Pyrex vessel with a high-pressure mercury lamp, the corresponding monoalkyl compounds 2 were obtained. The photo products were identified by comparison with authentic samples which were obtained on an alternative route. The same compounds 2 could also be synthesized by thermolysis of 1 in N,N-dimethylform- amide. On the other hand, compounds 2 could not be dealkylated to give 2-amino-3H-phenoxa- zin-3-ones neither by photolysis nor pyrolysis.
