2294-76-0Relevant articles and documents
Formation of 2-Pentylpyridine from the Thermal Interaction of Amino Acids and 2,4-Decadienal
Kim, Young-Suk,Hartman, Thomas G.,Ho, Chi-Tang
, p. 3906 - 3908 (1996)
To study the mechanism of 2-pentylpyridine formation in model systems, 2,4-decadienal was reacted with five amino acids (glycine, aspartic acid, asparagine, glutamic acid, and glutamine) at 180°C for 1 h (pH 7.5). In addition to 2-pentylpyridine, 3-pentylpyridine was also tentatively identified from the thermal reactions. The relative yields of alkylpyridine formation from the reactions were asparagine > glutamine > aspartic acid > glutamic acid > glycine. When amide-15N-labeled glutamine and asparagine were heated with 2,4-decadienal, the relative contribution of amide nitrogens to the formation of alkylpyridine was determined. Approximately half of nitrogen atoms in 2-pentylpyridine formed were contributed by the amide nitrogens of asparagine, whereas almost all of them came from the amide nitrogens in glutamine. The results above may indicate that both free ammonia and α-amino groups bound in amino acids can contribute to the formation of alkylpyridines, but free ammonia does so more effectively.
Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
supporting information, p. 5022 - 5037 (2021/05/04)
Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
Manganese-Catalyzed Kumada Cross-Coupling Reactions of Aliphatic Grignard Reagents with N-Heterocyclic Chlorides
Petel, Brittney E.,Purak, Merjema,Matson, Ellen M.
supporting information, p. 1700 - 1706 (2018/07/13)
Herein we report the use of manganese(II) chloride for the catalytic generation of C(sp 2)-C(sp 3) bonds via Kumada cross-coupling. Rapid and selective formation of 2-alkylated N-heterocyclic complexes were observed in high yields with use of 3 mol% MnCl 2 THF 1.6 and under ambient reaction conditions (21 °C, 15 min to 20 h). Manganese-catalyzed cross-coupling is tolerant toward both electron-donating and electron-withdrawing functional groups in the 5-position of the pyridine ring, with the latter resulting in an increased reaction rate and a decrease in the amount of nucleophile required. The use of this biologically and environmentally benign metal salt as a catalyst for C-C bond formation highlights its potential as a catalyst for the late-stage functionalization of pharmaceutically active N-heterocyclic molecules (e.g., pyridine, pyrazine).
