Abstract
The 1, 3-dipolar cycloaddition of 4-benzyloxy-6-methylpyrimidine 1-oxide (Ia) with dimethyl acetylenedicarboxylate (DMAD) gave dimethyl α-oxo-α'-(4-benzyloxy-6-methyl-2-pyrimidinyl) succinate (IIa), which was readily hydrolyzed to methyl 4-benzyloxy-6-methyl-2-pyrimidineacetate (IIIa). A similar reaction of 4-methoxy-(Ib) and 4-ethoxy-6-methylpyrimidine 1-oxide (Ic) gave corresponding methyl 2-pyrimidineacetates (IIIb, c). On the other hand, 6-methyl-4-piperidinopyrimidine 1-oxide (Id) reacted with DMAD to give a betaine derivative, 1-(6-methyl-4-piperidino-1-pyrimidinio)-1, 2-bis (methoxycarbonyl) ethenyl-2-oxide (IV).
