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