OF ARTS AND SCIENCES. 153 



Action of Nitric Acid. 



/S-monobrompyromucic acid is readily oxidized by dilute nitric acid. 

 In order to determine the product formed, we heated the acid with 

 twice its weight of concentrated nitric acid (sp. gr. 1.42) diluted with 

 five times its weight of water. After the oxidation was complete, 

 we extracted the solution thoroughly with ether, and obtained, on 

 evaporating the ether, a white crystalline acid which was readily 

 soluble in water. After recrystallization from water it melted at 

 176-177°, and gave a percentage of bromine, which showed it to be 

 monobromt'umaric acid (isobrommaleic acid). 



0.2300 grm. substance gave 0.2218 grm. AgBr, 



Calculated for CiHsBrOi. Found. 



Br 41.03 41.04 



By oxidation with nitric acid monobromfumaric acid had therefore 

 been formed according to the equation, 



C,U,UrO^ +30 = C.HjBrO, + CO.. 



Ethyl Pyrojiucate with oxe Molecule of Bromine. 



We have made six fi-uitless attempts to prepare a monobrompyro- 

 mucic acid melting at 156-157°, according to the method described by 

 SchifF and Tassinari,* by the addition of one molecule of bromine to 

 ethyl pyromucate, and the decomposition of the product thus obtained 

 by an alcoholic solution of potassic hydrate. Aside from the S-morio- 

 bromjiyromucic acid, whicii could readily be isolated, we have been 

 able to find only the two isomeric dibrompyromucic acids hereafter de- 

 scribed which result from the decomposition of the tetrabromide of the 

 ethyl ether. In separating these two acids we followed the method 

 which w-e had already found most eiHcacions, namely, the fractional 

 crystallization of the calcium salts, but iu other respects we adiiered 

 strictly to the directions given by SchifiE and Tassinari. The acid ob- 

 tained from the less soluble calcium salt melted at 160-167°, and 

 crystallized from water in the twinned forms characteristic of the 

 /33-dibrompyromucic acid. 



0.1444 grm. substance gave 0.2020 grm. AgBr. 



Calculated for Cr.ILBr.Oj. Found. 



Br 59.26 " ' 59.53 



* Gazzetta Cliiinica, viii. 298. 



