Abstract
Practical synthetic routes for the preparation of 1-(7-chlorobenzothiazol-2-yl)-1-methylethylamine (VII), a key intermediate of the barnyardgrass-controlling herbicide, 3-[[1-(7-chlorobenzothiazol-2-yl)-1-methyl]ethyl]-2, 3-dihydro-6-methyl-5-phenyl-4H-1, 3-oxazin-4-one (MI-3069), were investigated. As the result, the intermediate VII was prepared in an excellent overall yield by cyclization of 2-amino-2-methylpropionitrile with 2-amino-6-chlorothiophenol, which was synthesized by hydrogenation of 2-nitro-6-chlorothiophenol derived from 2, 3-dichloronitrobenzene. This practical route consisted of shorter steps with relatively cheaper reactants than the reported method.
