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

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