PROCEEDINGS 



OF THE 



AMERICAN ACADEMY 



OP 



ARTS AND SCIENCES. 



VOL. XXIX. 

 PAPERS READ BEFORE THE ACADEMY. 



I. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 



HARVARD COLLEGE. 



ON CERTAIN SUBSTITUTED CROTONOLACTONES AND 



MUCOBROMIC ACID.* 



By Henry B. Hill and Robert W. Cornelison. 



Presented April 12, 1893. 



Several years ago a dichlorpyromucic acid was described by Hill 

 and L. L. Jackson, f wbich differed from all the substituted pyromucic 

 acids then known, in that it was readily decomposed by concentrated hy- 

 drochloric acid at 100° at ordinary pressures. Carbonic dioxide was 

 evolved and a neutral body was formed which melted at 52-53°, and 

 contained a percentage of chlorine which corresponded to the formula 

 C 4 H 3 C10 2 . A body of similar properties melting at 77° had previ- 

 ously been found in small quantity by Hill and Sanger $ among the 

 products formed from pyromucic tetrabromide by the action of an 

 alcoholic solution of sodic hydrate. A complete analysis of this body 

 had shown that its formula was C 4 H 3 BrO ;2 , but a lack of material ren- 



* A part of the work described in the following paper was presented in the 

 form of a thesis to the Faculty of Arts and Sciences of Harvard University in 

 May, 1893, by Robert W. Cornelison, then candidate for the degree of Doctor 

 of Philosophy. 



t These Proceedings, XXIV. 348. 1 Ibid., XXI. 158. 



VOL. XXIX. (N. S. XXI.) 1 



