diff --git a/core/indigo-core/molecule/src/molecule_tautomer_enumerator.cpp b/core/indigo-core/molecule/src/molecule_tautomer_enumerator.cpp
index 95e64ea7f8..c38900642b 100644
--- a/core/indigo-core/molecule/src/molecule_tautomer_enumerator.cpp
+++ b/core/indigo-core/molecule/src/molecule_tautomer_enumerator.cpp
@@ -394,7 +394,8 @@ bool TautomerEnumerator::_performProcedure()
       "[#1:0][N&v3,n,O,S:1][*:2]=,:[N&v3,n,O,S:3]>>[N,n,O,S:1]=[A,a:2]-[N,n,O,S:3][#1:0]",
       "[#1:0][N&v3,n,O,S:1][*:2]=,:[*:3][*:4]=,:[N&v3,n,O,S:5]>>[N,n,O,S:1]=[A,a:2]-[A,a:3]=[A,a:4]-[N,n,O,S:5][#1:0]",
       "[#1:0][N&v3,n,O,S:1][*:2]=,:[*:3][*:4]=,:[*:5][*:6]=,:[N&v3,n,O,S:7]>>[N,n,O,S:1]=[A,a:2]-[A,a:3]=[A,a:4]-[A,a:5]=[A,a:6]-[N,n,O,S:7][#1:0]",
-      "[#1:0][N&v3,n,O,S:1][*:2]=,:[*:3][*:4]=,:[*:5][*:6]=,:[*:7][*:8]=,:[N&v3,n,O,S:9]>>[N,n,O,S:1]=[A,a:2]-[A,a:3]=[A,a:4]-[A,a:5]=[A,a:6]-[A,a:7]=[A,a:8]-[N,n,O,S:9][#1:0]"
+      "[#1:0][N&v3,n,O,S:1][*:2]=,:[*:3][*:4]=,:[*:5][*:6]=,:[*:7][*:8]=,:[N&v3,n,O,S:9]>>"
+      "[N,n,O,S:1]=[A,a:2]-[A,a:3]=[A,a:4]-[A,a:5]=[A,a:6]-[A,a:7]=[A,a:8]-[N,n,O,S:9][#1:0]"
 #else
         "[O,S,Se,Te;X1:1]=[C:2][CX4;R0,R1,R2:3][#1:0]>>[#1:0][O,S,Se,Te;X2:1]-[#6;X3:2]=[C,c;X3:3]", // Rule 1:  1,3 Keto-enol
         "[#1:0][O,S,Se,Te;X2:1]-[#6;X3:2]=[C,c;X3:3]>>[O,S,Se,Te;X1:1]=[C:2][CX4;R0,R1,R2:3][#1:0]", // Rule 1:  1,3 Keto-enol