# Is pentamine or pentylamine the correct name?

For $\ce{CH3CH2CH2CH2CH2NH2}$, is the correct name pentylamine or pentamine?

"The -yl ending means "a fragment of an alkane formed by removing a hydrogen".

How does the above definition apply to this problem?

Does it mean, if the N wasn't there it would be a carbon and 3 hydrogens would attach to the carbon; but with the nitrogen there there is only 2 hydrogens attached to a the nitrogen?

Thank you

• – user7951 Jul 24 '16 at 9:43

The following IUPAC guidelines suggest the correct systematic nomenclature for simple primary amines.

P-62.2.1.2

Primary amines are systematically named in the following ways:

(1) by adding the suffix ‘amine’ to the name of the parent hydride;

(2) by adding the name of the substituent group R - to the parent hydride ‘azane;

(3) by adding the name of the substituent group R - to the term ‘amine’ used as a preselected parent hydride name for NH3; this method is used only with monoamines.

Method (1) gives the preferred IUPAC name (PIN). So in your example this would give pentan-1-amine.

Method (3) gives what is often the more commonly used name, in your example this would give pentylamine.

Both names are 'fine' and in reality method (3) is the one that you will most often see used/written on bottles of reagent etc. But for the correct IUPAC identifier method (1) should be used.

You should also note that pentamine is a wholly different compound:

## Other example:

By method (1). Methanamine

By method (2). Methylamine

• The last image shows up as a completely black square for me. – f'' Jul 24 '16 at 16:21
• @f''. I do indeed mean method (3). There was a discrepancy between my initial post and the 2013 IUPAC recommendations (thats to Loong for pointing it out), just forgot to update the link. Image looks fine to me? Will try re-adding it anway – NotEvans. Jul 24 '16 at 16:24
• Thanks for the response. FYI It is showing me this black square @NotNicolaou i.stack.imgur.com/SsZ5ks.png – K-Feldspar Jul 24 '16 at 21:08

A wikipedia search of each chemical confirmed that it is pentylamine. The name pentylamine has two parts. The first part, pentyl, means that there are 5 carbons with 11 hydrogens attached to them. This is a pentyl group https://en.wikipedia.org/wiki/Pentyl The second part, the amine, is the NH2 part. This is when an ammonia (NH3) molecule loses one hydrogen and instead bonds with the organic group, in this case the pentyl group. There are only 2 hydrogens attached to the nitrogen because nitrogen has a charge of -3, whereas carbon has a charge of -4 (in this case, not in all cases).

To the name pentamine, which you asked for (and probably meant pentanamine). Others have already mentioned, that it's a trivial name of $$\ce{MeN(CH2CH2N^+Me2Et)2}$$. (I'm not sure that it's correct, some other source sources claim “Pentamin” trade name, for its bromide salt.)