Eg. Lubenets et al., SYNTHESIS AND PROPERTIES OF NAPHTHOQUINONYLAMINO-SUBSTITUTED BENZOCROWN ETHERS, Russian chemical bulletin, 43(3), 1994, pp. 410-412
Naphthoquinonylaminobenzocrown ethers were synthesized by reactions of
4'-aminobenzocrown ethers with 1,4-naphthoquinones. A hypsochromic sh
ift of the long-wave absorption band was found to appear in the electr
on spectra when the compounds synthesized reacted with alkaline or alk
aline-earth metal salts.