166 



Colchicine 



acid (prepared by di-bcnzoylation of triinethylcolchiciuic acid and 

 preferential hydrolysis of the O-ben/.oyI group) was oxidized by cold 

 alkaline permanganate to two products, namely N-benzoylcolchinic 

 anhydride, C^aH^iOjN, and a corresponding lactone, N-benzoylcol- 

 chide, CjcjH^mOijN, which he formulated--' as derivatives of 1:2- 

 dihydro-2-methylnaphthalene. With the recognition of ring B as 7- 



MeO 



MeO 



NHBz 



MeO 



UcO\ 



MeO 



X 



y CO 



I ! 



CO o 



( XVI ) 



MeO 

 MeO 



N 



MeO 



CH2.CH2 



\ 

 CHo 



CH.COoH 



CO 



CO2H 



( XVIII ) 



membered in the colchinol series, it was at once evident that A- 

 benzoylcolchinic anhydride might be better represented by formula 



(XV) and A^-benzoylcolchide by a corresponding lactone structure. 

 To test this view. Cook, Johnston, and London-^*' deaminated the 

 anhydride and showed that the lesidtant deaminocolchinic anhydride 

 was not identical with ():7:8-triniethoxy--^methylnaphtlialene-l:2-di- 

 carboxylic anhydride — as it would be on the Windaus formulation — 

 nor indeed could it be a naphthalene derivative since it showed 

 ethylenic behavior towards reduction. From the reduction products. 

 Horning, Ullyot, and their colleagues''^ isolated a dihydride and 

 established its structure as (XVI 1) in synthesis and cyclization of the 

 oxaloacetic acid (XVIIl) . Thereby the 7-membered rings in A^- 

 benzoylcolchinic anhydride (XV) and its deaminati(jn product 



(XVI) are unequivocally proved. 



Accordingly both lines of degradation — the first, through A^- 

 acetylcolchinol, involving a process which makes ring C benzenoid; 

 the second producing A'-benzoylcolchinic anhydride ai)parently by 



