Benzoinestrar

Benzoinestrar is an organic ester that is derived from benzoin, a hydroxy ketone that is obtained from the bark of Styrax species or by the benzoin condensation of aromatic aldehydes. In benzoinestrar the hydroxyl group of benzoin is esterified with a carboxylic acid, most commonly benzoic acid or a substituted benzoic acid, resulting in a bis‑aryl ketone with an ester functionality. The molecular formula of the most studied variant is C16H14O3, with a molar mass of 258.28 g·mol‑1.

The industrial synthesis of benzoinestrar typically proceeds in two steps. First, benzoin is produced by a catalytic benzoin condensation, often with a tin(II) chloride catalyst. In the second step, the free hydroxyl of benzoin reacts with an acid chloride or anhydride in the presence of a base such as pyridine or triethylamine to form the ester. Reaction conditions are mild, requiring temperatures below 80 °C, and the product is isolated by crystallization or recrystallization from ethanol or ether.

Benzoinestrar is valued largely for its fragrance properties, giving a warm, vanilla‑like aroma that is used in perfumery and flavoring. It also serves as a synthetic intermediate in the preparation of certain pharmaceutical intermediates where the ketone or ester moiety is further elaborated into active drug substances. The compound is considered to be of low acute toxicity; however, as with many aromatic esters, prolonged skin contact and inhalation in high concentrations should be avoided, and it should be handled with gloves and eye protection in a well‑ventilated laboratory.