# Is rotation/flip of skeletal structural formula of Sildenafil/Claim 6 okay?

I want to show visually the similarities between Sildenafil (Viagra) and the molecule on the right:

Is it allowed to flip the skeletal structural formula and rotate bond strings of the molecule on the right to better show the similarities like I did it in the following figure?

The molecule on the right is flipped at the horizontal line and the bottom left C$_2$H$_5$ is rotated outwards. In both cases, the structure is the same, but I stumbled on things like enatiomeres and optical isomerism, and now I'm confused. I red "Graphical representation standards for chemical structure diagrams (IUPAC Recommendations 2008)" partially, which seems to allow transformations like tried above, but as non-chemist, I'm still unsure.

• Hi @Pi.Lilac, sorry for the downvotes earlier, your choice of the word Viagra made an anti-spam system think you were a spammer. That's been corrected now, and welcome to Chemistry.SE :) – CalvT Apr 27 '17 at 14:35
• yes, free rotation about single bonds not part of rings, but don't rotate groups about double or triple bonds or change relative positions in rings etc. – porphyrin Apr 27 '17 at 14:58