Synthesis and antitumor evaluation of novel monoindolyl-4-trifluoromethylpyridines and bisindolyl-4-trifluoromethylpyridines
摘要:
A series of novel monoindolyl-4-trifluoromethylpyridines and bisindolyl-4-trifluoromethylpyridines was designed and synthesized as potential antitumor agents. They were evaluated for preliminary cytotoxic activity against P388 and A-549 cells with IC50 values. 4-Trifluoromethyl-2,6-bis[3'-(N-tosyl-6'-methoxyl-indolyl)] pyridine was identified as the most potent in this series. (C) 2001 Elsevier Science Ltd. All rights reserved.
The titanium tetrachloride-mediated addition of allyltrimethylsilane or 1,8-bis(trimethylsilyl)-2,6-octadiene and trifluoroaceticanhydride led to trifluoromethyl-diallylcarbinol or (dl)-1-trifluoromethyl-2,5-divinylcyclopentanol, respectively, in fair yields; this latter was further converted into several 1-trifluoromethyl-2-vinylcyclopentane derivatives.
Diallyllactones (obtained from cyclic anhydrides via a double allylation reactionpromoted by titaniumtetrachloride) were cycloisomerised using 5 mol% of cyclooctadienyl ruthenium dichloride in ethanol providing the corresponding exomethylene spirolactones in good yields, with moderated to good diastereomeric excess.
A number of approaches to the synthesis of 2-chloro- and 2,6-dichloro-4-trifluoromethylpyridine are described. The first method for 2-chloro- and 2,6-dichloro-4-trifluoromethylpyridine is based on commercially available ethyl trifluoroacetate. An alternative access to 2,6-dichloro-4-trifluoromethyl pyridine uses trifluoroacetaldehyde as starting material. 2-Chloro-4-trifluoromethylpyridine is prepared from ethyl(trifluoroacetylvinyl)-ether in two steps.