# 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)
Calcd for C\({}_{17}\)H\({}_{14}\)ClN\({}_{3}\)O\({}_{3}\) (343.77), %: C, 59.40; H, 4.11; N, 12.22. Found: C, 59.20; H, 3.93; N, 12.01. 2.3.5. \(N^{\prime}\)-(3-Chlorobenzylidene)-3-(2-oxobenzo[d]oxazol-3(2H)-yl)propanehydrazide (12) Yield 0.44 g (92%), mp 160-162 \({}^{\circ}\)C;  
\({}^{1}\)H-NMR (400 MHz): $ 2.73, 3.11 (2t, 2H, \(J=6.7\) Hz, CH\({}_{2}\)CO), 4.07-4.18 (m, 2H, CH\({}_{2}\)N), 7.06-7.14 (m, 1H, Har), 7.18-7.62 (m, 6H, Har), 7.63, 7.70 (2s, 1H, H\({}_{\rm ar}\)), 7.91, 8.07 (2s, 1H, N=CH), 11.51 (s, 0.65H, NH), 11.61 (s, 0.35H, NH);\({}^{13}\)C-NMR (101 MHz): $ 30.37, 32.27, 38.00, 38.18 (CH2 CO, CH2N), 109.39, 109.52, 109.57, 122.12, 123.80, 125.53, 125.66, 125.89, 126.33, 129.42, 130.59, 130.95, 133.61, 136.24, 141.72, 141.95, 153.59, 166.26, 172.04 (C\({}_{\rm ar}\), N=CH, CO); IR (KBr): \(\
u_{\rm max}=3182\), 3066 (NH), 1780 (C=O), 1662 (C=N) cm\({}^{-1}\). Anal. Calcd for C17H14 ClN3O3 (343.77), %: C, 59.40; H, 4.11; N, 12.22. Found: C, 59.18; H, 3.94; N, 12.03. 2.3.6. \(N^{\prime}\)-(4-Chlorobenzylidene)-3-(2-oxobenzo[d]oxazol-3(2\(H\))-yl)propanehydrazide **(13)** Yield 0.39 g (81%), mp 202-204 \({}^{\circ}\)C; \({}^{1}\)H-NMR (400 MHz): $ 2.72, 3.10 (2t, 2H, \(J=6.7\) Hz, CH2 CO), 4.01-4.17 (m, 2H, CH2N), 7.10 (t, 1H, \(J=7.8\) Hz, Har), 7.17-7.39 (m, 3H, Har), 7.42, 7.47 (2d, 2H, \(J=8.3\) Hz, Har), 7.57, 7.67 (2d, 2H, \(J=8.3\) Hz, Har), 7.91, 8.08 (2s, 1H, N=CH), 11.47 (s, 0.65H, NH), 11.55 (s, 0.35H, NH); \({}^{13}\)C-NMR (101 MHz): $ 30.36, 32.30, 37.97, 38.22 (CH2 CO, CH2N), 109.42, 109. 53, 122.12, 123.81, 128.32, 128.66, 128.78, 128.84, 130.96, 132.97, 134.17, 141.96, 141.99, 145.09, 153.58, 166.14, 171.94 (C\({}_{\rm ar}\), N=CH, CO); IR (KBr): \(\
u_{\rm max}=3194\), 3084 (NH), 1754 (C=O), 1672 (C=N) cm\({}^{-1}\). Anal. Calcd for C17H14 ClN3O3 (343.77), %: C, 59.40; H, 4.11; N, 12.22. Found: C, 59.18; H, 3.89; N, 12.01. 2.3.7. \(N^{\prime}\)-(4-Bromobenzylidene)-3-(2-oxobenzo[d]oxazol-3(2H)-yl)propanehydrazide **(14)** Yield 0.48 g (89%), mp 210-212 \({}^{\circ}\)C; \({}^{1}\)H-NMR (400 MHz): $ 2.72, 3.10 (2t, 2H, \(J=6.7\) Hz, CH2 CO), 4.06-4.18 (m, 2H, CH2N), 7.11 (t, 1H, \(J=7.8\) Hz, Har), 7.7-4.40 (m, 3H, Har), 7.50, 7.57 (2d, \(J=8.2\) Hz, Har), 7.61 (s, 2H, Har), 7.90, 8.06 (2s, 1H, N=CH), 11.47 (s, 0.65H, NH), 11.55 (s, 0.35H, NH); \({}^{13}\)C-NMR (101 MHz): $ 30.35, 32.29, 37.96, 38.21 (CH2 CO, CH2N), 109.44, 109. 54, 122.13, 122.94, 123.83, 128.57, 128.90, 130.96, 131.71, 133.77, 133.31, 141.96, 142.09, 145.16, 153.58, 166.14, 171.95 (C\({}_{\rm ar}\), N=CH, CO); IR (KBr): \(\
u_{\rm max}=3193\), 3066 (NH), 1752 (C=O), 1671 (C=N) cm\({}^{-1}\). Anal. Calcd for C17H14 BrN3O3 (388.22), %: C, 52.60; H, 3.64; N, 10.82. Found: C, 52.39; H, 3.38; N, 10.59. 2.3.8. \(N^{\prime}\)-(4-Nitrobenzylidene)-3-(2-oxobenzo[d]oxazol-3(2\(H\))-yl)propanehydrazide **(15)** Yield 0.43 g (86%), mp 232-234 \({}^{\circ}\)C; \({}^{1}\)H-NMR (400 MHz): $ 2.76, 3.14 (2t, 2H, \(J=6.7\) Hz, CH2 CO), 4.06-4.22 (m, 2H, CH2N), 7.10 (t, 1H, \(J=7.8\) Hz, Har), 7.16-7.37 (m, 3H, Har), 7.80, 7.91 (2d, 2H, \(J=8.5\) Hz, Har), 8.02, 8.19 (2s, 1H, N=CH), 8.19, 8.25 (2d, 2H, \(J=8.5\) Hz, Har), 11.71 (s, 0.65H, NH), 11.79 (s, 0.35H, NH); \({}^{13}\)C-NMR (101 MHz): $ 30.36, 32.33, 37.93, 38.14 (CH2 CO, CH2N), 109.46, 109. 55, 109.58, 122.15, 123.85, 123.91, 127.59, 127.95, 130.95, 140.32, 140.91, 141.96, 143.93, 147.58, 153.59, 166.55, 172.33 (C\({}_{\rm ar}\), N=CH, CO); IR (KBr): \(\
u_{\rm max}=3182\), 3079 (NH), 1752 (C=O), 1669 (C=N) cm\({}^{-1}\). Anal. Calcd for C17H14N4O5 (354.32), %: C, 57.63; H, 3.98; N, 15.81. Found: C, 57.41; H, 3.71; N, 15.58. 2.3.9.