4-Ethoxymethylene-2-[1]-naphthyl-5 (4H)-oxazolone 1b was synthesized from 1-naphthoyl- glycine and triethyl orthoformate as a fluorescent analogue of the hapten 4-ethoxymethylene- 2-phenyl-5 (4H)-oxazolone. A simple and general method has been devised to prepare conjugates of type 6 between 1b and amines and amino acids by direct reaction. Compounds 6 are stable in solid form and in aqueous solution at 20° C, but are a mixture ...
