2.3- Dioxonucine dihydrate oxidation

Both strychnine (9, 113) and brucine (9, 114, 115) are oxidized at 50°—85° to C17 Wieland acid (2,3 dioxonucine dihydrate) (CXXV) and Ci6 Hanssen acid (nucinecarboxylic acid) (CXXVI). The yields from brucine (about 12-18% in each case) are much better than those from strychnine (about 5% of the C17 acid and 1% of the C16 acid), as might be expected. These two acids are also produced by oxidation of a wide range of compounds diifering only in the benzene ring area, for example 2 aminostrychnine (42) and C19 Hanssen acid (CXXVII) (113). The... 

The oxidation of vomicine yields three products the acid CCLXXXIV, analogous to dioxonucine dihydrate (Wielands C17 acid, CXXV), the acid CCLXXXV, the analog of carboxyaponucine (Hanssen s Cie acid, CXXVI), and the base CCLXXXVI, which has no analog in strychnine... 

Dibromohydroxynucine has been converted to 2,3-dioxonucine dihydrate (XCIX) by transformation (aqueous ammonia) of the dibromobase to the hydroxy amide CVIII (R = NHj) (167) followed by hydrolysis of the amide to the hydroxy acid, CnHaOsNs (CVIII, R = OH), and oxidation (CrOs) of the hydroxyl to a ketone. The oxidation of the hydroxy acid to 2,3-dioxonucine dihydrate is accompanied by hydrolysis of the lactam. The neutral hydroxy acid, C17H22O6N2, has been obtained directly by hydrolysis of the dibromobase with aqueous barium hydroxide solution (109). 

CXVII to the dihydro derivative (obtainable also by the chromic acid oxidation of dihydrovomicine) a part of the material is simultaneously decarboxylated to the dihydro derivative of CXVI. The acid, C18H24O7N2, in analogy with dioxonucine dihydrate (Wieland s CiT-acid) exists in the hydrated form (lactam ring hydrolyzed). However, unlike Wieland s acid, CXVIII is not reduced by catalytic means and cannot be oxidized to CXVII. 

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