Condensation of hydroxypyridone 7 with ethyl pyruvate and p-chlorothiophenol, reduction, and cyclization afforded 77% of lactone 6. Protection of the pyridone, acylation of the enolate with tigloyl chloride, and deprotection provided keto lactone 22. Reduction and dehydrative cyclization completed short and efficient syntheses of 2 and 3.
Condensation of hydroxypyridone 7 with ethyl pyruvate and p-chlorothiophenol, reduction, and cyclization afforded 77% of lactone 6. Protection of the pyridone, acylation of the enolate with tigloyl chloride, and deprotection provided keto lactone 22. Reduction and dehydrative cyclization completed short and efficient syntheses of 2 and 3.
Condensation of hydroxypyridone 7 with ethyl pyruvate and p-chlorothiophenol, reduction, and cyclization afforded 77% of lactone 6. Protection of the pyridone, acylation of the enolate with tigloyl chloride, and deprotection provided keto lactone 22. Reduction and dehydrative cyclization completed short and efficient syntheses of 2 and 3.