A new and efficient general method for the synthesis of 2-spirobenzopyrans: First synthesis of cyclic analogues of precocene I and related compounds

✍ Scribed by Suneel Y Dike; Jaysukhlal R Merchant; Niteen Y Sapre

• Publisher: Elsevier Science
• Year: 1991
• Tongue: French
• Weight: 569 KB
• Volume: 47
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)86481-4

✦ Synopsis

A new synthesis of spirobenzopyran has been accomplished by Friedel-Crafts reaction of various m-dihydroxybenzenes and cycloalkylidene acetic acid in the presence of a Lewis acid. Chromones, flavones and related heterocyclic compounds belonging to benzopyran family are widely distributed in nature and have been found to play an important role in a number of biological processes.1-4 Precocene I and Precocene II are two anti-juvenile hormones possessing potential insecticidal activity. 5 Apart from these, a new class of compounds structurally related to benzopyrans has a Spiro ring attached to the 2 position of the heterocyclic ring. Robustadial A and B are two representative natural products isolated recently from antimalarial Chinese herbal medicinal extract of Eucalyptus robusta leaves.