• Title/Summary/Keyword: ${\alpha}$-iodination

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Novel synthetic method for the preparation of α-iododaphnetin using benzyltrimethylammonium dichloroiodate

  • Kim, Taek-Soo;Kim, Bo-Ram;Park, Jeong Hoon;Yang, Seung Dae
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.2 no.1
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    • pp.56-60
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    • 2016
  • Benzyltrimethylammonium dichloroiodate in the presence of $ZnCl_2$ has been used for aromatic iodination of electron rich aromatic compounds. However, Baylis-Hillman type regioselective ${\alpha}$-iodination was carried out electronically rich coumarin compound under mild reaction condition with excellent chemical yield. Finally, $BBr_3$ demethylation gave ${\alpha}$-iododaphnetin.

Direct radio-iodination of folic acid for targeting folate receptor-positive tumors

  • Huynh, Phuong Tu;Lee, Woonghee;Ha, Yeong Su;Yoo, Jeongsoo
    • Journal of Radiopharmaceuticals and Molecular Probes
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    • v.4 no.1
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    • pp.3-10
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    • 2018
  • The folate receptor (FR) is a promising cell membrane-associated target for nuclear imaging of various cancers (via imaging $FR-{\alpha}$) and potentially also inflammatory diseases (via imaging $FR-{\beta}$), through the use of folic acid-based radioconjugates. However, there have been several drawbacks of previously reported radioconjugates, such as a short half-life of the radiolabel ($^{68}Ga\;t_{1/2}$ 68 min), a complex and time-consuming multistep radiosynthesis, and a high renal uptake of radiolabeled folate derivatives. The goal of this study was to develop an imaging probe by directly labeling folate with radioactive iodine without using an extra prosthetic group. The radiolabeling of folate was optimized using various labeling conditions and the labeled tracers were isolated by high-performance liquid chromatography. The in vitro stability of labeled folate was checked in phosphate-buffered saline and serum. The tumor-targeting efficacy of the probe was also evaluated by biodistribution studies using a murine 4T1 tumor model.

Synthesis of L-3-[$^{123}I$]iodo-${\alpha}$-methyltyrosine and Biodistribution in 9L Glioma Bearing Rats (L-3-[$^{123}I$iodo-${\alpha}$-methyltyrosine 합성과 9L Glioma 이식 백서 분포조사)

  • Yang, Seung-Dae;Lim, Sang-Moo;Woo, Kwang-Sun;Chung, Wee-Sup;Chun, Kwon-Soo;Suh, Yong-Sup;Lim, Jong-Seok;Park, Hyon;Yun, Yong-Ki;Lee, Jong-Doo
    • The Korean Journal of Nuclear Medicine
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    • v.29 no.1
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    • pp.105-109
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    • 1995
  • L-3-[$^{123}I$]iodo-${\alpha}$-methyltyrosine([$^{123}I$] IMT) was synthesized by electrophilic radio-iodination using chloramine-T and Iodobead in phosphate buffered solution. And the biodistribution was examined in 9L glioma bearing rats. The radiosynthesis of [$^{123}I$]IMT with iodobead was simpler and higher in radiochemical yield(88%) than the method using chloramine-T(83%) as radioiodinating reagent. The highest yield was obtained from the reaction using 1 piece of Iodobead, $200{\mu}g$ ${\alpha}$-methyltyrosine in $100{\mu}l$ phosphate-buffered solution(pH 5.5) and the reaction was completed in 7min. 24 hours after the injection, the biodistribution in 9L glioma transplanted rats revealed the in vivo deiodination, the excretion via kidney, and 3 times higher uptake in the tumor than normal brain. These results suggest the promising clinical use of [$^{123}I$] IMT in the various malignancies.

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Production and Evaluation of Anti-Gastrin Serum for Radioimmunoassay (방사면역측정을 위한 항 Gastrin 혈청의 생산 및 평가)

  • Park, Hyoung-Jin;Kwon, Hyeok-Yil;Lee, Yun-Lyul;Shin, Won-Im;Suh, Sang-Won;Oh, Yang-Suk
    • The Korean Journal of Physiology
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    • v.23 no.1
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    • pp.89-98
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    • 1989
  • In order to produce antibody for use in radioimmunoassay of gastrin in physiological concentration, four rabbits of New Zealand white were immunized with synthetic human gastrin-17-I conjugated to hemocyanin with EDC. Among them, only one rabbit produced antibody that could bind 50% of $^{125}I-gastrin$ at a final dilution of 1:25,000. $^{125}I-gastrin$ was prepared with synthetic human gastrin-17-I and $NaI^{125}$ by lactoperoxidase technique. The product was then purified on a column of Sephadex Gl5/G5O (7:3, w/w) followed by a column of DEAE sephadex A-25. The specific radioactivity of the purified $^{125}I-gastrin$ was in the range of 347-1429 ${\mu}Ci/nmole$ when determined by the self-displacement method. The effective affinity constant $(K_{eff})$, total binding sites (N), heterogeneity index $({\alpha})$ and average affinity constant $(K_{0})$ of the anti-gastrin serum calculated from Scatchard plot as well as Sips plot were $1.77{\times}10^{11}/M$, 255 nM, 0.84 and $0.79{\times}10^{11}/M$, respectively. When radioimmunoassay was performed with the anti-gastrin serum, it was confirmed that the mean concentration of gastrin immunoreactivity in plasma was increased by feeding in humans and rats, and also increased by bombesin administration in rats. The results indicate that the anti-gastrin serum produced in the present investigation is suitable for radioimmunological determination of gastrin in physiological concentration.

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