The synthesis of methyl 2-(benzyloxycarbonyl)amino-3-dimethylaminopropenoate. The synthesis of trisubstituted pyrroles, 3-amino-2H-pyran-2-ones, fused 2H-pyran-2-ones and 4H-pyridin-4-ones

Methyl 2-(benzyloxycarbonyl)aimno-3-dimemylaminopropenoate (2) was prepared from methyl N-(benzyloxycarbonyl)glycinate (1) and t-butoxybis(dimethylamino)methane, and used as a reagent for preparation of substituted 3-(benzyloxycarbonyl)amino-4H-quinolizin-4-ones 5 and 6, −2H-pyran-2-ones 17–19, −2H-1-benzopyran-2-ones 28–31, and -naphthopyrans 32–35, −2H-pyrano[3,2-c]pyridine-2,5-dione 46, -pyrano-[4,3-b]pyran-2,5-dione 47, -pyrano[3,2-c]benzopyran-2,5-dione 48, -pyrano[2,3-c]pyrazol-6-ones 49 and 50, -pyrano[2,3-d]pyrirnidin-7-ones 51 and 52 derivatives. In the reaction of 2 with 1,3-diketones trisubsti tuted pyrroles 14–16 were formed. Selective removal of benzyloxycarbonyl group was achieved by cat alytic transfer hydrogenation with Pd/C in the presence of cyclohexene to afford free 3-amino compounds 7, 8, 20, 36–38 and 53–57 in yields better than 80%.