Aldehyde and seek: Toxic aldehydes drive exhaustion in tumor-infiltrating T cells

Aldehydes are named based on the systematic nomenclature rules set by the IUPAC. For acyclic aldehydes, the longest carbon chain containing the aldehydic (–CHO) group is considered the parent chain. The aldehyde is named by replacing the last letter “e” in the hydrocarbon name with “al”. For instance, a simple, seven-carbon-membered acyclic aldehyde is called heptanal, derived from heptane. The carbon chain is numbered starting from the aldehydic carbon, although the aldehydic...

Vanillin—a flavoring agent in vanilla, cinnamaldehyde—a molecule responsible for the distinct smell of cinnamon, and acetone—a strong-smelling ingredient in nail polish removers, all belong to a class of carbonyl compounds called aldehydes and ketones (Figure 1). Although both aldehydes and ketones contain the characteristic carbonyl (C=O) bond, their chemical structures vary with respect to the groups directly attached to the carbonyl carbon.
In aldehydes (Figures 1a and 1b), the...

Some common aldehydes and ketones are popularly known by their common names used historically and predate the IUPAC nomenclature.   
Common names of aldehydes are derived from the names of their corresponding acid. For instance, the two-carbon aldehyde–acetaldehyde derives its name from the corresponding acid–acetic acid. Similarly, formaldehyde derives its name from formic acid and benzaldehyde from benzoic acid.
Aliphatic ketones are named by suffixing the word “ketone” to the...

Protecting groups are compounds that can bind to a specific functional group in the presence of other functional groups to protect them from undesired chemical reactions. These compounds can selectively bind to particular functional groups and advance chemoselective reactions in polyfunctional systems (Figure 1). After the functional group has served its purpose, it is removed by reacting it with specific compounds.

In mass spectrometry, the fragmentation of aliphatic aldehydes and ketones generally occurs through three key mechanisms: α-cleavage, inductive cleavage, and the McLafferty rearrangement.

Infrared spectroscopy, also known as vibrational spectroscopy, is mainly used to determine the types of bonds and functional groups in molecules. In aldehydes and ketones, the carbonyl (C=O) bond shows an absorption around 1710 cm-1. The C=O bond vibration of an aldehyde occurs at lower frequencies than that of a ketone. In addition to the C=O absorption in an aldehyde, the aldehydic C–H bond also gives two peaks in the 2700–2800 cm-1 range. This absorption, coupled with the...