19F and 1H NMR of aldimines of fluoroamino acids with pyridoxal??5′??phosphate

C Beguin, S Hamman

Index: Beguin, Claude; Hamman, Sylvain Organic Magnetic Resonance, 1981 , vol. 16, # 2 p. 129 - 132

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Citation Number: 5

Abstract

Abstract 1 H and 19 F 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). pK A Values were derived from 1 H and 19 F titration curves. The imine nitrogen of the aldimines is very basic (∼ 13) and sensitive to the electron withdrawing effect of fluorine. The pyridine nitrogen is less basic ...