Amidine (source code)
= Amidine
An <amidine> is a nitrogen analogue of an oxoacid derivative. In ordinary organic-chemistry usage it most often means a <carboxamidine>, whose central carbon is bonded to two nitrogens, conventionally represented by $\mathrm{R-C(=NR_1)-N(R_2)R_3}$. The IUPAC class is broader than only carbon-centred examples, so the intended structural subclass should be stated.<Amidines in the IUPAC Gold Book>[Entry A00267; definition and common organic usage]{ref}
A simple unsubstituted-nitrogen pattern is $\mathrm{R-C(=NH)-NH_2}$. Choosing $\mathrm{R=CH_3}$ gives $\mathrm{CH_3-C(=NH)-NH_2}$ and an atom count of $\mathrm{C_2H_6N_2}$. Compare an <amide>, $\mathrm{R-C(=O)-NH_2}$: replacing the doubly bonded oxygen with an imino nitrogen changes the characteristic group. Similar spelling does not make the two classes chemically identical.
<Imidoesters> react with <amines> to give <amidines>. This conversion connects a functional-group definition with experimental <protein cross-linking>, where amino groups on a <protein> can be modified by an appropriate reagent.<Imidoesters in NLM MeSH>[D007096, Scope Note]{ref} The structural pattern alone does not specify one reaction rate or one acid–base constant for every substituted <amidine>.
Back to article page
