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A. K. Singh et al. / Tetrahedron Letters 54 (2013) 5099–5102
6. General procedure for the synthesis of N-acyl-N0-arylureas 4: To a solution of
carboxamide 1 (1 mmol) and 2 (1 mmol) in EtOAc (12 mL), N,N-dibromo-p-
(0.1 mmol) was stirred in water (2 mL) at room temperature for 18–30 h
(Table 3). After completion of reaction (monitored by TLC), water (5 mL) was
added, and the mixture was extracted with EtOAc (3 ꢀ 5 mL). The combined
organic phase was dried over anhyd Na2SO4, filtered, and evaporated under
reduced pressure. The resulting crude product was purified by silica gel column
chromatography using a mixture of EtOAc–n-hexane (1:19) as eluent to afford
an analytically pure product.
toluenesulfonamide
3 (1 mmol) and K2CO3 (3 mmol) were added and the
mixture was stirred under nitrogen at room temperature for 5–6 h (Table 2).
After completion of reaction (monitored by TLC), water (10 mL) was added, and
the mixture was extracted with EtOAc (3 ꢀ 5 mL). The combined organic phase
was dried over anhyd Na2SO4, filtered, and evaporated under reduced pressure.
The resulting crude product was purified by silica gel column chromatography
using a mixture of EtOAc–n-hexane (1:9) as eluent to afford an analytically pure
product.
8. General procedure for the solvent-free ring-opening of styrene oxide: A mixture of
styrene oxide 9 (1 mmol) and nucleophile NuH (1 mmol) and N-acylurea 4a
(0.05 mmol) was stirred under solvent-free condition at 60 °C for 0.4–4.0 h
(Table 4). After completion of reaction (monitored by TLC), water (5 mL) was
added, and the mixture was extracted with EtOAc (3 ꢀ 5 mL). The combined
organic phase was dried over anhyd Na2SO4, filtered, and evaporated under
reduced pressure. The resulting crude product was purified by silica gel column
chromatography using a mixture of EtOAc–n-hexane (1:19) as eluent to afford
an analytically pure product. Compound 10c9: White solid, 1H NMR (400 MHz,
CDCl3) d: 2.85 (s, 1H), 3.98–4.10 (m, 1H), 4.16–4.18 (m, 1H), 5.11–5.18 (m, 1H),
6.96–7.02 (m, 3H), 7.29–7.48 (m, 7H); 13C NMR (100 MHz, CDCl3) d: 158.43,
139.78, 129.63, 128.60, 128.26, 126.39, 121.36, 114.73, 73.38, 72.67. EI-MS (m/z)
214 (M+). Anal. Calcd for C14H14O2: C, 78.48; H, 6.59%. Found: C, 78.31; H, 6.85%.
Compound 11c9: White solid, 1H NMR (400 MHz, CDCl3) d: 2.27–2.31 (m, 1H),
3.80–3.92 (m, 1H), 3.95–4.02 (m, 1H), 5.29 (dd, J = 8.3, 3.9, 1H), 6.89–6.94 (m,
3H), 7.20–7.41 (m, 7H); 13C NMR (100 MHz, CDCl3) d: 157.86, 137.91, 129.49,
128.79, 128.19, 126.36, 121.31, 115.98, 81.22, 67.66. EI-MS (m/z) 214 (M+). Anal.
Calcd for C14H14O2: C, 78.48; H, 6.59%. Found: C, 78.24; H, 6.89%.
Characterization data of representative compounds.
Compound 4a2: White solid, yield 89%, mp 189ꢁ191 °C (lit. mp: 191ꢁ193 °C),2
1H NMR (400 MHz, CDCl3) d: 10.92 (s, 1H), 9.52 (s, 1H), 8.04–8.02 (m, 2H), 7.66–
7.58 (m, 3H), 7.55–7.51 (m, 2H), 7.39–7.34 (m, 2H), 7.17–7.13 (m, 1H); 13C NMR
(100 MHz, CDCl3) d: 168.61, 150.98, 137.53, 132.92, 132.14, 128.95, 128.44,
128.19, 123.65, 120.32. EI-MS (m/z) 240 (M+). Anal. Calcd for C14H12N2O2: C,
69.99; H, 5.03; N, 11.66%. Found: C, 69.71; H, 5.38; N, 11.54%. These observed
spectral and elemental analyses’ data compare quite favourably to those
reported in the literature.2 Compound 4n: White solid, yield 78%, mp
182ꢁ184 °C, 1H NMR (400 MHz, CDCl3) d: 10.63 (s, 1H), 9.97 (s, 1H), 7.53–
7.51 (m, 2H), 7.35–7.31 (m, 2H), 7.15–7.11 (m, 1H), 2.23 (s, 3H); 13C NMR
(100 MHz, CDCl3) d: 169.99, 148.06, 139.68, 128.98, 128.12, 121.85, 22.04, EI-MS
(m/z) 178 (M+). Anal. Calcd for C9H10N2O2: C, 60.66; H, 5.66; N, 15.72%. Found: C,
60.98; H, 5.83; N, 15.46%.
7. General procedure for the ring-opening of styrene oxide (9) in water: A mixture of
styrene oxide
9
(1 mmol), nucleophile NuH (1 mmol), and N-acylurea 4a