Pantolactone is an intermediate chemical compound.

The name defines the structure of the molecule:

• "Panto" comes from the Greek word "Pantos" which means "everything". This is a reference to the presence of the compound in almost all living cells as part of pantothenic acid as a molecule (vitamin B5).
• "lactone" is a term used in organic chemistry to describe cyclic esters. An ester is a compound derived from an acid, in this case, a carboxylic acid, in which at least one hydroxyl-OH group is replaced by an alkyl-O-alkyl group. When this ester forms a ring structure, it is called lactone.

The synthesis process takes place in several stages:

• Step 1: Preparation of raw materials. The raw materials for the synthesis of pantolactone are generally an aldehyde and ketone suitable.
• Step 2: Aldol Reaction. Aldehyde reacts with ketone in the presence of a suitable catalyst to produce an Aldol product. This reaction is typically catalyzed by a chiral organocatalyst, such as L-histidine-modified-ionic-liquid.
• Step 3: Hydrogenation. Aldol is hydrogenated to produce pantolactone. This step is typically catalyzed by a suitable hydrogenation catalyst, such as Cu-/sio2.
• Step 4: Purification and drying. The resulting pantolactone is then purified, typically through filtration and washing, and dried.

What it is for and where

 It is a cyclic organic compound with a functional lactone group. This compound is often used as a starting material in the synthesis of various pharmaceutical products.

Cosmetics

Humectant. Hygroscopic compound used to minimise water loss in the skin and to prevent it from drying out by facilitating faster and greater absorption of water into the stratum corneum of the epidermis.  The epidermis is the most superficial of the three layers that make up human skin (epidermis, dermis and hypodermis) and is the layer that maintains hydration in all three layers. In turn, the epidermis is composed of five layers: horny, the most superficial, granular, spinous, shiny, and basal. Humectants have the ability to retain the water they attract from the air in the stratum corneum and have the function of moisturising the skin. They are best used before emollients, which are oil-based.

Skin conditioning agent. It is the mainstay of topical skin treatment as it has the function of restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants that can be added in the formulation.

Other uses

It can be used as a pharmaceutical reference standard for the quantification of the analyte in pharmaceutical formulations by gas chromatography.

It has demonstrated significant antimicrobial activity (1).

In cosmetics it is included as an emollient.

• Molecular formula: C₆H₁₀O₃
• Molecular Weight: 130.14
• CAS: 599-04-2
• UNII J288D7O0JS
• EC Number: 209-963-3
• DSSTox Substance ID: 
• MDL number  MFCD00005392
• PubChem Substance ID   329823396
• Beilstein/REAXYS Number: 80957

Synonyms: 

• 2,4-dihydroxy-3,3-dimethylbutyric acid gamma-lactone
• D-(-)-Pantolactone

References_______________________________________________________________

(1) Baldé MA, Tuenter E, Matheeussen A, Traoré MS, Cos P, Maes L, Camara A, Diallo MST, Baldé ES, Balde AM, Pieters L, Foubert K. Bioassay-guided isolation of antiplasmodial and antimicrobial constituents from the roots of Terminalia albida. J Ethnopharmacol. 2021 Mar 1;267:113624. doi: 10.1016/j.jep.2020.11362