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