L. S. Monteiro et al.
FULL PAPER
59.0–60.0 °C (diethyl ether/n-hexane). 1H NMR (300 MHz,
CDCl3): δ = 1.19 (t, J = 7.2 Hz, 3 H, CH2CH3), 2.42 (s, 3 H, γCH3),
143.30 (C), 146.02 (C), 164.12 (C=O) ppm. C14H18BrNO4S
(376.27): calcd. C 44.69, H 4.82, N 3.72, S 8.52; found C 45.02, H
3.49 (q, J = 7.2 Hz, 2 H, CH2CH3), 3.73 (s, 3 H, CH3 OMe), 5.23 4.89, N 3.87, S 8.32.
[br. s, 2 H, CH2 Z(NO2)], 7.46 (d, J = 8.7 Hz, 2 H, ArH), 8.22 (d,
Z(NO2)-N(Et)-Z-ΔPhe(β-Br)-OMe (Z-9a): The general procedure
J = 8.7 Hz, 2 H, ArH) ppm. 13C NMR (75.4 MHz, CDCl3): δ =
12.84 (CH3), 27.00 (γCH3), 44.43 (CH2), 52.32 (OCH3), 66.03 [CH2
Z(NO2)], 123.73 (CH), 127.88 (CH), 129.45 (C), 132.95 (C), 143.61
(C), 147.57 (C), 154.22 (C=O), 164.00 (C=O) ppm. C15H17BrN2O6
(401.21): calcd. C 44.90, H 4.27, N 6.98; found C 45.23, H 4.40, N
7.07.
described above was followed using Z(NO2)-Z-ΔPhe(β-Br)-OMe
(Z-6a; 0.109 g, 0.250 mmol) as reactant to afford a colorless oil
(0.076 g) consisting of a mixture of product and reactant in a 45:55
ratio. Purification by column chromatography (diethyl ether/petro-
leum ether) afforded Z-9a (0.034 g, 30%) as a yellowish solid; m.p.
117.0–118.0 °C (from ethyl acetate/n-hexane). 1H NMR (400 MHz,
CDCl3): δ = 1.33 (t, J = 7.6 Hz, 3 H, CH2CH3), 3.42 (s, 3 H, CH3
OMe), 3.71 (br. m, 2 H, CH2CH3), 5.28 [s, 2 H, CH2 Z(NO2)],
7.30–7.40 (m, 5 H, ArH), 7.50 (d, J = 8.4 Hz, 2 H, ArH), 8.21 (d,
J = 8.4 Hz, 2 H, ArH) ppm. 13C NMR (100.6 MHz, CDCl3): δ =
13.13 (CH2CH3), 43.85 (CH2), 52.26 (OCH3), 66.20 [CH2 Z(NO2)],
123.67 (CH), 127.90 (CH), 128.16 (CH), 128.31 (CH), 129.90 (CH),
131.28 (C), 138.32 (C), 138.60 (C), 143.71 (C), 147.56 (C), 153.89
(C=O), 164.19 (C=O) ppm. C20H19BrN2O6 (463.28): calcd. C
51.85, H 4.13, N 6.05; found C 51.91, H 4.15, N 6.12.
Z(NO2)-N(Et)-Z-ΔAbu(β-Br)-OMe (Z-8a): The general procedure
described above was followed using Z(NO2)-Z-ΔAbu(β-Br)-OMe
(Z-5a; 0.187 g, 0.500 mmol) as reactant to afford a yellowish oil
(0.178 g) consisting of a mixture of product and reactant in a 37:63
product/reactant ratio. Purification by column chromatography (di-
ethyl ether/petroleum ether) afforded Z-8a (0.066 g, 33%) as a col-
orless oil; m.p. 73.0–73.5 °C (diethyl ether/n-hexane). 1H NMR
(300 MHz, CDCl3): δ = 1.20 (t, J = 7.2 Hz, 3 H, CH2CH3), 2.85
(s, 3 H, γCH3), 3.55 (q, J = 7.2 Hz, 2 H, CH2CH3), 3.71 (s, 3 H,
CH3 OMe), 5.21 [s, 2 H, CH2 Z(NO2)], 7.45 (d, J = 8.7 Hz, 2 H,
ArH), 8.19 (d, J = 8.7 Hz, 2 H, ArH) ppm. 13C NMR (100.6 MHz,
CDCl3): δ = 12.83 (CH3), 26.83 (γCH3), 44.17 (CH2), 52.36
(OCH3), 65.78 [CH2 Z(NO2)], 123.61 (CH), 127.81 (CH), 130.02
(C), 142.90 (C), 143.99 (C), 147.47 (C), 154.00 (C=O), 163.64
(C=O) ppm. C15H17BrN2O6 (401.21): calcd. C 44.90, H 4.27, N
6.98; found C 44.89, H 4.40, N 7.03.
Z-N(Et)-Z-ΔPhe(β-Br)-OMe (Z-9b): The general procedure de-
scribed above was followed using Z-Z-ΔPhe(β-Br)-OMe (Z-6b;
0.133 g, 0.341 mmol) as reactant to afford a colorless oil (0.135 g)
consisting of a mixture of product and reactant in a 38:62 ratio.
Purification by column chromatography (diethyl ether/petroleum
ether) afforded Z-9b (0.051 g, 36%) as a colorless oil. 1H NMR
(300 MHz, CDCl3): δ = 1.32 (t, J = 7.5 Hz, 3 H, CH2CH3), 3.33
(s, 3 H, CH3 OMe), 3.72 (q, J = 7.5 Hz, 2 H, CH2CH3), 5.19 (s, 2
H, CH2 Z), 7.30–7.37 (m, 10 H, ArH) ppm. 13C NMR (100.6 MHz,
CDCl3): δ = 14.08 (CH2CH3), 43.54 (CH2), 52.06 (OCH3), 67.66
(CH2 Z), 127.85 (CH), 127.94 (CH), 128.15 (CH), 128.20 (CH),
128.32 (CH), 129.57 (CH), 131.64 (C), 136.22 (C), 137.43 (C),
138.87 (C), 154.39 (C=O), 164.17 (C=O) ppm. HRMS (ESI): calcd.
for C20H20NNaO4Br 440.04734; found 440.04658.
Z-N(Et)-Z-ΔAbu(β-Br)-OMe (Z-8b): The general procedure de-
scribed above was followed using Z-Z-ΔAbu(β-Br)-OMe (Z-5b;
0.318 g, 0.970 mmol) as reactant to afford a colorless oil (0.322 g)
consisting of a mixture of product and reactant in a 43:57 ratio.
Purification by column chromatography (diethyl ether/petroleum
ether) afforded Z-8b (0.138 g, 40%) as a colorless oil that failed to
crystallize. 1H NMR (300 MHz, CDCl3): δ = 1.19 (t, J = 7.2 Hz, 3
H, CH2CH3), 2.84 (s, 3 H, γCH3), 3.52 (q, J = 7.2 Hz, 2 H,
CH2CH3), 3.59 (s, 3 H, CH3 OMe), 5.22 (s, 2 H, CH2 Z), 7.28–
7.39 (m, 5 H, ArH) ppm. 13C NMR (100.6 MHz, CDCl3): δ = 12.91
(CH3), 26.74 (γCH3), 43.95 (CH2), 52.12 (OCH3), 67.19 (CH2 Z),
127.72 (CH), 127.84 (CH), 128.31 (CH), 130.30 (C), 136.50 (C),
142.11 (C), 154.53 (C=O), 163.82 (C=O) ppm. HRMS (ESI): calcd.
for C15H18NNaO4Br 378.03169; found 378.03114.
Attempted Synthesis of Boc-N(Et)-Z-ΔPhe(β-Br)-OMe (Z-9c): The
general procedure described above was followed using Boc-Z-
ΔPhe(β-Br)-OMe (Z-6c; 0.178 g, 0.500 mmol) as reactant to afford
a colorless oil (0.175 g) consisting of a mixture of product and reac-
tant in a 15:85 ratio that could not be separated.
Nosyl-N(Et)-Z-ΔPhe(β-Br)-OMe (Z-9f): The general procedure de-
scribed above was followed using Nosyl-Z-ΔPhe(β-Br)-OMe (Z-6f;
0.309 g, 0.700 mmol) as reactant to afford Z-9f (0.294 g, 90%) as
a colorless oil; m.p. 118.0–119.0 °C (ethyl acetate/n-hexane). 1H
NMR (300 MHz, CDCl3): δ = 1.37 (t, J = 7.2 Hz, 3 H, CH2CH3),
3.41 (s, 3 H, CH3 OMe), 3.66 (br. m, 2 H, CH2CH3), 7.31–7.41 (m,
5 H, ArH), 8.14 (d, J = 8.7 Hz, 2 H, ArH Nosyl), 8.39 (d, J =
8.7 Hz, 2 H, ArH Nosyl) ppm. 13C NMR (100.6 MHz, CDCl3): δ =
14.06 (CH2CH3), 44.74 (CH2), 52.39 (OCH3), 124.02 (CH), 128.13
(CH), 128.34 (CH), 129.13 (CH), 129.19 (C), 130.20 (CH), 138.47
(C), 142.26 (C), 145.35 (C), 150.17 (C), 164.58 (C=O) ppm.
C18H17BrN2O6S (469.31): calcd. C 46.07, H 3.65, N 5.97, S 6.83;
found C 45.98, H 3.72, N 5.98, S 6.85.
Nosyl-N(Et)-Z-ΔAbu(β-Br)-OMe (Z-8f): The general procedure de-
scribed above was followed using Nosyl-Z-ΔAbu(β-Br)-OMe (Z-5f;
0.081 g, 0.214 mmol) as reactant to afford Z-8f (0.081 g, 93%) as
a light-yellow solid; m.p. 108.0–109.0 °C (diethyl ether/n-hexane).
1H NMR (300 MHz, CDCl3): δ = 1.23 (t, J = 7.2 Hz, 3 H,
CH2CH3), 2.85 (s, 3 H, γCH3), 3.58 (br. m, 2 H, CH2CH3), 3.67
(s, 3 H, CH3 OMe), 8.04 (d, J = 8.7 Hz, 2 H, ArH), 8.35 (d, J =
8.7 Hz, 2 H, ArH) ppm. 13C NMR (75.4 MHz, CDCl3): δ = 13.82
(CH2CH3), 27.64 (γCH3), 45.20 (CH2), 52.43 (OCH3), 123.91
(CH), 128.11 (C), 128.96 (CH), 145.74 (C), 147.09 (C), 149.99 (C),
163.72 (C=O) ppm. C13H15BrN2O6S (407.24): calcd. C 38.34, H
3.71, N 6.88, S 7.87; found C 38.76, H 3.85, N 6.92, S 7.85.
Tos-N(Et)-Z-ΔPhe(β-Br)-OMe (Z-9g): The general procedure de-
scribed above was followed using Tos-Z-ΔPhe(β-Br)-OMe (Z-6g;
0.205 g, 0.500 mmol) as reactant to afford Z-9g (0.194 g, 89%) as a
colorless oil; m.p. 99.0–100.0 °C (diethyl ether/n-hexane). 1H NMR
(300 MHz, CDCl3): δ = 1.33 (t, J = 7.2 Hz, 3 H, CH2CH3), 2.45
Tos-N(Et)-Z-ΔAbu(β-Br)-OMe (Z-8g): The general procedure de-
scribed above was followed using Tos-Z-ΔAbu(β-Br)-OMe (Z-5g;
0.085 g, 0.244 mmol) as reactant to afford Z-8g (0.072 g, 78%) as
a colorless oil; m.p. 93.0–94.0 °C (diethyl ether/n-hexane). 1H NMR
(400 MHz, CDCl3): δ = 1.19 (t, J = 7.2 Hz, 3 H, CH2CH3), 2.43 (s, 3 H, CH3 Tos), 3.39 (s, 3 H, CH3 OMe), 3.62 (br. q, J = 7.2 Hz,
(s, 3 H, CH3 Tos), 2.82 (s, 3 H, γCH3), 3.46 (br. m, 2 H, CH2CH3), 2 H, CH2CH3), 7.31–7.38 (m, 7 H, ArH), 7.83 (d, J = 8.4 Hz, 2 H,
3.60 (s, 3 H, CH3 OMe), 7.29 (d, J = 8.8 Hz, 2 H, ArH), 7.73 (d, ArH Tos) ppm. 13C NMR (75.4 MHz, CDCl3):
δ
=
14.00
J = 8.8 Hz, 2 H, ArH) ppm. 13C NMR (100.6 MHz, CDCl3): δ =
(CH2CH3), 21.57 (Tos CH3), 44.11 (CH2), 52.16 (OCH3), 127.88
13.79 (CH2CH3), 21.51 (Tos CH3), 27.45 (γCH3), 44.63 (CH2), (CH), 128.17 (CH), 128.21 (CH), 129.36 (CH), 129.82 (CH), 129.90
52.10 (OCH3), 127.76 (CH), 128.51 (C), 129.23 (CH), 137.23 (C), (C), 136.80 (C), 138.86 (C), 140.48 (C), 143.63 (C), 164.89
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Eur. J. Org. Chem. 2011, 6764–6772