Alkylthiocolchicines and n-deacetyl-alkylthiocolchicines and their antileukemic activity

A series of alkylthiocolchicines (methyl, ethyl, n-butyl, n-hexyl, n-octyl, and pinanyl) was prepared from colchicine by treatment with the appropriate alkyl mercaptan and p-toluenesulfonic acid. Some of these compounds (methyl-, ethyl-, and n-butylthiocolchicines) were deacetylated in good yields with 2 N hydrochloric acid in methanol. These compounds were tested for their antileukemic activity in an in vitro assay against L-1210 (mouse leukemia). Preliminary results showed that methylthiocolchicine is more active and the other alkylthiocolchicines are much less active than colchicine. N-Deacetyl-methylthiocolchicine is as active as colchicine.