The acetyl group is part of any organic compounds such as acetylcholine and acetyl-CoA . In IUPAC nomenclature , acetyl is called ethanoyl , although this term is rarely heard . The acetyl moiety is a component of many organic compounds , including the neurotransmitter acetylcholine , acetyl-CoA , acetylcysteine , and the analgesics acetaminophen and acetylsalicylic acid ( better known as aspirin ) .