“…According to the results from NMR study in CDCl 3 , the molecules 13-24 may be classified into three groups: o-unsubstituted (13,15,16,20), o-monofluorinated (14, 17-19, 21, 22), and o,odifluorinated derivatives (23,24). An additional long-range spin-spin coupling between the aromatic fluorine and phenylalanine a-proton was observed only in o-monofluorinated derivatives, which supports the presence of interaction between the fluorine and the amide hydrogen (the longrange J coupling in 2-fluoro-N-methylbenzamide was reported 38 ). In addition, a significant downfield shift of NH signals was observed in o-monofluorinated derivatives compared to o-unsubstituted and o,o-difluorinated derivatives …”