What does amidine mean?
An amidine is an organic compound defined by the presence of the functional group C(=NH)–NH₂, in which a single carbon atom is double-bonded to an imino nitrogen and single-bonded to an amino nitrogen. Formally, amidines can be viewed as oxoacids in which both the hydroxyl and oxo groups have been replaced by nitrogen-containing groups. This structure makes amidines notably basic — typically far more basic than the related amides — which underlies their importance in chemistry and medicine. The term is essentially confined to technical contexts: organic synthesis, enzyme studies, and drug design, where the 'amidine group' of a larger molecule often governs how it binds to biological targets. Well-known relatives include guanidine, a particularly strongly basic member of the broader family. For students of chemistry, recognizing an amidine means spotting two nitrogens sharing one carbon, one bearing a double bond — a small structural signature with outsized consequences for reactivity.
nounAn amidine is an organic compound containing the functional group C(=NH)–NH₂ (or its N-substituted derivatives), formally derived from an oxoacid by replacing the hydroxyl group with an amino group and the oxo group with an imino group. Amidines are nitrogen-rich bases, generally stronger bases than the corresponding amides.
- In organic chemistry, any compound containing the divalent group C(=NH)–NH₂ or its N-substituted derivatives, characterized as strongly basic nitrogen compounds.
"The chemist synthesized a new amidine derivative to test its activity as a chelating agent."
"Guanidine, the simplest cyclic example of its class, is often cited alongside amidines in discussions of strong organic bases."
"The pharmaceutical researchers noted that the drug's amidine moiety was responsible for its high affinity for the enzyme's active site."
As a countable class noun, amidine takes the regular plural 'amidines' when referring to multiple members of the compound class.
"Several substituted amidines were screened for inhibitory activity against trypsin-like proteases."
Swap just one oxygen atom of an everyday amide for a nitrogen and you get an amidine — a change so small it transforms a mild compound into a strongly basic one.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of amidine
The word amidine was coined in nineteenth-century German chemical literature, combining 'amide' with the suffix '-ine', following the pattern by which early organic chemists named nitrogen compound classes such as amines and amides. It entered English scientific usage through translation of German research during the period when structural organic chemistry was being established. Its root connects it to 'ammonia' (via Latin 'sal ammoniacus') and to the family of nitrogen-compound names built on the same amide/amine framework.
How amidine is actually used
Amidine is almost exclusively a technical term used in organic chemistry, biochemistry, and pharmacology; it rarely appears outside scientific literature. In speech and writing it functions as a count noun, and chemists frequently refer to 'the amidine group' or 'an amidine moiety' when discussing part of a larger molecule.
Easily confused with amidine
An amide contains the carbonyl group C(=O)–NH₂, whereas an amidine replaces that oxygen with an imino (=NH) group, giving C(=NH)–NH₂.
An amine is a simple nitrogen compound derived from ammonia by alkyl or aryl substitution, while an amidine is a specific functional group containing both an imino and an amino nitrogen attached to one carbon.