=7.8\) Hz, Har), 7.18-7.31 (m, 3.65H, H\({}_{\rm ar}\)), 7.33, 7.36 (2d, 1.35H, \(J=7.9\) Hz, Har), 7.62, 7.72 (2 dd, 2H, \(J=8.2\), 5.8 Hz, Har), 7.93, 8.10 (2s, 1H, N=CH), 11.42 (s, 0.65H, NH), 11.50 (s, 0.35H, NH);  
\({}^{13}\)C-NMR (101 MHz): $ 30.38, 32.29, 38.00, 38.24 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 109.43, 109.54, 109.57, 109.59, 115.69 (d, \(J^{2}=21.9\) Hz), 115.77 (d, \(J^{2}=21.9\) Hz), 122.13, 123.82, 128.85 (d, \(J^{3}=8.5\) Hz), 129.20 (d, \(J^{3}=8.5\) Hz), 130.65 (d, \(J^{4}=2.9\) Hz), 130.76 (d, \(J^{4}=2.9\) Hz), 130.97, 141.97, 142.14, 145.29, 153.59, 162.88 (d, \(J^{1}=247.5\) Hz), 166.05, 171.87 (C\({}_{\rm ar}\), N=CH, CO);  
IR (KBr): \(\
u_{\rm max}=3182,3078\) (NH), 1757 (C=O), 1662 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{17}\)H\({}_{14}\)FN\({}_{3}\)O\({}_{3}\) (327.32), %: C, 62.38; H, 4.31; N, 12.84. Found: C, 62.11; H, 4.17; N, 12.78. 2.3.3. \(N^{\prime}\)-(2,4-Difluorobenzylidene)-3-(2-oxobenzo[d]oxazol-3(2H)-yl)propanehydrazide (10) Yield 0.4 g (83%), mp 192-194 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): $ 2.72, 3.10 (2t, 2H, \(J=6.7\) Hz, CH\({}_{2}\)CO), 4.08-4.16 (m, 2H, CH\({}_{2}\)N), 7.06-7.38 (m, 6H, H\({}_{\rm ar}\)), 7.74, 7.84 (2 dd, 1H, \(J=15.6\), 8.3 Hz, H\({}_{\rm ar}\)), 8.07, 8.25 (2s, 1H, N=CH), 11.51 (s, 0.65H, NH), 11.62 (s, 0.35H, NH);  
\({}^{13}\)C-NMR (101 MHz): $ 30.35, 32.31, 37.95, 38.17 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 104.13, 104.38, 104.64, 109.43, 109.52, 109.57, 112.35, 112.38, 112.47, 112.50, 112.56, 112.60, 112.68, 112.72, 118.38, 118.42, 118.48, 118.52, 122.14, 123.83, 127.59, 127.63, 127.69, 127.73, 127.82, 127.86, 127.92, 127.97, 130.95, 135.30, 138.42, 141.95, 153.58, 159.39, 161.82, 162.03, 164.31, 166.12, 171.98 (C\({}_{\rm ar}\), N=CH, CO);  
IR (KBr): \(\
u_{\rm max}=3183,3091\) (NH), 1783 (C=O), 1667 (C=N) cm\({}^{-1}\). Anal. Calcd for C\({}_{17}\)H\({}_{13}\)F\({}_{2}\)N\({}_{3}\)O\({}_{3}\) (345.31), %: C, 59.13; H, 3.79; N, 12.17. Found: C, 58.89; H, 3.52; N, 11.92. 2.3.4. \(N^{\prime}\)-(2-Chlorobenzylidene)-3-(2-oxobenzo[d]oxazol-3(2H)-yl)propanehydrazide (11) Yield 0.35 g (73%), mp 162-164 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): $ 2.73, 3.12 (2t, 2H, \(J=6.7\) Hz, CH\({}_{2}\)CO), 4.02-4.24 (m, 2H, CH\({}_{2}\)N), 7.05-7.15 (m, 1H, Har), 7.18-7.52 (m, 6H, Har), 7.78, 7.91 (2d, 2H, \(J=7.7\) Hz, Har), 8.32, 8.47 (2s, 1H, N=CH), 11.60 (s, 0.65H, NH), 11.72 (s, 0.35H, NH);  
\({}^{13}\)C-NMR (101 MHz): $ 30.39, 32.34, 37.94, 38.14 (CH\({}_{2}\)CO, CH\({}_{2}\)N), 109.44, 109.53, 109.56, 122.12, 123.80, 126.59, 127.49, 129.81, 130.95, 131.16, 139.32, 141.96, 142.30, 153.59, 166.20, 172.04 (C\({}_{\rm ar}\), N=CH, CO);  
IR (KBr): \(\
u_{\rm max}=3182,3069\) (NH), 1770, 1760 (C=O), 1669 (C=N) cm\({}^{-1}\). Anal.