Organic Reactions Volume 4 - Sciencemadness Dot Org

310 ORGANIC REACTIONS
OH O O
LJoCH3
Br
1
Brfy* .
i^ r (1) HBr
x
-HBr Brr^ |] Br
X
1
I JoCH8 ~^
X
I J0CH3"
H Br
OH
Br(^])Br [O]
OCH3 (2) Rearrangement Brk^JOCH3
[O]
O
I!
• Vl*
Br 1 IjOCH;
2;6-dichloroquinone; 27 with glacial acetic acid as solvent, leads to the
rearranged product, 2,5-dichloro-3,6-dibromoquinone. At 10-20° the
product consists chiefly of the normal substitution product, with only
a small amount of rearranged material. Such rearrangements can occur
|C1 , _ Boiling Br
+ 2Br2 ^
^ 2 AoOH Cl
in solvents other than glacial acetic acid, however, for oxidation of
2,6-dichloro-4~nitrophenol with bromine in water at 100° gives 2,5dichlor
o-3,6-dibr omoquinone. 27 2 8
»
It has been observed by several investigators that oxidation in aqueous
medium may result in hydrolysis of an amino group to a hydroxyl
group. Thus in the oxidation of diaminothymol 4 a hydroxyquinone
results. Other workers 29,30> 31 have reported similar results with aqueous
OH O
H2Nr^NCH(CH3)2 FeCi8 H0XXCH(CH3)2
H3Ck5JI Steam-distil* H 3ctJ
I Il
NH2
O
27
Ling, J. Chem. Soc, 61, 558 (1892).
28
Ling, /. Chem. Soc, 51, 783 (1887).
29
Fittig and Siepermann, Ann., 180, 23 (1875).
30
Ladenburg and Engelbrecht, Ber., 10, 1219 (1877).
31
Mazzara, Ber., 23, 1390 (1890).