Microwave-assisted rapid cyclization of lapachol, a main constituent of Heterophragma adenophyllum.
Cyclization reactions of lapachol (1) isolated from Heterophragma adenophyllum have been studied under microwave irradiation under different conditions using alumina (acidic, basic and neutral)/silica gel/montmorillonite (KSF and K-10) as solid support along with neat reaction using 2-3 drops of DMF giving naturally occurring dehydro-alpha-lapachone (2), alpha-lapachone (3), beta-lapachone (4) depending upon the nature of support and irradiation time. A novel naphthoquinone derivative adenophyllone (5) can be synthesized from lapachol using DMF under microwaves.
Department of Chemistry, University of Rajasthan, Jaipur-302004, India. pahupsingh@yahoo.co.uk
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Singh
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Natani
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Jain
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Arya
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Dandia
D029402:Bignoniaceae / Q000737:chemistry*; D003500:Cyclization; D008872:Microwaves; D015394:Molecular Structure; D009285:Naphthoquinones / Q000528:radiation effects*; D013057:Spectrum Analysis
D009285:Naphthoquinones; C008252:lapachol