Zum basenkatalysierten H/D‐Austausch des acetylenischen Wasserstoffatoms in aromatischen Alkinylverbindungen

On the Base‐Catalysed H/D‐Exchange of the Acetylenic Hydrogen Atom in Aromatic Alkynyl Compounds H/D‐exchange rates for a number of compounds of the general type 1 (X = p ‐CH 3 O, m ‐CH 3 O, p ‐CF 3 , m ‐CF 3 , p ‐CH 3 , p ‐Cl, H; Z O, NH, CH 2 ) were determined in N ‐methyl‐pyrrolidine (NMP)/D 2 O mixtures at 25° (see Table 1 ). It is shown that the log k values of the H/D‐exchange correlate nicely (r = 0.995) with the chemical shift of the acetylenic proton in 1 . Thus, the H/D‐exchange rate is given by log k (min −1 ) = 2.91 · δ (ppm) ‐ 7.79 for the NMP/D 2 O mixture at 25°.