Amidines are a class of oxoacid derivatives.
The oxoacid from which an amidine is derived must be of the form RnE(=O)OH, where R is a substituent. The −OH group is replaced by an −NH2 group and the =O group is replaced by =NR, giving amidines the general structure RnE(=NR)NR2 [1][2][3].
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When the parent oxoacid is a carboxylic acid, the resulting amidine is a carboxamidine or carboximidamide (IUPAC name), and has the following general structure:
Carboxamidines are frequently referred to simply as amidines, as they are the most commonly encountered type of amidine in organic chemistry. The simplest amidine is formamidine, HC(=NH)NH2.
Examples of amidines include DBU and diminazene.
The most common way to make primary amidines is by the Pinner reaction.
An amidinate salt has the general structure M+[RNRCNR]- [4] and can be accessed by reaction of a carbodiimide with an organometallic compound such as methyl lithium. They are used widely as ligands in organometallic complexes.