M. Kurono et al. / Tetrahedron 60 (2004) 1773–1780
1779
(1H, t, J¼5.0 Hz, CONHCH2), 8.13 (1H, m, CH2NHCOAr),
8.16 (1H, d, J¼8.4 Hz, H-1100). 13C NMR (CDCl3,
100 MHz) d 10.1, 11.0, 11.3, 13.5, 16.8, 17.0, 17.2, 18.0,
19.4, 26.8, 27.2, 27.6, 28.1, 28.7, 29.4, 30.2, 30.3, 31.8,
35.0, 35.1, 36.1, 38.6, 39.7, 39.8, 41.0, 46.1, 52.5, 56.2,
59.1, 63.8, 66.4, 72.4, 73.4, 74.1, 74.8, 76.5, 80.7, 95.5,
109.3, 119.2, 121.9 (q, J¼273.0 Hz), 122.2, 133.0, 134.0,
142.3, 142.9, 157.6, 164.3, 164.8, 165.3, 165.9, 169.4,
171.6, 215.3. 19F NMR (CDCl3, 376.5 MHz) d -64.83.
ESI-Q-TOF-MS Calcd for C55H81F3N5Oþ16 1124.5630
([MþH]þ). Found 1124.5658.
3:1) to remove the oxiammonium salt, the fractions were
concentrated, and separated by HPLC (Develosil ODS-UG-5
(i.d. 10.0£250 mm), 85% CH3CN/H2O, 4.0 ml/min, Tr¼15,
17 min) to give the pure Z isomer 6a (1.6 mg, 10% in two
steps) as a light yellow oil, and the pure E isomer 7a
(6.0 mg, 37% in two steps) as a light yellow oil. The total
yield was in the range of 30–56% on repeated runs. The Z or
E configurations for the above reported oximes were
1
assessed by H NMR spectroscopy. In the Z isomer 6a the
H-3 chemical shift (3.41 ppm) is down-field by 0.94 ppm in
comparison with the corresponding H-3 chemical shift
(2.47 ppm) for the E isomer 7a. Conversely, the H-1 is more
shielded (0.1 ppm) in the Z isomer 6a (1.83 ppm) than the
corresponding signal in the E isomer 7a (1.93 ppm).
7.1.13. 2-(N-tert-Butoxycarbonyl-aminooxy)-N-(3-ben-
zoyl-phenyl)-acetamide (21). To a solution of N-tert-
butoxycarbonyl-aminooxy acetic acid (16, 101 mg,
0.53 mmol) in CH2Cl2 was added 3-aminobenzophenone
(20, 219 mg, 1.06 mmol) and EDC·HCl (253 mg,
1.32 mmol). The mixture was stirred for 1 h at room
temperature, diluted with CH2Cl2 and washed with 5%
NaHCO3 aqueous solution. The organic layer was dried
over Na2SO4. After evaporation of the solvent, the residue
was purified by column chromatography (silica gel 2.0 g,
ethyl acetate/hexane¼1:3, then 1:1) to give 21 (140.0 mg,
72%) as a colorless solid.
7.1.16. Compound 6a. IR (KBr) lmax 3406, 2930, 1768,
1
1700, 1541, 1282, 1077, 987 cm21. H NMR (600 MHz,
CDCl3) d 0.79 (3H, d, J¼6.8 Hz, 7-CH3), 0.84–1.82 (19H,
m), 0.87 (3H, d, J¼7.0 Hz, 13-CH3), 0.97 (3H, d, J¼7.0 Hz,
25-CH3), 0.97 (3H, d, J¼7.0 Hz, H-26), 0.98 (3H, d,
J¼7.0 Hz, 15-CH3), 1.09 (3H, d, J¼7.1 Hz, 19-CH3), 1.11
(3H, d, J¼7.0 Hz, 3-CH3), 1.83 (3H, s, H-1), 1.99 (1H, tt,
J¼10.0, 4.2 0Hz, H-12b), 2.12 (1H, m, H-25), 2.26 (3H, d,
J¼0.8 Hz, 5 -CH3), 2.54 (1H, br s, 18-OH), 2.66 (1H, m,
H-19), 2.66 (1H, dd, J¼17.3, 4.1 Hz, H-21a), 2.77 (1H, dd,
J¼16.3, 9.8 Hz, H-20a), 2.92 (1H, dd, J¼16.3, 3.2 Hz,
H-20b), 2.98 (1H, dd, J¼17.5, 8.3 Hz, H-21b), 3.17 (1H, td,
J¼9.4, 2.5 Hz, H-6), 3.23 (1H, dd, J¼10.0, 2.1 Hz, H-14),
3.27 (1H, dd, J¼5.6, 2.0 Hz, H-23), 3.41 (1H, sext,
J¼7.0 Hz, H-3), 3.43 (3H, s, OCH3), 3.70 (1H, td, J¼8.0,
1.5 Hz, H-18), 4.36 (1H, m, H-22), 4.55 (1H, br s, 30-OH),
4.59 (2H, s, H-100), 5.09 (1H, t, J¼6.0 Hz, H-24), 5.21 (1H,
d, J¼9.1 Hz, H-30), 7.45 (1H, t, J¼7.9 Hz, H-700), 7.49 (1H,
t, J¼7.9 Hz, H-1200), 007.49 (1H, t, J¼7.9 Hz, H-1400), 7.51
(1H, t, J¼7.9 Hz, H-6 ),070 .60 (1H, t, J¼7.5 Hz, H-1300), 7.81
(1H, t, J¼6.4 Hz, H-11 ), 7.81 (1H, t, J¼6.4 Hz, H-1500),
7.82 (1H, dd, J¼2.0, 1.4 Hz, H-400), 7.93 (1H, dd, J¼7.5,
1.9 Hz, H-800), 8.12 (1H, br s, CONHAr). 13C NMR
(150 MHz, CDCl3) d 10.2, 10.9, 13.7, 15.4, 16.9, 17.3,
18.0, 18.0, 19.4, 26.7, 27.3, 27.6, 28.0, 28.7, 29.5, 30.1,
30.8, 31.5, 32.5, 34.5, 34.9, 36.0, 41.0, 45.8, 52.4, 59.0,
63.9, 66.4, 72.6, 74.1, 74.4, 75.0, 76.4, 80.6, 95.7, 121.0,
123.9, 126.3, 128.3, 128.4, 129.0, 130.1, 130.1, 132.7,
137.2, 137.4, 138.4, 142.1, 143.0, 164.8, 165.8, 165.9,
168.9, 169.5, 196.2, 215.3. ESI-Q-TOF-MS calcd for
7.1.14. Compound 21. Mp 129–130 8C (as white tiny
needles from ether-hexane). IR (KBr) lmax 3262, 2980,
2934, 1725, 1663, 1591, 1559, 1486, 1448, 1321, 1286,
1256, 1163, 1114, 721 cm21. 1H NMR (400 MHz, CDCl3) d
1.45 (9H, s, C(CH3)3), 4.43 (2H, s, COCH2O), 7.46 (1H, dd,
J¼8.0, 5.5 Hz, Ar-H), 7.48 (2H, ddd, J¼8.0, 5.5, 2.0 Hz,
Ar-H), 7.55–7.59 (2H, m, Ar-H), 7.82 (2H, m, Ar-H), 8.01
(1H, ddd, J¼8.0, 2.0, 1.0 Hz, Ar-H), 8.06 (1H, t, J¼2.0 Hz,
Ar-H), 8.10 (1H, s, CONH), 10.52 (1H, s, CH2ONH). 13C
NMR (100.6 MHz, CDCl3) d 28.0, 76.6, 83.6, 121.5, 123.8,
125.7, 128.2, 128.9, 130.0, 132.4, 137.4, 137.9, 138.2,
158.5, 167.5, 169.3. Anal. Calcd for C20H22N2O5: C, 64.85;
H, 5.99, N, 7.56. Found: C, 64.86; H, 5.95, N; 7.52.
7.1.15. Photoaffinity probe bearing the benzophenone
photophore (6a, 7a). To a solution of 21 (12.0 mg,
32.40 mmol) in CH2Cl2 (0.8 ml) was slowly added TFA
(0.8 ml) at 0 8C. After being stirred for 3 h, the reaction
mixture was evaporated. To remove TFA, the residue was
dissolved in water and concentrated under reduced pressure
to provide the aminooxy compound 22, which was used in
the coupling reaction with 1b without purification.
þ
C56H79N2O15 1019.5480 ([MþH]þ). Found 1019.5478.
7.1.17. Compound 7a. IR (KBr) lmax 3432, 2933, 1767,
1
To a solution of 1b (12.7 mg, 16.08 mmol) in 50% DMA/
H2O (0.1 ml) was added a solution of 22 in 50% DMA/H2O
(0.8 ml). This mixture was carefully maintained at pH 6
with 0.1 N NaOH. The progress of reaction was monitored
by HPLC (Develosil ODS-UG-5 (i.d. 4.6£250 mm), 85%
CH3CN/H2O, 1.0 ml/min, and UV 254 nm). After stirring
magnetically for 48 h at room temperature, the reaction
mixture was poured into a cold 0.01 N HCl solution, and
stirring magnetically for 3 h at room temperature. The two
regioisomeric (E and Z) oximes were detected by HPLC
(Develosil ODS-UG-5 (i.d. 4.6£250 mm), 85% CH3CN/
H2O, 1.0 ml/min, and UV 254 nm), the Z isomer eluted at
12 min, while the E isomer eluted at 14 min. The reaction
mixture was separated by short column chromatography on
silica gel (Develosil ODS-10/20, CH3CN/H2O¼1:1, then
1661, 1540, 1283, 1099, 918 cm21. H NMR (600 MHz,
CDCl3) d 0.77 (3H, d, J¼6.8 Hz, 7-CH3), 0.88–1.68 (19H,
m), 0.79 (3H, d, J¼7.0 Hz, 13-CH3), 0.96 (3H, d, J¼7.0 Hz,
25-CH3), 0.97 (3H, d, J¼7.1 Hz, H-26), 0.97 (3H, d,
J¼6.5 Hz, 15-CH3), 1.07 (3H, d, J¼7.0 Hz, 19-CH3), 1.09
(3H, d, J¼7.0 Hz, 3-CH3), 1.82 (1H, tt, J¼13.1, 5.5 Hz,
H-12b), 1.93 (3H, s, H-1), 2.11 (1H, m, H-25), 2.26 (3H, d,
J¼0.8 Hz, 50-CH3), 2.47 (1H, sext, J¼6.9 Hz, H-3), 2.69
(1H, m, H-19), 2.75 (1H, dd, J¼17.5, 4.8 Hz, H-21a), 2.76
(1H, dd, J¼16.3, 9.8 Hz, H-20a), 2.92 (1H, dd, J¼16.3,
3.1 Hz, H-20b), 2.97 (1H, dd, J¼17.5, 8.3 Hz, H-21b), 3.15
(1H, t, J¼9.8 Hz, H-6), 3.24 (1H, dd, J¼10.0, 2.2 Hz,
H-14), 3.26 (1H, br s, 18-OH), 3.28 (1H, dd, J¼5.6, 2.8 Hz,
H-23), 3.44 (3H, s, OCH3), 3.70 (1H, td, J¼8.0, 2.0 Hz,
H-18), 4.38 (1H, m, H-22), 4.55 (1H, d, J¼16.2 Hz, H-100a),