Within: sulfate ester.

A compound has sulfate monoester (acid or anion) when it has any of the groups below. A parent group is never matched itself, and its count of a compound is the number of occurrences of all of them together.

Groups directly under it

In the ATB

• 197 annotated compounds have it;
• 0 of them have experimental reference data;
• 5 are monofunctional: this is their only group, once (rings count as groups, so a phenol is not).

The annotated compounds are those with experimental reference data plus small, neutral organic compounds (up to 12 heavy atoms), not every ATB molecule. Through the API: GET /api/v1/molecules?functional_group=sulfate_monoester.

Annotation scheme 2.