- IrIII-Catalyzed Selective ortho-Monoiodination of Benzoic Acids with Unbiased C?H Bonds
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An iridium-catalyzed selective ortho-monoiodination of benzoic acids with two equivalent C?H bonds is presented. A wide range of electron-rich and electron-poor substrates undergo the reaction under mild conditions, with >20:1 mono/di selectivity. Importantly, the C?H iodination occurs selectively ortho to the carboxylic acid moiety in substrates bearing competing coordinating directing groups. The reaction is performed at room temperature and no inert atmosphere or exclusion of moisture is required. Mechanistic investigations revealed a substrate-dependent reversible C?H activation/protodemetalation step, a substrate-dependent turnover-limiting step, and the crucial role of the AgI additive in the deactivation of the iodination product towards further reaction.
- Weis, Erik,Johansson, Magnus J.,Martín-Matute, Belén
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supporting information
p. 10185 - 10190
(2020/07/31)
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- Copper-catalyzed domino reaction of carbodiimides and benzoic acid derivatives for the synthesis of quinazolinediones
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Quinazolinediones were obtained from 2-iodobenzoic acids and carbodiimide derivatives under mild reaction conditions via a copper-catalyzed domino reaction. The absence of an external base was essential to avoid the generation of amide by-products. Both alkyl- and aryl-substituted carbodiimides gave the corresponding quinazolinediones. However, the use of aryl-substituted carbodiimides resulted in low yields due to an undesired elimination process.
- Duangjan, Chanikan,Rukachaisirikul, Vatcharin,Saithong, Saowanit,Kaeobamrung, Juthanat
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supporting information
p. 3537 - 3540
(2018/08/29)
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- Synthesis of DIBAC analogues with excellent SPAAC rate constants
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In search for increased reactivity in strain-promoted azide alkyne cycloadditions (SPAAC), the synthesis of new and more reactive cyclooctynes is of pivotal importance. To identify cyclooctynes with enhanced reactivity, without loss of stability, the synthesis and kinetic analysis of new dibenzoazacyclooctyne (DIBAC) analogues were conducted. Starting from iodobenzyl alcohol analogues and ortho-ethynylaniline various substituted dihydrodibenzo[b,f]azocines were produced. Subsequent bromination and elimination proved to be difficult depending on the aromatic substitution pattern, yielding chloro-, bromo-, and methoxy-substituted DIBACs in moderate yield. In the elimination reaction towards nitro- and Br,Cl-DIBAC, the corresponding cyclooctene was obtained instead of the cyclooctyne. Additionally, a dimethoxy-substituted DIBAC analogue was prepared following an alternative route involving light-induced deprotection of a cyclopropenone derivative. In total, four DIBAC analogues were successfully prepared showing excellent rate constants in the SPAAC reaction ranging from 0.45 to 0.9 M-1 s -1, which makes them comparable to the fastest cyclooctynes currently known. This journal is the Partner Organisations 2014.
- Debets, Marjoke F.,Prins, Jasper S.,Merkx, Donny,Van Berkel, Sander S.,Van Delft, Floris L.,Van Hest, Jan C. M.,Rutjes, Floris P. J. T.
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supporting information
p. 5031 - 5037
(2014/07/07)
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- SUBSTITUTED AZADIBENZOCYCLOOCTYNE COMPOUNDS AND THEIR USE IN METAL-FREE CLICK REACTIONS
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The invention relates to a substituted azadibenzocyclooctyne compound according to Formula (5): The invention also relates to a conjugate wherein a substituted azadibenzocyclooctyne according to the invention is conjugated to a label, and to the use of these conjugates for bioorthogonal labeling, imaging or modification of a target molecule, e.g. surface modification. The invention further relates to a method for the modification of a target molecule, wherein a conjugate according to the invention is reacted with a compound comprising a 1,3-dipole or a 1,3-(hetero)diene.
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Page/Page column 27
(2014/12/12)
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- 2-iodoxybenzenesulfonic acid as an extremely active catalyst for the selective oxidation of alcohols to aldehydes, ketones, carboxylic acids, and enones with oxone
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Electron-donating group-substituted 2-iodoxybenzoic acids (IBXs) such as5-Me-IBX (1g), 5-MeO-IBX (1h), and 4,5-Me2-IBX were superior to IBX 1a as catalysts for the oxidation of alcohols with Oxone (a trad emark of DuPont) under nonaqueous conditions, although Oxone was almost insoluble in most organic solvents. The catalytic oxidation proceeded more rapidly and cleanly in nitromethane. Furthermore, 2-iodoxybenzenesulfonic acid (IBS, 6a) was much more active than modified IBXs. Thus, we established a highly efficient and selective method for the oxidation of primary and secondary alcohols to carbonyl compounds such as aldehydes, carboxylic acids, and ketones with Oxone in nonaqueous nitromethane, acetonitrile, or ethyl acetate in the presence of 0.05-5molpercentof 6a, which was generated in situ from 2-iodobenzenesulfonic acid (7a) or its sodium salt. Cycloalkanones could be further oxidized to α,β- cycloalkenones or lactones by controlling the amounts of Oxone under the same conditions as above. When Oxone was used under nonaqueous conditions, Oxone wastes could be removed by simple filtration. Based on theoretical calculations, we considered that the relatively ionic character of the intramolecular hypervalent iodine-OSO2 bond of IBS might lower the twisting barrier of the alkoxyperiodinane intermediate 16.
- Uyanik, Muhammet,Akakura, Matsujiro,Ishihara, Kazuaki
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supporting information; experimental part
p. 251 - 262
(2009/06/28)
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- The synthesis and electronic absorption spectra of 3-phenyl-3(4- pyrrolidino-2-substituted phenyl)-3H-naphtho[2,1-b]pyrans: Further exploration of the ortho substituent effect
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Introduction of a substituent into a sterically demanding 2-position of a 3-(4-pyrrolidinophenyl) ring of a 3,3-diaryl-3H-naphtho[2,1-b]pyran results in the generation of an additional short wavelength absorption band leading to organic photochromes that
- Gabbutt, Christopher D.,Heron, B. Mark,Instone, Alicia C.
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p. 737 - 745
(2007/10/03)
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- Condensed pyrazole derivatives, process for producing the same and use thereof
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Novel pharmaceutical compositions for inhibiting Th2-selective immune response and pharmaceutical compositions for inhibiting cyclooxygenase comprising condensed pyrazole derivatives represented by the general formula (I): or salts thereof.
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