78540-03-1Relevant academic research and scientific papers
Successive Pd-Catalyzed Decarboxylative Cross-Couplings for the Modular Synthesis of Non-Symmetric Di-Aryl-Substituted Thiophenes
Douglas, Liam Z.,Forgione, Pat,Liu, Jiang Tian,Messina, Cynthia
supporting information, (2020/08/17)
Oligothiophenes are important organic molecules in a number of burgeoning industries as semi-conducting materials due to their extensive π-conjugation and charge transport properties. Typically, non-symmetric, di-aryl-substituted thiophenes are prepared by the successive formation of Grignards, organotin, and/or boronic acid intermediates that can be subsequently employed in cross-coupling reactions. While reliable, these approaches present synthetic difficulties due to the reactivity of organo-metallic/pseudo-metallic species, and produce considerable amounts of waste due to necessary pre-functionalization. We have developed a decarboxylative cross-coupling route as an effective strategy for the modular and less wasteful synthesis of a wide range of non-symmetric, di-arylthiophenes. This method uses a thiophene ester building block for successive decarboxylative palladium-catalyzed couplings that allows for the efficient synthesis and evaluation of the opto-electronic properties of a library of candidate semi-conductors with functional groups that could be challenging to access using previous routes.
Additive-Free Palladium-Catalyzed Decarboxylative Cross-Coupling of Aryl Chlorides
Daley, Ryan A.,Liu, En-Chih,Topczewski, Joseph J.
supporting information, p. 4734 - 4738 (2019/06/27)
The cross-coupling of sodium (hetero)aryl carboxylates with (hetero)aryl chlorides proceeds with 1 mol % palladium catalyst and does not require inorganic base, silver salts, or copper salts. This coupling uses two low energy partners, and the only stoichiometric byproducts are carbon dioxide and sodium chloride. The substrate scope includes less activated aryl chlorides and carboxylates (>25 examples). The palladium loading could be reduced to 0.1 mol %, and Buchwald-style precatalysts could be used.
Macrocyclic prolinyl acyl guanidines as inhibitors of β-secretase (BACE)
Boy, Kenneth M.,Guernon, Jason M.,Wu, Yong-Jin,Zhang, Yunhui,Shi, Joe,Zhai, Weixu,Zhu, Shirong,Gerritz, Samuel W.,Toyn, Jeremy H.,Meredith, Jere E.,Barten, Donna M.,Burton, Catherine R.,Albright, Charles F.,Good, Andrew C.,Grace, James E.,Lentz, Kimberley A.,Olson, Richard E.,Macor, John E.,Thompson, Lorin A.
, p. 5040 - 5047 (2015/11/09)
The synthesis, evaluation, and structure-activity relationships of a class of acyl guanidines which inhibit the BACE-1 enzyme are presented. The prolinyl acyl guanidine chemotype (7c), unlike compounds of the parent isothiazole chemotype (1), yielded compounds with good agreement between their enzymatic and cellular potency as well as a reduced susceptibility to P-gp efflux. Further improvements in potency and P-gp ratio were realized via a macrocyclization strategy. The in vivo profile in wild-type mice and P-gp effects for the macrocyclic analog 21c is presented.
Palladium-catalyzed decarboxylative cross-coupling reaction between heteroaromatic Carboxylic acids and Aryl halides
Bilodeau, Francois,Brochu, Marie-Christine,Guimond, Nicolas,Thesen, Kris H.,Forgione, Pat
experimental part, p. 1550 - 1560 (2010/06/12)
"Chemical Equation Presented" A full overview of the decarboxylative cross-coupling reaction between heteroaromatic carboxylic acids and aryl halides is described. This transformation employs palladium catalysts with short reaction times providing facile synthesis of aryl-substituted heteroaromatics. The effect of each reaction parameter including solvent, base, and additive employed as well as the full substrate scope of this transformation are reported. Mechanistic evidence is also disclosed that sheds light on possible reaction pathways.
Carboxylation of indoles and pyrroles with CO2 in the presence of dialkylaluminum halides
Nemoto, Koji,Onozawa, Satoru,Egusa, Naoki,Morohashi, Naoya,Hattori, Tetsutaro
experimental part, p. 4512 - 4514 (2009/11/30)
The Lewis acid-mediated carboxylation of arenes with CO2 has been successfully applied to 1-substituted indoles and pyrroles by using dialkylaluminum chlorides instead of aluminum trihalides. Thus, the carboxylation of 1-methylindoles, 1-benzyl-, and 1-phenylpyrroles proceeds regioselectively with the aid of an equimolar amount of Me2AlCl under CO2 pressure (3.0 MPa) at room temperature to afford the corresponding indole-3-carboxylic acids and pyrrole-2-carboxylic acids in 61-85% yields, while the same treatment of 1,2,5-trimethylpyrrole affords the 3-carboxylic acid in 52% yield.
N,N,N',N',N' '-pentamethyldipropylenetriamine (PMDPTA): A versatile auxiliary for site selective lithiation reactions
Thurner, Angelika,Faigl, Ferenc,Agai, Bela,Toke, Laszlo
, p. 443 - 449 (2007/10/03)
Efficient lithiation processes were developed with PMDPTA, a tridentate ligand of butyllithium reagent for site selective metallation of aromatic and heteroaromatic compounds.
N-phenylpyrrole: A kinetic, though not thermodynamic preference for dilithiation
Faigl,Schlosser
, p. 10271 - 10278 (2007/10/02)
Under appropriate conditions the clean preparation of either the α-monolithiated or the o,α-dilithiated derivative of N-phenylpyrrole is possible. In the latter case, the first deprotonation occurs at the α-position. Dimetalation is kinetically but not thermodynamically favored.
Ortho-METALLATION REACTIONS OF VARIOUS N-SUBSTITUTED PYRROLES
Cartoon, M. E. K.,Cheeseman, G. W. H.
, p. 123 - 136 (2007/10/02)
Two routes for the preparation of 2,3-disubstituted pyrroles have been explored.The first involves the directed palladation of a 2-dimethylaminomethylpyrrole and the second the lithiation of a 2-oxazolinopyrrole.
LITHIATION REACTIONS OF 1-(2'-BROMOPHENYL)PYRROLE AND RELATED COMPOUNDS
Cartoon, M. E. K.,Cheeseman, G. W. H.
, p. 1 - 9 (2007/10/02)
9-Keto-9H-pyrroloindole is formed by the intramolecular cyclisation of the dilithio derivatives generated from either 1-(2'-carboxyphenyl)pyrrole or 1-(2'-bromophenyl)pyrrole-2-carboxylic acid.The reaction of the 2'-lithio derivative of 1-phenylpyrrole with various electrophiles is also described.
