
TY  - JOUR
A1  - Badger, GM 
A1  - Drewer, RJ 
A1  - Lewis, GE 
T1  - Photochemical Reactions of Azo Compounds. II. Photochemical Cyclodehydrogenations of Methyl- and Dimethylazobenzenes
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1963
VL  - 16
IS  - 6
SP  - 1042
EP  - 1050
KW  - 
UR  - https://doi.org/10.1071/CH9631042 
N2  - Substituted benzo[c]cinnolines have been prepared from substituted azobenzenes by photochemical cyclodehydrogenation in 22N sulphuric acid. The reaction seems to involve a photochemical disproportionation as rearrangement products of the corresponding hydrazobenzenes were also formed.   4-Methylazobenzene gave 2-methylbenzo[c]cinnoline. 3-Methylazobenzene gave a mixture of 1- and 3-methylbenzo[c]cinnolines: and 2-methylazobenzene gave 4-methylbenzo[c]cinnoline and benzo[c]cinnoline. The latter result is noteworthy as it indicates that cyclization can proceed with elimination of a methyl substituent. Similar elimination was observed with 2,2'-dimethylazobenzene, which gave 4-methyl-benzo[c]cinnoline as well as the expected 4,7-dimethylbenzo[c]cinnoline. Photochemical cyclodehydrogenations of 4,4'-dimethylazobenzene and of 3,3'-dimethyl-azobenzene have also been studied. 
ER  -

