246 



SCIENCE PROGRESS 



in glacial acetic acid proceeds according to a dimolecular law 

 when an excess of hydrochloric acid is present. But if the 

 concentration of the acid is relatively small the reaction is 

 unimolecular, as Blanksma has stated. The exceptional be- 

 haviour of this compound is perhaps an indication that the 

 chlorine comes right away from the chloroamide, and then 

 slowly rechlorinates the compound in the para- position. The 

 latter process, involving the interaction of two kinds of molecule, 

 the concentration of each being proportioned to that of the 

 unchanged chloroamide, might well work out as a dimolecular 

 reaction, especially if the chlorination of the anilide were so 

 much slower than the hydrolysis of the chloroamide as to 

 become the dominant factor in determining the velocity of the 



action. 



/CH.CO.NH 2 



, and camphor 



-These two com- 



(b) Camphor carboxamide, C 8 H U <^ 



x CO 

 y CH . CO . NC 5 H 10 

 carboxypiperidide, C 8 H U <( 



x CO 

 pounds, which are related somewhat closely to ethylaceto- 



CH 2 . CO . OC 2 H 5 

 acetate, , diflfer from it in that they are capable 



CO.CH3 

 of changing, not only into the "enolic" form, but also by the 

 " inversion " of the active a-carbon atom into stereoisomerides, 

 possessing the same general structure as the original com- 

 pounds, but differing in the relative positions of the — H and 

 — CO . NH 2 radicles. In this respect they resemble a-bromo- 

 camphor, the mechanism for inversion being supplied in each 

 case by the production of an " enolic " isomeride. In the case of 

 a-bromocamphor the inversion takes place only on the addition 

 of an alkali, 1 and even then only a minute quantity of the enolic 

 form appears to be produced. 



The amide and piperidide of camphor carboxylic acid differ 

 from a-bromocamphor in that inversion takes place without the 



1 Kipping, Proc. Chem. Soc. 1905, 21, 125. 



