HTLL AND CORNELISON. — CROTONOLACTONES. 



9 



halogen atoms in the a- and /?-bromcrotonolactones are attached to 

 different carbon atoms is easily given. The o/3-dibromcrotonolactoue 

 yields with hydriodic acid an iodine derivative which cau be reduced 

 to /3-bromcrotonolactone. This same iodine compound gives with 

 aniline a phenylamidobromcrotonolactone which on reduction is con- 

 verted into the same phenylatnidocrotonolactone that may be made 

 by the action of aniline upon the a-bromcrotonolactone : 



O 



It is evident that the acid described by Hill and L. L. Jackson 

 under the provisional name of the ^-dichlorpyromucic acid, since it 

 readily gives the a-chlorcrotonolactone on decomposition with mineral 

 acids, must in fact be the •yS-dichlorpyrornucic acid, and its structure 



HC = C - COOH 



)o 



310 = CC1 



It is perhaps worthy of note that, although the $h- and the yS-di- 

 chlorpyromucic acids give the two isomeric chlorcrotonolactones when 

 heated with acids, they give the same a-chlorcrotonolactone when 

 they are treated with bromine in aqueous solution, and the resulting 

 product it reduced. Evidently two isomeric dichlorbromfurfurans are 

 first formed, which yield the corresponding addition products with 

 bromine, but these addition products are attacked by water in such a 

 way that in each case the chlorine is left in the a position with regard 

 to the oxidized carbon : 



C1C = 



CBr 



\ 



C1C- 



O 



HC = 



CC1 



HC 



CBr. 



X 

 / 



CClBr 



C1C- 



HC 



CO 



X 

 / 



CClBr 



