Bell — On a Series of Bases derived from Pyrrol. 49 



HOOC -C-C-C-C- COOH 



four of the carbon affinities, represented as unsaturated in the diagram, 

 being satisfied by hydrogen, the remaining four by hydroxyl (OH) 

 groups. Of the exact arrangement of these hydroxyl groups we know 

 nothing, but since saccharic acid is with still greater certainty a deri- 

 vative of normal hexane, it is probably their position which determines 

 the isomerism of the two acids, and consequently of galactose and 

 glucose. 



To explain the genesis of tetraphenol and pyrrol we need for 

 the present only consider the OH groups connected with the carbon 

 atoms which lie next the carboxyl groups. These may be supposed to 

 enter into reaction as follows : — 



Tetraphenol fragment. 



= C (OH) 

 = C (OH) 



= C 



>0 + HoO 



= c 



Ethyl-pyrrol fragment. 



(1) 



= C (OH) 

 = C (OH) 



1 



^ ^K.iCS,) = >N (C3H5) + 2 HoO 

 = C 



(2) 



If in reaction (1) one COOH group persists, we get pyromucic 

 acid ; if both remain, dehydromucic acid is the result. Similarly, if 

 in reaction (2) one COOH group persists, becoming amidated 

 (COJSIIC2H5), we get diethyl-carbo-pyrrol-amide ; if both, we get 

 the triethyl-dicarbo-pyrrol-amide. 



A little consideration will show how the remaining hydroxyl 

 groups could be eliminated from mucic acid, whatever their arrange- 

 ment may be. 



It should be observed that Fittig doubts the connexion of mucic 

 acid with normal adipic acid. But even if it should be shown that 

 one or both of the COOH groups exist as lateral and not as terminal 

 chains, the above explanation will remain, in principle, unaltered. 



This would also be the case if it should be found that mucic acid 

 is a derivative of the group — 



I I 

 - C - C - and pyrrol of the form 



-C-C- 

 I I 



which is by no means impossible. 



R. I. A. PROC, SER. II., VOL. III. — SCIENCE. 



H 



H 



C- 



-C 



r 



|>NH 



c- 



-C 



H 



H, 



