93406-12-3Relevant academic research and scientific papers
UV-Light-Induced N-Acylation of Amines with α-Diketones
Xu, Zhihui,Yang, Tianbao,Tang, Niu,Ou, Yifeng,Yin, Shuang-Feng,Kambe, Nobuaki,Qiu, Renhua
supporting information, p. 5329 - 5333 (2021/07/21)
Herein, we develop a mild method for N-acylation of primary and secondary amines with α-diketones induced by ultraviolet (UV) light. Forty-six examples with various functional groups are explored at room temperature with irradiation by three 26 W UV lamps (350-380 nm). The yield reaches 97%. The gram scale experiment product yield is 76%. Moreover, this system can be applied to the synthesis of several amino acid derivatives. Mechanistic studies show that benzoin is generated in situ from benzil under UV irradiation.
Mechanistic insights into boron-catalysed direct amidation reactions
Arkhipenko, Sergey,Sabatini, Marco T.,Batsanov, Andrei S.,Karaluka, Valerija,Sheppard, Tom D.,Rzepa, Henry S.,Whiting, Andrew
, p. 1058 - 1072 (2018/02/07)
The generally accepted monoacyloxyboron mechanism of boron-catalysed direct amidation is brought into question in this study, and new alternatives are proposed. We have carried out a detailed investigation of boron-catalysed amidation reactions, through study of the interaction between amines/carboxylic acids and borinic acids, boronic acids and boric acid, and have isolated and characterised by NMR/X-ray crystallography many of the likely intermediates present in catalytic amidation reactions. Rapid reaction between amines and boron compounds was observed in all cases, and it is proposed that such boron-nitrogen interactions are highly likely to take place in catalytic amidation reactions. These studies also clearly show that borinic acids are not competent catalysts for amidation, as they either form unreactive amino-carboxylate complexes, or undergo protodeboronation to give boronic acids. It therefore seems that at least three free coordination sites on the boron atom are necessary for amidation catalysis to occur. However, these observations are not consistent with the currently accepted 'mechanism' for boron-mediated amidation reactions involving nucleophilic attack of an amine onto a monomeric acyloxyboron intermediate, and as a result of our observations and theoretical modelling, alternative proposed mechanisms are presented for boron-mediated amidation reactions. These are likely to proceed via the formation of a dimeric B-X-B motif (X = O, NR), which is uniquely able to provide activation of the carboxylic acid, whilst orchestrating the delivery of the amine nucleophile to the carbonyl group. Quantum mechanical calculations of catalytic cycles at the B3LYP+D3/Def2-TZVPP level (solvent = CH2Cl2) support the proposal of several closely related potential pathways for amidation, all of which are likely to be lower in energy than the currently accepted mechanism.
An open-source approach to automation in organic synthesis: The flow chemical formation of benzamides using an inline liquid-liquid extraction system and a homemade 3-axis autosampling/product-collection device
O'Brien, Matthew,Hall, April,Schrauwen, John,van der Made, Joyce
supporting information, p. 3152 - 3157 (2018/03/21)
Several open-source hardware and software technologies (RAMPS, Python, PySerial, OpenCV) were used to control an automated flow chemical synthesis system. The system was used to effect the synthesis of a series of benzamides. An inexpensive Raspberry Pi single board computer provided an electronic interface between the control computer and the RAMPS motor driver boards.
An Unconventional Reaction of 2,2-Diazido Acylacetates with Amines
H?ring, Andreas P.,Biallas, Phillip,Kirsch, Stefan F.
supporting information, p. 1526 - 1539 (2017/04/01)
We have discovered that 2,2-diazido acylacetates, a class of compounds with essentially unknown reactivity, can be coupled to amines through a new strategy that does not involve any reagents. 2,2-Diazido acetate is the unconventional leaving group under carbon–carbon bond cleavage. This reaction leads to the construction of amide bonds, tolerates various functionalities and is performed equally well in numerous solvents under experimentally simple conditions. We also demonstrate that the isolation of the 2,2-diazido acylacetate compounds can be circumvented: Acylacetates were easily fragmented when treated with (Bu4N)N3 and iodine in the presence of an amine at room temperature. By using this method, a broad range of acylacetates with various structural motifs were directly transformed into amides.
Intensified azeotropic distillation: A strategy for optimizing direct amidation
Grosjean, Christophe,Parker, Julie,Thirsk, Carl,Wright, Allen R.
experimental part, p. 781 - 787 (2012/08/07)
The direct synthesis of amides from the corresponding carboxylic acids and amines is shown to operate under varying degrees of mixed kinetic and mass transfer rate control when water is removed by azeotropic distillation. Unless the volumetric heat input rate is reported, it is not possible to make a valid comparison between different catalysts, as the difference in Qboil alone can be responsible for the apparent difference in observed rate. A systematic approach is developed to quantify the contribution of boil-up rate to conversion rate and so decouple the physical rates from the chemistry. Intensive boiling is used to improve the removal of water during azeotropic distillation and considerably enhance conversion. The results show that some acylations previously thought to be difficult or impossible can be achieved in the absence of coupling agents under green conditions. The use of a cascade of CSTR flow reactors operating under intensified conditions is assessed for scale up of direct amidation reactions and compared to a production scale batch reactor. The findings and conclusions of this work have general applicability to all condensation reactions.
To catalyze or not to catalyze? Insight into direct amide bond formation from amines and carboxylic acids under thermal and catalyzed conditions
Arnold, Kenny,Davies, Bryan,Giles, Richard L.,Grosjean, Christophe,Smith, Gillian E.,Whiting, Andrew
, p. 813 - 820 (2007/10/03)
Kinetic studies show that the direct formation of amides from amines and carboxylic acids without catalyst does occur under relatively low temperature conditions, but is highly substrate dependent. Boric and boronic acid-based catalysts improve the reacti
