By R.H.F Manske, H.L. Holmes
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Additional info for Alkaloids: Chemistry and Pharmacology, Volume 12
E. The reactions of delsoline are quite similar to those of delcosine. Thus, the formation of a carbinolamine 36 S. W. PELLETIER AND L. H. KEITH ether showed the presence of a secondary hydroxyl in ring A which was assumed to be a t C-1. Oxidation with mercuric acetate produced anhydrohydroxy-N-desethyldelsolinewhich could be realkylated with ethyl iodide, showing the presence of an N-ethyl group. And O-acetyloxodelsoline is cleaved by lead tetraacetate to a secodiketone that loses methanol on recrystallization, demonstrating the presence of two vicinal tertiary hydroxyls, one of which is CL to a methoxyl group.
The major product of this oxidation wits the neutral y-lactone (LIII), which also contained an aldehyde group capable of being further oxidized to a carboxylic acid (LIV). Treatment of LIII with alkali opened the lactone ring and, after acidification, the hydroxy acid LV was obtained. The latter could be lactonized again by heating in sulfuric acid but the product (LVI)lost one methoxyl group, giving an a,P-unsaturated ketone in the process. The formation ofa y-lactone in the periodate oxidation of demethyleneoxodeltamine (LII) and the fact that deltamine (XLVIII) is stable t o periodate oxidation unequivocally determines the position of the hydroxyl a t C-10.
H. KEITH which possesses an N-methyl instead of an N-ethyl. Vigorous treatment of aconitine (partial structure CXXIV) with nitrous acid (81a)resulted in the cleavage of the N-ethyl and formation of the nitroso derivative CXXV. Acetylation of cxxv CXXIV * CHaCHz-N 5 OAc 5 OAc H CXXXI CXXXII CXXV with acetyl chloride gave a mixture of CXXVI and its acetolysis product CXXVII in 14% and 57% yields, respectively. Treatment of CXXVI with phosgene produced CXXVIII, which was then converted to the N-formyl derivative CXXIX, a compound identical with an authentic sample of triacetyloxonitine prepared by permanganate oxidation of triacetylaconitine (CXXX).