H. Ikeda et al. / Tetrahedron 63 (2007) 5677–5689
5687
(d, J¼7.6 Hz, 1H), 7.86 (d, J¼8.7 Hz, 2H), 7.80 (ma) and
7.77 (mi) (d, J¼7.5 Hz, 1H), 7.49 (t, J¼7.9 Hz, 1H), 6.74 (d,
J¼8.7 Hz, 2H), 4.12 (mi) and 4.03 (ma) (br s, 2H), 3.74 (m,
2H), 3.49 (br t, 2H), 3.24 (br t, 2H), 3.08 (s, 6H), 1.43 (mi)
and 1.37 (ma) (br s, 9H); 13C NMR (150 MHz, CDCl3)
d 173.70, 171.53 (d), 168.24 (d), 156.35 (d), 152.94, 152.84,
143.26, 134.93 (d), 129.31, 128.03 (d), 125.36, 125.06,
120.56 (d), 111.60, 79.89 (d), 49.19 (d), 40.28, 38.63 (d),
36.19 (d), 32.35 (d), 28.30, 25.33; HRMS (FAB+) calcd for
C27H37N6O6 [(M+H)+] 541.2775, observed 541.2779.
31.74 (d), 29.12 (d), 28.81 (d), 28.04 (d), 26.06, 25.07,
24.28 (d); HRMS (FAB+) calcd for C30H43N6O6 [(M+H)+]
583.3244, observed 583.3248.
4.1.21. General procedure for the preparation of the pho-
toactive peptide nucleic acid monomer unit.
4.1.21.1. N-(2-(Azobenzene-4-carbonylamino)acetyl)-
N-(2-((tert-butoxy)carbonylamino)ethyl)glycine (Azo–
Gly–BocPNA–OH, 45). To a solution of 20 (50 mg,
0.18 mmol) in DMF (10 mL) were added Azo–OSu
(73 mg, 0.20 mmol) and TEA (3.5 mL, 0.27 mmol). The
reaction mixture was stirred at room temperature for 15 h.
The reaction mixture was evaporated and the residue was
flash-chromatographed (0–10% MeOH/CH2Cl2) to give 45
4.1.20.3. N-(2-((tert-Butoxy)carbonylamino)ethyl)-N-
(4-(3-(40-dimethylaminophenylazo)benzoylamino)buta-
noyl)glycine (m-MR–GABA–BocPNA–OH, 42). The
compound 42 was obtained in 91% yield as an orange pow-
1
(95 mg, quant.) as an orange powder. H NMR (600 MHz,
1
der in the same way as for the preparation of 40. H NMR
CD3OD) d 7.95 (d, J¼7.1 Hz, 2H), 7.85–7.75 (m, 4H),
7.5–7.4 (m, 3H), 4.3–4.0 (m, 2H), 3.94 (ma) and 3.90 (mi)
(br d, J¼9.4 Hz, 2H), 3.50–3.35 (m, 2H), 3.2–3.1 (m, 2H),
1.34 (mi) and 1.31 (ma) (s, 9H); 13C NMR (150 MHz,
CD3OD) d 175.80 (d), 171.46 (d), 169.39 (d), 158.45 (d),
157.74 (d), 155.73, 153.92 (d), 132.87, 130.33, 129.73 (d),
124.06, 123.74 (d), 80.36 (d), 69.14, 42.64 (d), 39.39 (d),
28.78, 26.24; HRMS (FAB+) calcd for C24H30N5O6
[(M+H)+] 484.2196, observed 484.2187.
(600 MHz, CDCl3) d 8.16 (ma) and 8.14 (mi) (s, 1H), 7.90
(br d, J¼7.9 Hz, 1H), 7.86 (br d, 2H), 7.84 (d, J¼8.6 Hz,
1H), 7.48 (t, J¼7.6 Hz, 1 H), 6.73 (d, J¼8.7 Hz, 2H), 4.12
(mi) and 3.98 (ma) (br s, 2H), 3.49 (m, 4H), 3.25 (m, 2H),
3.08 (mi) and 3.07 (ma) (s, 6H), 2.56 (ma) and 2.34 (mi) (br
t, 2H), 1.99 (m, 2H), 1.43 (mi) and 1.38 (ma) (br s, 9H); 13C
NMR (150 MHz, CDCl3) d 174.95 (d), 171.50 (d), 167.75
(d), 156.40 (d), 152.87, 152.66 (d), 143.17 (d), 135.08 (d),
129.31 (d), 128.43 (d), 125.41 (d), 124.19 (d), 121.16 (d),
111.61, 79.73 (d), 49.34 (d), 40.30, 39.88 (d), 38.69 (d),
30.36 (d), 28.34, 25.32, 23.72 (d); HRMS (FAB+) calcd for
C28H39N6O6 [(M+H)+] 555.2931, observed 555.2928.
4.1.21.2.
N-(3-(Azobenzene-4-carbonylamino)pro-
pionyl)-N-(2-((tert-butoxy)carbonylamino)ethyl)glycine
(Azo–b-Ala–BocPNA–OH, 46). The compound 46 was ob-
tained in 82% yield as an orange powder in the same way as
1
4.1.20.4. N-(2-((tert-Butoxy)carbonylamino)ethyl)-N-
(6-(3-(40-dimethylaminophenylazo)benzoylamino)penta-
noyl)glycine (m-MR–C4–BocPNA–OH, 43). The com-
pound 43 was obtained in 91% yield as an orange powder
for the preparation of 45. H NMR (600 MHz, DMSO-d6)
d 8.71 (ma) and 8.63 (mi) (br t, 1H), 8.2–8.0 (m, 2H), 7.94
(m, 4H), 7.61 (m, 3H), 6.86 (ma) and 6.79 (mi) (br t, 1H),
3.95 (mi) and 3.92 (ma) (s, 2H), 3.50 (ma) and 3.40 (mi)
(br t, 2H), 3.37 (ma) and 3.32 (mi) (br t, 2H), 3.08 (ma)
and 3.05 (mi) (m, 2H), 2.65 (ma) and 2.59 (mi) (m, 2H),
1.35 (mi) and 1.34 (ma) (s, 9H); 13C NMR (150 MHz,
DMSO-d6) d 171.50 (d), 171.07 (d), 165.26 (d), 155.56,
153.86, 153.18 (d), 151.90, 131.96 (d), 129.50, 128.41 (d),
122.69 (d), 122.30 (d), 77.67 (d), 47.55 (d), 37.98 (d),
36.08 (d), 31.83 (d), 28.14 (d), 25.18; HRMS (FAB+) calcd
for C25H32N5O6 [(M+H)+] 498.2353, observed 498.2358.
1
in the same way as for the preparation of 40. H NMR
(600 MHz, DMSO-d6) d 8.68 (ma) and 8.66 (mi) (br t, 1H),
8.23 (br s, 1H), 7.91 and 7.88 (each d, J¼7.7 Hz, 1H), 7.82
(br d, J¼8.9 Hz, 2H), 7.58 (br t, J¼7.6 Hz, 1H), 6.84 (d,
J¼8.9 Hz, 2H), 3.75 (mi) and 3.70 (ma) (br s, 2H), 3.5–3.2
(m, 6H), 3.06 (s, 6H), 2.32 (mi) and 2.20 (ma) (br t, 2H),
1.54 (m, 4H), 1.35 (mi) and 1.33 (ma) (br s, 9H); 13C NMR
(150 MHz, DMSO-d6) d 172.96 (d), 172.24 (d), 165.60,
155.57, 152.68, 152.36, 142.51, 135.79, 128.89 (d), 128.05
(d), 124.89, 123.92 (d), 120.65 (d), 111.55, 77.54 (d), 48.23
(d), 37.99 (d), 31.77 (d), 28.81 (d), 28.23, 28.19, 25.18,
22.23 (d); HRMS (FAB+) calcd for C29H41N6O6 [(M+H)+]
569.3088, observed 569.3082.
4.1.21.3. N-(4-(Azobenzene-4-carbonylamino)buta-
noyl)-N-(2-((tert-butoxy)carbonylamino)ethyl)glycine
(Azo–GABA–BocPNA–OH, 47). The compound 47 was ob-
tained in 88% yield as an orange powder in the same way as
1
for the preparation of 45. H NMR (600 MHz, DMSO-d6)
4.1.20.5. N-(2-((tert-Butoxy)carbonylamino)ethyl)-N-
(6-(3-(40-dimethylaminophenylazo)benzoylamino)hexa-
noyl)glycine (m-MR–C5–BocPNA–OH, 44). The com-
pound 44 was obtained in 95% yield as an orange powder
d 9.00 (ma) and 8.71 (mi) (br t, 1H), 8.18 (ma) and 8.06
(mi) (d, J¼7.9 Hz, 2H), 7.93 (m, 4H), 7.62 (m, 3H), 7.15–
7.00 (m, 1H), 3.73 (mi) and 3.67 (ma) (s, 2H), 3.40–3.25
(m, 4H), 3.08 (mi) and 3.02 (ma) (q, J¼5.3 Hz, 2H), 2.38
(mi) and 2.25 (ma) (br t, J¼6.1 Hz, 2H), 1.76 (m, 2H),
1.36 (mi) and 1.34 (ma) (s, 9H); 13C NMR (150 MHz,
DMSO-d6) d 172.46, 171.42, 165.15 (d), 155.54, 155.50,
153.10 (d), 151.91, 136.76, 131.85, 129.48, 128.55 (d),
122.66, 122.16, 77.46 (d), 53.09, 47.78, 46.81, 29.40,
28.21, 28.16 (d), 24.63 (d); HRMS (FAB+) calcd for
C26H34N5O6 [(M+H)+] 512.2509, observed 512.2516.
1
in the same way as for the preparation of 40. H NMR
(600 MHz, DMSO-d6) d 8.62 (br t, 1H), 8.23 (ma) and
8.20 (mi) (br s, 1H), 7.89 (m, 2H), 7.82 (ma) and 7.76 (mi)
(d, J¼9.1 Hz, 2H), 7.59 (br t, J¼8.0 Hz, 1H), 6.84 (ma)
and 6.68 (mi) (d, J¼9.1 Hz, 2H), 3.95 (mi) and 3.88 (ma)
(br s, 2H), 3.35–3.25 (m, 4H), 3.06 (s, 6H), 3.01 (m, 4H),
2.32 (ma) and 2.16 (mi) (br t, J¼7.1 Hz, 2H), 1.54 (m,
4H), 1.35 (mi) and 1.33 (ma) (br s, 9H); 13C NMR
(150 MHz, DMSO-d6) d 172.42 (d), 171.38 (d), 165.47,
155.45, 152.83 (d), 152.25 (d), 142.47 (d), 135.77 (d),
129.01, 127.81 (d), 124.94 (d), 123.74, 120.45 (d), 111.31
(d), 77.53 (d), 47.30 (d), 45.80 (d), 39.35 (d), 37.96 (d),
4.1.21.4. N-(6-(Azobenzene-4-carbonylamino)penta-
noyl)-N-(2-((tert-butoxy)carbonylamino)ethyl)glycine
(Azo–C4–BocPNA–OH, 48). The compound 48 was ob-
tained in 92% yield as an orange powder in the same way