Synthesis and transformations of methyl (Z)-2-((tert- butoxycarbonyl)amino)-3-(dimethylamino)propenoate

Methyl (Z)-2-((tert-butoxycarbonyl)amino)-3-(dimethylamino)propenoate (3) was prepared in 2 steps from glycine methyl ester hydrochloride (1). Acid catalysed reactions of 3 with various alkyl-, aryl-, and heteroarylamines 4a-g, performed at 20-80 °C, proceeded by substitution of the dimethylamino group giving the corresponding substitution products, 3-N-substituted methyl (Z)-2-((tert-butoxycarbonyl)-amino)amino)propenoates 5a-g. Treatment of 3 with ambident 1,3- nucleophiles, such as 2-pyridineacetonitrile (6), 2-aminothiazole (4d), 2-aminopyridine (4f), and 4-hydroxy-6-methyl-2H-pyran-3-one (7) in acetic acid at 85-120 °C afforded fused pyridones 8 and 12, pyrimidones 9 and 10 and pyranones 11 and 13.