OF ARTS AND SCIENCES. 135 



V. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 

 HARVARD COLLEGE. 



ON SUBSTITUTED PYROMUCIC ACIDS. 



FIRST PAPER. 

 By Henuy B. Hill and Chakles R. Sanger. 



Communicated November 12, 18S4. 



ON BROMPYRO.MUCIC ACIDS. 



Although pyromucic acid has long been known and has been made 

 the subject of many investigations, its behavior toward the haloo-ens 

 has been studied by but few chemists. As early as 1837 Malaguti * 

 showed that ethyl pyromucate, when treated with dry chlorine, took 

 up four atoms of chlorine forming tlie ethyl ether of pyromucic tetra- 

 chloride. This ether he treated with potassic hydrate, but isolated 

 no product resulting from this decomposition. In 18G5 Schmelz and 

 Beilstein t studied the action of aqueous chlorine and bromine upon 

 the acid, and described the resulting four-carbon compounds muco- 

 chloric and mucobromic acids. A few years later Limpricht,;}: with 

 several of his pupils, pursued the subject further in the same direction, 

 and isolated, among the products formed by the action of bromine and 

 water upon pyromucic acid, fumaric acid, and its half aldehyde ; they 

 made, however, no experiments concerning the action of dry bromine. 

 Toennies,§ working in Baeyer's laboratory, in 1878, prepared the pyro- 

 mucic tetrabromide by the action of dry bromine upon pyromucic acid, 

 and found that it could be converted into a dibrompyromucic acid melt- 

 ing ai 184-186° by the action of alcoholic potash. Toennies did not 

 publish, however, any very extended description of this acid, although 

 he mentions its stability in resisting the action of various oxidizing 



* Ann. Chim. Phys., Ixiv. 282; Ixx. 37L 



t Ann. Chem. u. Pharm., Suppl., iii. 27G. 



t Ann. Chem. u. Pliarm., clxv. 253. 



§ Bericlite d. deutsch. chem. Gesellscli., xi. 1086; xii. 1203. 



