In order to clarify the mechanism of Fischer indolization of 2-methoxyphenylhydrazones, Fischer indolization of ethyl pyruvate 2-(2-methoxyphenyl)phenylhydrazone (2) was carried out with hydrochloric acid in ethanol and zinc chloride in acetic acid. The reactions proceeded smoothly to give N-arylindoles (11-14) and some chlorinated diphenylamine derivatives (8-10) as by-products. Consideration of the indole products revealed that the Fischer indolization proceeded mainly at the unsubstitued phenyl nucleus rather than at the 2-methoxyphenyl nucleus. This result is inconsistent with the previous result that Fischer indolization of diarylhydrazones proceeded at the electron-richer nucleus. The structures of the diphenylamines were determined by chemical means and the mechanism of their formation is discussed.
The reaction of dimethyl sulfoxide–trifluoroacetic anhydride complex with anilines, phenols, and thiophenols was studied, and the following results were obtained. (1) The yields of a methylthiomethylated product were improved with anilines. The reaction proceeded without significant amount of tar, the unreacted anilines being easily recovered. (2) Selective ortho-methylthiomethylation took place with
Catalytic hydrodesulfurization of ortho-aminobenzyl sulfides
申请人:Monsanto Company
公开号:EP0185128A1
公开(公告)日:1986-06-25
Ortho-alkylanilines are prepared by catalytic hydrodesulfurization of ortho-aminobenzyl sulfides using a cobalt-molybdenum oxide catalyst. For example, 2-methyl-6-trifluoromethylaniline is prepared by catalytic hydrodesulfurization of 3-trifluoromethyl-2-aminobenzyl sulfides. The substituted anilines prepared by the method of this invention are useful as intermediates in the synthesis of compounds shown to have herbicidal activity.