Related Experiment Video
Updated: Jun 1, 2026

Constructing Cyclic Peptides Using an On-Tether Sulfonium Center
Published on: September 28, 2022
4-Amino-pyridinium 4-carb-oxy-butano-ate
Abstract:
The asymmetric unit of the title salt, C(5)H(7)N(2) (+)·C(5)H(7)O(4) (-), contains two 4-amino-pyridinium cations and two 4-carb-oxy-butano-ate anions. Each 4-amino-pyridinium cation is planar, with a maximum deviation of 0.005 (2) Å. Both 4-carb-oxy-butano-ate anions adopt an extended conformation. In the crystal structure, the cations and anions are linked via N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, forming a two-dimensional network parallel to the bc plane.
Related Concept Videos
Organic Compounds
Nomenclature of Carboxylic Acid Derivatives: Amides and Nitriles
The IUPAC and common names of amides are derived from the parent carboxylic acid, by replacing the suffix “oic acid” and “ic acid,” respectively, with “amide.” In the following example, the IUPAC name ethanamide is derived from ethanoic acid, and the common name, acetamide, is obtained from acetic acid.
Carboxylic Acid Derivatives: Overview
Nomenclature of Carboxylic Acid Derivatives: Acid Halides, Esters, and Acid Anhydrides
The IUPAC and common names of acid halides are derived from the corresponding carboxylic acids, by changing “ic acid” to “yl halide.” For example, as shown below, the IUPAC name ethanoyl chloride is derived from ethanoic acid, and the common name, acetyl chloride, is obtained from acetic acid.
Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
IUPAC Nomenclature of Carboxylic Acids
For acyclic saturated monocarboxylic acids, the longest hydrocarbon chain containing the –COOH carbon is identified as the parent chain. Then, the last -e of the parent hydrocarbon name is replaced with a suffix -oic acid.

