124302-98-3Relevant academic research and scientific papers
Convenient synthesis of racemic 4,4-difluoro glutamic acid derivatives via Michael-type additions of Ni(II)-complex of dehydroalanine Schiff bases
Tokairin, Yoshinori,Soloshonok, Vadim A.,Konno, Hiroyuki,Moriwaki, Hiroki,R?schenthaler, Gerd-Volker
, (2019)
Michael-type addition reactions of Ni(II)-complex of a dehydroalanine Schiff base and ethyl bromodifluoroacetate in the presence of copper for the synthesis of racemic 4,4,-difluoroglutamic acid derivatives were developed. These reactions proceeded smooth
Synthesis of α-Amino Acids via Asymmetric Phase Transfer-Catalyzed Alkylation of Achiral Nickel(II) Complexes of Glycine-Derived Schiff Bases
Belokon, Yuri N.,Bespalova, Natalia B.,Churkina, Tatiana D.,Cisarova, Ivana,Ezernitskaya, Marina G.,Harutyunyan, Syuzanna R.,Hrdina, Radim,Kagan, Henri B.,Kocovsky, Pavel,Kochetkov, Konstantin A.,Larionov, Oleg V.,Lyssenko, Konstantin A.,North, Michael,Polasek, Miroslav,Peregudov, Alexander S.,Prisyazhnyuk, Vladimir V.,Vyskocil, Stepan
, p. 12860 - 12871 (2007/10/03)
Achiral, diamagnetic Ni(II) complexes 1 and 3 have been synthesized from Ni(II) salts and the Schiff bases, generated from glycine and PBP (7) and PBA (11), respectively, in MeONa/MeOH solutions. The requisite carbonyl-derivatizing agents pyridine-2-carboxylic acid(2-benzoyl-phenyl)-amide 7 (PBP) and pyridine-2-carboxylic acid(2-formyl-phenyl)-amide 11 (PBA) were readily prepared from picolinic acid and o-aminobenzophenone or picolinic acid and methyl o-anthranilate, respectively. The structure of 1 was established by X-ray crystallography. Complexes 1 and 3 were found to undergo C-alkylation with alkyl halides under PTC conditions in the presence of β-naphthol or benzyltriethylammonium bromide as catalysts to give mono- and bis-alkylated products, respectively. Decomposition of the complexes with aqueous HCI under mild conditions gave the required amino acids, and PBP and PBA were recovered. Alkylation of 1 with highly reactive alkyl halides, carried out under the PTC conditions in the presence of 10% mol of (S)- or (R)-2-hydroxy-2′ -amino-1,1′-binaphthyl 31a (NOBIN) and/or its N-acyl derivatives and by (S)- or (R)-2-hydroxy-8′-amino-1,1′-binaphthyl 32a (iso-NOBIN) and its N-acyl derivatives, respectively, gave rise to α-amino acids with high enantioselectivities (90-98.5% ee) in good-to-excellent chemical yields at room temperature within several minutes. An unusually large positive nonlinear effect was observed in these reactions. The Michael addition of acrylic derivatives 37 to 1 was conducted under similar conditions with up to 96% ee. The 1H NMR and IR spectra of a mixture of the sodium salt of NOBIN and 1 indicated formation of a complex between the two components. Implications of the association and self-association of NOBIN for the observed sense of asymmetric induction and nonlinear effects are discussed.
Highly efficient catalytic synthesis of α-amino acids under phase-transfer conditions with a novel catalyst/substrate pair
Belokon, Yuri N.,Kochetkov, Konstantin A.,Churkina, Tatiana D.,Ikonnikov, Nikolai S.,Larionov, Oleg V.,Harutyunyan, Syuzanna R.,Vyskocil, Stepan,North, Michael,Kagan, Henri B.
, p. 1948 - 1951 (2007/10/03)
A facile and fast enantioselective synthesis of α-amino acids with high ee values was achieved by the asymmetric alkylation of the glycine derivative 1 under phase-transfer conditions with (R)-2-amino-2′-hydrozy-1,1′-binaphthyl (NOBIN; see sceme). The ee value of the amino acid products. This occures as a results of a significant positive nonlinear effect in the alkylation reaction.
