new index atom name original index 1 C 15 2 C 13 3 C 14 4 C 10 5 C 11 6 C 6 7 C 7 8 C 8 9 C 5 10 C 12 11 C 9 12 O 3 13 O 4 14 O 1 15 O 2 16 H 25 17 H 23 18 H 24 19 H 21 20 H 22 21 H 17 22 H 18 23 H 19 24 H 20 25 H 16 26 H 27 27 H 26