PAPER
4-Alkylidene-4H-3,1-benzoxazine Derivatives
1497
IR (neat): 1674, 1643, 1601 cm–1.
Anal. Calcd for C14H16ClNO2; C, 63.28; H, 6.07; N, 5.27. Found: C,
63.13; H, 6.13; N, 5.34.
1H NMR: d = 1.26 (t, J = 7.3 Hz, 3 H), 1.51 (d, J = 6.9 Hz, 3 H),
1.77 (d, J = 7.3 Hz, 3 H), 3.55 (dt, J = 9.2, 7.3 Hz, 1 H), 3.71 (dt,
J = 9.2, 7.3 Hz, 1 H), 4.10 (q, J = 7.3 Hz, 1 H), 5.25 (q, J = 6.9 Hz,
1 H), 7.15 (ddd, J = 7.8, 7.3, 1.4 Hz, 1 H), 7.19 (dd, J = 7.8, 1.4 Hz,
1 H), 7.24 (ddd, J = 7.8, 7.3, 1.4 Hz, 1 H), 7.33 (dd, J = 7.8, 1.4 Hz,
1 H).
(4Z)-6-Chloro-2-(1-ethoxyethyl)-4-ethylidene-4H-3,1-benzox-
azine (2i)
Yellow oil; Rf = 0.30 (C6H6).
IR (neat): 1672, 1643 cm–1.
MS: m/z (%) = 231 (98) [M+], 73 (100).
1H NMR: d = 1.26 (t, J = 7.3 Hz, 3 H), 1.50 (d, J = 6.9 Hz, 3 H),
1.77 (d, J = 7.3 Hz, 3 H), 3.51–3.57 (m, 1 H), 3.66–3.72 (m, 1 H),
4.09 (q, J = 6.9 Hz, 1 H), 5.25 (q, J = 7.3 Hz, 1 H), 7.12 (d, J = 8.7
Hz, 1 H), 7.19 (dd, J = 8.7, 2.3 Hz, 1 H), 7.30 (d, J = 2.3 Hz, 1 H).
Anal. Calcd for C14H17NO2; C, 72.70; H, 7.41; N, 6.06. Found: C,
72.70; H, 7.32; N, 5.91.
(4Z)-7-Chloro-4-ethylidene-2-(1-methoxy-1-methylethyl)-4H-
3,1-benzoxazine (2e)
Colorless crystal; Rf = 0.36 (C6H6); mp 54–55 °C (cyclohexane).
IR (KBr): 1672, 1636, 1595 cm–1.
MS: m/z (%) = 265 (60) [M+], 73 (100).
Anal. Calcd for C13H16ClNO2; C, 63.28; H, 6.07; N, 5.27. Found: C,
63.47; H, 5.97; N, 5.46.
(4Z)-4-Ethylidene-6,7-dimethoxy-2-(1-methoxypropan-2-yl)-
4H-3,1-benzoxazine (2j)
Pale-yellow solid; Rf = 0.39 (THF–hexane, 1:7); mp 113–114 °C
(hexane–Et2O).
1H NMR: d = 1.53 (s, 6 H), 1.77 (d, J = 7.3 Hz, 3 H), 3.32 (s, 3 H),
5.23 (q, J = 7.3 Hz, 1 H), 7.11 (dd, J = 8.2, 2.3 Hz, 1 H), 7.22 (d,
J = 2.3 Hz, 1 H), 7.24 (d, J = 8.2 Hz, 1 H).
MS: m/z (%) = 265 (16), [M+], 73 (100).
IR (KBr): 1670, 1638, 1607 cm–1.
Anal. Calcd for C14H16ClNO2; C, 63.28; H, 6.07; N, 5.27. Found: C,
63.25; H, 6.11; N, 5.18.
1H NMR: d = 1.54 (s, 6 H), 1.77 (d, J = 6.9 Hz, 3 H), 3.33 (s, 3 H),
3.88 (s, 3 H), 3.89 (s, 3 H), 5.03 (q, J = 6.9 Hz, 1 H), 6.76 (s, 1 H),
6.79 (s, 1 H).
6-Chloro-2-(1-methoxypropan-2-yl)-4-methylene-4H-3,1-ben-
zoxazine (2f)
MS: m/z (%) = 291 (36) [M+], 73 (100).
Pale-yellow crystal; Rf = 0.39 (EtOAc–hexane, 1:10); mp 108–109
°C (hexane).
IR (KBr): 1672, 1638 cm–1.
Anal. Calcd for C16H21NO4; C, 65.96; H, 7.27; N, 4.81. Found: C,
65.81; H, 7.51; N, 5.01.
1H NMR: d = 1.51 (s, 6 H), 3.30 (s, 3 H), 4.69 (d, J = 3.2 Hz, 1 H),
4.79 (d, J = 3.2 Hz, 1 H), 7.19 (d, J = 8.2 Hz, 1 H), 7.28 (dd, J = 8.2,
2.3 Hz, 1 H), 7.42 (d, J = 2.3 Hz, 1 H).
13C NMR: d = 24.34, 51.78, 76.87, 87.12, 122.21, 122.36, 127.96,
130.75, 133.07, 136.74, 150.55, 161.63.
Acknowledgment
We are grateful to Mrs. Miyuki Tanmatsu of this university for
determining mass spectra and performing combustion analyses.
MS: m/z (%) = 251 (89) [M+], 73 (100).
References
Anal. Calcd for C13H14ClNO2; C, 62.03; H, 5.61; N, 5.56. Found: C,
61.80; H, 5.71; N, 5.52.
(1) Krantz, A.; Spencer, R. W.; Tam, T. F.; Liak, T. J.; Copp, L.
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6-Chloro-2-(1-ethoxyethyl)-4-methylene-4H-3,1-benzoxazine
(2g)
Pale-yellow oil; Rf = 0.25 (C6H6).
IR (neat): 1660, 1634 cm–1.
1H NMR: d = 1.26 (t, J = 7.3 Hz, 3 H), 1.49 (d, J = 6.9 Hz, 3 H),
3.50–3.56 (m, 1 H), 3.64–3.70 (m, 1 H), 4.08 (q, J = 6.9 Hz, 1 H),
4.69 (d, J = 3.2 Hz, 1 H), 4.80 (d, J = 3.2 Hz, 1 H), 7.17 (d, J = 8.7
Hz, 1 H), 7.27 (dd, J = 8.7, 2.3 Hz, 1 H), 7.42 (d, J = 2.3 Hz, 1 H).
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G.; Soliani, M. J. Org. Chem. 2004, 69, 2469.
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Org. Lett. 2003, 5, 3843.
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Konishi, H. Tetrahedron 2004, 60, 11639.
MS: m/z (%) = 251 (26) [M+], 207 (67), 73 (100).
Anal. Calcd for C13H14ClNO2; C, 62.03; H, 5.61; N, 5.56. Found: C,
61.95; H, 5.60; N, 5.56.
(4Z)-6-Chloro-4-ethylidene-2-(1-methoxypropan-2-yl)-4H-3,1-
benzoxazine (2h)
Beige oil; Rf = 0.36 (CH2Cl2–hexane, 1:2).
IR (neat): 1672, 1639 cm–1.
1H NMR: d = 1.53 (s, 6 H), 1.78 (d, J = 7.3 Hz, 3 H), 3.32 (s, 3 H),
5.24 (q, J = 7.3 Hz, 1 H), 7.14 (d, J = 8.2 Hz, 1 H), 7.19 (dd, J = 8.2,
2.3 Hz, 1 H), 7.30 (d, J = 2.3 Hz, 1 H).
13C NMR: d = 9.65, 24.38, 51.73, 76.93, 98.62, 121.18, 123.40,
127.74, 129.44, 132.88, 136.30, 144.06, 161.66.
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Krapivin, G. D. Tetrahedron 2007, 63, 474.
MS: m/z (%) = 265 (88) [M+], 73 (100).
Synthesis 2009, No. 9, 1494–1498 © Thieme Stuttgart · New York