• Journal of Radiopharmaceuticals and Molecular Probes
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• v.5 no.2
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• pp.83-88
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• 2019

In order to understand the in vivo biodistribution of repebody protein (RB), an efficient and simple radiolabeling method for the protein is needed. We demonstrate a detailed protocol for the radiosynthesis of an ¹¹¹In radiolabeled tetrazine prosthetic group and its application to the efficient radiolabeling of trans-cyclooctene-group conjugated repebody protein using inverse-electron-demand Diels-Alder reaction. First, 1,2,4,5-tetrazine (Tz) conjugated with a DOTA chelator, was used for preparing the radiolabeled DOTA complex with ¹¹¹In. Second, the trans-cyclooctene (TCO) functionalized repebody protein was synthesized which allows for the preparation of radiolabeled proteins by copper-free click chemistry. Following incubation with the ¹¹¹In-radiolabeled DOTA complex (¹¹¹In-Tz), the TCO-functionalized RB (TCO-RB) was radiolabeled successfully with ¹¹¹In, with a high radiochemical yield (69.5%) and radiochemical purity (>99%). The radiolabeling of repebody protein by copper-free click chemistry was accomplished within 20 min, with great efficiency in aqueous conditions. These results clearly indicate that the present radiolabeling method will be useful for the efficient and convenient radiolabeling of trans-cyclooctene-group containing biomolecules.

• Journal of the Korean Chemical Society
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• v.16 no.1
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• pp.33-39
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• 1972

The stabilization energies by interconjugations at the transition states in various Diels-Alder reactions were calculated. It has been found that the stabilization energies are inversely proportional to resonance energies of isolated molecules of polyene and heterocyclic system before reactions. It has been noted that the resonance energies of dienes are smaller than those of dienophiles in two different molecules. Therefore, the possibility of charge-transfer from dienes to dienophiles is hinted.

• Journal of the Korean Chemical Society
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• v.16 no.3
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• pp.142-148
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• 1972

The intermolecular orbital theory was applied to the Diels-Alder reaction of naphthalene, phenanthrene and 1,2-benzanthracene with maleic anhydride. The expected positions of thermal addition in the alternant bydrocarbons were in agreement with experiment. It was also possible to explain the relative proportions of two isomeric adducts with the calculated stabilization energies. Comparison of the results with paralocalization energies of Brown gave agood linear correlation.

• Journal of the Korean Magnetic Resonance Society
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• v.8 no.1
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• pp.62-69
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• 2004

Bicyclolactones obtained from the Diels-Alder cycloaddition of 3,5-dibromo-2-pyrone can undergo various palladium catalyzed cross coupling reactions to afford aryl bicyclolactones. The resulting coupled products can be readily converted into various 3-OH cyclohexenes via lactone ring openings, while those bearing dienyl units underwent highly diastereoselective Diels-Alder cycloadditions with selected dienophiles to funish multiply functionalized polycarbocycles. Bromo-bicyclic diene furnished two different diastereomers endo-form (62%) and exo-form (38%) upon cycloadditions with N-Et maleimide (NEM), and their stereochemistries were identified with NMR.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.2885-2886
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• 2011

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.47-50
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• 2008

The diastereoselectivity of Diels-Alder reactions were studied on the silica surface supported with different concentrations of cerium ion as efficient Lewis acid catalysts under solvent-free conditions. The results showed that the diastereoselectivity of reaction was highly improved in these conditions. The cerium ion was grafted on silica surface by using ion exchange method.

• Bulletin of the Korean Chemical Society
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• v.4 no.5
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• pp.197-200
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• 1983

The Diels-Alder cycloaddition reactions between dienes and allenic ketones were studied theoretically using CNDO/2 method. It was found that the reaction is a neutral electron demand type with matrix element control and the reactivity, the regio- and stereo-selectivities can be correctly predicted based on interaction energies calculated with the 4-center FMO formalism.

• Bulletin of the Korean Chemical Society
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• v.35 no.11
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• pp.3254-3260
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• 2014

Intramolecular Diels-Alder (IMDA) reaction of vinylarenes bearing a Z-alkenyl tether, prepared from Morita-Baylis-Hillman (MBH) adducts, afforded arene-fused isoindoline derivatives in good yields. Vinylfurans, vinylthiophenes, and vinylnaphthalenes could be used successfully as dienes, while vinylbenzene failed under the same reaction conditions.

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.389-391
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• 1999

• Bulletin of the Korean Chemical Society
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• v.20 no.5
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• pp.621-623
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• 1999