atom_id atom_symbol chemical_shift multiplet coupling_constant 15 H 2.38 s NA 16 H 2.38 s NA 17 H 2.38 s NA 18 H 6.76 s NA 19 H 12.44 s NA 20 H 6.87 s NA 21 H 4.89 dd 7.4,3.8 22 H NA NA NA 23 H 2.36 m NA 24 H 2.20 m NA 25 H 2.97 ddd 18,8.1,4.8 26 H 2.67 ddd 18,8.3,4.8