Jyuzo Nakayama

Reduction of diazonium salts with silyl and stannyl hydrides : A new route for the replacement of amino-groups of aromatic amines by hydrogen

Abstract Diazonium salts are reduced by silyl or stannyl hydrides in ethers and acetonitrile to give the corresponding arenes with elimination of the diazonium group, thus providing a new route for replacement by hydrogen of the amino group attached to an aromatic nucleus. The treatment of p-chloro- and p-methoxybenzenediazonium fluoroborates with tri-n-butyltin deuteride resulted in the formation of chlorobenzene and anisole containing only about 40% of deuterium. The reduction of benzene- and p-chlorobenzenediazonium fluoroborates with tri-n-butyltin hydride in a mixture of acetonitrile and benzene (1:2) afforded biphenyl (8·4%), 1,4-dihydrobiphenyl (about 1%), and 4-chlorobiphenyl (16·8%). These findings indicate that aryl radicals are involved as intermediates.

General synthesis of dibenzotetrathiafulvalenes

A wide variety of dibenzotetrathiafulvalenes (1) were synthesized starting from anthranilic acids. Aprotic diazotization of anthranilic acids by isopentyl nitrite in the presence of carbon disulphide and isopentyl alcohol in boiling 1,2-dichloroethane gave 2-isopentoxy-1,3-benzodithioles (2). Compounds (2) were converted into 1,3-benzodithiolylium tetrafluoroborates (3) by treatment with tetrafluoroboric acid. Treatment of the salts (3) with base afforded tetrathiafulvalenes (1).