10178
C. Wiles et al. / Tetrahedron 59 (2003) 10173–10179
96%) as a colourless oil. (Found C, 63.38; H, 7.42; N, 5.47
C H O N requires C, 63.14; H, 7.57; N, 5.26%); d
DCM (3£50 ml). The combined organic extracts were dried
(MgSO ) and concentrated in vacuo to afford, after
4
1
4
20
4
H
(
400 MHz, CDCl /TMS) 1.44 (9H, s, 3£CH ), 3.95 (2H, d,
recrystallisation (DCM/hexane), the ester 28 (0.85 g, 97%)
as a cream solid; spectroscopic data as previously reported
in the literature.
3
3
J¼5.6 Hz, COCH NH), 5.08 (1H, br s, NH), 5.17 (2H, s,
2
CH Ph) and 7.36 (5H, m, Ar); d (100 MHz, CDCl /TMS)
3
2
C
2
8.3 (3£CH ), 42.5 (C(CH ) ), 67.0 (CH Ph), 80.0
3
3 3
2
(
1
NHCH CO), 128.4 (2£CH), 128.5 (2£CH), 128.6 (CH),
2
35.2 (C ), 155.7 (CO) and 170.3 (OCONH); m/z (E.I)
0
þ
2
66 (M þ1, 1%), 265 (1), 256 (75), 166 (100) and 91 (25);
Acknowledgements
GC–MS R ¼7.56 min.
T
Full financial support provided by Novartis (C.W. and P.W.)
is gratefully acknowledged.
2
9
4
.3.11. Acetic acid phenyl ester 22. Purified sodium
hydride 29 (0.06 g, 2.33 mmol) in THF (5 ml) was added to
a stirred solution of phenol 23 (0.20 g, 2.13 mmol) in THF
(
20 ml), after stirring at room temperature for 10 min, acetyl
chloride 24 (0.17 g, 2.13 mmol) was added; the reaction
mixture was stirred for a further 1 h prior to concentrating in
vacuo. The aqueous layer was neutralised with sodium
hydrogen carbonate (50 ml) and the product extracted into
DCM (3£50 ml). The combined organic extracts were
References
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2000.
dried (MgSO ) and concentrated in vacuo to afford, after
4
recrystallisation (DCM/hexane), the ester 22 (0.26 g, 90%)
as a cream solid; spectroscopic data as reported in the
literature.
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3
0
4
.3.12. Acetic acid 4-nitrophenyl ester 25. Purified
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3
.59 mmol) in THF (20 ml), after stirring at room
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for a further 1 h and subsequently concentrated in vacuo, the
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(
(
3£50 ml). The combined organic extracts were dried
MgSO ) and concentrated in vacuo to afford, after
4
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2
9
4
.3.13. Benzoic acid phenyl ester 27. Purified sodium
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after stirring at room temperature for 10 min, benzoyl
chloride 30 (0.25 ml, 2.15 mmol) was added. The reaction
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hydrogen carbonate (50 ml) and the product extracted
into DCM (3£50 ml). The combined organic extracts were
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4
recrystallisation (DCM/hexane), the ester 27 (0.41 g, 98%)
as a pale yellow solid; spectroscopic data as previously
reported in the literature.
18. Kim, S.; Kim, Y. C.; Lee, J. I. Tetrahedron Lett. 1983, 24,
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1
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3
0
4
.3.14. Benzoic acid 4-nitrophenyl ester 28. Purified
sodium hydride 29 (0.10 g, 3.96 mmol) in THF (10 ml) was
added to a stirred solution of 4-nitrophenol 26 (0.50 g,
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3
.59 mmol) in THF (25 ml). The reaction mixture was
stirred for 10 min prior to quenching with benzoyl chloride
0 (0.50 g, 3.60 mmol). The reaction mixture was stirred for
3
a further 1 h and subsequently concentrated in vacuo, the
aqueous layer was neutralised with sodium hydrogen
carbonate (50 ml) and the reaction products extracted into
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