An improved synthesis of methyl 1,3-Dihydro-2H-pyrrolo[3,4-b]quinoline-2-carboxylate

Optimization of an old route leads very easily, in four steps, to methyl 1,3-dihydro-2H-pyrrolo[3,4-b]quinoline-2-carboxylate in 45% yield from commercial starting materials. This procedure can be compared to recently described methods whose yields were only 23-28% and required five to seven steps from advanced intermediates and chromatographic purifications. Moreover, using this method, the title compound can now be obtained in large quantities.