95885-53-3Relevant academic research and scientific papers
Arylation of azlactones using diaryliodonium bromides and silver carbonate: Facile access to α-tetrasubstituted amino acid derivatives
Chai, Zhuo,Wang, Biao,Chen, Jia-Nan,Yang, Gaosheng
supporting information, p. 2714 - 2718 (2014/09/29)
With the combined use of silver carbonate, diaryliodonium bromides were successfully utilized as aryl source to realize the highly efficient arylation of azlactones under mild conditions. The reaction worked well with various alkyl- and aryl-substituted azlactones, providing a range of α-tetrasubstituted amino acid derivatives in moderate to high yields.
Cyclopalladation and reactivity of amino esters through C - H bond activation: Experimental, kinetic, and density functional theory mechanistic studies
Laga, Eduardo,Garcia-Montero, Angel,Sayago, Francisco J.,Soler, Tatiana,Moncho, Salvador,Cativiela, Carlos,Martinez, Manuel,Urriolabeitia, Esteban P.
supporting information, p. 17398 - 17412 (2014/01/06)
The orthopalladation, through C - H bond activation, of a large number of amino esters and amino phosphonates derived from phenylglycine, and having different substituents at the aryl ring and the C-α atom, as well as on the N-amine atom, has been studied. The experimental observations indicated an improvement in the yields of the orthopalladated compounds when the N-amine and/or the C-α atom are substituted, when compared with the unsubstituted methyl phenylglycinate derivatives. In contrast, substitutions at the aryl ring do not promote significant changes in the orthometalation results. Furthermore, the use of hydrochloride salts of the amino esters has also been shown to have a remarkably favorable effect on the process. All these observations have been fully quantified at different temperatures and pressures by a detailed kinetic study in solution in different solvents and in the presence and absence of added Bronsted acids and chloride anions. The data collected indicate relevant changes in the process depending on these conditions, as expected from the general background known for cyclopalladation reactions. An electronic mechanism of the orthopalladation has been proposed based on DFT calculations at the B3LYP level, and a very good agreement between the trends kinetically measured and the theoretically calculated activation barriers has been obtained. The reactivity of the new orthopalladated amino phosphonate derivatives has been tested and it was found that their halogenation, alkoxylation and carbonylation resulted in formation of the corresponding functionalized ortho- haloaminophosphonates, ortho-alkoxyaminophosphonates and oxoisoindolinylphosphonates. Remote control: The orthopalladation, through C - H bond activation, of substituted amino esters and amino phosphonates derived from phenylglycine has been studied (see scheme). Determination of the reaction rates indicated a clear acceleration of the C - H activation rate when the n-amine and/or the C-α atom are substituted. Substitutions at the aryl ring do not promote changes. The use of hydrochloride salts of the amino esters also has a strong accelerating effect on the process.
Palladium-catalyzed alpha-arylation of azlactones to form quaternary amino acid derivatives.
Liu, Xiaoxiang,Hartwig, John F
, p. 1915 - 1918 (2007/10/03)
[reaction: see text] The synthesis of alpha-aryl-alpha-alkyl amino acid derivatives from alpha-amino acids by the arylation of azlactone derivatives is reported. Arylation of azlactones derived from alanine, valine, phenalanine, phenyl glycine, and leucin
A reinvestigation of the α-alkylation of 4-monosubstituted 2-phenyloxazol-5(4H)-ones ('azlactones'): A general entry into highly functionalized α,α-disubstituted α-amino acids
Obrecht,Bohdal,Ruffieux,Muller
, p. 1423 - 1429 (2007/10/02)
Novel, more reliable and general reaction conditions for the α-alkylation of 4-monosubstituted 2-phenyloxazol-5(4H)-ones (= 4-monosubstituted 2-phenyl-azlactones) rac-2 to 4,4-disubstituted 2-phenyloxazol-5(4H)-ones rac-1 were found. Thus, a whole range of highly functionalized rac-1 were prepared in medium-to-good overall yields (40-90%). Azlactones rac-1 are ideal precursors for the synthesis of optically pure α,α-disubstituted (R)- and (S)-α-amino acids.
Synthesis of 4,4-Disubstituted 1,3-Thiazol-5(4H)-thiones
Jenny, Christjohannes,Heimgartner, Heinz
, p. 374 - 388 (2007/10/02)
An easy synthesis for the 1,3-thiazol-5(4H)-thiones 5, a class of heterocycles which have hitherto only been available with difficulty, is described.Reaction of 3-amino-2H-azirines 25 with thiocarboxylic acids at 0 deg yields monothiodiamides of type 20 (Scheme 6) which, on treatment with Lawesson reagent at 100 deg, undergo thiation and cyclization to give 5 in good yield.
