“…Diethyl bromomethylenediphosphonate (5b),[11,12] pale yellow oil; decomposes on distillation; crude yield 1.72 g (94 %); 31 P-NMR (CDCl3), δ: 13.4 (s); 1 H-NMR (CDCl3), δ:1.27 (t, 12H, 3 JHH=7.0, CH3CH2O), 3.81 (t, 1H, 2 JPH=17.0, CHBr), 3.91-4.35 (m, 8H, CH3CH2O);13 C-NMR (CDCl3), δ: 16.7 (d, 3 JPC=2.6, CH3CH2O), 29.9 (t, 1 JPC=142.2, CHBr), 64.7 (d, 2 JPC=11.9,…”