An aminal or aminoacetal is a functional group or type of chemical compound that has two amine groups attached to the same carbon atom: -C(NR2)(NR2)-. Again R can be hydrogen or an alkyl group.
The aminal and the hemiaminal groups are the cousins of hemiacetals and acetals with nitrogen replaced by oxygen. Aminals are encountered in for instance the Fischer indole synthesis.
Hemiaminal ethers are also sometimes called aminals although it is discouraged by the IUPAC. They have the following structure: R‴-C(NR'2)(OR")-R⁗. The glycosylamines are examples of cyclic hemiaminal ethers.