Reactive asymmetrical dicarboxylic acid esters and reagents for the investigation of cardiac glycosides

摘要

New reactive asymmetrical dicarboxylic acid ester compounds of the formula (I) wherein R1 is an alkyl radical containing up to 3 carbon atoms or is a digoxin or digitoxin residue, R2 and R3, which may be the same or different, are alkoxy radicals containing up to 3 carbon atoms or together represent an oxygen atom, X is a cyanomethoxy, succinimide-N-oxy, N-methyl-pyridiniumoxy, 2,4-dinitrophenoxy, 2,4,5-trichlorophenoxy, pentachlorophenoxy, phenylthio, p-nitrophenoxy, n-nitrophenylthio, piperidyl-N-oxy, phthalimido-N-oxy or benztriazol-N-oxy radical and n is 2, 3, 4 or 5, are useful for the preparation of reagents for the investigation of cardiac glycosides (Digitalis glycosides).