( 646 ) 
groups by others. COOH,!) CH;*) CH,OH %) and SO;H *) when 
in ortho- or para-position in regard to OH may be replaced by 
bromine with formation of tribromophenol. A chlorine atom may, 
by indirect substitution enter in the place of bromine (HAntTscH, ®) 
CHatraway and ORTON ®) while chlorine may again in turn be 
replaced by NO» (ARMSTRONG 7) 
OH OH OH 
Oe ae Ue me 
\ Cl Cl / eT age \ Cl 
ie iw ~ ve 
SO,H NO, NO: 
A group COOH may further be replaced by CsH;NN and also 
by NO. 
We, therefore, see that during the indirect substitution the follo- 
wing groups may successively replace each other: COOH, 5O3H, 
Br, Cl, NOs; the nitro-derivatives are, therefore, the most stable so that 
the phenol derivatives finally produce picric acid and the methyl- 
aniline derivatives trinitro-phenylmethylnitramine. In the direct 
nitration a similar substitution is not noticed; benzoic acid and 
benzenesulphonic acid are nitrated and halogenated without elimination 
of the COOH or SOzH-group. 
In the same manner, tribromobenzene (1.3.5) yields on nitration 
successively mono- di- and trinitro-tribromobenzene without any sub- 
stitution of bromine atoms taking place; a behaviour totally different 
from that of tribromophenol. 
The group CH3 behaves in many cases analogous to OH, NH, 
and NHX. It is not impossible that we meet also here with 
indirect substitution, witness the researches of AuweRS, ZINCKE and 
1) BENEDIKT, Ann. 199. 128. 
2) BAUMANN and BrIEGER, Ber. 12. 804. 
3) Auwers and Birrner, Ann. 302. 133. 
4) p-Pctassium phenolsulphonate readily assimilates three mols. of bromine, the 
liquid remains elear and slowly deposits tribromophenol (more rapidly on heating). 
5) Ber. 30. 2334, 33. 505. 
$) Journ. Chem. Soc. 1901. 823. 
1) Zeitschrift 1871, 516. 
