360 PROCEEDINGS OP THE AMERICAN ACADEMY 



We have also prepared several other trisubstituted pyromucic acids, 

 which may convenieutly be described here. , 



/5y-DlCHLOR-S-BROMPYROMUCIC AciD. 



Hill and Sanger * found that jBy dibrompyromucic acid was easily 

 converted into tribrompyromucic acid by the action of bromine at 

 ordinary temperatures. 



If /3y dichlorpyromucic acid is exposed to the vapors of bromine at 

 ordinary temperatures, bromine is rapidly absorbed, hydrobromic acid 

 is evolved, and the gain in weight approaches that required by the dis- 

 placement of hydrogen by bromine. The product was treated with 

 small quantities of boiling water to remove unaltered dichlorpyromucic 

 acid, and then recrystallized from dilute alcohol, and finally from water. 

 The acid is readily soluble in alcohol or ether, dissolves freely in boil- 

 ing benzol, more sparingly in cold benzol. Even in boiling water it is 

 very sparingly soluble. It crystallizes in short clustered prisms, which 

 melt at 185-186°. 



0.3189 grm. substance dried over HgSO^ gave 0.5817 grra. AgCl 

 and AgBr. 



Calculated for 

 CsHClaBrOj. Found. 



Cl^ + Br 58.08 57.99 



^y-DlBROM-S-CHLORPYKOMUCIC AciD. 



This acid we made by treating the ethyl /3y dibrompyromucate 

 with chlorine and decomposing the product with alcoholic sodic hy- 

 drate. On acidifying the aqueous solution of the sodium salts thus 

 obtained, a crystalline acid was precipitated, which after one recrystal- 

 lization from dilute alcohol melted at 192-193°. After recrystalliza- 

 tion from benzol the melting point rose to 193-194°. The acid was 

 readily soluble in alcohol, ether, or hot benzol ; sparingly soluble in 

 cold benzol, or even in boiling water. 



0.2315 grm. substance dried over H^^SO^ gave 0.3960 grm. AgCl 

 and AgBr. 



Calculated for 

 CsIIClBroOa. Found. 



CI + Br, 64.19 64.37 



We have attempted to prepare these acids also by the decomposition 

 with alcoholic sodic hydrate of products formed by the addition of 



* These Proceedings, xxi. 172. 



