amides of sulfinic acids,
RS(=O)OH; thus
RS(=O)NR2, e.g.
PhS(=O)NHCH3 N-methylbenzenesulfinamide.
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1368 (https://doi.org/10.1351/pac199567081307)