Efficient Synthesis of Chiral 5-Methoxycarbonylpyridin-2(1H)-ones and 3-Bromo-5-methoxycarbonylpyridin-2(1H)-ones

Dino Gnecco, María L. Orea, Hugo Pilotzi, David M. Aparicio, Jorge R. Juárez, Joel L. Terán
2019 Heterocycles  
Starting with both the mixture of methyl (S)-3-(1-phenylethylamino)acrylate 1-(E/Z) and the mixture of methyl [(R)-3-(2-tert-butyldimethylsilyloxy)-1-phenylethylamino]acrylate 2-(E/Z), the corresponding chiral 5-methoxycarbonylpyridin-2(1H)-ones were synthesized in high yields. By employing these chiral pyridin-2(1H)-ones, the corresponding 3-bromo-5-methoxycarbonylpyridin-2(1H)-ones were prepared in high yields. INTRODUCTION Functionalized pyridin-2(1H)-ones are key structural features in
more » ... ous natural products. These compounds are generally prepared by oxidation of pyridinium salts diversely substituted and used as starting materials to synthesize different kinds of alkaloids. 1-5 In addition, 5-methoxycarbonylpyridin-2(1H)-ones and 3-halo-5-methoxycarbonylpyridin-2(1H)-ones are prepared preferentially by aza-annulation of -dienamino esters derived from -keto esters and methyl propiolate. 6-15 In this sense, Anghelide and co-workers in 1974 reported the synthesis of 5-methoxycarbonylpyridin-2(1H)-ones by heating of -dienamino ester derivatives (R = alkyl or aryl) derived from the corresponding -keto esters in refluxing dimethylformamide (DMF) in good yields. However, when they carried out the aza-annulation of -dienamino esters (R 1 = H) obtained from methyl HETEROCYCLES, Vol. 98, No. 2, 2019 Br microwave, 120 °C 216 HETEROCYCLES, Vol. 98, No. 2, 2019 methyl propiolate β-enamino ester
doi:10.3987/com-18-14016 fatcat:gacvqfmth5bajibbs6nvpirvpu