Compounds having two
acyl groups substituted on ammonia or a primary amine acyl-NR-acyl. They are also known as secondary
amides and, especially the cyclic examples derived from diacids, as
imides, e.g.
[RC(=O)]2NR,
RS(=O)2NHC(=O)R.
Source:
PAC, 1995, 67, 1307
(Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995))
on page 1331