61985-23-7Relevant academic research and scientific papers
Facile access to imidazole derivatives: Carboxylic acids and δ-lactones
Rivera-Hernández, Alejandro,López-Jimeno, Isabel S.,Carmona-Reyes, Genaro A.,Alfredo-Toscano,Penieres-Carrillo, José Guillemo,álvarez-Toledano, Cecilio
, p. 4829 - 4832 (2015)
The nucleophilic addition of bis-(TMS)ketene acetals to doubly N-activated imidazole under mild conditions, leads to their corresponding dihydroimidazolyl carboxylic acids in a first instance. Subsequent reaction of these acids can be efficiently turned i
Palladium-Catalyzed Oxidative C–H Alkoxycarbonylation of Arenes with Alkylcarbazates Directed by N-Heterocyclic Substituents
Yogesh Kumar, Gujjenahalli Ramalingaiah,Begum, Noor Shahina
supporting information, p. 4698 - 4704 (2020/07/04)
With alkyl carbazates as the green ester source, a novel palladium-catalyzed oxidative free radical carbonylative transformation of the C–H bond on aromatic rings to produce esters has been developed. Good yields of the corresponding products have been obtained with wide functional group tolerance and excellent regioselectivity. A variety of alkyl carbazates are found to be suitable reactants for the ortho-alkoxycarbonylation on the aromatic ring.
Enantioselective Syntheses of Strychnos and Chelidonium Alkaloids through Regio- and Stereocontrolled Cooperative Catalysis
Fyfe, James W. B.,Hutchings-Goetz, Luke S.,Snaddon, Thomas N.,Yang, Chao
supporting information, p. 17556 - 17564 (2020/08/14)
We describe enantioselective syntheses of strychnos and chelidonium alkaloids. In the first case, indole acetic acid esters were established as excellent partner nucleophiles for enantioselective cooperative isothiourea/Pd catalyzed α-alkylation. This provides products containing indole-bearing stereocenters in high yield and with excellent levels of enantioinduction in a manner that is notably independent of the N-substituent. This led to concise syntheses of (?)-akuammicine and (?)-strychnine. In the second case, the poor performance of ortho-substituted cinnamyl electrophiles in the enantioselective cooperative isothiourea/Ir catalyzed α-alkylation was overcome by appropriate substituent choice, leading to enantioselective syntheses of (+)-chelidonine, (+)-norchelidonine, and (+)-chelamine.
One-pot protection-glycosylation reactions for synthesis of lipid II analogues
Mitachi, Katsuhiko,Mohan, Priya,Siricilla, Shajila,Kurosu, Michio
supporting information, p. 4554 - 4558 (2014/05/06)
(2,6-Dichloro-4-methoxyphenyl)(2,4-dichlorophenyl)methyl trichloroacetimidate (3) and its polymer-supported reagent 4 can be successfully applied to a one-pot protection-glycosylation reaction to form the disaccharide derivative 7 d for the synthesis of lipid II analogues. The temporary protecting group or linker at the C-6 position and N-Troc protecting group of 7 d can be cleaved simultaneously through a reductive condition. Overall yields of syntheses of lipid II (1) and neryl-lipid II Nε-dansylthiourea are significantly improved by using the described methods. Sweet synthetic methods: A one-pot protection glycosylation reaction of the diol glycosyl acceptor is developed for synthesis of the lipid II disaccharide (see figure, Troc=2,2,2-trichloroethoxycarbonyl). Improved syntheses of lipid II and neryl-lipid II analogues are summarized.
Palladium-catalyzed C3-benzylation of indoles
Zhu, Ye,Rawal, Viresh H.
supporting information; experimental part, p. 111 - 114 (2012/03/07)
A general method for regioselective C3-benzylation of indoles has been developed. Various 3-substituted indoles and benzyl methyl carbonates with different electronic properties react under mild conditions to afford a diverse range of 3-benzylindolenine products in good yields.
On the reactivity of imidazole carbamates and ureas and their use as esterification and amidation reagents
Heller, Stephen T.,Sarpong, Richmond
body text, p. 8851 - 8859 (2011/12/02)
The optimization, substrate scope, and mechanism of esterification and amidation of carboxylic acids mediated by imidazole-based reagents are discussed. The innate reactivity of carbonylimidazole reagents with a range of nucleophiles is also explored. New reagents developed for the synthesis of α,β-unsaturated esters are described, as are reagents for the preparation of tertiary amides directly from carboxylic acids.
Chemoselective esterification and amidation of carboxylic acids with imidazole carbamates and ureas
Heller, Stephen T.,Sarpong, Richmond
supporting information; experimental part, p. 4572 - 4575 (2010/12/25)
Imidazole carbamates and ureas were found to be chemoselective esterification and amidation reagents. A wide variety of carboxylic acids were converted to their ester or amide analogues by a simple synthetic procedure in high yields.
Direct N-carbamoylation of 3-monosubstituted oxindoles with alkyl imidazole carboxylates
Trost, Barry M.,Zhang, Yong,Zhang, Ting
experimental part, p. 5115 - 5117 (2009/10/24)
(Chemical Equation Presented) Regioselective N-carbamoylation of oxindoles was achieved through the use of imidazole carboxylate reagents. This reaction provides ready access to N-carbamoyl-3-monosubstituted oxindoles.
Electroreductive acylation of aromatic imines with acylimidazoles
Kise, Naoki,Morimoto, Shinji
, p. 1765 - 1771 (2008/09/18)
The intermolecular reductive coupling of aromatic imines with acylimidazoles was effected by electroreduction in the presence of chlorotrimethylsilane and gave α-amino-α-aryl ketones. This method was also effective for the synthesis of α-amino-α-aryl esters using methoxycarbonylimidazole as an electrophile.
Electroreductive acylation of aromatic ketones with acylimidazoles
Kise, Naoki,Agui, Syun,Morimoto, Shinji,Ueda, Nasuo
, p. 9407 - 9410 (2007/10/03)
The intermolecular reductive coupling of aromatic ketones with acylimidazoles was effected by electroreduction in the presence of chlorotrimethylsilane and gave α-trimethylsiloxy ketones and esters. The best result was obtained using Bu4NPF6 as a supporting electrolyte and a Pb cathode in THF. The α-trimethylsiloxy-containing products were transformed to the corresponding α-hydroxy ketones and esters by treatment with TBAF in THF. This method was also effective for the intramolecular reductive coupling of δ- and ε-keto acylimidazoles.
