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2003 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.
3
-Methyl-2-pyridin-4-yl-1,3-oxazine
2267
CH), 1.87–1.89 (1H, mCH), 2.29 (3H,s, N-CH ), 2.42–2.48 (1H, m, CH),
3
2.73–2.83 (1H, m, CH), 3.38–3.56 (2H, m, CH and CH), 7.11–7.13 (2H, dd
J 4, 1 Hz,¼CH), 8.27–8.29 (2H, dd J 4,1 Hz,¼CH). ꢀ (74.45 MHz; CDCl )
C
3
7
.39 (q), 18.74 (t), 33.58 (t), 35.23 (q), 48.11 (t), 62.17 (t), 92.57 (s), 123. 35
þ
(d), 149.79 (d), 151.09 (s). EI m/z: (Found M , 207.1508, C H N O
1
requires 207.1508) 136, 130, UV (MeOH) ꢁmax 258 nm.
2
18
2
2
-(4-Fluorobenzoyl)-3-methyl-2-pyridin-4-yl-1,3-oxazine. Obtained in
3% yield on a 3 mmol scale.
dH 1.42 (1H br d), 2.04 (1H, m), 2.35 (3H, s), 3.10 (1H, d of t), 3.41
1H, t of d), 3.8 (1H, t of d), 4.04 (1H, m), 6.98 (2H, t J¼9 Hz), 7.52 (2H,
d J¼7 Hz), 8.18 (2H, dd J¼7 Hz, 9 Hz), 8.60 (2H, d J¼7 Hz).
-(4-Methylthiobenzoyl)-3-methyl-2-pyridin-4-yl-1,3-oxazine. Obtained
8
(
2
in 51% yield on a 10 mmol scale.
ꢀH 1.40 (1H, br d), 2.05 (1H, br m), 2.34 (3H, s, NMe), 2.48 (3H, s,
SMe), 3.12 (1H, d of t), 3.44 (1H, t of d), 3.82 (1H, t of d), 4.02 (1H, br d
of t), 7.12 (2H, d J¼8.5 Hz), 7.54 (2H, d J¼7 Hz), 8.06 (2H, d J¼8.5 Hz),
8
.60 (2H, d J¼7 Hz).
Hydrolysis of alkylated, hydroxyalkylated or acylated oxazines. The
oxazine (about 6 mmol) was dissolved in a mixture of acetic acid:water
7
ꢁ
:3 (10 mL) and heated at 70–80 C for 30 min. Most of the solvent was
evaporated and water (25 mL) was added. The product was extracted into
dichloromethane (3 ꢂ 10 mL). The combined extracts were washed with
water, sodiumhydrogen carbonate solution; dried over sodiumsulfate
and evaporated. The crude product was purified on a flash column.
1-Pyridin-4-yl-propan-1-one 4. On a 4 mmol scale a yield of 96% was
obtained.
ꢀ
1
lmax (neat) cm : 3000, 2880, 2840, 1695, 1560, 1480, 1420, 1380,
220, 1200, 745.
d (300 MHz; CDCl ): 1.14–1.19 (3H, t J 7 Hz, CH ), 2.19–2.99 (2H,
1
H
3
3
q J 7 Hz, CH ), 7.67 7.69 (2H, dd J 4, 1 Hz,¼CH), 8.73–8.75 (2H, d J
2
4
Hz,¼CH). ꢀ (74.45 MHz; CDCl ) 7.70 (q), 32.16 (t), 121. 07 (d), 142.73
C
3
þ
(s), 150.69 (d), 189.00 (s). EI m/z 135 M , 106, 78 (100%), 51. UV
MeOH) ꢁmax 275 nm.
(
1-(4-Methylthiophenyl)-2-pyridin-4-ylethanedione. Obtained in 93%
yield on a 4 mmol scale.
dH 2.54 (3H, s, SMe), 7.34 (4H, overlapping d), 7.78 (2H, d J¼7 Hz),
7.88 (2H, d J¼8.5 Hz).
ACKNOWLEDGMENT
We thank Professor Keith Jones for helpful advice and comments.