Alkoxy - substituted 3-(aminophenyl)-coumarins are prepared by hydrogenation of the corresponding nitrophenylcoumarin derivative in the presence of Raney nickel or a noble metal catalyst. The novel amino compounds are useful, by virtue of fluorescence in ultraviolet light, as optical brighteners, as ultraviolet light filters, in the preparation of polyureas and photoresist polymers. Also, the novel amino compounds can be phosgenated to yield the corresponding isocyanates.
X-ray screens having reduced mottle and exhibiting improved image quality are prepared using europium-activated fluorohalide phosphors having an aminocoumarin brightening agent added thereto.
