Synthesis and Identification of some Benzoxazole Derivatives via Mannich Reaction

The p-Hydroxybenzyldehyde is one of the aromatic compounds which contains two important functional groups (OH, CHO). In this work, the p-hydroxybenzyldehyde has been introduced into different reactions. The first one involves the synthesis of ether via Williamson reaction, in which p-hydroxybenzyldehyd reacts with chloroacetic acid to afford compound (1), then compound (1) in presence of sodium bicarbonate gives the anion (2). Which reacts with propargyl bromide to give the acetylenic compound (3). The compound (3) in turn reacts with secondary amine via Mannich reaction to give the acetylenic amines(4a-f). Finally, the compounds (4a-f) undergo reaction with o-amino phenol to give benzoxazole derivatives (5a-f). The structure of synthesized compounds had been elucidated by the available physical and spectral data.