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Compounds Containing a N-CO-N or Related Group

Urea and Its Derivatives Rule C-971

971.1 - The compound is named "urea" and numbered as shown.

971.2 - Derivatives of urea formed by replacement of hydrogen are named (a) as substitution products of urea or (b), if the substituent carries also a group to be cited as principal group, by use of the prefix "ureido-" for the group NH2-CO-NH-. If necessary, locants N and N' or 1 and 3, respectively, are added; the point of attachment of a ureido radical is denoted N or 1.

Examples to Rule C-971.2

(a) N,N'-Dimethylurea
or 1,3-Dimethylurea

(a) N,N-Diethylurea
or 1,1 -Diethylurea

(a) N-Acetyl-N-phenylurea
or 1-Acetyl-1-phenylurea

(a) Isopropylideneurea

(b) 2-(N'-Methylureido)-1-naphthoic acid
or 2-(3-Methylureido)-1-naphthoic acid

The following trivial names are retained for urea derivatives (numbered as shown) and may be associated with prefixes denoting substituents, derivatives being named in the usual way:

Allophanic acid

Hydantoic acid


971.3 - The bivalent radical -NH-CO-NH- is named "ureylene" and is used in nomenclature for assemblies of identical units (see Subsection C-0.7) when the terminal nitrogen atoms are attached to radicals carrying the same group to be cited as a suffix, but it is not used for compounds in which the -NH-CO-NH- group forms part of a ring (for example, not for barbituric acid).

Example to Rule C-971.3

4,4'-Ureylenedi-1-naphthalenesulfonic acid

See Recommendations'93 Table 31(a)

Compounds Containing a N-CO-N or Related Group C-972, C-973, C-974, C-975
Compounds Containing a N-CO-N-N or More Complex Group C-981, C-982, C-983, C-984, C-985


This HTML reproduction of Sections A, B and C of IUPAC "Blue Book" is as close as possible to the published version [see Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, Pergamon Press, Oxford, 1979. Copyright 1979 IUPAC.] If you need to cite these rules please quote this reference as their source.

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