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B. S. Moon et al. / Bioorg. Med. Chem. Lett. 17 (2007) 200–204
uptakes of [18F]2 and [18F]3 increased with time elapsed
but the uptake of [18F]1 and [18F]4 decreased. On the ba-
sis of these results, the ratios of tumor-to-blood (T/B)
and tumor-to-brain (T/Br) for radiotracers were com-
pared with [18F]FET (T/Bl ratio: 1.80 0.13; T/Br ratio:
2.81 0.24).21 The T/Bl ratios of [18F]1, [18F]2, and
[18F]4 were similar to that of [18F]FET. However, the
T/Bl ratio of [18F]3 was higher than that of [18F]FET
at 60 min post-injection (p < 0.05). The T/Br ratio of
[18F]2 was higher than that of [18F]FET (p < 0.05). The
T/Br ratios of [18F]1, [18F]3, and [18F]4 were similar to
that of [18F]FET. These results demonstrate that
[18F]ortho-FPT ([18F]2) showed similar T/Bl ratio with
[18F]FET and better T/Br ratios in 9L tumor bearing
rat than [18F]FET. [18F]MFET ([18F]3) showed better
T/Bl ratio than [18F]FET and similar T/Br ratios than
[18F]FET. In the PET study of the brain tumor, the im-
age contrast of [18F]fluoroalkyltyrosines appears to be
similar to that of [18F]FET (data not shown). Moreover,
[18F]fluoroalkyltyrosine can be efficiently radiolabeled
with F-18. Therefore, it is expected that [18F]ortho-
FPT ([18F]2) may have potential application in the
detection of brain tumors and [18F]MFET may have
some advantage in peripheral tumor imaging. In conclu-
sion, [18F]ortho-FPT ([18F]2) and [18F]MFET ([18F]3)
might show a possibility to use a more useful tumor
imaging agent than [18F]FET.
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Acknowledgments
19. Lee, K. C.; Lee, S. Y.; Choe, Y. S.; Chi, D. Y. Bull. Korean
Chem. Soc. 2004, 25, 1225.
This study was supported by Korea Science and Engi-
neering Foundation (KOSEF) and Ministry of Science
& Technology (MOST), Republic of Korea, through
its National Nuclear Technology Program. Thanks to
Kwang Sun Woo and Wee Sup Jung for technical
assistance.
20. Structure analysis data. ortho-FET (1): 1H NMR
(300 MHz, CD3OD) d 7.07 (s, 1H), 7.02 (dd, J = 8.1,
2.2 Hz, 1H), 6.77 (d, J = 8.1 Hz, 1H), 4.67 (dt, J = 47.4,
6.9 Hz, 2H), 3.72 (t, J = 4.5 Hz, 1H), 3.19–3.17 (m, 1H),
3.04–2.92 (m, 3H); MS (FAB) m/z: 228 (MH+). HRMS
(FAB) Calcd for C11H15NO3F (MH+) 228.1036. Found:
1
228.1036. ortho-FPT (2): H NMR (300 MHz, CD3OD) d
7.05 (d, J = 1.8 Hz, 1H), 6.99 (dd, J = 8.1, 2.4 Hz, 1H),
6.76 (d, J = 1H), 4.46 (dt, J = 47.4, 6.3 Hz, 2H), 3.74–3.71
(m, 1H), 3.20–3.18 (m, 1H), 2.96–2.93 (m, 1H), 2.70 (t,
J = 7.5 Hz, 2H), 2.04–1.88 (m, 2H); MS (FAB) m/z: 242
(MH+). HRMS (FAB) Calcd for C12H17NO3F (MH+)
242.1192. Found: 242.1189. MFET (3): 1H NMR
References and notes
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(300 MHz, CD3OD)
d 7.20–7.14 (m, 1H), 6.93 (d,
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J = 8.1 Hz, 1H), 4.56 (dt, J = 47.4, 6.6 Hz, 2H), 3.83 (s,
3H), 3.76–3.72 (m, 1H), 3.27–3.22 (m, 1H), 3.06–2.95 (m,
3H); MS (FAB) m/z: 242 (MH+). HRMS (FAB) Calcd for
C12H17NO3F (MH+) 242.1192. Found: 242.1192. MFPT
(4): 1H NMR (300 MHz, CD3OD) d 7.15–7.11 (m, 2H),
6.91 (d, J = 8.1 Hz, 1H), 4.44 (dt, J = 47.4, 6.3 Hz, 2H),
3.82 (s, 3H), 3.75–3.72 (m, 1H), 3.24–3.22 (m, 1H), 2.95–
2.92 (m, 1H), 2.68 (t, J = 7.5 Hz, 2H), 2.02–1.93 (m, 2H);
MS (FAB) m/z: 256 (MH+). HRMS (FAB) Calcd for
C13H19NO3F (MH+) 256.1349. Found: 256.1349.
21. Moon, B. S.; Kim, S. W.; Lee, T. S.; Ahn, S. H.; Lee, K.
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