TRANSACTIONS OF SECTION B. • 625 



6. On the Constitution of the Acid Amides. 

 By J. B. Cohen, Ph.D., Yorkshire College. 



Formation of the Acid Amiden. — These compounds are usually obtained by 

 three methods, to which the following equations are assigned : 



1. R or H . NHj + R or H . CO^H = R or H . NH . CO . R or H + HjO 



2. RorH.NHj + R.COCI = R or H . NH . CO . R +HC1 



3. R or H . NH2+ R or H . CO,R = R or H . NH . CO . R or H + R . OH 



In 2 and 3 the mode of formation would point to the following constitution for 

 the acid amides, which until recently has been generally accepted : 



R or H . NH 



I 

 R or H . C : 



Carbonyl formula. 



The first equation might be construed so as to yield a body of the constitution 



R or H . N 



.11 . . 



R or IJ . C ,0H . 

 Hydroxyl formula. 



Derivatives of this class have actually been obtained by Pinner and others, and 

 termed imido-ethers, and are therefore isdmeric with derivatives of the substances 

 having the first foi-mula : 



H.N H.N.R 



II I 



R.C.OR R.C:0 



Imido ether. Alkjl amide. 



Evidence upon which the choice of formula of the acid amide itself rests is of a 

 very unsatisfactory kind. 



The action of cone. HCl, cone. NaOH, PC1„ P.p.,, or Br would satisfy either 

 formula. 



One reaction appears definitely in favour of the carbonyl formula, whereas there 

 are two which point equally distinctly to the hydro.vyl formula. 



Caustic soda and sodium ethylate unite with a few acid amides to form Na 

 derivatives, in which the Na may be replaced by an alkyl group by the action of 

 alkyl iodide, and yields a compound in which the new group is undoubtedly attached 

 to the N atom. 



H.N.R'- 



I 

 R' . C : O. 



On the other hand, many aftid atnideS unite with silver oxide to form silver 

 compounds in which one atom of H is replaced by Ag, and these bodies treated 

 with alkyl iodide yield the isomeric imido-ethers. 



Beckmann's reaction, which Consists in a molecular change produced by PCL 

 and other reagents on ketoximes forming isomeric acid amides, points at least to the 

 intermediate formation of a compound of the hydroxyl formula. 



Since working on the aroma-tic amides it has frequently struck me as curious 

 that of the series fcrmanilide, acetanilide, &c., including benzanilide and oxanilide, 

 the first — formanilide— should possess chemical and physical properties so totally 

 ditferent from the others of the series. 



Formanilide crystallises in long prisms from alcohol, whereas the others, includ- 

 ing benzanilide, form glistening plates all so similar in appearance that it would be 

 impossible to identify them by their exterior alone. Formanilide, of which the 

 formula is usually written CgH^NH . COH, yields with NaOH and Ag„0, Na and 

 Ag compounds, which none other of the series do. This evidently points to a 

 fundamental diilerence in constitution. 



Recent Viexos on the Constitution of the Acid Amides.— ThM and Enoch showed 

 that the Ag compound of benzamide differs from the Na compound by the fact 

 1894. 



