Acylierung von Heterocyclen mit Kohlensäurederivaten. IV. Umsetzung von Benzoxazolin 2‐thion mit Arylcyanaten. Kinetik und Mechanismus

• Published in: Journal für Praktische Chemie
• Main Authors: Glatt, Hans‐Horst, Bacaloglu, Radu, Csunderlik, Carol, Muntean, Doina, Martin, Dieter
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1984
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1002/prac.19843260118; http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fprac.19843260118; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fprac.19843260118; https://onlinelibrary.wiley.com/doi/pdf/10.1002/prac.19843260118

Acylation of Heterocycles with Carbonic Acid Derivatives. IV. Reaction of Benzoxazolin‐2‐thione with Aryl Cyanates. Kinetics and Mechanism The arylcyanate benzoxazoline‐2‐thione ( 1 ) reaction in the presence and absence of the tertiary amines yields 1‐aryloxyiminocarbonylbenzoxazoline‐2‐thione ( 2 ) and 2‐thiocyanatobenzoxazole (4). A mechanism is proposed based on the influences of the reactants concentration, the concentration and basicity of tertiary amines, the solvent‐water concentration, the arylcyanate substituents electronic effects on the reaction rate and the apparent activation parameters. This mechanism consists in the nucleophilic attack of the benzoxazoline‐2‐thione S‐atom on the cyanate, followed by rearrangement through a four‐center transition state.