24013-90-9Relevant academic research and scientific papers
The Relative Importance of Ground-state Conformation and Orbital Orientation in Intramolecular Catalysis: Hydrolysis of Aryl Hydrogen Biphenyl-2,2'-dicarboxylates
Chandrasekar, Ramamurthy,Venkatasubramanian, Nagaswami
, p. 421 - 424 (1983)
The pH-rate profile for the hydrolysis of 4-nitrophenyl hydrogen biphenyl-2,2'-dicarboxylate (diphenate) shows a pH-independent region in the pH range 5-9, and obeys rate law (i).Compared with 4-nitro- -phenyl benzoate, the hydrolysis of 4-nitrophenyl hydrogen diphenate proceeds 800 times faster at pH 6.0.This is explained by invoking intramolecular nucleophilic catalysis by the neighbouring carboxylate ion.The negligible solvent isotope effect at pH 6.0 (kH2O/kD2O 1.22) and the low negative entropy of activation (-7.2 cal K-1 mol-1), the high value of the Hammett reaction constant (ρ 2.19) and Broensted constant (β -0.95) for variations in the leaving group provide evidence for nucleophilic catalysis.The effective molarity for the intramolecular cyclisation of 4-nitrophenyl hydrogen diphenate has been calculated to be ca. 200, which is close to that observed for this phenomenon in glutarates and quite low in comparison with that obtained for succinates.This has been taken to indicate that the reactivity of diphenic acid esters is governed more by steric factors which affect the proper orientation of the orbitals than the ground-state conformation arising out of restriction of rotamer distribution.
An efficient synthesis of biaryl diamides via Ullmann coupling reaction catalyzed by CuI in the presence of Cs2CO3 and TBAB
Dong, Fang,Liu, Jian-Quan,Wang, Xiang-Shan
, p. 5271 - 5283 (2018/04/12)
Abstract: CuI accompanyied by Cs2CO3 and TBAB was confirmed to be an efficient catalyst combination to promote an Ullmann coupling reaction. It facilitated 2-bromobenzamides to undergo a coupling reaction for the synthesis of symmetrical biaryldiamides in moderate yields at 120?°C under Pd-free conditions. Graphical Abstract: [Figure not available: see fulltext.].
Pd/C-Catalyzed Homocoupling Reaction for the Synthesis of Symmetrical Biaryl Diamides
Shen, Guodong,Wang, Yichen,Zhao, Xiliang,Huangfu, Xinlei,Tian, Yanmeng,Zhang, Tongxin,Yang, Bingchuan
supporting information, p. 2030 - 2035 (2017/09/13)
Pd/C was found to be an efficient and convenient metal catalyst in the homocoupling reaction for the synthesis of symmetrical biaryl diamides. The catalyst system Pd/C-KOAc showed high catalytic activity, and a variety of symmetrical biaryl diamides were conveniently synthesized from 2-halo- N -phenylbenzamides in moderate to good yields.
A convenient palladium catalyzed synthesis of symmetric biaryls, biheterocycles and biaryl chiral diamides
Goswami, Shyamaprosad,Adak, Avijit Kumar,Mukherjee, Reshmi,Jana, Subrata,Dey, Swapan,Gallagher, John F.
, p. 4289 - 4295 (2007/10/03)
A series of symmetrical diamido biaryls has been synthesized in good yield by direct homocoupling of iodoarylbenzamides by palladium-catalysis. No cross product has been isolated from the reaction mixture of two different iodoarylbenzamides under similar conditions. However, only in the case of 2-iodo-N-phenylbenzamide, the intramolecularly coupled product phenanthridone has been isolated as a minor product along with the major intermolecularly coupled product. Biphenyl chiral diamides have been synthesized by this coupling method. This coupling reaction also works well with the reductive dimerization of functionalized heterocyclic compounds. Thus 6,6′-dipivaloylamino-3, 3′-bipyridine and 6,6′-dimethyl-2,2′-bipyridine have been efficiently synthesized. In two cases, the X-ray crystal structures have been solved to establish the structures of symmetrical and chiral diamido biaryls and their supramolecular networks.
