Radiolabeling of EGCG with 125I and its biodistribution in mice

The aim of the present study was to label EGCG with ¹²⁵I and to determine its radiopharmaceutical potential in mice. EGCG was labeled with ¹²⁵I using the iodogen method. The labeling yield and the radiochemical purity of ¹²⁵I–EGCG were determined by radio thin-layer chromatography (RTLC). The Labeling yield was approximately 89.4 %. The radiochemical purity was approximately 96.4 %. The biodistribution studies of the labeled compound (specific activity; 0.47 TBq/μg) were performed in male Kunming mice. The uptakes of ¹²⁵I–EGCG in some organs were determined at different time after injection to the mice. The radioactivity in each organ was counted and the percentage of injected activity per gram of tissue weight (%ID/g) for each organ and blood was calculated. Incorporation of radioactivity in the various tissue/organ was confirmed by microautoradiography. ¹²⁵I–EGCG uptake in the stomach and salivary gland was higher than other organ/tissue. The black silver grains was concentrated in the nucleus, cytoplasm, intercellular substance and capillaries of that various organs, and its unevenly distributed. Thus, ¹²⁵I–EGCG may be radiopharmaceutical for the imaging of the stomach and salivary gland.     

Two polymorphs of safinamide,a selective and reversible inhibitor of monoamine oxidase B

Two polymorphs of safinamide {systematic name: (2S)‐2‐[4‐(3‐fluorobenzyloxy)benzylamino]propionamide}, C₁₇H₁₉FN₂O₂, a potent selective and reversible monoamine oxidase B (MAO‐B) inhibitor, are described. Both forms are orthorhombic and regarded as conformational polymorphs due to the differences in the orientation of the 3‐fluorobenzyloxy and propanamide groups. Both structures pack with layers in the ac plane. In polymorph (I), the layers have discrete wide and narrow regions which are complementary when located next to adjacent layers. In polymorph (II), the layer has long flanges protruding from each side, which interdigitate when packed with the adjacent layers. N—H...O hydrogen bonds are present in both structures, whereas N—H...F hydrogen bonding is seen in polymorph (I), while N—H...N hydrogen bonding is seen in polymorph (II).     

Radiosynthesis,chromatographic evaluation and biodistribution of [125I]iododobutamine as a radiotracer for myocardial perfusion imaging

Journal of Radioanalytical and Nuclear Chemistry - The objective of this work was to develop a potential selective radiotracer for the non-invasive assessment of heart imaging. [125I]iododobutamine...     

5-O-(4-[125 I]Iodobenzyl)-L-ascorbic acid: electrophilic radioiodination and biodistribution in mice

As a part of our efforts to develop potential imaging agents for ascorbate bioactivity, 5-O-(4-[(125)I]iodobenzyl)-L-ascorbic acid ([(125)I]1) was prepared through a two-step sequence which involved radioiodo-destannylation of a protected tributylstannyl precursor 6, followed by hydrolysis in acidic methanol of the protecting groups in 61% overall radiochemical yield, with a radiochemical purity of over 98% and a specific activity of more than 15.4?GBq/μmol. Tissue distribution of [(125)I]1 in tumor-bearing mice showed signs of distribution profiles similar to the reported results for 6-deoxy-6-[(18)F]fluoro-L-ascorbic (6-(18)FAsA) acid and 6-deoxy-6-[(131)I]iodo-L-ascorbic acid (6-(131)IAsA) but with notable differences in the adrenal glands, in which considerably lower uptake of radioactivity and rapid clearance with time were observed. Pretreatment of mice with a known inhibitor of ascorbate transport, sulfinpyrazone, did not produce any significant change in the adrenal uptake of radioactivity after injection of [(125)I]1 compared to the control, suggesting that uptake in the adrenal glands is independent of the sodium-dependent vitamin C transporter 2 transport mechanism. Introduction of a bulky substituent at C-5 on AsA, such as an iodobenzyloxy group, may not be suitable for the design of analogs that may still be able to maintain characteristic distribution properties in vivo seen with AsA itself.     

Synthesis of fluorine and iodine analogues of clorgyline and selective inhibition of monoamine oxidase A

A series of fluorine and iodine analogues of clorgyline was synthesized and evaluated for inhibitory potency and selectivity toward monoamine oxidase A (MAO-A). Among them, N-[3-(2,4-dichloro-6-iodophenoxy)propyl]-N-methyl-2-propynylami ne (3d), N-[3-(4-chloro-2-fluorophenoxy)propyl]-N-methyl-2-propynylamine (3f) and N-[3-(2-chloro-4-fluorophenoxy)propyl]-N-methyl-2-propynylamine (3g) were found to have high inhibitory potency and selectivity toward MAO-A comparable to those of clorgyline itself. Thus, they were considered for advanced development as radiofluorinated and radioiodinated ligands that may be useful for functional MAO-A studies in the living brain with positron emission tomography and single photon emission computer tomography.     

Synthesis of new indoyl-1,3,4-oxadiazole and oxadiazine derivatives. Potential monoamine oxidase inhibitor activity

New indolyl-1,3,4-oxadiazole and oxadiazine derivatives were prepared as reversible monoamine oxidase inhibitors. The compound 5-(3-methylindolyl)-1,3,4-oxadiazol-2(3H)one was shown to be a good monoamine oxidase B inhibitor.     

Synthesis and evaluation of iodinated benzamide derivatives as selective and reversible monoamine oxidase B inhibitors.

A new series of iodinated analogues of N-(2-aminoethyl)benzamide was synthesized and evaluated for inhibitory potency and specificity toward monoamine oxidase type-B (MAO-B). Among them, N-(2-aminoethyl)-2-chloro-4-iodobenzamide hydrochloride (2d) showed high inhibitory potency and selectivity against MAO-B. The type of MAO-B inhibition by 2d was non-competitive and the inhibition constant (Ki) was 0.80 microM. Strong and selective in vivo MAO-B inhibition by 2d was also confirmed. The brain MAO-B inhibition by 2d was reversible and the enzyme activity completely returned to the control value 24 h after administration. Compound 2d was, therefore, considered to be a candidate for advanced development as a radioiodinated ligand that may be useful for functional MAO-B studies in the living brain using single photon emission computer tomography.     

Thin-layer chromatography of hydrazidic monoamine oxidase inhibitor drugs.

Seven solvent systems for the thin-layer chromatographic separation of hydrazidic monoamine oxidase inhibitor drugs have been developed. Detection of compounds at the microgram level was performed with the aid of thirteen spray reagents.     

新型手性单胺氧化酶选择性抑制剂的设计、合成与生物活性研究

本文以取代的手性苯乙胺为原料,设计合成了4种新型叔胺盐酸盐化合物.通过NMR,IR和MS等表征方法对所合成目标产物的结构进行确定.在生物活性方面,首先通过CCK-8法测定4种化合物对正常细胞增殖的影响,实验结果表明:部分化合物对小鼠成纤维细胞L929表现出一定的细胞毒性.酶的选择性实验说明R构型影响小分子对单胺氧化酶(MAO)的选择性抑制活性,另一方面取代基的给电子能力也会对酶的活性有影响.     

Photochemical Reactions. 125th communication [1]. Photochemistry of homoconjugated cyclobutanones. I. Synthesis and photolysis of a Spiro [3.6]deca-5, 7-dien-1-one

The title compound 4 was prepared in 54% overall yield from eucarvone ( 5 ). On triplet sensitization 4 gives two products resulting from a 1,2-acyl shift ( 8 and 9 ), whereas singlet excitation of 4 causes decarbonylation and ketene elimination ( 4 → 10 and 11 ).     

Preparation of [3H]6-nitroquipazine, a potent and selective 5-hydroxytryptamine uptake inhibitor

The synthesis of 6-nitroquipazine, a very potent and selective 5-hydroxytryptamine (5-HT; serotonin) uptake inhibitor, labeled with tritium is described. High specific activity [3H]6-nitroquipazine could be prepared by the nitration of [3H]quipazine using a mixture of equal volumes of sulfuric acid and nitric acid. The radiochemical yield was approximately 50% based on [3H]quipazine. The radiochemical purity was more than 95% from high performance liquid chromatography(HPLC) and thin layer chromatography(TLC) determinations. [3H]6-Nitroquipazine would be a new suitable radioligand for studying 5-HT transporter complex in brain and platelets.     

Benzo- and indoloquinolizine derivatives. I. Synthesis of 4b,5,6,7,8,8a,10,11,16,16b-decahydrodibenz[f,h] indolo[2,3-a] quinolizine

Two 4b 5,6,7,8,8a,10,11,16,16b-decahydrodibenz[f,h]indolo-[2,3-a]quinolizine epimers have been synthesized starting from trans-1,2,3,4,4a,10b-hexahydrophenanthridine. The structural assignment of both isomers is discussed by use of ir and pmr spectroscopy.     

Synthesis of 99m TcN(IPDTC)2 and its biodistribution in mice

In order to seek a new class of brain perfusion imaging agent containing[ ^99m TcN]²+ core, the bis(N-isopropyl dithiocarbamato)nitrido technetium-99m complex [ ^99m TcN(IPDTC)₂ ] (IPDTC:N-isopropyldithiocarbamato) has been synthesized through a simple and efficient method,which can be utilized for the preparation of a radiopharmaceutical througha lyophilized formulation. The radiochemical purity of the complex was over90% determined by thin layer chromatography. No decomposition of the complexwas observed at room temperature over a period of 12 hours. Its partitioncoefficient indicated that it was a good lipophilic complex. Biodistributionin mice demonstrated that the complex was significantly retained into thebrain. The brain uptake (ID%/g) was 3.90, 2.67 and 1.54 and the brain/bloodratios were 1.26, 1.06 and 0.85 at 5, 30 and 60-minute post-injection, respectively.The results showed that the complex may lead to a further development of theradiopharmaceutical as a brain perfusion tracer.     

Synthesis of C-labeled imipramine and its biodistribution in mice: a potential tracer for positron emission tomography

A tricyclic antidepressant, C-labeled imipramine was synthesized by N-methylation of desipramine with 11CH3I to assist in the imaging of the human imipramine receptor by positron emission tomography. The radiochemical yield after purification of 11C-imipramine by high performance liquid chromatography was 28-63% at a specific activity of 26-53 Ci/mmol. The time required for synthesis, including purification was 30 min from the end of 11CH3I trapping. The organ distribution of 11C-imipramine was investigated in mice at various times after i.v. injection. The main accumulation of radioactivity was in the kidney, followed by the lung and the heart. In the brain, the radioactivity levels in the hypothalamus and striatum were the highest and remained constant, differentiating them from other portions of the brain. Furthermore, the result of a binding assay with 3H-labeled imipramine suggested that the regional distribution of 11C-imipramine in the same mouse brain correlated to that of the high affinity imipramine binding site.     

Synthesis of a water-soluble pillar[6]arene dodecaamine and its selective binding of acidic amino acids in water

A water-soluble pillar[6]arene dodecaamine has been synthesized. ¹H NMR and fluorescence studies indicate that pillar[6]arene dodecaamine could selectively and strongly bind acidic amino acids, i.e. glutamic acid and aspartic acid in water. And the complexation behavior of pillar[6]arene dodecaamine towards acidic tripeptide glutathione and short chain length (C₃ to C₈) dicarboxylic acids in water is also investigated.     

Heterocycles with a Benzothiadiazeypine Moiety. I. Synthesis of Pyrrolo[1,2-b]-s-triazolo[3,4-d] [1,2,5]benzothiadiazepine 5,5-Dioxide

Condensation of 2-nitrobenzenesulfonyl chloride with 2-ethoxycarbonyl-1H-pyrrole in the presence of potassium tert-butoxide and 18-crown-6 furnished 2-ethoxycarbonyl-1-(2-nitrobenzenesulfonyl)-1H-pyrrole. Reduction of nitro group to amino and subsequent cyclization by heating the aminoester in the presence of 2-hydroxypyridine as a bifuctional catalyst led to 11-oxo(10H)-pyrrolo[1,2-b] [1,2,5]benzothiadiazepine 5,5-dioxide. Treatment of the latter compound with di-4-morpholinylphosphinic chloride gave the corresponding phosphinyloxyimine, which on reacting with formylhydrazine underwent intramolecular cyclization to afford the title tetracyclic ring.     

Furopyridines. I. Synthesis of furo[2,3-c]pyridine

The parent framework of furo[2,3-c]pyridine has been synthesized. 3-Furoic acid chloride ( 2 ) was reduced with bis(triphenylphosphine) copper(1) tetrahydroborate to afford 3-furaldehyde ( 3 ) which was condensed with malonic acid to give β-(3-furyl)acrylic acid ( 4 ). The acrylic acid 4 was converted to the acid azide ( 5 ), which in turn was cyclized to give furo[2,3-c]pyridin-7(6H)-one ( 6 ) by heating at 180° in diphenylmethane. The pyridone 6 was chlorinated with phosphorus oxychloride, followed by reduction with zinc and acetic acid to give furo[2,3-c]pyridine ( 8 ).     

Preparation of 125I-Lanreotide and its biodistribution in murine model of melanoma

Lanreotide, a somatostatin analogue, was radioiodinated with ¹²⁵I to explore the possibility of using ¹²³I labeled lanreotide as a diagnostic radiopharmaceutical for tumors overexpressing somatostatin (SST) receptors. Radioiodination was carried out with ¹²⁵I using chloramine T as the oxidant. The labeling yield was >90%. Characterization of ¹²⁵I-Lanreotide was carried out by paper electrophoresis as well as HPLC. ¹²⁵I-Lanreotide was purified by chromatography using a C18 Sep-Pak column. Radiochemical purity of the purified ¹²⁵I-Lanreotide thus obtained was >99%. Significant tumor uptake of ¹²⁵I-Lanreotide was observed in C57BL/6 mice bearing melanoma.