Method for the preparation of (.+-.)-calanolide A and intermediates thereof
US5874591A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 9, 1997 |
| Grant date | Feb 23, 1999 |
| Priority date | — |
| Expiry date | Sep 9, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02A50/30
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
A method of 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 or paraldehyde in the presence of an acid catalyst with heating, or a two-step reaction including an aldol reaction with acetaldehyde and cyclization either under acidic conditions or neutral Mitsunobu conditions, to produce chromanone 7. Reduction of chromanone 7 with sodium borohydride, in the presence of cerium trichloride, produced (.+-.)-calanolide A. A method for resolving (.+-.)-calanolide A into its optically active forms by a chiral HPLC system or by enzymatic acylation and hydrolysis is also disclosed. Finally, a method for treating or preventing viral infections using (.+-.)-calanolide A or (-)-calanolide A is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.