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Helvetica Chimica Acta – Vol. 89 (2006)
Phenylmethyl (4S)-4-Methyl-6-oxo-1,3-oxazinane-3-carboxylate (38). Yield: 43%. Clear colourless
oil. [a]2D0 =+143.4 (c=1.0, MeOH). IR (NaCl): 2900, 2800, 1766, 1713, 1454, 1266, 1159, 988, 771, 750,
1
699. H-NMR (300 MHz, CDCl3; rotamers): 7.34 (s, 5 H); 5.82–5.79 (br. s, 1 H); 5.16 (s, 2 H); 5.04 (d,
J=10.5, 1 H); 4.24 (br. s, 1 H); 2.81 (dd, J=6.7, 16.0, 1 H); 2.47 (dd, J=10.3, 16.0, 1 H); 1.30 (d,
J=6.3, 3 H). 13C-NMR (75 MHz, CDCl3; rotamers): 169.4; 153.8; 135.1; 128.3; 128.1; 127.8; 71.5; 67.8;
46.0; 36.8; 20.6. Anal. calc. for C13H15NO4 (249.26): C 62.64, H 6.07, N 5.62; found: C 62.92, H 6.27, N 5.87.
Phenylmethyl (4S)-4-Ethyl-6-oxo-1,3-oxazinane-3-carboxylate (39). Yield: 35%. Clear colourless oil.
[a]2D0 =+135.4 (c=0.4, MeOH). IR (NaCl): 2969, 2880, 1761, 1713, 1455, 1414, 1260, 1156, 1005, 770, 743,
1
698. H-NMR (300 MHz, CDCl3; rotamers): 7.31 (s, 5 H); 5.82 (d, J=9.8, 1 H); 5.14 (s, 2 H); 4.95 (d,
J=10.7, 1 H); 4.11–4.05 (m, 1 H); 2.78 (dd, J=7.0, 16.1, 1 H); 2.47 (dd, J=10.0, 16.1, 1 H); 1.76–1.54
(m, 2 H); 0.90–0.85 (t, J=11.2, 3 H). 13C-NMR (75 MHz, CDCl3): 169.5; 154.2; 135.2; 128.3; 128.1;
127.9; 127.7; 127.3; 72.0; 67.7; 50.7; 34.4; 27.5; 8.7. HR-MS: 263.1152 (M+, C14
N
N
Phenylmethyl (4S)-6-oxo-4-propyl-1,3-oxazinane-3-carboxylate (40). Yield: 45%. Clear colourless
oil. [a]2D0 =+135.5 (c=0.4, MeOH). IR (NaCl): 2960, 2934, 1762, 1713, 1414, 1261, 1244, 1156, 1109,
997, 772, 740, 698. 1H-NMR (300 MHz, CDCl3; rotamers): 7.33 (s, 5 H); 5.82 (d, J=9.9, 1 H); 5.15 (s, 2
H); 4.96 (d, J=10.8, 1 H); 4.19 (br. s, 1 H); 2.80 (dd, J=7.0, 16.2, 1 H); 2.45 (dd, J=9.8, 16.2, 1 H);
1.70–1.47 (m, 2 H); 1.33–1.26 (m, 2 H); 0.89 (t, J=10.8, 3 H). 13C-NMR (75 MHz, CDCl3): 169.5;
154.2; 135.2; 128.3; 128.1; 127.9; 127.8; 71.9; 67.8; 49.4; 36.8; 35.0; 17.8; 13.4. HR-MS: 277.1310 (M+,
C
N
N
Phenylmethyl (4R)-4-(1-methylethyl)-6-oxo-1,3-oxazinane-3-carboxylate (41). Yield: 45%. Clear col-
ourless oil. [a]2D0 =+147.8 (c=1.0, MeOH). IR (NaCl): 2964, 2800, 1761, 1714, 1455, 1262, 1155, 1130,
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1009, 990, 772, 738, 698. H-NMR (300 MHz, CDCl3; rotamers): 7.33 (s, 5 H); 5.89 (br. s, 1 H); 5.16 (s,
2 H); 4.89 (d, J=10.8, 1 H); 4.12–4.05 (m, 1 H); 2.72 (dd, J=7.0, 16.1, 1 H); 2.54 (dd, J=10.5, 16.1, 1
H); 2.10–1.99 (m, 1 H); 0.92–0.88 (m, 6 H). 13C-NMR (75 MHz, CDCl3; rotamers): 169.9; 154.7;
135.1; 128.3; 128.3; 127.8; 72.8; 67.9; 54.5; 31.7; 31.3; 18.2; 16.3. 277.1309 (M+, C15
N
N
277.1314).
Phenylmethyl (4S)-4-Butyl-6-oxo-1,3-oxazinane-3-carboxylate (42).Yield: 38%. Clear colourless oil.
[a]2D0 =+64.8 (c=0.1, MeOH). IR (NaCl): 2957, 2932, 2861, 1762, 1713, 1455, 1264, 1155, 1000, 771, 751,
698. 1H-NMR (300 MHz, CDCl3; rotamers): 7.33 (s, 5 H); 5.86 (d, J=9.9, 1 H); 5.13 (s, 2 H); 4.98 (br. s, 1
H); 4.25–4.15 (m, 1 H); 2.83 (dd, J=7.0, 16.2, 1 H); 2.46 (dd, J=9.7, 16.2, 1 H); 1.78–1.48 (m, 2 H); 1.28
(br. s, 4 H); 0.86 (t, J=9.7, 3 H). 13C-NMR (75 MHz, CDCl3): 169.4; 154.2; 135.2; 128.3; 128.1; 128.0;
127.8; 71.9; 67.9; 49.6; 35.0; 34.4; 26.6; 22.0; 13.5. Anal. calc. for C16H21NO4 (291.34): C 65.96, H 7.27,
N 4.81; found: C 65.87, H 7.11, N 4.64.
Phenylmethyl (4S)-4-(2-Methylpropyl)-6-oxo-1,3-oxazinane-3-carboxylate (43). Yield: 31%. Clear
colourless oil that crystallised on standing. M.p. 30–328. [a]1D8 =+120.1 (c=0.3, MeOH). IR (NaCl):
2957, 2871, 1761, 1714, 1414, 1260, 1157, 998, 771, 752, 698. 1H-NMR (300 MHz, CDCl3; rotamers):
7.33 (s, 5 H); 5.85 (d, J=10.4, 1 H); 5.16 (s, 2 H); 4.98 (d, J=10.7, 1 H); 4.28 (s, 1 H); 2.86 (dd, J=7.2,
16.2, 1 H); 2.40 (dd, J=9.2, 16.2, 1 H); 1.68–1.52 (m, 2 H); 1.40–1.31 (m, 1 H); 0.90–0.88 (m, 6 H).
13C-NMR (75 MHz, CDCl3): 169.3; 154.1; 135.1; 128.3; 128.2; 127.9; 71.7; 67.9; 47.9; 44.1; 35.5; 24.0;
22.6; 21.4. Anal. calc. for C16H21NO4 (291.34): C 65.96, H 7.27, N 4.81; found: C 65.83, H 7.44, N 4.74.
Phenylmethyl (4R)-4-[(1S)-1-Methylpropyl]-6-oxo-1,3-oxazinane-3-carboxylate (44). Yield: 30%.
Clear colourless oil. [a]2D0 =+111.6 (c=0.5, MeOH). IR (NaCl): 2964, 2934, 1762, 1714, 1455, 1261,
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1158, 1133, 1001, 772, 742, 698. H-NMR (300 MHz, CDCl3; rotamers): 7.33 (s, 5 H); 5.90 (br. s, 1 H);
5.16 (s, 2 H); 4.91 (d, J=10.5, 1 H); 4.14–4.08 (m, 1 H); 2.67–2.52 (m, 2 H); 1.93–1.86 (m, 1 H);
1.33–1.06 (m, 2 H); 0.90–0.87 (m, 6 H). 13C-NMR (75 MHz, CDCl3): 170.1; 154.6; 135.1; 128.3; 128.1;
127.9; 127.7; 73.0; 67.9; 53.3; 37.8; 30.3; 25.1; 12.6; 11.2. Anal. calc. for C16H21NO4 (291.34): C 65.96, H
7.27, N 4.81; found: C 66.14, H 7.41, N 4.64.
Phenylmethyl 6-Oxo-4-phenyl-1,3-oxazinane-3-carboxylate (45). Yield: 35%. Colourless solid. M.p.
70–748. IR (KBr): 3039, 2931, 1763, 1704, 1407, 1267, 1144, 997, 877, 807, 754, 698. 1H-NMR (300
MHz, CDCl3; rotamers): 7.36–7.24 (m, 10 H); 6.93 (br. s, 1 H); 6.05 (br. s, 1 H); 5.29 (d, J=10.2, 1
H); 5.10 (s, 2 H); 3.07–2.79 (m, 2 H). 13C-NMR (75 MHz, CDCl3): 168.7; 145.5; 134.9; 128.8; 128.1;
127.9; 127.6; 124.9; 73.0; 67.9; 53.5; 37.1. Anal. calc. for C18H17NO4 (311.33): C 69.44, H 5.50, N 4.50;
found: C 69.43, H 5.61, N 4.42.