ethyl 4-azido-2-(hydroxymethyl)-5-methylpyrimidine-6-carboxylate

ethyl 6-chloro-2-formyl-5-methylpyrimidine-4-carboxylate

tert-butyl 3-azido-(2S)-[(tert-butoxycarbonyl)amino]propionate

tert-butyl(2S)-[(tert-butoxycarbonyl)amino]-3-phenylmethanesulfonyloxypropionate