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R. Nirmala et al. / Tetrahedron Letters 54 (2013) 5181–5184
16. Spectroscopic data for representative examples: (4-Nitrophenyl) ethyl 3-(2-
oxoazepan-1-yl) propyl carbamate (3a): Pale yellow solid; mp 81–83 °C; Rf
0.62 (DCM/MeOH, 95:5); IR (KBr) 3289, 2937, 1719, 1621, 1519, 1346,
1264 cmÀ1; dH (400 MHz, DMSO-d6) 1.52–1.59 (m, 6H), 1.61–1.64 (m, 2H),
2.39–2.41 (m, 2H), 2.96–3.01 (m, 2H), 3.27 (t, J = 7.1 Hz, 2H), 3.32–3.34 (m, 2H),
5.16 (s, 2H), 7.36 (br s, 1H), 7.60 (d, J = 8.4 Hz, 2H), 8.24 (d, J = 8.4 Hz, 2H); dC
(100 MHz, DMSO-d6) 22.1, 27.1, 27.4, 28.2, 35.5, 37.1, 43.9, 47.5, 63.0, 122.6,
127.1, 144.3, 145.9, 154.7, 173.6; Anal. Calcd for C17H23N3O5: C, 58.44; H, 6.64;
N, 12.03. Found: C, 58.34; H, 6.65; N, 12.07; ESI-m/z calcd for (C17H23N3O5+H)+
350.2, found 350.2. (Thiophen-2-yl) methyl 3-(2-oxoazepan-1-yl) propyl
carbamate (3f): Pale yellow sticky; Rf 0.46 (DCM/MeOH, 95:5); IR (KBr) 3434,
2929, 2856, 1715, 1626, 1525, 1443, 1248 cmÀ1; dH (400 MHz, DMSO-d6) 1.52–
1.59 (m, 6H), 1.62–1.64 (m, 2H), 2.38–2.41 (m, 2H), 2.94–2.99 (m, 2H), 3.24–
3.27 (m, 2H), 3.41–3.49 (m, 2H), 5.16 (s, 2H), 7.00–7.01 (dd, J = 4.9 Hz, 3.6 Hz,
1H), 7.12 (d, J = 2.8 Hz, 1H), 7.18 (t, J = 5.2 Hz, 1H), 7.52 (d, J = 5.0 Hz, 1H); dC
(100 MHz, DMSO-d6) 23.4, 28.5, 28.7, 29.6, 36.9, 38.4, 45.3, 48.9, 60.0, 127.1,
127.4, 128.2, 139.6, 156.1, 174.9; Anal. Calcd for C15H22N2O3S: C, 58.04; H,
7.14; N, 9.02. Found: C, 58.10; H, 7.15; N, 9.05; ESI-m/z calcd for
(C15H22N2O3S+H)+ 311.1, found 311.2. 2-Oxoindolin-3-yl-3-(2-oxoazepan-1-
yl)propyl carbamate (3i): Colourless sticky; Rf 0.52 (DCM/MeOH, 95:5); IR
(KBr) 3465, 2932, 1721, 1624, 1471, 1250 cmÀ1; dH (400 MHz, DMSO-d6) 1.54–
1.64 (m, 8H), 2.39–2.41 (m, 2H), 2.98–3.00 (m, 2H), 3.25–3.28 (m, 2H), 3.31–
3.34 (m, 2H), 5.74 (s, 1H), 6.81–6.83 (d, J = 7.8 Hz, 1H), 6.96 (t, J = 7.4 Hz, 1H),
7.23–7.25 (m, 2H), 7.46 (br s, 1H), 10.50 (s, 1H); dC (100 MHz, DMSO-d6) 23.4,
28.4, 28.7, 29.6, 36.9, 38.7, 45.4, 49.0, 70.4, 110.2, 122.1, 125.2, 126.3, 130.0,
143.1, 155.5, 174.5, 175.0; Anal. Calcd for C18H23N3O4: C, 62.59; H, 6.71; N,
12.17. Found: C, 62.50; H, 6.74; N, 12.07; ESI-m/z calcd for (C18H23N3O4+H)+
346.2, found 346.2. See Supplementary data for spectral data of all other
compounds.
17. 1,2-Diphenylethane-1,2-diyl bis(3-(2-oxoazepan-1-yl)propylcarbamate) (5): Pale
yellow solid; mp 194–196 °C; Rf 0.66 (DCM/MeOH, 95:5); IR (KBr) 3263, 2938,
2859, 1723, 1625, 1538, 1456, 1245 cmÀ1; dH (400 MHz, DMSO-d6) 1.50–1.59
(m, 12H), 1.62–1.64 (m, 4H), 2.33–2.39 (m, 4H), 2.67–2.70 (m, 4H), 3.16–3.20
(m, 4H), 3.28–3.29 (m, 4H), 5.85 (s, 2H), 7.18–7.27 (m, 12H); dC (100 MHz,
DMSO-d6) 23.0, 28.0, 28.4, 29.2, 36.5, 38.0, 45.0, 48.6, 76.0, 127.2, 127.3, 127.9,
137.4, 154.9, 174.5; ESI-m/z calcd for (C34H46N4O6+H)+ 607.3, found 607.3.
20. General procedure for the synthesis of
e-caprolactam derived amides (9):
14. (a) Srinivas, A. S. S. V.; Mathiyazhagan, K.; Sharatha, D. S.; Ponpandian, T.;
Revathy, K.; Reddy, G. O.; Kumarai, M.; Rajagopal, S. US 2010/0152188.; (b)
Virendra, K.; Punthalir, N.; Ponpandian, T.; Daivasigamani, P.; Srinivas, A. S. S.
V.; Ramachandran, U.; Sriram, R.; Reddy, G. O.; Sridharan, R.; Raheem, K. A. WO
2008/087514.
Carboxylic acids (6) (0.5 g) were dissolved in THF (12 mL) then CDI
(1.2 equiv) and DBU (1.2 equiv) were added successively at room
temperature. The resulting mixture was stirred at room temperature for 1 h
then poured into water (80 mL) and extracted with ethyl acetate (2 Â 150 mL).
The combined organic layer was washed with water (2 Â 120 mL), brine
solution (1 Â 100 mL) and dried over anhydrous Na2SO4. The solvent was
removed by evaporation and the obtained crude product was purified by
column chromatography using DCM/MeOH (98:2) as eluent. N-(3-(2-oxo-
azepan-1-yl)-propyl)-2-phenyl acetamide (9a): Colourless sticky; Rf 0.32 (DCM/
MeOH, 95:5); dH (400 MHz, CDCl3) 1.61–1.64 (m, 8H), 2.51 (br s, 2H), 3.17 (br s,
2H), 3.45–3.46 (m, 4H), 3.53 (s, 2H), 6.80 (br s, 1H), 7.25–7.32 (m, 5H); dC
(100 MHz, CDCl3) 23.4, 27.0, 28.4, 29.9, 35.9, 37.1, 43.9, 45.2, 49.7, 127.1, 128.8,
129.2, 135.2, 171.6, 177.0; ESI-m/z calcd for (C17H24N2O2+H)+ 289.2, found
289.1. (E)-N-(3-(2-oxoazepan-1-yl)propyl)cinnamamide (9g): Colourless sticky;
Rf 0.48 (DCM/MeOH, 95:5); dH (400 MHz, CDCl3) 1.64–1.73 (m, 8H), 2.53–2.56
(m, 2H), 3.32–3.34 (m, 4H), 3.47 (t, J = 6.0 Hz, 2H), 6.47 (d, J = 15.6 Hz, 1H),
7.31–7.34 (m, 4H), 7.49–7.51 (m, 2H), 7.59 (d, J = 15.6 Hz, 1H); dC (100 MHz,
CDCl3) 23.5, 27.2, 28.5, 30.0, 35.5, 37.3, 45.2, 49.7, 121.6, 127.9, 128.8, 129.5,
135.2, 140.3, 166.1, 177.3; ESI-m/z calcd for (C18H24N2O2+H)+ 301.2, found
301.1. See Supplementary data for spectral data of all the other compounds.
15. General procedure for the synthesis of e-caprolactam derived carbamates (3 and
5): Hydroxy compound (1) (0.5 g) was dissolved in THF (12 mL) then CDI
(1.2 equiv) and DBU (1.2 equiv) were added successively at room temperature.
The resulting mixture was stirred at 70 °C for 2 h and the mixture was cooled
to room temperature then poured into water (80 mL) and extracted with ethyl
acetate (2 Â 150 mL). The combined organic layer was washed with water
(2 Â 120 mL), brine solution (1 Â 100 mL) and dried over anhydrous Na2SO4.
The solvent was removed by evaporation and the obtained crude product was
purified by column chromatography using DCM/MeOH (99:1) as eluent.