Einwirkung von Halogenen auf Thioharnstoffe

Hugershoff, A.

doi:10.1002/cber.190103402286

Cited by 62 publications

(16 citation statements)

References 3 publications

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“…[18,19] However,the corresponding route to the isoselenourea 1-Se gave low yields, [19] necessitating the development of anew route to 1-Se.Inaone-pot process, 2 [18a] was added to phenyl isoselenocyanate (3)t og enerate selenourea 4,w hich was then cyclized to give 5 in what is the first reported seleno-Hugerschoff reaction (Figure 2B). [20,21] Adapting the previously reported approach, in situ addition of NEt 3 and MsCl followed by gentle heating affected cyclization to give isoselenourea 1-Se in good yield. Thereaction could be performed on agram scale giving 1.1 g (3.1 mmol) of 1-Se in 64 %yield from 2 and 3.…”

Section: Resultsmentioning

confidence: 95%

The Importance of 1,5‐Oxygen⋅⋅⋅Chalcogen Interactions in Enantioselective Isochalcogenourea Catalysis

et al. 2020

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The importance of 1,5‐O⋅⋅⋅chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N‐acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5‐O⋅⋅⋅Ch interactions in enantioselective catalysis. Importantly, the selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes including nitronate conjugate addition and formal [4+2] cycloadditions. A gram‐scale synthesis of the most active selenium analogue was developed using a previously unreported seleno‐Hugerschoff reaction, allowing the challenging kinetic resolutions of tertiary alcohols to be performed at 500 ppm catalyst loading. Density functional theory (DFT) and natural bond orbital (NBO) calculations support the role of orbital delocalization (occurring by intramolecular chalcogen bonding) in determining the conformation, equilibrium population, and reactivity of N‐acylated intermediates.

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Section: Resultsmentioning

confidence: 95%

The Importance of 1,5‐Oxygen⋅⋅⋅Chalcogen Interactions in Enantioselective Isochalcogenourea Catalysis

et al. 2020

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“…We suspect that this reflects the reaction of benzoyl [ 14 C]isothiocyanate with the HPLC medium. The benzoyl [ 14 C] isothiocyanate was then reacted with aniline 5 without further isolation to give thiourea 7 after 15 min, and conversion to the thiazole was effected using N ‐bromosuccinimide in trifluoroacetic acid (TFA) . The crude reaction mixture consisted of 41% of 8 , 15% of 8b , and 24.5% of 9 .…”

Section: Resultsmentioning

confidence: 99%

Preparation of two D2 partial agonists in C‐14 and stable isotope labeled forms

Elmore

Powell

Xiong

et al. 2012

Labelled Comp Radiopharmac

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In support of a program to develop a treatment for diseases resulting from an imbalance in dopamine levels, two drug candidates, 1 and 2, were prepared in stable isotope and C‐14 labeled forms. Both compounds contained an aminothiazole ring, and the C‐14 label was introduced into the ring using KS14CN. However, the use of KS14CN to form [14C]‐2 gave poor results; therefore, benzoyl [14C]isothiocyanate was used instead, which led to a much improved yield. The stable isotope labeled forms were prepared with the label in the side chain from [2H5]ethyl iodide for [2H5]‐1 and from 1‐[13C]methyl [15N2]pyrazole[13C]carboxaldehyde, which was prepared in turn from [carbonyl‐13C]DMF, [15N2]hydrazine sulfate, and [13C]methyliodide for [13C2, 15N2]‐2. Copyright © 2012 John Wiley & Sons, Ltd.

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“…The known 2-aminobenzothiazoles (abbreviated as 2-AB in the following list) were prepared by the methods reported in the literature: 2-AB (6), 6-methoxy-2-AB (7), 6-acetyl-2-AB (8), 6-diethylsulphamoyl-2-AB (9), 6-methylsulphonyl-2-AB (IO), 6-nitro-ZAB (II), 6-methyl-4-nitro-2-AB (1 2), and 4-chloro-6nitro-2-AB (13).…”

Section: Benzothiazolylazo Dyesmentioning

confidence: 99%