# What is the proper description/name of this amide/ester structure?

What is the proper description/name of this amide/ester structure?

In IUPAC speak it is a carbamic acid methyl ester.

The IUPAC name for the compound drawn according to Chemspider structure search is Carbamic acid, N-[5-(propylthio)-1H-benzimidazol-2-yl]-, methyl ester 1

Most working chemists would call it a methyl carbamate

• A common alternative name is urethane. I wouldn't list all the possible alternatives, but this one is used commonly (particularly in polymer/adhesive industry), so I thought it would be important to mention. This isn't at all common in most fields of chemistry, as far as I know, but if trying to understand chemistry in the world around us, I believe it's useful information without being the information overload that listing all possible names would be. May 30, 2018 at 17:56
• In IUPAC speak it is still methyl carbamate, actually. May 30, 2018 at 19:00
• Furthermore, in preferred IUPAC speak, it is propylsulfanyl instead of propylthio and the locant N isn’t necessary when the name is written out in full. Also note that, as drawn in the question, the compound is the 6-(propylsulfanyl) and not the 5-(propylsulfanyl) isomer.
– user7951
Jun 6, 2018 at 18:52

According to the current (corrected) version of Nomenclature of Organic Chemistry – IUPAC Recommendations and Preferred Names 2013 (Blue Book), the names of esters are generally formed by placing the alcoholic component in front of the name of the acid component as a separate word (e.g. ethyl acetate).

P-65.6.1 General methodology
Neutral salts and esters are both named using the name of the anion derived from the name of the acid. Anion names are formed by changing an ‘-ic acid’ ending of an acid name to ‘-ate’ and an ‘-ous acid’ ending of an acid name to ‘-ite’. Then, salts are named using the names of cations, and esters the names of organyl groups, cited as separate words in front of the name of the anion.

In this case, the corresponding acid is a carbamic acid.

P-65.2.1.1 The contracted name ‘carbamic acid’ (from carbonamidic acid), for $\ce{H2NCO-OH}$, (…), are retained and are the preferred IUPAC names.

Therefore, the methyl ester is named as methyl carbamate.

The complete name of the compound that is given in the question is
methyl [6-(propylsulfanyl)-1​H-benzimidazol-2-yl]carbamate.

A similar example given in the Blue Book is 2-hydroxypropyl (2-aminoethyl)carbamate.