Method for the preparation of (+)-calanolide A and intermediates thereof
US5489697A · kind A · utility
14Cited by
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7Claims
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Key dates
| Filing date | Aug 3, 1994 |
| Grant date | Feb 6, 1996 |
| Priority date | — |
| Expiry date | Aug 3, 2014 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07D493/14
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
A method for preparing (.+-.)-calanolide A, 1, a potent HIV reverse transcriptase inhibitor, from chromene 4 is provided. Useful intermediates for preparing (.+-.)-calanolide A and its derivatives are also provided. According to the disclosed method, chromene 4 intermediate was reacted with acetaldehyde diethyl acetal in the presence of an acid catalyst with heating to produce chromanone 7. Reduction of chromene 7 with sodium borohydride, in the presence of cerium trichloride, produced (.+-.)-calanolide A, which was purified chromatographically.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.