A stereoselective synthesis of coriolic acid and dimorphecolic acid

✍ Scribed by A.V. Rama Rao; E. Rajarathnam Reddy; G.V.M. Sharma; P. Yadagiri; J.S. Yadav

• Book ID: 104204451
• Publisher: Elsevier Science
• Year: 1986
• Tongue: French
• Weight: 662 KB
• Volume: 42
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)87295-1

✦ Synopsis

A convenient stereoselective synthesis of coriolic acid (1) and dimorphecolic acid (g, the two natural divalent cation ionophores and the self defensive substances in rice plant agamst rice blast disease, is described. on oxtdation with activated manganese dtoxide in chloroform gave the aldehyde 2 m 89% yield. 2 on Crignard reaction with n-pentyl magnesium bromide in ether afforded the alcohol & in 69% yield, which was protected by benzoylation to give _fJ m 85% yield. Depyranylatron of fi using pyridimum p-toluene sulphonate (PPTS)'4 yrelded benzoate-alcohol E in 78% yield. Direct oxidation of 12 as well as its THP ether fi with Jones reagent led to a complex mixture. However, step-wise oxidation of alcohol 12 with pyridinium dtchromate in CH2CI; resulted in the formation of corresponding aldehyde 13 which was directly subjected to alkaline silver oxide oxidation followed by esterification with etherial diazo-