A. Napieraj et al. / Tetrahedron 56 (2000) 6299±6305
6305
1
.37 (3H, t, J7.2 Hz, CH CH OP(O)), 4.05±4.27 (4H, m,
(6.12 g, 0.04 mol) and ketone diethyl acetal (15) (0.08 mol)
was placed in a distillation ¯ask and heated up to 1808C in
the reacting mixture until EtOH distilled off. The residue
was distilled in vacuo to give the forerun consisting of the
acetal (15) used in excess. The high boiling fraction was
pure enamide (17) or a tautomeric mixture of (17) and (16).
Both compounds were colorless liquids.
3
2
CH CH OP(O)), 4.29 (4H, q, J7.2 Hz, CH CH OCO),
3
2
3
2
8
.12 (1H, dd, J13.3, 10.5 Hz, vCH), 9.68 (1H, br t,
NH); d 0.15.
P
Reduction of (5a) followed by dephosphorylation. 4-
Aminobutan-2-ol tosylate. A solution of (5a) (1.1 g,
0.005 mol) in EtOH (5 ml) was added with stirring to the
suspension of sodium borohydride (0.76 g, 0.02 mol) in
EtOH (15 ml). Stirring was continued for 12 h at room
temperature. Solvent was then evaporated and the residue
Acknowledgements
was dissolved in CHCl (50 ml). The solution was washed
3
Financial support by a grant 3 T-09A 103 14 from the Polish
Committee of Scienti®c Researches (KBN) is gratefully
acknowledged.
with water (2£15 ml), dried (MgSO ) and evaporated. The
4
solution of p-toluenesulfonic acid monohydrate (0.95 g,
0.005 mol) in EtOH (10 ml) was added to the residue and
the mixture was re¯uxed for 6 h. It was then concentrated,
References
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2
Crystalline tosylate was ®ltered off and recrystallized from
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1
2
3
3
4
1
5
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200, 2900, 1604, 1510, 1200, 1140, 1100, 1050, 800,
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9
0.005 mol of (5d). Yield Ð 0.92 g (57%) of a white solid,
2
1
5
1
15±216.
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6
21
4
(
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2
180, 1140, 930, 800, 770, 700 cm ; d (DMSO-d6)
1
1
1
2
H
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1
3
1
.80±2.91 (2H, m, CH NH ), 4.67 (1H, t, J7.0 Hz,
2
0
0
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5
1
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6 4
2
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2
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2
gen at room temperature. for 2 h. The solvent was then
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®
could not be distilled without decomposition. Distilled
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