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Updated: Jun 1, 2026

Preparation and In Vivo Use of an Activity-based Probe for N-acylethanolamine Acid Amidase
Published on: November 23, 2016
5-[(E)-(2,6-Dichloro-benzyl-idene)amino]-2-hy-droxy-benzoic acid
Abstract:
There are two geometrically different mol-ecules in the asymmetric unit of the title compound, C(14)H(9)Cl(2)NO(3). The 5-amino-2-hy-droxy-benzoic acid units [r.m.s. deviations of 0.0323 and 0.0414 Å] and 2,6-dichloro-benzaldehyde groups [r.m.s. deviations of 0.0285 and 0.0226 Å] are roughly planar and oriented at dihedral angles of 11.69 (13) and 83.12 (6)° in the two mol-ecules. An intra-molecular O-H⋯O hydrogen bond completes an S(6) ring motif in each mol-ecule. The two mol-ecules form dimers with each other through inter-molecular O-H⋯N and C-H⋯O hydrogen bonds, completing an R(2) (2)(8) ring motif. The dimers are inter-linked via inter-molecular O-H⋯N and C-H⋯O hydrogen bonds, forming polymeric sheets.
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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...
Acid Halides to Carboxylic Acids: Hydrolysis
As shown below, the mechanism involves a nucleophilic attack by water at the carbonyl carbon to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen π bond along with the departure of a halide ion. A final proton transfer step yields carboxylic acid...

