azo-hydrazone tautomerism at chemicalize.org

I've recently been searching azo dye structures at chemicalize.org (mainly by CAS Registry Number). These structures are subject to azo-hydrazone tautomerism. When I search for the structures at chemiscalize.org, I've noticed that some dyes are displayed as the azo form while others are displayed as the hydrazone form. Is chemicalize applying some sort of rules/logic in deciding which structure to display, or is it purely random?

Another observation I've made is that when I search one particular azo dye (orange I) by name, the azo form is displayed, but when I search by CAS Registry Number (523-44-4) the hydrazone form is displayed. 

Any insight would be helpful. Thanks!

When a structure is imported from a common name or a CAS number, we rely on various external sources to get the corresponding structure. So the raw output of name or CAS number to structure conversion will be the form chosen by those sources. When using our API, Instant JChem or other Chemaxon tools, you could then apply your desired standardization rules.

I think chemicalize currently doesn't apply any standardization rules, but I'll let my colleague confirm that.

Only the "Chem Search" feature uses standardization - to make sure we find what you were looking for. Can you confirm which feature you experience this issue with?

The "Chem Search" standardization applies some rules to the stored structures in order to find your query structure no matter how you draw it (or how it is specified when you search by name which is then converted to a structure). We'll review which of those rules affects your queries and report back here in the forum.

Andras

I've been using the Properties Viewer tool