542
A. A. Taubinger et al.
LETTER
3J = 6.7 Hz, 3 H, 4-H), 1.35 [s, 9 H, C(CH3)3], 2.89 (dd,
3J = 8.3 Hz, 3J = 6.7 Hz, 1 H, 2-H), 3.49 (s, 3 H, OCH3), 3.54
(ddq, 3J = 9.1 Hz, 3J = 7.0 Hz, 1 H, 3-H), 4.85 (dd, 3J = 9.6,
8.4 Hz, 1 H, 1¢-H), 4.96 (d, 2J = 12.6 Hz, 1 H, OCHaHbPh),
5.05 (d, 2J = 12.6 Hz, 1 H, OCHaHbPh), 6.87 (d, 3J = 9.2 Hz,
1 H, NH), 7.13 (d, 3J = 9.9 Hz, 1 H, 2¢-H), 7.22–7.39 (m, 10
H, C6H5). 13C NMR (126 MHz, CDCl3): d = 19.5 (q, C-4),
28.3 [q, C(CH3)3], 46.5 (d, C-3), 52.0 (q, OCH3), 53.3 (d, C-
1¢), 56.2 (d, C-2), 66.6 (t, OCH2Ph), 79.8 [s, C(CH3)3],
126.2, 127.7, 128.1, 128.1, 128.5, 128.7 (6 d, 2 C6H5), 136.6,
139.9 (2 s, C6H5 ipso), 155.0 (s, NHCO2t-Bu), 155.4 (s,
NHCO2Bn), 173.1 (s, C-1). IR (DRIFT): n =3416, 3337
(NH), 3065, 3033, 2978 (CH), 1722 (C=O), 1604, 1587,
1500 (C=C) cm–1. MS (FAB pos.): m/z (%) = 479 (3) [M +
Na]+, 457 (4) [M + H]+, 357 (89), 282 (10), 178 (26), 163
(d, 3J = 6.5 Hz, 3 H, 4-H), 1.05 (dtt, 2J = 13.1 Hz, 3J = 7.8,
6.5 Hz, 2 H, CH2CH2CH3), 1.36 [s, 9 H, C(CH3)3], 2.57 (dd,
3J = 10.9 Hz, 3J = 3.6 Hz, 1 H, 2-H), 2.68 (ddt, 2J = 13.3 Hz,
3J = 6.7, 4.9 Hz, 1 H, NHCHaHb), 2.94 (ddt, 2J = 13.2 Hz,
3J = 6.6, 5.9 Hz, 1 H, NHCHaHb), 3.86 (ddq, 3J = 10.8 Hz,
3J = 8.8, 6.5 Hz, 1 H, 3-H), 4.94 (dd, 3J = 8.4, 3.5 Hz, 1 H,
1¢-H), 4.98 (d, 2J = 12.4 Hz, 1 H, OCHaHbPh), 5.02 (d,
2J = 12.5 Hz, 1 H, OCHaHbPh), 6.95 (d, 3J = 8.4 Hz, 1 H,
NHCO2t-Bu), 7.21 (d, 3J = 8.5 Hz, 2 H, C6H4Cl: 2¢¢-H, 6¢¢-
H), 7.30–7.36 (m, 7 H, C6H4Cl: 3¢¢-H, 5¢¢-H, Ph), 7.49 (d,
3J = 8.8 Hz, 1 H, NH), 7.92 (t, 3J = 5.4 Hz, 1 H, NHCH2). 13
C
NMR (126 MHz, CDCl3): d = 13.6 (q, CH2CH3), 18.4 (q, C-
4), 19.7 (t, CH2CH3), 28.4 [q, C(CH3)3], 31.1 (t,
CH2CH2CH3), 39.0 (t, NHCH2), 47.4 (d, C-3), 52.6 (d, C-1¢),
56.2 (d, C-2), 66.6 (t, OCH2Ph), 79.5 [s, C(CH3)3], 127.3 (d,
C6H4Cl: C-2¢¢, C-6¢¢), 128.0, 128.1, 128.5 (3 d, Ph), 128.5 (d,
C6H4Cl: C-3¢¢, C-5¢¢), 132.8 (s, C6H4Cl: C-4¢¢), 136.5 (s, Ph),
140.1 (s, C6H4Cl: C-1¢¢), 155.5 (s, NHCO2t-Bu), 155.6 (s,
NHCO2Bn), 171.3 (s, C-1). IR (DRIFT): n = 3344 (NH),
3067, 3035, 2966, 2934, 2874 (CH), 1688, 1645 (C=O,
amide I), 1537 (NHCO, amide II) cm–1. MS (FAB pos.):
m/z (%) = 554 (30) [M + Na]+, 532 (34) [M + H]+, 476 (24),
432 (100), 238 (77), 180 (12), 165 (15), 140 (12), 91 (79).
Anal. Calcd for C28H38ClN3O5 (532.07): C, 63.21; H, 7.20;
N, 7.90. Found: C, 63.24; H, 7.18; N, 8.15.
(15), 106 (17), 91 (100). HRMS (EI): m/z calcd for
12
C
1H3314N216O6: 457.2339; found: 457.2344.
25
(15) Palomo, C.; Aizpurua, J. M.; Urchegui, R.; Iturburu, M.
J. Org. Chem. 1992, 57, 1571; see also ref. 13a.
(16) CCDC 668750 (27), CCDC 668751 (15), and CCDC 668749
(17) contain the supplementary crystallographic data for this
paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via
(17) (a) Palomo, C.; Aizpurua, J. M.; Cuevas, C. J. Chem. Soc.,
Chem. Commun. 1994, 1957. (b) Palomo, C.; Aizpurua, J.
M.; Cuevas, C.; Mielgo, A.; Galarza, R. Tetrahedron Lett.
1995, 36, 9027.
(18) (2S,3S,1¢R)-3-(Benzyloxycarbonylamino)-N-butyl-2-
[(tert-butyloxycarbonylamino)-4-chlorphenylmethyl]-
butanamide (24)
(19) Baldwin, J. E.; Adlington, R. M.; Gollins, D. W.; Schofield,
C. J. J. Chem. Soc., Chem. Commun. 1990, 720.
(20) Baldwin, J. E.; Adlington, R. M.; Gollins, D. W.; Schofield,
C. J. Tetrahedron 1990, 46, 4733.
(21) (a) Speeter, M. E.; Maroney, W. H. J. Am. Chem. Soc. 1954,
76, 5810. (b) Testa, E.; Fontanella, L.; Cristiani, G. F. Justus
Liebigs Ann. Chem. 1959, 626, 114. (c) Metzger, C. Chem.
Ber. 1971, 104, 59. (d) Bose, A. K.; Banik, B. K.; Mathur,
C.; Wagle, D. R.; Manhas, M. S. Tetrahedron 2000, 56,
5603.
BuNH2 (23 mL, 233 mmol) and NaN3 (2 mg, 31 mmol) were
added to a solution of b-lactam 2b (81 mg, 176 mmol) in
anhyd DMF (1 mL) under argon. The mixture was stirred for
42 h at r.t. (TLC), poured into brine (6 mL), and extracted
with Et2O (3 × 10 mL). The combined organic layers were
dried (MgSO4), concentrated, and purified by
(22) Buttero, P. D.; Molteni, G.; Roncoroni, M. Tetrahedron Lett.
2006, 47, 2209.
chromatography (SiO2, n-hexane–EtOAc, 4:1 → 2:1)
yielding 24 (74 mg, 139 mmol, 79%) as a colorless solid: mp
176–178 °C; [a]D20 +3.9 (c 1.00, CHCl3). 1H NMR (500
MHz, DMSO-d6): d = 0.72 (t, 3J = 7.2 Hz, 3 H, CH2CH3),
0.86 (dtq, 2J = 13.7 Hz, 3J = 7.9, 7.0 Hz, 2 H, CH2CH3), 0.98
(23) Alcaide, B.; Almendros, P.; Cabrero, G.; Ruiz, M. P. J. Org.
Chem. 2007, 72, 7980.
(24) Amundsen, L. H.; Nelson, L. S. J. Am. Chem. Soc. 1951, 73,
242.
Synlett 2008, No. 4, 539–542 © Thieme Stuttgart · New York