Cyansäureester, 27 [1]. Triazino‐benzimidazole aus 2‐Amino‐benzimidazol‐1‐imidsäureestern und carbonylanalogen Verbindungen

• Published in: Journal für Praktische Chemie
• Main Authors: Martin, Dieter, Graubaum, Heinz
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1979
• Subjects: Carbonic acid
• Online Access: http://dx.doi.org/10.1002/prac.19793210305; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fprac.19793210305; https://onlinelibrary.wiley.com/doi/pdf/10.1002/prac.19793210305

Cyanic Acid Esters. 27. Triazino‐benzimidazoles from 2‐Amino‐benzimidazole‐1‐imid‐esters and Carbonyl Analogic Compounds The Cyclocondensation of 2‐amino‐benzimidazole‐1‐imid‐esters with aldehydes, carbonic acid anhydrides and isocyanates has been investigated. With aldehydes in the presence of piperidine 4‐aryloxy‐1,2‐dihydro‐1,3,5‐triazino[1,2‐a]benzimidazoles 3 and with carbonic acid anhydrides 4‐aryloxy‐1,3,5‐triazino[1,2‐a]benzimidazoles 5 are formed. Isocyanates react with the imid esters to the corresponding 3‐substituted ureas 8 which on heating undergo acyl migration of the carbamoyl group followed by cyclocondensation to 4‐imino‐2‐oxo‐1,2,3,4‐tetrahydro‐1,3,5‐triazino[1,2‐a]benzimidazoles 12 .