Direct synthesis of ring-fused quinolines and pyridines catalyzed by NN_HY-ligated manganese complexes (Y = NR₂ or SR)

Abstract

A robust NNS-manganese(i) complex has been developed that can efficiently catalyze the dehydrogenation coupling of γ-amino alcohols with ketones or secondary alcohols in a one-step synthesis of quinolines and pyridines with high yields.

Cr and Co-modified Cu/Al2O3 as an efficient catalyst for the continuous synthesis of bis(2-dimethylaminoethyl)ether

“…In recent years, alternative approaches such as C-N coupling 7,8 and catalytic amination of alcohols with amines [9][10][11][12][13] have drawn much attention. The avoidance of alkyl halides not only saves cost, but also diminishes pollution, especially for diamines such as BDMAEE.…”

Efficient transfer hydrogenation of ketones using molybdenum complexes by comprehensively verifying the auxiliary ligands

“…To prepare the complexes Mo1–Mo3 , the N 1 , N 1 -dialkyl- N 2 -(5,6,7,8-tetrahydroquinolin-8-yl)ethane-1,2-diamine ligands 23 (dialkyl: NMe 2 for L1 ; NEt 2 for L2 ; N i Pr 2 for L3 ) were reacted individually with Mo(CO) 6 in toluene at 100 °C for 12 hours, and the following work-up process gives pure [ fac -NN H N]Mo(CO) 3 ( Mo1 and Mo2 ) and [NN H ]Mo(CO) 4 ( Mo3 ) in good yields (Scheme 2). Meanwhile, the reaction of these ligands with the newly prepared molybdenum precursors, 24 Mo(η 3 -C 3 H 5 )(CO) 2 (CH 3 CN) 2 Br and Mo(PPh 3 ) 2 (CO) 2 (CH 3 CN) 2 , provided the complexes [Mo(NN H N)(CO) 2 Br] ( Mo4 and Mo5 ), [Mo(NN H )(η 3 -C 3 H 5 )(CO) 2 Br] ( Mo6 ) and [Mo(NN H N)(PPh 3 ) 2 (CO)Br] ( Mo7 and Mo8 ) in good yields (Scheme 2).…”

“…The tridentate ligands ( L1–L4 ) containing 5,6,7,8-tetrahydroquinolin-8-amine were prepared using a previously reported procedure. 23…”

“…Along with our ongoing work on the ligand-oriented 20 design of late transition metal catalysts (Fe, Co, Ni) towards ethylene catalysis, 21 Ru and Mn complexes have been extensively explored as efficient catalysts for the (de)hydrogenation of fine chemicals. 22,23 Using N 1 , N 1 -dialkyl- N 2 -(5,6,7,8-tetrahydroquinolin-8-yl)ethane-1,2-diamines 23 along with auxiliary ligands, molybdenum complexes ( Mo1–Mo8 ) have been prepared and characterized. Systematic variations with respect to the steric and electronic substituents in the N 1 , N 1 -dialkyl- N 2 -(5,6,7,8-tetrahydroquinolin-8-yl)ethane-1,2-diamines and in the auxiliary ligands (Br, PPh 3 or CO) have been performed to develop the most efficient catalysts.…”

“…80 °C; withdraw time 2 min, followed by 20 °C min −1 to 250 °C, maintaining for 5 min, then 20 °C min −1 to 280 °C, and withdraw time 10 min. The tridentate ligands (L1-L4) containing 5,6,7,8-tetrahydroquinolin-8amine were prepared using a previously reported procedure 23.…”