Permanganate in acetone, oxidation

Two syntheses of hernandaline (197) have been carried out. Dutschewska and Mollov (162) prepared it by potassium permanganate in acetone oxidation of thalmelatine (201), while Cava et al. (158) performed the synthesis... 

Potassium permanganate in acetone oxidation of a bisbenzylisoquinoline results in selective cleavage at the C-1 to C-a benzylic bond of the isoquinoline moiety which is unsubstituted at C-8. Relative stereochemistry does not affect the site of the oxidation. The product is an aldehydo lactam showing 1640-1645 cm" and 1690-1720 cm (5.82-5.92 and 6.08-6.17/a) which can be used for characterization purposes. The C-8 hydrogen peri to the new lactam carbonyl appears in the NMR spectrum as a singlet between 87.20 and 7.42. To exemplify, in the case of the oxidation of (H-)-hernandezine, the C-8 peri proton singlet is found at 87.23. The yields range from 5 to 35% and it is preferable to protect phenolic functions by acetylation prior to oxidation. ... 

This oxidation has been utilized in the determination of the location of the phenolic function in ( + )-tiliacorine, which had been formulated as either 11 or 12. Permanganate in acetone oxidation of its (9-acetyl derivative, followed by ester hydrolysis, yielded secotiliacorine aldehydo lactam, 212, 282, and 310 sh (4.10, 3.44, and 2.94). This product showed a strong bathochromic shift in base, 230, 292, and 340 nm (4.00, 3.27, and 3.21), indicative of a... 

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