Microwave-Assisted Improved Regioselective Synthesis of 12 H -Benzopyrano[3,2- c ][1]benzopyran-5-ones by Radical Cyclisation

• Published in: Organic chemistry International Vol. 2011; pp. 1 - 6
• Main Authors: Basu, Pradipta Kumar, Ghosh, Amrita
• Format: Journal Article
• Language: English
• Published: 15.09.2011

Two new effective methodologies have been adopted for the preparation of 4-(2 ′ -bromobenzyloxy)benzopyran-7-ones 3(a–h) . In the first methodology, 4-hydroxy[1]benzopyran-2-ones 1(a–d) was alkylated with 2-bromobenzyl bromide 2a or 2-bromo-5-methoxy benzyl bromide 2b under phase transfer catalysis...