The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform
Roger Alberto - One of the best experts on this subject based on the ideXlab platform.
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conjugation of a novel histidine Derivative to biomolecules and labelling with 99mtc oh2 3 co 3
Organic and Biomolecular Chemistry, 2004Co-Authors: Dave R Van Staveren, Stefan Mundwiler, Ulrich Hoffmanns, Bernhard Spingler, Nils Metzlernolte, Roger AlbertoAbstract:The new histidine Derivative 3-{1-[3-(9H-fluoren-9-ylmethoxycarbonylamino)-propyl]-1H-imidazol-4-yl}-2-(3-trimethylsilanyl-ethylcarboxyamino)-propionic acid methyl ester (7) has been prepared via alkylation of the histidine Urea Derivative (7S)-5,6,7,8-tetrahydro-7-(methoxycarbonyl)-5-oxoimidazo-[1,5-c]-pyrimidine (2) with Fmoc-protected 3-iodopropyl-amine, followed by ring opening with 2-trimethylsilylethanol. After Fmoc cleavage by HNEt2, the histidine amine Derivative was coupled to biotin, to the pentapeptide leucine-enkephalin and to Vitamin B12-b-acid by amide formation, employing TBTU as the coupling reagent. In order to make the histidine accessible for labelling, the teoc protecting group was removed by either NBu4F (for the biotin conjugate) or by TFA (for the enkephalin and B12 conjugates). Reaction of a 10−4 M solution of the bioconjugates with [99mTc(H2O)3(CO)3]+ at 50 °C for 30 min led to the formation of one single new peak in the HPLC radiochromatogram in each case, confirming quantitative labelling of the respective biomolecules. To assess the nature of the labelled compounds, the rhenium analogues with Re(CO)3 were also synthesised and similar retention times confirmed the identity with the 99mTc labelled conjugates.
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Conjugation of a novel histidine Derivative to biomolecules and labelling with [99mTc(OH2)3(CO)3]+
Organic and Biomolecular Chemistry, 2004Co-Authors: Dave R Van Staveren, Stefan Mundwiler, Ulrich Hoffmanns, Bernhard Spingler, Nils Metzler-nolte, Roger AlbertoAbstract:The new histidine Derivative 3-{1-[3-(9H-fluoren-9-ylmethoxycarbonylamino)-propyl]-1H-imidazol-4-yl}-2-(3-trimethylsilanyl-ethylcarboxyamino)-propionic acid methyl ester (7) has been prepared via alkylation of the histidine Urea Derivative (7S)-5,6,7,8-tetrahydro-7-(methoxycarbonyl)-5-oxoimidazo-[1,5-c]-pyrimidine (2) with Fmoc-protected 3-iodopropyl-amine, followed by ring opening with 2-trimethylsilylethanol. After Fmoc cleavage by HNEt2, the histidine amine Derivative was coupled to biotin, to the pentapeptide leucine-enkephalin and to Vitamin B12-b-acid by amide formation, employing TBTU as the coupling reagent. In order to make the histidine accessible for labelling, the teoc protecting group was removed by either NBu4F (for the biotin conjugate) or by TFA (for the enkephalin and B12 conjugates). Reaction of a 10−4 M solution of the bioconjugates with [99mTc(H2O)3(CO)3]+ at 50 °C for 30 min led to the formation of one single new peak in the HPLC radiochromatogram in each case, confirming quantitative labelling of the respective biomolecules. To assess the nature of the labelled compounds, the rhenium analogues with Re(CO)3 were also synthesised and similar retention times confirmed the identity with the 99mTc labelled conjugates.
Helong Cheng - One of the best experts on this subject based on the ideXlab platform.
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synthesis of a new Urea Derivative a dual functional organocatalyst for knoevenagel condensation in water
ChemInform, 2014Co-Authors: Wenjun Le, Hongfei Lu, Juntao Zhou, Helong ChengAbstract:The phenylalanine—Urea compound (I) is synthesized and utilized as catalyst for Knoevenagel condensations under mild conditions.
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Synthesis of a New Urea Derivative: A Dual‐Functional Organocatalyst for Knoevenagel Condensation in Water.
ChemInform, 2014Co-Authors: Wenjun Le, Hongfei Lu, Jun‐tao Zhou, Helong ChengAbstract:The phenylalanine—Urea compound (I) is synthesized and utilized as catalyst for Knoevenagel condensations under mild conditions.
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synthesis of a new Urea Derivative a dual functional organocatalyst for knoevenagel condensation in water
Tetrahedron Letters, 2013Co-Authors: Wenjun Le, Hongfei Lu, Juntao Zhou, Helong ChengAbstract:A phenylalanine–Urea compound-catalyzed Knoevenagel condensation in water is reported. Various aldehydes and active methylene compounds undergo condensation at room temperature to give the desired products in high yields. The mechanism of the condensation of aldehydes with Meldrum’s acid catalyzed by the novel Urea Derivative is also disclosed.
Dave R Van Staveren - One of the best experts on this subject based on the ideXlab platform.
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conjugation of a novel histidine Derivative to biomolecules and labelling with 99mtc oh2 3 co 3
Organic and Biomolecular Chemistry, 2004Co-Authors: Dave R Van Staveren, Stefan Mundwiler, Ulrich Hoffmanns, Bernhard Spingler, Nils Metzlernolte, Roger AlbertoAbstract:The new histidine Derivative 3-{1-[3-(9H-fluoren-9-ylmethoxycarbonylamino)-propyl]-1H-imidazol-4-yl}-2-(3-trimethylsilanyl-ethylcarboxyamino)-propionic acid methyl ester (7) has been prepared via alkylation of the histidine Urea Derivative (7S)-5,6,7,8-tetrahydro-7-(methoxycarbonyl)-5-oxoimidazo-[1,5-c]-pyrimidine (2) with Fmoc-protected 3-iodopropyl-amine, followed by ring opening with 2-trimethylsilylethanol. After Fmoc cleavage by HNEt2, the histidine amine Derivative was coupled to biotin, to the pentapeptide leucine-enkephalin and to Vitamin B12-b-acid by amide formation, employing TBTU as the coupling reagent. In order to make the histidine accessible for labelling, the teoc protecting group was removed by either NBu4F (for the biotin conjugate) or by TFA (for the enkephalin and B12 conjugates). Reaction of a 10−4 M solution of the bioconjugates with [99mTc(H2O)3(CO)3]+ at 50 °C for 30 min led to the formation of one single new peak in the HPLC radiochromatogram in each case, confirming quantitative labelling of the respective biomolecules. To assess the nature of the labelled compounds, the rhenium analogues with Re(CO)3 were also synthesised and similar retention times confirmed the identity with the 99mTc labelled conjugates.
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Conjugation of a novel histidine Derivative to biomolecules and labelling with [99mTc(OH2)3(CO)3]+
Organic and Biomolecular Chemistry, 2004Co-Authors: Dave R Van Staveren, Stefan Mundwiler, Ulrich Hoffmanns, Bernhard Spingler, Nils Metzler-nolte, Roger AlbertoAbstract:The new histidine Derivative 3-{1-[3-(9H-fluoren-9-ylmethoxycarbonylamino)-propyl]-1H-imidazol-4-yl}-2-(3-trimethylsilanyl-ethylcarboxyamino)-propionic acid methyl ester (7) has been prepared via alkylation of the histidine Urea Derivative (7S)-5,6,7,8-tetrahydro-7-(methoxycarbonyl)-5-oxoimidazo-[1,5-c]-pyrimidine (2) with Fmoc-protected 3-iodopropyl-amine, followed by ring opening with 2-trimethylsilylethanol. After Fmoc cleavage by HNEt2, the histidine amine Derivative was coupled to biotin, to the pentapeptide leucine-enkephalin and to Vitamin B12-b-acid by amide formation, employing TBTU as the coupling reagent. In order to make the histidine accessible for labelling, the teoc protecting group was removed by either NBu4F (for the biotin conjugate) or by TFA (for the enkephalin and B12 conjugates). Reaction of a 10−4 M solution of the bioconjugates with [99mTc(H2O)3(CO)3]+ at 50 °C for 30 min led to the formation of one single new peak in the HPLC radiochromatogram in each case, confirming quantitative labelling of the respective biomolecules. To assess the nature of the labelled compounds, the rhenium analogues with Re(CO)3 were also synthesised and similar retention times confirmed the identity with the 99mTc labelled conjugates.
Li Ming Wang - One of the best experts on this subject based on the ideXlab platform.
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Urea-Derivative Catalyzed Enantioselective Hydroxyalkylation of Hydroxyindoles with Isatins.
Molecules, 2019Co-Authors: Hao Wu, Li Ming Wang, Junwei ZhangAbstract:The enantioselective transformations of indoles preferentially take place in the more-reactive azole ring. However, the methods for the enantioselective functionalization of the indole benzene ring are scarce. In this paper, a series of bifunctional (thio)Urea Derivatives were used to organocatalyze the enantioselective Friedel-Crafts hydroxyalkylation of indoles with isatins. The resulting products were obtained in good yields (65–90%) with up to 94% enantiomer excess (ee). The catalyst type and the substrate scope were broadened in this methodology.
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Urea Derivative catalyzed enantioselective aldol reaction of isatins with ketones.
Chirality, 2018Co-Authors: Li Ming Wang, Mei Jun Zhao, Zhe Chen, Hong Wen MuAbstract:: Urea Derivative has been used to catalyze the asymmetric aldol reaction of isatins with ketones. The resulting 3-alkyl-3-hydroxy-indolin-2-ones products were obtained in good yields (70%-94%) with high enantioselectivities (up to 87%ee).
Bernhard Spingler - One of the best experts on this subject based on the ideXlab platform.
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conjugation of a novel histidine Derivative to biomolecules and labelling with 99mtc oh2 3 co 3
Organic and Biomolecular Chemistry, 2004Co-Authors: Dave R Van Staveren, Stefan Mundwiler, Ulrich Hoffmanns, Bernhard Spingler, Nils Metzlernolte, Roger AlbertoAbstract:The new histidine Derivative 3-{1-[3-(9H-fluoren-9-ylmethoxycarbonylamino)-propyl]-1H-imidazol-4-yl}-2-(3-trimethylsilanyl-ethylcarboxyamino)-propionic acid methyl ester (7) has been prepared via alkylation of the histidine Urea Derivative (7S)-5,6,7,8-tetrahydro-7-(methoxycarbonyl)-5-oxoimidazo-[1,5-c]-pyrimidine (2) with Fmoc-protected 3-iodopropyl-amine, followed by ring opening with 2-trimethylsilylethanol. After Fmoc cleavage by HNEt2, the histidine amine Derivative was coupled to biotin, to the pentapeptide leucine-enkephalin and to Vitamin B12-b-acid by amide formation, employing TBTU as the coupling reagent. In order to make the histidine accessible for labelling, the teoc protecting group was removed by either NBu4F (for the biotin conjugate) or by TFA (for the enkephalin and B12 conjugates). Reaction of a 10−4 M solution of the bioconjugates with [99mTc(H2O)3(CO)3]+ at 50 °C for 30 min led to the formation of one single new peak in the HPLC radiochromatogram in each case, confirming quantitative labelling of the respective biomolecules. To assess the nature of the labelled compounds, the rhenium analogues with Re(CO)3 were also synthesised and similar retention times confirmed the identity with the 99mTc labelled conjugates.
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Conjugation of a novel histidine Derivative to biomolecules and labelling with [99mTc(OH2)3(CO)3]+
Organic and Biomolecular Chemistry, 2004Co-Authors: Dave R Van Staveren, Stefan Mundwiler, Ulrich Hoffmanns, Bernhard Spingler, Nils Metzler-nolte, Roger AlbertoAbstract:The new histidine Derivative 3-{1-[3-(9H-fluoren-9-ylmethoxycarbonylamino)-propyl]-1H-imidazol-4-yl}-2-(3-trimethylsilanyl-ethylcarboxyamino)-propionic acid methyl ester (7) has been prepared via alkylation of the histidine Urea Derivative (7S)-5,6,7,8-tetrahydro-7-(methoxycarbonyl)-5-oxoimidazo-[1,5-c]-pyrimidine (2) with Fmoc-protected 3-iodopropyl-amine, followed by ring opening with 2-trimethylsilylethanol. After Fmoc cleavage by HNEt2, the histidine amine Derivative was coupled to biotin, to the pentapeptide leucine-enkephalin and to Vitamin B12-b-acid by amide formation, employing TBTU as the coupling reagent. In order to make the histidine accessible for labelling, the teoc protecting group was removed by either NBu4F (for the biotin conjugate) or by TFA (for the enkephalin and B12 conjugates). Reaction of a 10−4 M solution of the bioconjugates with [99mTc(H2O)3(CO)3]+ at 50 °C for 30 min led to the formation of one single new peak in the HPLC radiochromatogram in each case, confirming quantitative labelling of the respective biomolecules. To assess the nature of the labelled compounds, the rhenium analogues with Re(CO)3 were also synthesised and similar retention times confirmed the identity with the 99mTc labelled conjugates.
