A compound has acetal/ketal 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

acetal acetal

within: acetal/ketal

ketal ketal

within: acetal/ketal

In the ATB

• 3,414 annotated compounds have it;
• 34 of them have experimental reference data;
• 255 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=acetal_or_ketal.

Annotation scheme 2.