ꢀ-Lactam Probes for Labeling of Bacterial Enzymes
A R T I C L E S
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[3R(1′R,4R)]-4-(2-Diethylamino-ethylsulfanyl)-3-(1-hydroxy-eth-
yl)-azetidin-2-one (12). TBAF (2.4 mL, 1 M solution in THF, 2.40
mmol, 3.0 equiv) was added directly to 8 (286.2 mg, 0.79 mmol,
1.0 equiv) within 10 min at 0 °C under nitrogen. The reaction
mixture was stirred overnight and then evaporated under reduced
pressure. The residue was purified by HPLC to afford 127.8 mg
(65%) of 12 as a colorless oil. 1H NMR (200 MHz, CDCl3): δ
4.77 (d, J ) 2.3 Hz, 1H, NH-CHS), 4.23 (m, 1H, CHO), 3.07
(dd, J ) 4.9, 2.3 Hz, 1H, OdC-CH), 2.60-2.80 (m, 4H,
S-CH2-CH2), 2.40-2.60 (m, 4H, N-(CH2-CH3)2), 1.30 (d, J )
6.4 Hz, 3H, CH3-CHO), 1.03 (tr, J ) 7.2 Hz, 6H, N-(CH2-CH3)2.
HRMS calcd for C11H23N2O2S+ (M + H+) 247.14747, found
247.1476.
HPLC to afford 15 (19.5 mg, 19%) as a colorless oil. H NMR
(600 MHz, CDCl3): δ 6.04 (br, 1H, N-H), 5.30 (psquint, J ) 6.5
Hz, 1H, CHO), 4.75 (d, J ) 2.5 Hz, 1H, NH-CHS), 3.25 (ddd, J
) 7.0, 1.7 Hz, 0.5 Hz, 1H, OdC-CH), 2.60 (2tr, J ) 7.5 Hz, 2H,
S-CHH), 2.45 (tr, J ) 7.4 Hz, 2H, COOCH2), 2.27 (dt, J ) 7.0,
2.6 Hz, 2H, CH2-C′CH), 1.97 (tr, J ) 2.6 Hz, 1H, C′CH), 1.85
(psquint, J ) 7.2 Hz, 2H, CH2-CH2-COO), 1.57-1.66 (m, 2H,
S-CH2-CH2), 1.39 (d, J ) 6.4 Hz, 3H, CH3-CHO), 1.22-1.40
(m, 10H, S-CH2-CH2-C5H10-CH3), 0.88 (tr, J ) 7.0 Hz, 3H,
S-C7H14-CH3). 13C NMR (151 MHz, CDCl3): δ 172.1, 165.3,
83.6, 69.2, 67.5, 63.8, 56.2, 33.0, 31.8, 30.1, 29.9, 29.1, 29.1, 28.9,
23.6, 22.6, 18.3, 17.8, 14.1. HRMS calcd for C19H32NO3S+ (M +
H+) 354.20974, found 354.2105.
[3R(1′R,4R)]-4-(2-Diethylamino-ethylsulfanyl)-1-hex-5-ynoyl-3-
(1-hydroxy-ethyl)-azetidin-2-one (16, NCO). Compound 12 (42.6
mg, 0.17 mmol, 1.0 equiv) was dissolved in 4 mL of DCM followed
by the addition of hex-5-ynoyl chloride (45.0 mg, 0.34 mmol, 2.0
equiv) in nitrogen atmosphere. After the mixture was stirred for
10 min, NEt3 (38.5 µL, 28.0 mg, 0.28 mmol, 1.6 equiv) was added
and stirred for 1 h. Subsequently, the solution was concentrated
under reduced pressure, and the residue was purified by HPLC to
afford 16 (5.0 mg, 9%) as a colorless oil. 1H NMR (600 MHz,
CDCl3): δ 5.50 (d, J ) 3.2 Hz, 1H, NH-CHS), 4.21 (psquint, J )
7.2 Hz, 1H, CHO), 3.48-3.54 (m, 1H, S-CH2-CHH), 3.36-3.42
(m, 1H, S-CHH-CH2), 3.24-3.32 (m, 2H, S-CHH-CHH), 3.13
(quart, J ) 7.2 Hz, 4H, N-(CH2-CH3)2, 3.13 (dd, J ) 7.3, 3.3
Hz, 1H, OdC-CH), 2.85 (dt, J ) 17.0, 7.4 Hz, 1H, N-CO-CHH),
2.81 (dt, J ) 17.1, 7.3 Hz, 1H, N-CO-CHH), 2.28 (dt, J ) 7.1,
2.6 Hz, 1H, CHH-C′CH), 2.28 (dt, J ) 6.8, 2.7 Hz, 1H, CH--
C′CH), 2.00 (tr, J ) 2.6 Hz, 1H, C′CH), 1.88 (psquint, J ) 7.2
[3R(1′R,4R)]-Hex-5-ynoic Acid 1-(2-Oxo-4-propylsulfanyl-aze-
tidin-3-yl)-ethyl Ester (13, SPHx). Compound 9 (68.2 mg, 0.36
mmol, 1.0 equiv) was dissolved in DCM (8 mL) followed by the
addition of hex-5-ynoyl chloride (70.6 mg, 0.54 mmol, 1.5 equiv)
in nitrogen atmosphere. Hex-5-ynoyl chloride was prepared as
described previously.24 After the mixture was stirred for 10 min,
NEt3 (75.3 µL, 54.7 mg, 0.54 mmol, 1.5 equiv) was added and
stirred for 1 h. Subsequently, the solution was evaporated and the
residue directly purified by flash column chromatography on silica
gel (ihexane/EtOAc 2:1) to afford a colorless oil, which was in
addition purified by HPLC to give 13 (9.8 mg, 10%) as a yellow
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oil. H NMR (600 MHz, CDCl3): δ 6.09 (br, 1H, N-H),), 5.29
(psquint, J ) 6.6 Hz, 1H, CHO), 4.75 (d, J ) 2.4 Hz, 1H,
NH-CHS), 3.24 (ddd, J ) 7.1, 2.4, 0.9, 1H, OdC-CH),
2.57-2.61 (2tr, J ) 7.3 Hz, 2H, S-CH2), 2.45 (tr, J ) 7.4 Hz,
2H, COOCH2), 2.27 (dt, J ) 6.9, 2.5 Hz, 2H, CH2-C′CH), 1.97
(tr, J ) 2.6 Hz, 1H, C′CH), 1.85 (psquint, J ) 7.2 Hz, 2H,
CH2-CH2-COO), 1.64 (psquint, J ) 7.2 Hz, 2H, S-CH2-CH2),
1.39 (d, J ) 6.4 Hz, 3H, CH3-CHO), 1.01 (tr, J ) 7.3 Hz, 3H,
S-CH2-CH2-CH3). 13C NMR (151 MHz, CDCl3): δ 172.1, 165.3,
83.2, 69.2, 67.6, 63.9, 56.3, 33.0, 32.2, 23.6, 23.3, 18.3, 17.8, 13.4.
HRMS calcd for C14H22NO3S+ (M + H+) 284.13149, found
284.1320; calcd for C14H21NNaO3S+ (M + Na+) 306.11343, found
306.1140.
Hz, 2H, CH2-CH2-CON), 1.38 (tr,
J ) 7.3 Hz, 6H,
N-(CH2-CH3)2, 1.38 (d, J ) 6.4 Hz, 3H, CH3-CHO). 13C NMR
(151 MHz, CDCl3): δ 170.6, 164.5, 83.1, 69.4, 65.8, 65.1, 58.1,
51.8, 46.7 (2×), 35.4, 27.6, 22.6, 21.3, 17.8, 8.8 (2×). HRMS calcd
for C17H29N2O3S+ (M + H+) 341.18934, found 341.1894.
[3R(1′R,4R)]-Hex-5-ynoic Acid 1-(2-Oxo-4-propylsulfanyl-1-
sulfo-azetidin-3-yl)-ethyl Ester (17, SPSO3).25 A solution of 13(20.0
mg, 0.07 mmol, 1.0 equiv) in dry pyridine (150 µL) was treated
with a pyridine-sulfur trioxide complex (44.9 mg, 0.28 mmol, 4.0
equiv) and immediately warmed to 90 °C. After being stirred for
1 h at 90 °C, the reaction mixture was allowed to cool to room
temperature and was stirred overnight. The solution was then poured
into 1 M aqueous KH2PO4 (1.9 mL) followed by the addition of
n-Bu4NHSO4 (25.2 mg, 0.07 mmol, 1.1 equiv). After being stirred
for 10 min, the solution was extracted with DCM, and the organic
phase was evaporated. The residue was purified by flash column
chromatography on silica gel (EtOAc f EtOAc/MeOH 98:2) to
afford 17 (8.7 mg, 34%) as a yellow oil. 1H NMR (600 MHz,
CDCl3): δ 5.39 (psquint, J ) 6.4 Hz, 1H, CHO), 5.13 (d, J ) 2.9
Hz, 1H, NH-CHS), 3.26 (dd, J ) 7.4, 2.9, 1H, OdC-CH),
2.74-2.82 (m, 1H, S-CHH), 2.82-2.91 (m, 1H, S-CHH), 2.46
(tr, J ) 7.3 Hz, 2H, COOCH2), 2.26 (dt, J ) 7.0, 2.6 Hz, 2H,
CH2-C′CH), 2.00 (tr, J ) 2.6 Hz, 1H, C′CH), 1.83 (psquint, J )
7.2 Hz, 2H, CH2-CH2-COO), 1.58-1.70 (m, 2H, S-CH2-CH2),
1.36 (d, J ) 6.4 Hz, 3H, CH3-CHO), 0.99 (t, J ) 7.3 Hz, 3H,
S-CH2-CH2-CH3). 13C NMR (151 MHz, CDCl3): δ 172.8, 165.0,
83.4, 69.3, 67.5, 62.0, 61.9, 33.5, 33.0, 23.5, 22.7, 18.5, 17.8, 13.6.
[3R(1′R,4R)]-Hex-5-ynoic Acid 1-(2-Benzylsulfanyl-4-oxo-aze-
tidin-3-yl)-ethyl Ester (14, SBzHx). Compound 10 (58.3 mg, 0.25
mmol, 1.0 equiv) was dissolved in DCM (6 mL) followed by the
slow addition of hex-5-ynoyl chloride (114.9 mg, 0.88 mmol, 3.6
equiv) in nitrogen atmosphere. After the mixture was stirred for
10 min, NEt3 (114 µL, 82.76 mg, 0.82 mmol, 3.3 equiv) was added
and stirred overnight. Subsequently, the solution was evaporated
and the residue directly purified by flash column chromatography
on silica gel (ihexane/EtOAc 3:1) to afford 15 (24.8 mg, 30%) as
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a yellow oil. H NMR (600 MHz, CDCl3): δ 7.26-7.36 (m, 5H,
Arom.), 5.57 (br, 1H, N-H), 5.23 (psquint, J ) 6.5 Hz, 1H, CHO),
4.69 (d, J ) 2.5 Hz, 1H, NH-CHS), 3.85 (s, 2H, S-CH2-Ph),
3.71 (ddd, J ) 7.0, 2.5, 0.9, 1H, OdC-CH), 2.42 (tr, J ) 7.4 Hz,
2H, COOCH2), 2.25 (dt, J ) 7.0, 2.6 Hz, 2H, CH2-C′CH), 1.97
(tr, J ) 2.6 Hz, 1H, C′CH), 1.82 (psquint, J ) 7.2 Hz, 2H,
CH2-CH2-COO), 1.31 (d, J ) 6.4 Hz, 3H, CH3-CHO). 13C NMR
(151 MHz, CDCl3): δ 172.1, 165.2, 137.7, 129.0, 128.7, 127.6,
83.2, 69.2, 67.3, 63.5, 56.2, 35.9, 33.0, 23.6, 18.2, 17.8. HRMS
calcd for C18H22NO3S+ (M + H+) 332.13149, found 332.1322.
[3R(1′R,4R)]-Hex-5-ynoic Acid 1-(2-Octylsulfanyl-4-oxo-azeti-
din-3-yl)-ethyl Ester (15, OctHx). Compound 11 (76.9 mg, 0.30
mmol, 1.0 equiv) was dissolved in 7 mL of DCM followed by the
addition of hex-5-ynoyl chloride (58.0 mg, 0.44 mmol, 1.5 equiv)
in nitrogen atmosphere. After the mixture was stirred for 10 min,
NEt3 (61.9 µL, 44.97 mg, 0.44 mmol, 1.5 equiv) was added and
stirred for 1 h. Subsequently, the solution was concentrated under
reduced pressure, and the residue was extracted with Et2O. The
organic phase was then washed with 1 M HCl and 10% NaHCO3,
and the combined organic solutions were dried over MgSO4 and
evaporated under reduced pressure. The residue was purified by
-
HRMS calcd for C14H20NO6S2 (M - H+) 362.07375, found
362.0746.
[3R(1′R,4R)]-Hex-5-ynoic Acid 1-(2-Benzylsulfanyl-4-oxo-1-
sulfo-azetidin-3-yl)-ethyl Ester (18, SBzSO3).25 A solution of 14
(20.0 mg, 0.06 mmol, 1.0 equiv) in dry pyridine (150 µL) was
treated with a pyridine-sulfur trioxide complex (38.4 mg, 0.24
mmol, 4.0 equiv) and immediately warmed to 90 °C. After being
stirred for 1 h at 90 °C, the reaction mixture was allowed to cool
to room temperature. The solution was then poured into 1 M
aqueous KH2PO4 (1.7 mL) followed by the addition of n-Bu4NHSO4
(24) Robert Luxenhofer, R. J. Macromolecules 2006, 39, 3509–3516.
(25) Luca Banfi, G. C. Tetrahedron 1994, 50, 11967–11982.
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J. AM. CHEM. SOC. VOL. 130, NO. 40, 2008 13407