OP ARTS AND SCIENCES. 205 



XVIL 



ON DIAMIDO-SULPIIOBENZIDE-DICARBONIC ACID. 

 By Arthur Michael axd T. H. Norton. 



Presented by E. N. Horsford, May 9th, 1877. 



Of the large number of amido-sulpho-benznic acids which are possi- 

 ble according to our present theories, but three have been obtained 

 thus far. Two of tiiese were prepared by Griess,* from the action of 

 sulphuric acid on meta-araido-benzoic acid. Limpricht and Uslarf 

 obtained the third by reduction of the mono-iiitro derivative of 

 meta-sulpho-beuzoic acid. It seemed therefore of interest to us to 

 study the action of sulphuric acid on ortlio-amido-benzoic acid and 

 para-amido-benzoic acids, not merely in oider to increase the list of 

 isomeric amido-sulpho-benzoic acids, but because of the possibility 

 that, by removal of the amido group, the as yet uuliuowu ortho-sulpho- 

 benzoic acid could be obtained. 



Our experiments were first directed to para-amido-benzoic acid ; and 

 here an unexpected character was assumed by the reaction, the re- 

 sults of which we briefly communicate. 



We prepared the para-amido-benzoic acid for our purpose from the 

 solid para-nitro-toluol, by oxidation and subsequent reduction of the 

 nitro group. lu the former operation it was observed that much 

 better results were obtained from treatment with potassium per- 

 manganate, than from the methods hitherto used for this body, 

 viz., with nitric acid or potassium bichromate and sulphuric acid. 

 The best proportions were found to be 2.V mol. KMuO^ to 1 mol. 

 C6H^(NO^)(CIl3) in a solution of 40 parts water to I part KMnO^. 

 The reduction was effected by means of tin and hydrochloric acid, in 

 proportions 1 part CaH^(NO^)(COOH) to 2.15 parts Su. In order 



* Jour. f. prakt. Cliemie [21, 5, 214. 

 t Ann. Chem. Pharm., 106, 29. 



