| 1. |
- Grintsevich, Sergey, et al.
(författare)
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An Alternative Approach to the Hydrated Imidazoline Ring Expansion (HIRE) of Diarene-Fused [1.4]Oxazepines
- 2020
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Ingår i: European Journal of Organic Chemistry. - : WILEY-V C H VERLAG GMBH. - 1434-193X .- 1099-0690. ; 2020:35, s. 5664-5676
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Tidskriftsartikel (refereegranskat)abstract
- A four-step approach to the "hydrated imidazoline ring expansion" (HIRE) is presented. In most cases, the ring expansion was the sole process. However, for the first time, an alternative course of the hydrated imidazoline evolution was discovered which gaveN-aminoethyl derivatives. These can, in principle, be converted into the target HIRE products under sufficiently forcing conditions. The approach offers improved flexibility with respect to the peripheral substituents and is also applicable to the synthesis of eleven-membered lactams. We observed that the latter can exist in two stable isomeric forms due to lactam-amide bond isomerization. The latter finding further demonstrates the value of medium-sized rings as multiple-conformer probes for biological target interrogation.
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| 2. |
- Reutskaya, Elena, et al.
(författare)
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Sulfur Oxidation Increases the Rate of HIRE-Type [1.4]Thiazepinone Ring Expansion and Influences the Conformation of a Medium-Sized Heterocyclic Scaffold
- 2021
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 86:8, s. 5778-5791
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Tidskriftsartikel (refereegranskat)abstract
- The hydrated imidazoline ring expansion (HIRE-type) reaction was investigated for a series of di(hetero)arene-fused [1.4]thiazepinones in comparison with their sulfone counterparts. The sulfones were found to undergo ring expansion at a much higher rate compared to the thioethers, much in line with the current mechanistic understanding of the process. Moreover, the amide bond cis- and trans-isomers of the ring-expanded products were found, in the case of sulfones, to be stabilized through an intramolecular hydrogen bond. The latter phenomenon was studied in detail by NMR experiments and corroborated by X-ray crystallographic information.
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