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