Synthesis and fluorescence properties of novel benzo[a]phenoxazin-5-one derivatives

Thirteen, benzo[a]phenoxazin-5-one derivatives 3a-m were synthesized from 4 -nitrosoaniline hydrochlorides 1a-m and ethyl 1,3-dihydroxynaphthoate 2 and their fluorescence properties were discussed in terms of the electronic ef fect of substituents. A coupling reaction was carried out with 6-carbethoxy -9-N-(2-hydroxyethyl)-N-methylamino-5H-benzo[a]phenoxazin-5-one (3k) and ac etyl-DL-alanine to afford N-[(6-carbethoxy-5-oxo-5H-benzo[a]phenoxazin)-9-y l]-N-methylaminoethylene acetyl-DL-alanine ester (4).