Triphenylphosphine-Mediated Reaction Between Dimethyl Acetylenedicarboxylate and NH-Acids Derived from Diaminobenzenes

Protonation of the 1:1 adduct produced in the reaction between triphenylphosphine and dimethyl acetylenedicarboxylate with ethyl 2-[(2-{[2-(ethyloxy)-2-oxoacetyl]amino}phenyl}amino]-2-oxoethanoate leads to a vinylphosphonium salt, which undergoes an intermolecular Wittig reaction to produce dimethyl 4-(acetyloxy)-1-(2-{[2-(ethyloxy)-2-oxoacetyl]amino}phenyl)-5-oxo-2, 5-dihydro-1H-pyrrole-2,3-dicarboxylate. Using ethyl 2-[(3-{[2-(ethyloxy)-2-oxoacetyl]amino}phenyl)amino]-2-oxoethanoate or ethyl 2-[(4-{[2-(ethyloxy)-2-oxoacetyl]amino}phenyl)amino]-2-oxoethanoate as an NH acid produces dimethyl 4-(acetyloxy)-1-(3-{3-(ethyloxy)-4,5-bis[(methyloxy)carbonyl]-2-oxo-2,5-dihydro-1H-pyrrol-1-yl}phenyl)-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylate or dimethyl 4-(ethyloxy)-1-(4-{3-(ethyloxy)-4,5-bis[(methyloxy)carbonyl]-2-oxo-2,5-dihydro-1H-pyrrol-1-yl}-5-oxo-2,5-dihydro-1H-pyrrole-2,3-dicarboxylate.

keywords:

• Acetylenic ester
• intramolecular Wittig rection
• pyrrole derivatives
• triphenylphosphine