Novel products from oxidation of the norditerpenoid alkaloid pseudaconine with HIO4

Oxidation of pseudaconine 8, a norditerpenoid alkaloid, with HIO4 led to a series of novel interesting products, depending greatly on reaction medium and work-up conditions, Treatment of 8 in MeOH-H2O (1:1) with NalO(4) gave compounds 10 and 11, but compound 12 was obtained quantitatively when the f inal reaction solution was alkalized with cone. NH4OH. The imine 12 was als o obtained in 100% yield by treating 8 in 5% HCl solution with NaIO4 follow ed by alkalizing the reaction products to pH >9 with cone. NH,OH. When the work up pH was 7-8, only N,O-mixed acetal-ketal 13 was formed in 96% yield, which was converted quantitatively to 12 by further alkalizing, When the r eaction mixture was alkalized to pH 7-8 with Na,CO,, a hemiacetalketal 14 w as afforded quantitatively, which was converted to 15 in 87% yield by furth er treatment with Na2CO3 or 5% NaOH metbanol. Compound 15 could be concerte d back to 14 by treatment with 10% HCl solution. Acetylation of the imine 1 2 gave the compounds 16 and 17 in 15% and 19% yields, respectively, All of the new compounds were isolated and fully characterized.