50930-41-1Relevant academic research and scientific papers
Selective and Additive-Free Hydrogenation of Nitroarenes Mediated by a DMSO-Tagged Molecular Cobalt Corrole Catalyst
Sch?fberger, Wolfgang,Timelthaler, Daniel,Topf, Christoph
, p. 2114 - 2120 (2021/07/22)
We report on the first cobalt corrole that effectively mediates the homogeneous hydrogenation of structurally diverse nitroarenes to afford the corresponding amines. The given catalyst is easily assembled prior to use from 4-tert-butylbenzaldehyde and pyrrole followed by metalation of the resulting corrole macrocycle with cobalt(II) acetate. The thus-prepared complex is self-contained in that the hydrogenation protocol is free from the requirement for adding any auxiliary reagent to elicit the catalytic activity of the applied metal complex. Moreover, a containment system is not required for the assembly of the hydrogenation reaction set-up as both the autoclave and the reaction vessels are readily charged under a regular laboratory atmosphere.
A New Photocage Derived from Fluorene
Reinfelds, Matiss,von Cosel, Jan,Falahati, Konstantin,Hamerla, Carsten,Slanina, Tomá?,Burghardt, Irene,Heckel, Alexander
supporting information, p. 13026 - 13035 (2018/09/10)
Photolabile protecting groups (PPGs or photocages) are increasingly subject to molecular design to meet requirements such as absorbance in the visible spectral range, high molar absorption coefficients, and high quantum yields of leaving group release. Improvements in these properties for the promising 3-diethylaminobenzyl (DEAMb) photocage, the photoactivity of which is based on the Zimmerman meta effect, are reported. Expansion of the aromatic system with a second aromatic ring resulted in improved spectral properties. A systematic trend relating the electronic (π-donor or acceptor) properties of the new aryl substituent and its position in the DEAMb ring to changes in the spectral properties could be observed. Conclusions from the experimental results were supported by computations obtained by using time-dependent DFT. A second generation of DEAMb-based photocages was designed. A rigid linker was introduced to ensure more efficient conjugation of the aromatic ring π systems by limiting rotational freedom. The resulting fluorenol (9-hydroxyfluorene)-based photocages had superior spectral properties to those of simple biphenyl systems. The best uncaging cross section achieved was 5320 m?1 cm?1 (?Φ365).
Organosilicon synthesis of isocyanates: III. Synthesis of aliphatic, carbocyclic, aromatic, and alkylaromatic isocyanatocatboxylic acid esters
Lebedev,Lebedeva,Sheludyakov,Ovcharuk,Kovaleva,Ustinova
, p. 1069 - 1080 (2008/02/05)
A series of aminoacid esters was prepared by treating the aminoacid suspensions in ethanol with thionyl chloride. Best conversion of aminoacid esters to corresponding isocyanates was achieved in the case of aromatic and carbocyclic aminoesters by phosgeneation of their N-silyl derivatives, and in the case of aliphatic and alkylaromatic aminoesters by phosgeneation of O-silyl or N,O-bissilylurethanes on their basis. In the last case additional step of esterification of the by-products isocyanatoalkylcarboxylic acid chlorides is required after phosgeneation. Unusual generation of cynnamates and intramolecular N→O-migration of trimethylsilyl group in the solutions of silylated alkylaromatic β-aminoacid esters were found. Pleiades Publishing, Inc., 2006.
Hydrogen bond controlled aggregation of guanidinium-carboxylate derivatives in the solid state
Zafar, Abdullah,Melendez, Rosa,Geib, Steven J,Hamilton, Andrew D
, p. 683 - 690 (2007/10/03)
In this paper, we report the synthesis and aggregation properties of new self-complementary organic molecules containing guanidinium and carboxylate groups. The crystal structures of the guanidinium carboxylates showed linear bidentate hydrogen bonding between the guanidinium and the carboxylate groups. In the case of phenyl derivative 7, steric factors force a non-planar geometry for the hydrogen bonding subunit. Substitution of the phenyl by a pyridine leads to the formation of an intramolecular hydrogen bond and a planar conformation for the subunit. As a result, the simple intramolecularly hydrogen bonded molecule maintains a rigid control of binding group disposition in a manner similar to more complex multiple fused ring systems.
