18 PROCEEDINGS OF THE AMERICAN ACADEMY. 



acid, and found the product to melt at the proper point, 118-119°. 

 Ou reduction with zinc and acetic acid it yielded the /3-bromcrotono- 

 lactone melting at 57-58°, and with aniline the a-phenylamido-/3- 

 bromcrotonolactone with its characteristic properties, both of which 

 bodies, as we shall afterwards show, may be made in the same way 

 from the dibromcrotonolactone. As we shall show more fully later, 

 we were unable to confirm the statement of Toennies that the dibrom- 

 crotonolactone could easily be converted into mucobromic acid by 

 oxidation with chromic acid. By the action of bromine in aqueous 

 solution a part of the /3y-dibrompyrornucic acid had been converted into 

 dibromcrotonolactone, according to the equation given by Toennies, 



C 6 H 4 Br 2 O a + Br 2 + H 2 = C 4 H 2 Br 2 2 + C0 2 + 2 HBr. 



The viscous oil which had been drained from the crystalline product 

 deposited a few more crystals of the lactone on long standing, but we 

 have not yet examined it further. The insoluble matter, which had 

 been removed by filtration before the extraction with ether, was 

 washed with a dilute solution of sodic carbonate. But a small amount 

 dissolved, and upon acidification 0.2 grm. of a sparingly soluble acid 

 was precipitated, which melted at 189-190°, and was evidently unal- 

 tered dibrompyromucic acid. The residue, insoluble in the alkaline 

 solution, weighed 1 grm., and consisted chiefly of mucobromylbromide. 

 It gave in alcoholic solution a deep blue evanescent color on the ad- 

 dition of sodic carbonate, and one crystallization from alcohol was 

 sufficient to raise the melting point to 50-57°. A part of the di- 

 bromp3'romucic acid had therefore been decomposed according to the 

 equation 



C 5 H 4 Br,0 3 + 2 Br 2 + H 2 = C 4 HBr 3 2 + C0 2 + 3 HBr. 



Mucobromylbromide is so slowly attacked by water that little muco- 

 bromic acid could have been formed under the conditions chosen ; but 

 it is found in abundance when the product of the reaction stands for 

 a long time in dilute solution. The alcoholic mother liquors obtained 

 from the recrystallization of the mucobromyi bromide were evaporated, 

 and the residue boiled with water under a reverse cooler until the 

 bromanhydride had been converted into mucobromic acid. A small 

 amount of insoluble material was then left, which had the odor of 

 tetrabromfurfuran, but we were unable to identify it with precision. 

 A preliminary experiment under essentially the same conditions had 

 already yielded us a crystalline body, which was proved by its melting 



