Synthesis of Indoles by Reductive Cyclization of Nitro Compounds Using Formate Esters as CO Surrogates
Alkyl and aryl formate esters were evaluated as CO sources in the Pd- and Pd/Ru-catalyzed reductive cyclization of 2-nitrostyrenes to give indoles. Whereas the use of alkyl formates requires the presence of a ruthenium catalyst such as Ru3(CO)12, the reaction with phenyl formate can be performed by using a Pd/phenanthroline complex alone. Phenyl formate was found to be the most effective CO source and the desired products were obtained in excellent yields, often higher than those previously reported using pressurized CO. The reaction tolerates many functional groups, including sensitive ones like a free aldehydic group or a pendant pyrrole. Detailed experiments and kinetic studies allow to conclude that the activation of phenyl formate is base-catalyzed and that the metal doesn't play a role in the decarbonylation step. The reactions can be performed in a single thick-walled glass tube with as little as 0.2 mol-% palladium catalyst and even on a 2 g scale. The same protocol can be extended to other nitro compounds, affording different heterocycles.
Ahmed Fouad, Manar,Ferretti, Francesco,Formenti, Dario,Milani, Fabio,Ragaini, Fabio
supporting information
p. 4876 - 4894
(2021/09/20)
Development of a scalable synthesis of a serotonin receptor antagonist
An efficient process was developed for the manufacture of MSA100, a serotonin receptor antagonist, via a five-step synthetic route furnishing a high quality of active pharmaceutical ingredient. Highlights of this synthesis include: (1) replacing carcinoge
Prashad, Mahavir,Liu, Yugang,Shieh, Wen-Chung,Schaefer, Frank,Hu, Bin,Girgis, Michael
p. 290 - 295
(2015/01/30)
Lewis-acid-catalyzed benzylic reactions of 2-methylazaarenes with aldehydes
Lewis-acid-catalyzed benzylic reactions of 2-methylazaarenes with aldehydes have been investigated. Series of azaarene derivatives were afforded by this reaction. 2-(Pyridin-2-yl)ethanols with common substituents were formed through the LiNTf2-promoted aldol reaction for the first time. 2-Alkenylpyridines, exclusively in the form of the E isomers, were synthesized in the presence of LiNTf2 cooperated with H2NTf. In the presence of La(Pfb)3 as catalysis, 2-alkenylquinolines were obtained in high yields through the reactions between 2-methylquinolines and aldehydes under air.
The present invention relates to salts of aryl compounds as discussed below and to methods of manufacture thereof, as well as other subject matter. More particularly, the invention relates to salts useful as intermediates for the synthesis of the cinnaman
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Page/Page column 12
(2009/01/20)
Kinetic Energy Release and Hammond Postulate During Intramolecular Aromatic Substitution in 2-Stilbazole Ions
In the mass spectra of 2-stilbazoles 1a - 1g and 3- and 4-stilbazoles (2 resp. 3), C13H10N+ ions, m/z = 180, are formed with high intensities by loss of a H-atom or of a substituent.This is the only fragmentation reaction available to metastable molecular