Cyclisation of 3-[cyclopent-2-enyl]-4-hydroxy[1]benzopyran-2-one

Authors
Majumdar, KC Choudhury, PK Biswas, P
Citation
Kc. Majumdar et al., Cyclisation of 3-[cyclopent-2-enyl]-4-hydroxy[1]benzopyran-2-one, I J CHEM B, 38(11), 1999, pp. 1248-1252
Citations number
28
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
INDIAN JOURNAL OF CHEMISTRY SECTION B-ORGANIC CHEMISTRY INCLUDING MEDICINAL CHEMISTRY
ISSN journal
03764699 → ACNP
Volume
38
Issue
11
Year of publication
1999
Pages
1248 - 1252
Database
ISI
SICI code
0376-4699(199911)38:11<1248:CO3>2.0.ZU;2-A
Abstract
3-[Cyclopent-2-enyl]-4-hydroxy[1]benzopyran-2-one 3 has been prepared by th e reaction of 3-chlorocyclopent-2-ene 2 and 4-hydroxy[1]benzopyran-2-one 1. Compound 3 or its acetate 4 on treatment with pyridine hydrotribromide in dichloromethane at 0-5 degrees C for 2 hr gives fused furo chromone 5 in 90 % yield. Compound 5 on refluxing in 50 % sulphuric acid rearranges to the fused furocoumarin 7 in 87 % yield.