76582-47-3Relevant academic research and scientific papers
19F and 1H NMR of Aldimines of Fluoroamino Acids with Pyridoxal-5'-phosphate
Beguin, Claude,Hamman, Sylvain
, p. 129 - 132 (1981)
1H and 19F NMR spectra were obtained for six Schiff bases (aldimines)formed by pyridoxal-5'-phosphate (PLP) with four fluorinated or their two parent non-fluorinated α-amino acids (phenylalanine and α-aminobutyric acid). pKA Values were derived from 1H and 19F titration curves.The imine nitrogen of the aldimines is very basic (ca. 13) and sensitive to the electron withdrawing effect of fluorine.The pyridine nitrogen is less basic in the aldimines (ca. 7) than in PLP (8.12) and is less sensitive to the electron withdrawing effect of the fluorine than is the imine nitrogen.The phosphate group has a pK in the same range (ca. 6) and the chemical shifts of some nuclei are sensitive to both pK values.Protonation of the aldimine causes the 1H signal to shift downfield at the methyl protons of the pyridine ring and at the aldehydic proton of the aldimine for the high pK value (except for the aldimines prepared from the β-fluorophenylalanine), but upfield at the aromatic proton and at the aldehydic proton of the aldimine for the low pK.Protonation of the aldimine causes the 19F signal of an aryl fluorine to shift downfield but gives an upfield shift at a β-fluorine.These data are related to the highly conjugated electronic structure of the Schiff bases.
A CONVENIENT SYNTHESIS OF erythro AND threo-3-FLUOROPHENYLALANINE FROM A PROTECTED GLYCINE SYNTHON
O'Donnell, Martin J.,Barney, Charlotte L.,McCarthy, James R.
, p. 3067 - 3070 (2007/10/02)
A facile synthesis of the title compounds (8 and 9) is descriebed; key steps include the mono-C-alkylation of the glycine Schiff base benzyl ester 1a with α-bromo-α-fluorotoluene, which provides the readily separable fluorinated diastereomers 2a and 3a, a
Reaction of Hydrogen Fluoride in Pyridine Solution with cis-Cyano-2- and cis-Amido-2-aziridines. Preparation of β-Fluoro-α-amino Acids and Esters by Means of Acidic Hydrolysis and Alcoholysis of β-Fluoro-α-Amino Nitriles and/or β-Fluoro-α-Amino Acid Amide
Ayi, Ayicoue I.,Guedj, Roger
, p. 2045 - 2051 (2007/10/02)
The addition of hydrogen fluoride generated from pyridinium poly(hydrogen fluoride) (i.e.Olah's reagent) to some cis-2-cyano- and cis-2-amido-aziridines has been examined.The reaction led to fluoroamine derivatives which upon acidic hydrolysis and alcohol
Stereoselective synthesis of erythro-3-fluorophenylalanine
Tsushima, Tadahiko,Nishikawa, Junko,Sato, Tomohiro,Tanida, Hiroshi,Tori, Kazuo,Tsuji, Teruji,Misaki, Susumu,Suefuji, Masahiro
, p. 3593 - 3594 (2007/10/02)
Reductive amination of 3-fluorophenylpyruvic acid was found to give erythro-3-fluorophenylalanine with high selectivity.
DETERMINATION OF THREO AND ERYTHRO CONFIGURATIONS OF 3-FLUOROPHENYLALANINE FOR VERIFYING STEREOCHEMICAL ASPECTS OF RECENTLY REPORTED SYNTHESES
Tsushima, Tadahiko,Sato, Tomohiro,Tsuji, Teruji
, p. 3591 - 3592 (2007/10/02)
Determination of threo and erythro configurations of both diastereoisomers of 3-fluorophenylalanine on the basis of chemical transformation and X-ray analysis has confirmed that the aziridine ring opening reaction gives the threo isomer stereoselectively, whereas the fluorodehydroxylation reaction affords both isomers nonselectively.
