164 



Colchicine 



parent hydrocarbon corresponding to (II; H for OMe) reproduces in 

 all essentials the behavior just described and, iurthcr, that this hydro- 

 carbon is isomerized to 9-methylphenanthrene by successive heating 

 with liydriodic acid and zinc dust. Such isonierization accounts lor 

 the isolation of 9-inethylphenanthrene by AVindaus-- during an at- 

 tempt to dcmethoxylatc dcaminocolchiuol methyl ether, and it con- 



OH 



Me 



OH 



(IX) 



Me 



c:o 



CHO 



OMe 



(X) 



tributed to his formulating the latter compound as either 2:3:4:6- or 

 2:3:4:7-tetramethoxy-9-methylphenanthrene, each of which, when 

 synthesized by Buchanan, Cook, and Loudon."-^ proved to be distinct 

 from the degradation product. Tarbell, Frank, and Fanta,-^' who pre- 

 pared deamino-iodocolchinol methyl ether from A^-acetyliodocolchinol 

 and oxidized it to a derivative of homodiphenic acid, likewise con- 

 clude in favor of a 7-membered ring B as in (II) . 



The first synthesis of a significant deri\ative of (II) was effected 

 by Buchanan. Cook, Loudon, and MacMillan.-" The sequence of re- 

 actions used lor the ring-contraction (II) -^(IV) was applied in the 



