Syntheses of biodynamic heterocycles: baker’s yeast-assisted cyclocondensations of organic nucleophiles and phenacyl chlorides

• Published in: Research on chemical intermediates 2017-08, Vol.43 (8), p.4327-4337
• Main Authors: Khillare, Lalit D., Pratap, Umesh R., Bhosle, Manisha R., Dhumal, Sambhaji T., Bhalerao, Mahendra B., Mane, Ramrao A.
• Format: Article
• Language: English
• Subjects: Acceleration; Acetonitrile; Amines; Baking yeast; Catalysis; Chemistry; Chemistry and Materials Science; Chlorides; Cost effectiveness; Inorganic Chemistry; Nucleophiles; Phenylenediamine; Physical Chemistry; Pyridines; Quinoxalines; Thiadiazoles; Yeast
• ISSN: 0922-6168; 1568-5675
• DOI: 10.1007/s11164-017-2880-0

Substituted phenacyl chlorides ( 1a – f ) were cyclocondensed with nucleophiles thiourea ( 2a ) and thiobenzamide ( 2b ) in presence of baker’s yeast ( Saccharomyces cerevisiae ) as whole-cell enzyme source in acetonitrile at room temperature to obtain 4-(4-substituted phenyl)thiazol-2-amines ( 3a – f ) and 4-(substituted phenyl)-2-phenylthiazoles ( 4a – f ), respectively. Moreover, substituted phenacyl chlorides also reacted with nucleophiles 2-amino-1,3,4-thiadiazole ( 2c ), o -phenylenediamine ( 2d ), 1-amino-2-mercapto-5-phenyl triazole ( 2e ), and pyridin-2-amine ( 2f ) at room temperature in presence of baker’s yeast to give fused heterocycles 6-(4-substituted phenyl)-2-phenylimidazo[2,1- b ][1,3,4]thiadiazoles ( 5a – f ), 2-(4-substituted phenyl)quinoxalines ( 6a – f ), 6-(4-substituted phenyl)-3-phenyl-7 H -[1,2,4]triazolo[3,4- b ][1,3,4]thiadiazines ( 7a – f ), and 2-(4-substituted phenyl) H -imidazo[1,2- a ]pyridines ( 8a – f ), respectively. The experimental conditions for these cyclocondensations were optimized to obtain the biodynamic heterocycles in high yield. The unique features of this work are use of baker’s yeast as a cheap and readily available natural source of biocatalyst, noticeable rate acceleration, convenient route to products, cost effectiveness, and scalability.