Chemoselective Hydrogenation of Nitrostyrene to Aminostyrene over Pd- and Rh-Based Intermetallic Compounds was written by Furukawa, Shinya;Yoshida, Yurika;Komatsu, Takayuki. And the article was included in ACS Catalysis in 2014.Application In Synthesis of 6-Nitro-1H-indole This article mentions the following:
A noble catalytic system based on intermetallic compounds was developed for the chemoselective hydrogenation of p-nitrostyrene (NS) to p-aminostyrene (AS). The main concept of the catalyst design was to construct polar active sites consisting of two types of metals with different electronegativities. We prepared a series of Pd- and Rh-based intermetallics and investigated their catalytic properties in detail in the catalytic transfer hydrogenation of nitrobenzene and NS in the presence of 4-methyl-1-cyclohexene (MC) or methanol as a hydrogen donor. FT-IR studies of adsorbed CO confirmed that the number of Pd ensembles exposed on a surface was greatly decreased by the formation of an intermetallic phase; hence, the particle surface consisted of two metal elements being coadjacent at the at. level. The product distribution achieved with Pd catalysts was dependent on the electronegativity of the second metal element: more electroneg. metals gave higher AS selectivity and lower p-ethylnitrobenzene selectivity. Rh catalysts selectively gave AS, and their AS yields increased as the electronegativity of the second metal increased. The results revealed that an increase in the electronegativity of the second metal element provided polar sites and enhanced the activation of methanol as a hydrogen donor, which accelerated the hydrogenation of the nitro group of NS and, hence, improved the yield of AS. The high selectivity of Rh catalysts was due to the absence of MC activation ability, which caused the hydrogenation of the vinyl group of NS. Pd13Pb9 exhibited the highest chemoselectivity toward AS (92%) among the investigated Pd catalysts. Moreover, RhPb2 exhibited not only high AS selectivity (93%) but also the highest NS conversion (94%) among the investigated catalysts. RhPb2 also exhibited high selectivity toward AS (91%), even when H2 was used as a hydrogen source. Thus, intermetallics that contain Pb, which was the most electroneg. metal used in this study, afforded good catalytic performance and were observed to be good catalysts for the chemoselective hydrogenation of NS. In the experiment, the researchers used many compounds, for example, 6-Nitro-1H-indole (cas: 4769-96-4Application In Synthesis of 6-Nitro-1H-indole).
6-Nitro-1H-indole (cas: 4769-96-4) belongs to indole derivatives. Indole produced by Proteus, Pseudomonas, Escherichia and other species was shown to be a growth promoting factor in Arabidopsis thaliana. Indole plays a fundamental role for QS in E. coli, being one of the signal molecules responsible for the transcription of a variety of genes (gabT, and tnaB ASTD). Application In Synthesis of 6-Nitro-1H-indole
Referemce:
Indole alkaloid derivatives as building blocks of natural products from Bacillus thuringiensis and Bacillus velezensis and their antibacterial and antifungal activity study,
Preparation of Indole Containing Building Blocks for the Regiospecific Construction of Indole Appended Pyrazoles and Pyrroles