666818-15-1Relevant articles and documents
An Alternative Approach to the Hydrated Imidazoline Ring Expansion (HIRE) of Diarene-Fused [1.4]Oxazepines
Grintsevich, Sergey,Sapegin, Alexander,Reutskaya, Elena,Peintner, Stefan,Erdélyi, Máté,Krasavin, Mikhail
, p. 5664 - 5676 (2020/07/21)
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 gave N-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.
Design of Conjugated Molecules Presenting Short-Wavelength Luminescence by Utilizing Heavier Atoms of the Same Element Group
Yamaguchi, Madoka,Tanaka, Kazuo,Chujo, Yoshiki
supporting information, p. 1342 - 1347 (2018/04/30)
The introduction of heavy atoms into conjugated molecules often induces a redshift in the emission spectra. Conversely, we report here a blueshifting effect in the absorption and emission bands of a conjugated organic dye by employing a heavier atom from the same element group. Boron complexes having oxygen- and sulfur-bridged structures in the ligand moiety were synthesized, and their optical properties were compared. Significant optical bands in the absorption and luminescence spectra of the sulfur-bridged complex were observed in a shorter wavelength region than those of the oxygen-bridged complex. Theoretical calculations suggest that replacement of the bridging atom by a heavier one should reduce molecular planarity because of the larger atom size. As a result, the degree of electronic conjugation decreases, and this is followed by a blueshift in the optical bands. Finally, a blue-emissive crystal is demonstrated.
Tricyclic dihydrobenzoxazepine and tetracyclic indole derivatives can specifically target bacterial DNA ligases and can distinguish them from human DNA ligase I
Yadav, Nisha,Khanam, Taran,Shukla, Ankita,Rai, Niyati,Hajela, Kanchan,Ramachandran, Ravishankar
, p. 5475 - 5487 (2015/05/20)
DNA ligases are critical components for DNA metabolism in all organisms. NAD+-dependent DNA ligases (LigA) found exclusively in bacteria and certain entomopoxviruses are drawing increasing attention as therapeutic targets as they differ in their cofactor requirement from ATP-dependent eukaryotic homologs. Due to the similarities in the cofactor binding sites of the two classes of DNA ligases, it is necessary to find determinants that can distinguish between them for the exploitation of LigA as an anti-bacterial target. In the present endeavour, we have synthesized and evaluated a series of tricyclic dihydrobenzoxazepine and tetracyclic indole derivatives for their ability to distinguish between bacterial and human DNA ligases. The in vivo inhibition assays that employed LigA deficient E. coli GR501 and S. typhimurium LT2 bacterial strains, rescued by ATP-dependent T4 DNA ligase or Mycobacterium tuberculosis NAD+-dependent DNA ligase (Mtb LigA), respectively, showed that the compounds can specifically inhibit bacterial LigA. The in vitro enzyme inhibition assays using purified MtbLigA, human DNA ligase I & T4 DNA ligase showed specific inhibition of MtbLigA at low micromolar range. Our results demonstrate that tricyclic dihydrobenzoxazepine and tetracyclic indole derivatives can distinguish between bacterial and human DNA ligases by ～5-folds. In silico docking and enzyme inhibition assays identified that the compounds bind to the cofactor binding site and compete with the cofactor. Ethidium bromide displacement and gel-shift assays showed that the inhibitors do not exhibit any unwanted general interactions with the substrate DNA. These results set the stage for the detailed exploration of this compound class for development as antibacterials.
