1.3.2-Benzothiazathiolium chlorides are obtained by the action of sulphur monochloride on a primary aromatic amine, its salts, or N-acyl derivatives. Four reactions are involved, (i) the formation of the heterocyclic ring, (ii) the chlorination of the aromatic ring, (iii) replacement of electron-attracting groups in the orthoand para-positions by chlorine, and (iv) the oxidation of the sulphur atom in position 2. A likely sequence of reactions is considered, and experimental evidence is given in support of each stage. HERZ t found that a primary aromatic amine, its salts, or N-acyl derivatives, when heated with an excess of sulphur monochloride give a 1,3,2-benzothiazathiolium chloride provided that the amine has at least one unsubstituted ortho-position. An unsubstituted position para to the amino-group is simultaneously chlorinated. o-Toluidine, for example, gives (I; R1 = Me, R2 = Cl). R'Deactivating groups such as nitro-, carboxylic acid, sulphonic acid, or arsonic acid in the para-position are displaced by ch1orine.l The o-nitro-groups in 2-nitrot For a review of the Herz reaction see ref. 2.

The 1,3,4-oxadiazotine is not isolable, since under the conditions of the reaction it will be converted into the C.

A number of sulphinylhydrazides, RCO*NH*NSO, have been prepared. They are readily hydrolysed to the corresponding hydrazide, and, on heating, are converted into the carboxylic acid or acid chloride.

For a review of the Herz reaction see W. K. Warburton, a P. Hope and L. A. Wiles, unpublished work.

Monocarboxylic acid amides frequently give monosulphides, (RCO*NH)2S, with sulphur monochloride. Diacyl hydrazides, (RCOoNH) 2, are not formed as was previously supposed. Formamide gives an adduct containing nitrogen but no sulphur. The evolution of hydrogen chloride from the reaction with benzamide shows first-order kinetics in its early stages.THE reaction of sulphur monochloride, S2C12, with carboxyamides has been studied by Naik,l and by Naik and Patel.2 The products described were :(i) monosulphides, (RKOoNH) $5, from acetamide, monochloroacetamide , n-butyr-(ii) a disulphide, (NCOCH=CO.NH~)~S~, from cyanoacetamide, (iii) diacyl hydrazides, (R*CO*NH)2, from trichloroacetamide , isobutyramide , n-valer-