28 PROCEEDINGS OF THE AMERICAN ACADEMY. 



The a-brorncrotonolactone is readily soluble in alcohol or chloroform, 

 somewhat more sparingly soluble iii ether or benzol, sparingly soluble 

 in cold carbonic disulphide, more readily in hot, and sparingly soluble 

 in ligroin. It dissolves quite freely in boiling water and distils slowly 

 with steam. It crystallizes in long transparent prisms of adamantine 

 lustre, which melt at 77°. It dissolves in alkalies with a deep yel- 

 low color and the formation of an alkaline bromide. It also reduces 

 argentic nitrate in ammoniacal solution on boiling. With aniline, 

 when dissolved in dilute alcohol, it gives the well crystallized a-phenyl- 

 amidocrotonolactoue. The a-bromcrotonolactone appeared to be iden- 

 tical with the body of like formula and the same melting point which 

 Hill and Sanger * obtained in small quantity as a by-product in the 

 preparation of the dibrompyromucic acids by the action of alcoholic 

 sodic hydrate upon pyromucic tetrabromide. Still their statements 

 concerning the behavior of their substance toward bromine were at 

 variance with our own observation, and a more vigorous proof of the 

 identity of the two bodies was necessary. Fortunately a small 

 amount (0.125 grm.) of their old preparation still remained, and we 

 were able to establish its identity with our own product, since it 

 gave with aniline the same a-phenylamidocrotonolactone melting at 

 217-218°, | and was attacked by brornine and water in the same way. 



Action of Bromine. 



a-Bromcrotonolactone is very slowly attacked by dry bromine at 

 ordinary temperatures. If one molecule is added, the lactone does 

 not dissolve at first, and the color of the bromine remains apparently 

 unchanged for several days. The reaction then seems to proceed, 

 more rapidly, and at the end of the sixth day we found that the color 

 had faded completely. The tube then opened with pressure, and a 

 large amount of hydrobromic acid escaped. Substitution had evi- 

 dently taken place, and the weight of the liquid product corresponded 

 precisely with that which would theoretically be required by the 

 replacement of one hydrogen atom by bromine. The product of 

 the reaction remained for a long time liquid, and its alcoholic solution 

 gave but a greenish color on the addition of sodic carbonate. After 

 long standing in desiccator a few large clear crystals appeared, which 

 from their melting point (90-91°) and other characters were shown 

 to be the a/3-dibromcrotonolactone. After distilling with steam, in 

 order to remove the dibromcrotonolactone, the aqueous solution left on 



* These Proceedings, XXI. 158. t See page 31. 



