A compound has hemiacetal/hemiketal 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

hemiacetal hemiacetal

within: hemiacetal/hemiketal

hemiketal hemiketal

within: hemiacetal/hemiketal

In the ATB

• 1,364 annotated compounds have it;
• 3 of them have experimental reference data;
• 14 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=hemiacetal_or_hemiketal.

Annotation scheme 2.